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DEPARTMENT OF THE ARMY FIELD MANUAL
ROUTE
RECONNAISSANCE
AND-
CLASSIFICATION, .
i Ce :.,C
DEPARTMENT OF THE ARMY APRIL 1955
DEPARTMENT OF THE ARMY . APRIL 1955
FM 5-36C 1
FIELD MANUAL
ROUTE RECONNAISSANCE AND
CLASSIFICATION
FM 5-36 DEPARTMENT OF THE ARMYCHANGES NO. 1 WASHINGTON 25, D. C., February 1956
FM 5-36, 26 April 1955, is changed as follows:
7. Route Classificatione. Relation of Route Classification to Vehicle
and Bridge Classification. Route classificationutilizes * * * in crossing it. This effect dependsupon the gross weight of the vehicle and itsweight distribution to the axles or tracks, theout to out distance of tires or tracks, tire size andtire pressure. The bridge classification * * * onthe route.
18. Bridge Reconnaissancea. The purpose of * * * of a route. These limit-
ing features include clear roadway width, hori-zontal clearance above curbs, overhead clear'ance,length (if a bottleneck), load-carrying capacity,traffic movement possibilities, estimated amountof repair or reinforcement required, ,and postingneeds. There are two * * * for tbh reconnais-sance.* * * * * * *
19. Bridge Classification
Table VII. Minimum Widths of Bridges Used in Bridge
Class Computations
(Superseded)
Minimum widthsBridge between curbsclassrange One- Two-
lane lane (ft)
4-12 9 ft 1813-30 11 ft 1831-60 13 ft 2 in. 2461- 14 ft 9 in. 27
* * * * * $ *
21. Bridge Marking
* * * * * *
b. Types. The two general types of bridge signsare circular signs and rectangular signs.
(1) Circular signs. The bridge classification* * * over two lanes (fig. 15()). Doublearrows and a single arrow are shown im-mediately beneath the two-way and one-way classification numbers respectively.A typical dual class sign is shown in figure
2
FLOATING BRIDGE
1 /
0;-Xt 0m
1 For single lane fixed bridge
2 For floating bridge
3 Indicating the limiting vehicle classes of a two lanebridge when used as a two lane bridge or as a singlelane bridge
Figure 15. (Superseded) Typical bridge class and infor-mation signs.
3
160. Wheeled and tracked vehicle sym-bols are placed on the signs in connectionwith the appropriate class numbers. Fig-ure 16® illustrates * * * for each lane(fig. 17).
(2) Rectangular signs. Additional instruc-tions and * * * information are needed.Bridges with smaller widths than thoseshown for bridge classes in table VII willrequire width signs. Classes of multi-lane bridges above class 30 will be re-duced when the lane width required bytable VII is not available. Their size is** * are sufficiently clear. The rectangu-lar signs may include data in the Englishor metric system or both based on thedecision of the local commander. Addi-tionally one of these systems may be re-placed by another system. The signswill include the following data:
(a) Width limitations for abnormally nar-row bridges. The inscription on therectangular sign consists of two hori-zontal arrows with the limiting widthsgiven in feet or meters (fig. 17.1 ().
(b) Height limitation for * * * above class70. The inscription on the rectangularsign consists of two vertical arrowswith the limiting height given in feetor meters (fig. 17.1 (). In addition a* * * reaching the bridge.
4
-/ 0
80 Da so 80it t .I..t 1
1 Indicating the limiting wheeled vehicle class and thelimiting tracked vehicle class.
2 Indicating combination of dual class and two-waybridge class signs.
Figure 16. (Superseded) Typical dual class bridge signs.
5
3.5M
II ft. 6 in.
3.5 M.lift. 6 in.
1 Height sign2 Width sign
Figure 17.1 (Added) Height and width signs.
c. Location. Bridge signs are * * * are asfollows:
* * * * * *
(2) Bridge information (rectangular) signsare placed immediately below the bridgeclassification (circular) signs (fig. 15().However, height restriction signs arenormally placed centrally on the over-head obstruction itself.
* * * * * * *
c.1 (Added) Restricted Lanes.
(1) Where it is necessary to confine trafficto restricted lanes on damaged bridges,physical barriers such as posts, barrels,etc. are used to define the lane. When-ever necessary such barricades will ex-tend throughout the length of the bridgeand 'along the approach roadways in sucha manner as to prevent traffic conges-tion. Adequate warning signs are alsoto be used.
(2) In the case of certain bridges, heavierloads can be taken on a restricted lane(such as center line of the bridge or theline of the rails on a road and rail bridge)than on other lanes. These restrictedlanes are to be marked by painted lines,studs, etc. and rectangular explanatorysigns will be placed at approaches to thebridge.
d. Examples. Example of bridge markings andguide signs are given in illustrations as follows:
* * * * * * *
(3.1) (Added) Typical height and width re-striction signs are indicated in figure17.1.
* * * * * * *
7
0
Figure 19. (Superseded) Typical two-lane bridge applica-tions of bridge class and information signs and road
guide signs.
B
30. Generala. The basis of * * * crossing the bridge. The
effect is the result of a combination of factorswhich includes the gross weight of the vehicle,the out-to-out distance of tires or tracks, tire sizeand pressure, the distribution of this weight, thespeed at which the vehicle crosses the bridge,and the resulting impact on the bridge. The ex-cessive loads * * * must be evaluated.
· * * * * * *
c. Narrow vehicles having an outside to outsidetire width, or track width, narrower than thatof the hypothetical vehicles of the classes whichwould otherwise apply are given a higher vehicleclassification, and vice versa for wider outside tooutside tire or track widths.
* * * * * * *
e. (Added) Each single vehicle or combinationof vehicles should have a classification for (a)empty, (b) cross country, and (c) on-highwayloading.
31. Vehicles Which Are Classified
a. Standard military vehicles * * * and com-bination vehicles.
* * * * * * *
(2) A combination vehicle is a military ve-hicle consisting of two or more single
9
vehicles, connected together, which moveas one unit. Examples include prime* * * 30 yards apart.
b. Classification numbers are * * * exceeding112 tons.
(1) (Superseded) Separate classificationnumbers are assigned to each single ve-hicle when one tows another and the dis-tance between them is greater than 30yards. If the vehicles are closer than 30yards and both are on one bridge spanat the same time then they are classedas a combination vehicle. In this casethe class of the combination is the sumof the classification numbers of the twovehicles.
* * * * * * *
32. Data Required for Vehicle Classification
a. The single vehicle * * vehicles are shown.
(1) (Added) Vehicles are to be classified forempty, cross country, and on-highwayloading when possible.
(2)' (Added) Other data required for vehicleclassification is as follows:
(a) Total loads, axle loads, track loads,fifth wheel loads, pintle and lunetteloads for empty cross country, and on-highway loading.
(b) Tire size, number of tires per axle, tire
10
pressure, and maximum load on onetire.
(c) Distance from nearest axle to lunetteor pintle.
b. The trailer dimensional * * * trailers areshown. For other data required for trailer clas-sification see a (1) above.
33. Marking of Vehicles* * * * * * *
b. Marking of vehicles is accomplished by frontvehicle classification signs and by side vehicleclassification signs (fig. 28). These signs have ayellow background with black numerals; however,they may be made in other contrasting colors con-sistent with camouflage requirements.
* * * * * * *
(2) Side vehicle classification * * * themfrom view. A side vehicle sign is placedon the right-hand side of classified tow-ing vehicles and trailers only. Side ve-hicle signs * * * capacity exceeding 11/2tons.
c. Other uses of * * * special purpose vehicles.
* * * * * . * * *
(2) (Superseded) In the case of towed ve-hicles, where the vehicles are less than 30yards apart and both are on one bridge
11
span at one time, they are classed ascombination vehicles. In these cases theclassification of the combination is thesum of the classification numbers of theseparate vehicles. This combinationclassification number is shown on a tem-porary front sign (fig. 30().
* * * * * * 1
12
El m
1 Single vehicles
Figure 27. (Superseded) Dimension data required forvehicle classification.
A Out-to-out track or tire width (inches)
B In-to-in track or tire width (inches)
C Distance from front axle to first rear axle or track(inches)
D Ground contact of track or distance between rearaxles (inches)
E Overall width (inches)F Net weight (tons)G Gross weight: 1. Off-highway
2. On-highwayH Axle loads: 1. Empty
2. Off-highway3. On-highway
13
I Tire size
J Tire pressure
K Dimension from rear tire to towing pintle or lunette
L Track width and track load
M Pay loads: 1. Off-highway2. On-highway
N Overall height
14
2 TrailersFigure 27.. (Superseded) Dimension data required for
vehicle classification-Continued.
A Out-to-out tire width of trailer (inches)
B In-to-in tire width of trailer (inches)
C Distance from rear axle of towing vehicle to firstaxle of trailer (inches)
D Distance from first to second axle of trailer (inches)
E Distance from second to third axle of trailer (inches)
F Overall width of trailer (inches)
G Gross weight of trailer (tons)
H Net weight (tons)
I Axle loads: 1. Empty2. Off-highway3. On-highway
J All spacing between tires
K Tire sizes
L Tire pressure
M Trailer load distribution to tractor
15
N Pay load: 1. Off-highway2. On-highway
O Dimensions from nearest tire to lunette
P Distance between front axle and first rear axle oftowing vehicle
Q Distance between dual axles of towing vehicle
16
APPENDIX IIIBRIDGE SPANS
4. Beam Bridgesa. The majority of * * * are as follows:
(2) Steel stringers.* * * * * * *
(e) (Added) Plate girder.* * * * * *, *
'., ® ,
SPAN SPAN
'I
Figure 41. (Superseded) Standard dimension data guidefor simple stringer bridges.
'Figure 49, (Superseded) Standard dimension data guidefor steel truss bridges.
Is
(4Ct~
wJ le E w a\~~~~~~~~#
18
|_ t tf~=
At! t~~~I0)E
U ~ C
0" SW
Figure 60. (Superseded) Comnon types of archconstruction.
Figure 67. Steel arch bridge, through type.
Figure 69. Suspension bridge with steel cable, steel rein-forcing truss, steel floor beams, and external sway
bracing.
APPENDIX IX
CLASSIFICATION TABLES FOR STANDARDPREFABRICATED RAFTS, FIXED BRIDGES,
AND FLOATING BRIDGES
Table XXII. (Superseded) Dual Classification Float-ing Bridge Capacities.
Table XXIII. (Superseded) Dual Classification RaftCapacities.
Table XXIV. (Superseded) Dual Classification of PanelBridge, Bailey Type, M2(150 inch roadway).
Table XXVI. (Superseded) Dual Classification Capac-ities, Short Fixed Spans ofMe Steel Treadway.
Table XXVII. (Added) Dual Classification of M, DeckBalk Fixed Span Class.
Table XXVIII. (Added) Dual Classification of Class 60Floating Bridge, Steel Super-structure Fixed Spans.
20
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Table XXVI. (Superseded) Dual Classification CapacitiesShort Fixed Spans of M2 Steel Treadway
No. ofType of construction tread- Clear Normal Caution Risk
ways span
Widened Bridge 1 2 2 20 90 * 110 * 14022 80 95 * 120
3 24 70 80 * 10026 60 70 9028 55 60 8130 50 55 7332 45 50 6534 40 45 57
Plywood Treadway Lane(Spans up to 34 ft.) 16 18 24
M2 Bridge (Narrow spacing) 4 36 (35) (45) (68)30 34 50
38 (28) (35) (60)27 31 46
40 (25) (29) (53)25 28 43
42 (22) (26) (47)
44 (20) (23) (42)21 24 37
46 (19)20 (22) (37)
5 48 (18) (21) (32)19 22 31
50 (17) (20) (29)18 21 30
52 (17) (19) (27)18 20 28
54 (16) (18) (25)17 19 27
56 (15) (17) (23)16 18 25
58 (15) (17) (22)16 18 24
Notes. 1. * Limited by roadway width.2. Upper figure represents wheel load class. EXAMPLE: (35)
Lower figure represents tracked load class. f 30S. 1 No truck ratings given for regular steel treadway lanes of widened
bridge, since spacing is normally too wide for trucks.4. 2 For 2-treadway span bridges without transverse stiffeners, use
0.8 of class given in table.
26
Table XXVII. (Added) Dual Classification of M4 Deck BalkFixed Span Class By Type of Construction and Type ofCrossing.
.Speetin Type of construction Normal Caution Risk
30 22 Balk Deck (80) (100) (100)18 Balk Roadway 60 80 90
22 Balk Deck (45) (70) (80)18 Balk Roadway 35 55 60
38 _____
22 Balk Deck (50) (70) (80)16 Balk Roadway 40 55 60
22 Balk Deck (23) (45) (55)18 Balk Roadway 25 40 45
45 _22 Balk Deck (30) (45) (55)16 Balk Roadway 30 40 45
Note. 1. Upper ratings represent wheel load class. ( )Lower ratings represent tracked load class. EXAMPLE: 60
27
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APPENDIX XGLOSSARY
*X * * * * * *
Gross weight of a vehicle. The weight of* * * cross-country (off-highway) operation.Highway gross weight of a vehicle is that weightof the vehicle when fully equipped and servicedfor operation, including the crew and the maxi-mum pay load of cargo and personnel for on-highway operation.* * * * * * *
Rated pay load of a military vehicle. Thetotal load * * * of the crew. Highway pay loadis the maximum pay load a vehicle can carry onhighways, exclusive of crew.* * * * * * *
Stringers. (Superseded) A system of longi-tudinal members supporting the deck.
Stringer bridge. (Superseded) A bridge de-signed with a stringer system, which is a systemof longitudinal beams supporting the deck.* * * * * * *
[AG 253 (22 Dec 55)]
By Order of Wilber M. Brucker, Secretary of the Army:
MAXWELL D. TAYLOR,General, United States Army,
Official: Chief of Staff.
JOHN A. KLEIN,Major General, United States Army,
The Adjutant General
30
DISTRIBUTION:Active Army:
Tec Svc, DA (2) ex- Co/Btry-Cont'd.cept COFENGRS Sig (1)(10). Ft & Cp (2)
TPMG (5) CGSC (5)Engr Bd (2) Armd Sch (100)Hq CONARC (10) Arty & GM SchArmy AA Comd (2) (100)OS Maj Comd (25) Engr Sch (135)OS Base Comd (2) Inf Sch (100)Log Comd (2) TC Sch (100)MDW (2) PM Sch (15)Armies (5) PMST Engr ROTCCorps (5) Units (2)Div (5) Div Engr (1)Engr Brig (3) Engr Dist (1)Engr Gp (2) Mil Dist (1)Bn (3) except Units organized un-
CML (1) der followingMED (1) TOE:QM (1) 7-11R, Inf RegtSig (1) (2)
Co/Btry (3) except 17-51R, ArmdCML (1) Regt (2)MED (1) 19-55R, MP BnQM (1) (1)
NG: State AG (6); units-same as Active Army ex-cept allowance is one copy to each unit.
USAR: None.For explanation of abbreviations used, see SR
320-50-1.
375803 31
*FM 5-36FIELD MANUAL] DEPARTMENT OF THE ARMYNo. 5-36 J WASHINGTON 25, D. C., 26 April 1955
ROUTE RECONNAISSANCE ANDCLASSIFICATION
SECTION I. INTRODUCTION Paragraphs Page
Purpose ----------------------- 1 3Scope ------------------------- 2 3References --------------------- 3 3
II. ROUTESGeneral ----------------------- 4 4Route Reconnaissance ----------- 5 4Route Reconnaissance Report --- 6 6Route Classification ------------ 7 9Route Numbering -------------- 8 13Route Signs .-. ........._ - 9 14
III. ROADSGeneral ----------------------- 10 17Types of Roads ---------------- 11 18Road Reconnaissance ----------- 12 19Road Reconnaissance Report 13 23Road Classification ------------- 14 26Road Signs -------------------- 15 30Directional Disks --------------- 16 38
IV. BRIDGES AND OTHER CROSS-ING MEANS
General ---------------------- 17 41Bridge Reconnaissance ---------- 18 44Bridge Classification ------------ 19 50Responsibility for Bridge Classifi-
cation ----------------------- 20 58Bridge Marking ------------ 21 58Tunnels ------------------------ 22 67Causeways, Snowsheds, and Gal-
leries ------------------------ 23 71
'This manual supersedes TC 24. 21 October 1953, TC 7, 26 March 1954, andthose portions of FM 5-10, 18 August 1948, FM 5-34, 30 August 1947, and FM5-35, 4 September 1952 pertaining to route reconnaissance and classification.
SECTION IV-Continued Paragraphs Page
Fords ------------------------- 24 74Crossings on Ice ---------------- 25 81Ferries ------------------------ 26 84Bypass Information ------------- 27 92Administrative Procedures ------- 28 94Traffic Control Over Bridges and
Other Crossing Means -------- 29 95V. VEHICLE CLASSIFICATION
General ----------------------- 30 99Vehicles Which Are Classified ---- 31 100Data Required for Vehicle Classifi-
cation ----------------------- 32 102Marking of Vehicles ----------- 33 103Responsibility for Vehicle Classifi-
cation ----------------------- 34 109Administrative Procedures ------- 35 111Classification of Standard Military
Vehicles ---------- _--------- 36 111APPENDIX I. REFERENCES -------------------- 157
II. GUIDES FOR DETERMININGLOAD-BEARING CAPACITY OFROADS ------------------------ 159
III. BRIDGE SPANS ------------------ 170IV. BRIDGE INTERMEDIATE SUP-
PORTS ------------------------ 198V. BRIDGE ABUTMENTS ----------- 203
VI. TUNNELS__- -.................... 207VII. DETAILED REQUIREMENTS FOR
CLASSIFICATION OF MASONRYARCH BRIDGES ------------ 212
VIII. ANALYSIS OF SUPERSTRUCTUREBY A NOMOGRAPHIC METHOD_ 228
IX. CLASSIFICATION TABLES FORSTANDARD PREFABRICATEDRAFTS, FIXED BRIDGES, ANDFLOATING BRIDGES ---------- 236
X. GLOSSARY ----------------------- 244XI. TABLES ------------ .......... 262
2
SECTION I
INTRODUCTION
1. PurposeThis manual provides, in a single volume, the in-
formation necessary for troops of all branches tounderstand the technical aspects of the reconnais-sance and classification of existing routes of com-munication in order to achieve full and proper utili-zation in military operations. Methods of surveyand reconnaissance for new routes are found in othermanuals.
2. ScopeThis manual covers the collection, compilation,
and dissemination of technical information concern-ing existing routes of communication, includingroads, bridges, and other crossing means, which areneeded to plan or execute movement of military ve-hicles. The manual discusses the information needed,the methods for obtaining it, how compiled, how itrelates to the vehicle and bridge classification system,and methods of dissemination to the user. Such in-formation would include the indicating of obstruc-tions and classifications of routes on maps and theuse of road signs.
3. ReferencesPertinent manuals and other military publications
are listed in appendix I.
3
SECTION II
ROUTES
4. GeneralA route is considered the road or roads, including
tracks and bridges, used when moving from one placeto another. It includes those roads, bridges, tunnels,fords, and ferries selected from a network in a givenarea for the movement of troops, equipment, andsupplies from one place to another. A route mayalso include the use of navigable waters, rail trans-portation facilities, and airplane landing facilities.
5. Route Reconnaissancea. Route reconnaissance is a special type of engi-
neer reconnaissance, although it is governed by thesame fundamentals that apply to all reconnaissance.It is usually made on the ground because of the needfor close physical inspections at, for example, bridgeand drainage sites. Aerial reconnaissance, however,is often useful and should supplement ground recon-naissance when this is practicable. Aerial photo-graphs and ground photographs save time and in-crease the value of reconnaissance reports.
b. The purpose of route reconnaissance is to gaininformation which will aid in the selection of a routeto be used for the movement of troops, troop equip-ment, and military supplies in tactical and strategicoperations.
4
c. Instructions for making a route reconnaissanceshould be simple, clear, and comprehensive. Theyshould state when, where, and to whom the reportsare to be submitted. They should specify the pointsbetween which the route is to extend, the area to bereconnoitered, and the items of information consid-ered particularly important. The information in-cludes the roads available; their physical character-istics; their estimated load-bearing capabilities (app.II); and the tunnels, bridges, fords, ferries, and ob-structions on the routes reconnoitered. The obstruc-tions include single lane roads; one-way bridges;bridges of limited load-carrying capacity; and over-head obstructions such as low hanging trees, low tun-nels, low bridge heights, limited stream-crossingfacilities, and other passage limitations.
d. General assignment limitations for making aroute reconnaissance include the points betweenwhich the route is to extend and the area in which itis to be located.
e. Specific assignment limitations for making aroute reconnaissance include the maximum weight,maximum width, and maximum height of vehiclesto be moved; the classification of the vehicles to bemoved; the approximate number of each class to bemoved per hour; and the approximate length of timethe route is to be used.
f. Information which should be obtained by a routereconnaissance includes the nature of the terrain,existing roads and their lengths, bridges and otherstream-crossing means, obstructions, and bottle-necks. Obstructions are classified as natural andartificial. The natural obstructions include water-
5
courses, slopes, untrafficable areas, timber areas, andswamps. The artificial obstructions include lowhanging trees, low underpasses, and low hangingwires. Bottlenecks include road gradients of morethan 6 percent, narrow bridges, narrow tunnels, anddensely populated areas.
g. Sources of information for route reconnaissanceinclude interrogation of local personnel, prisonersof war, and deserters; ground maps; ground photo-graphs; ground reconnaissance; aerial photographs;and aerial reconnaissance.
6. Route Reconnaissance Reporta. The route reconnaissance report should be ac-
curate, clear, concise, relevant, and specific. Thepreferable method of preparing this report is insimplified map form (fig. 1) with symbols indicatingthe limiting features. It is accompanied by a roadreconnaissance report (par. 13) and such bridge,tunnel, ferry, and ford reconnaissance reports as arenecessary. The route report is supported by mili-tary sketches of limiting features; by local maps;and by photographs showing the terrain, the roads,tunnels, bridges, ferries, fords, and other stream-crossing means.
b. Symbols used in preparing route reconnaissancemap reports are given in figure 2 and in para-graph 7b.
c. A checklist for use in obtaining the data fromwhich to prepare a route reconnaissance reportfollows:
(1) Length between well-marked points, ineither miles or kilometers and decimalfractions thereof.
6
o NK-U X ATE,8 L20' MV 8
TITLE BLOCK/ will include-
IV 79 NAME,RANK,UNIT,DATE,
98 4s z2H MAP REF., and SCALE.
Figure 1. Example of a route reconnaissance report.
(2) Sharp curves, each with its radius in feet ormeters.
(3) Steep grades, each with its maximum gra-dient in percent and length of any gradegreater than 6 percent.
(4) The road width of bottlenecks, each withthe width of its traveled way in feet ormeters, and its length in either miles orkilometers and decimal fractions thereof.
7
SHARP CURVE[•z ffi ~~~RADIUS IN FEET OR METERS
0 STEEP GRADE (ARROWS POINTpi ig Y/1 I V~UPHILL) (GRADE IN PERCENT)
CONSTRICTION(WIDTH AN FEET OR METERS)
ARCH CONSTRICTION14w/ 4H (WIDTH AND HEIGHT IN FEET OR METERS)
.15B'.__ L,'l HUNDERPASS CONSTRICTION_1w 14H VA lln(WIDTH AND HEIGHT IN FEET OR METERS)
BRIDGE BYPASS(EASY) BPE
BRIDGE BYPASS(DIFFICULT) BPD
BRIDGE BYPASS(IMPOSSIBLE) BPI
LEVEL CROSSING
Figure B. Symbols used to represent obstructions.
(5) Underpass limitations, each with its lim-iting height and width in feet or meters.
(6) Bridge bypasses, each classified as easy,difficult, or impossible.
7. Route Classificationa. General. Route classification is the simple
classification of a route to assist staff officers inplanning a normal road movement. It includesminimum widths of roads, types of roads, load-carrying capacity of roads and bridges on the route,and the existence and effect of obstructions or otherlimiting factors. It is not as detailed as the classi-fication of a road (par. 14), which is used mainly forengineer purposes. Road classification includeswidth, length, alinement, drainage, foundation, sur-face, and details of specific obstructions, but doesnot include bridge classification.
b. Basis of Route Classification. The basis ofroute classification is the road classification and theload-carrying capacity of the roads and bridgesalong the route. Bridge classification is discussed inparagraph 19. The route classification includes fac-tors as follows:
(1) Width-expressed in feet (ft) or meters (m).(2) Type-categorized, for the purpose of route
classification, as all-weather (X), limitedall-weather (Y), or fair-weather (Z). Thesetypes of roads are defined in paragraph 11.This information permits the type of roadto be intelligently described in makingroute reconnaissance reports and interpret-ing them.
(3) Load-carrying capacity-determined by theclassification number of the highest classvehicle that can use the route in convoy.This is normally governed by the classifica-tion of the weakest bridge on the route as
9
determined by methods outlined in appen-dix VII, VIII, and TM 5-260, and describedbriefly in paragraph 19 of this manual.
(4) Load-bearing capacity-determined fromdesign curves for flexible road pavementsand for concrete road pavements given inappendix II. Such capacity does not neces-sarily preclude the use of vehicles of aheavier classification, as does the carryingcapacity described above. It is merely anindication of the type of traffic which theroad will bear in continual use.
c. Route Classification Formula. The route classi-fication formula is developed from route classificationsymbols arranged in sequence as follows: width ofroad, type of road, and load-carrying capacity.
(1) Examples.(a) A route having a traveled roadway of 20
feet, a limited all-weather type with aload-carrying capacity of class 50, wouldbe expressed by the following formula:
20ftY50
(b) A route having a traveled roadway widthof 10.5 meters, an all-weather type with aload-carrying capacity of class 70, wouldbe expressed by the following formula:
10.5mX70
(2) Obstructions. Obstructions or bottlenecksoccurring singly or of a temporary natureare not the limiting factor for classifying aroute. They are noted in the formula and
10
described completely in the accompanyingreport or on an overlay. Where such anobstruction exists, the route classificationformula is followed by the symbol (Ob), forexample-
20ftY50(0b)
(3) Snow blockage. The effects of snow blockageon military traffic depend upon the amountof snow clearance that is feasible. This, inturn, depends upon the availability of laborand equipment. Where snow blockage is aregular, recurrent, and serious factor, theroute classification formula is followed bythe symbol (T), Cir example-
20ftY50(T)
d. Structures Classification Symbols. Structuresclassification symbols are to be used on maps andoverlays to indicate the trafficability of structuresencountered on the route being classified:
(1) The bridge classification symbol consists ofa miniature reproduction of the bridge classsign of the bridge concerned. Figures tothe left of the sign between vertical arrowsindicate the overhead clearance, figuresbetween horizontal arrows below the signindicate width of roadway, figures to theright indicate length of bridge, letters BP-indicate bypass conditions (fig. 3 (0).
(2) The tunnel classification symbol consists ofa hollow square inclosing the letter "T."Figures to the left between vertical arrows
11
indicate overhead clearance at critical point(usually the springing line for an archedtunnel); figures between horizontal arrowsbelow the square indicate roadway width;figures to the right indicate length (fig. 30).
(3) The ford classification symbol consists of acircle enclosing the word FORD. Figuresbelow the circle indicate length, usablewidth and depth at normal water level (fig.3 0).
(4) The ferry classification symbol consists of
T- L-270L T2 114' 0 ) BPE 13 L=80
22' 22 '
FORD 14 40L=400' FERRYW= 35 FERRY
1 For bridge2 For tunnel3 For ford4 For ferry
Figure 3. Typical structures classification symbols.
12
circle enclosing the class number. Theword FERRY is placed just below the circle.Figures to the left between vertical arrowsindicate overhead clearance. Figures be-tween horizontal arrows below the wordFERRY indicate width at critical point(fig. 3 ().
e. Relation of Route Classification to Vehicle andBridge Classification. Route classification utilizesthe vehicle class numbers and the bridge class num-bers to determine the safe load-carrying capacity ofa route and its branches. The vehicle classificationsystem represents, by a whole number, the effect avehicle will have on a bridge in crossing it. Thiseffect depends upon the gross weight of the vehicleand its weight distribution to the axles or tracks.The bridge classification system represents, by awhole number, the safe load-carrying capacity of abridge under normal crossing conditions. As men-tioned in b(3) above, the load-carrying capacity ofa route is expressed by the classification number ofthe highest class vehicle that can use the route inconvoy, taking into consideration the classificationof the weakest bridge on the route.
f. Responsibility for Route Classification. Routeclassification is the responsibility of the appropriateengineer officer.
8. Route Numbering
a. One route number is used to designate eachmain supply route and each lateral route throughoutthe entire length of each.
b. Main supply routes and axes are given oddnumbers.
13
c. Lateral routes are given even numbers.d. Responsibility for allotting blocks of route
numbers to army groups and other units operatingin any theater rests with the theater commander.
9. Route Signs
a. Route signs (fig. 4) indicate location, distance,direction, route numbers, and similar information tohelp drivers. In order to differentiate between routesigns and guide signs along a road, which may beonly a segment of a given route (par. 15d), the routesigns are rectangular in shape and are placed with thelong axis vertical. If signs are manufactured locallyand availability of material is critical, alternativecircular signs as illustrated in figure 4 may be used.Route signs have a white background on which thelegend or symbol is superimposed in black. Thelegend on a route sign consists of-
(1) The route number.(2) The appropriate directional disk marking.
b. The direction of traffic may also be' shown onroute signs. In the case of main supply routes, thereare no standard terms to indicate which stream oftraffic is moving to the front and which is moving tothe rear. But, as shown in figure 4, indications maybe used depending upon the language and the signadopted. On route signs of lateral routes, the stand-ard letters N, E, S, W, NE, SE, NW, and SW areused to indicate the general direction of movementof each traffic stream.
c. Additional route signs may be erected whenmoves take place within other friendly national areas.However, the erection of these additional signs must
14
ma - -
0 o 7
E RI ii, 15
15
be arranged mutually between the commandersconcerned.
d. Objective of this system of route signing is toenable Allied Armies to move freely in each other'sterritory. The system is capable of being super-imposed on any existing civil system of route signing.
16
SECTION III
ROADS
10. Generala. A road is an open way provided for the con-
venient passage of personnel and vehicles. Selectedroads with selected tracks, bridges, and other stream-crossing means form a route which is used whenmoving personnel, vehicles, and animals from placeto place.
b. Types of roads vary through wide limits. Thepermanent all-weather road is the highest type. Acleared way through timber is probably the lowesttype. Types of existing roads are briefly classifiedand described, from the standpoint of trafficability,in paragraph 11.
c. Road reconnaissance (par. 12a) is primarilyconcerned with obtaining information about existingroads which is necessary for the selection of a route.The information required, the methods used, andthe obstructions to be observed and recorded arediscussed in paragraph 12b and c.
d. The road reconnaissance report is made on aStandard Road Reconnaissance Report form whichis described and illustrated in paragraph 13.
e. Road classification considers two groups of roadcharacteristics-elements and attributes-and is ex-pressed in fraction form (par. 14). It does not
332944 0-55---2 1 7
include a description of the bridge classificationsystem which is described in paragraph 19.
f. Road signs are classified in four groups: stop,warning, regulatory, and guide (par. 15). The useof directional disks (par. 16) is supplementary to theuse of other guide signs.
11. Types of RoadsRoad types, for the purpose of route classification,
are defined below. They are classified from thestandpoint of trafficability. The examples givenare based on materials used and can be shifted fromone category to another by the theater commanderto fit local conditions.
a. All-weather road (X)-any road which, withreasonable maintenance, is passable throughout theyear to a volume of traffic never appreciably lessthan its maximum dry-weather capacity. This typeof road has a waterproof surface and is only slightlyaffected by rain, frost, thaw, or heat. At no time isit closed to traffic by weather effects other than snowblockage. Examples of roads in this category are-
(1) Concrete.(2) Bituminous surface.(3) Brick or stone pavement.
b. Limited all-weather road (Y)-any road which,with reasonable maintenance, can be kept open inbad weather to a volume of traffic which is consider-ably less than its maximum dry-weather capacity.This type of road does not have a waterproof surfaceand is considerably affected by rain, frost, or thaw.Traffic may be completely halted for short periodsof a day or so at a time. Heavy use during adverse
s18
weather conditions may lead to a complete collapseof the road. Examples of this category are-
(1) Crushed rock or waterbound macadam.(2) Gravel or lightly metaled surface.
c. Fair-weather road (Z)-a road which quicklybecomes impassable in bad weather and which cannotbe kept open by normal maintenance. This type ofroad is so seriously affected by rain, frost, or thawthat traffic is brought to a complete halt for longperiods. Examples of this category are-
(1) Natural or stabilized soil.(2) Sand-clay.(3) Shell.(4) Cinders.(5) Disintegrated granite.
d. The symbols X, Y, and Z are used only in theroute classification formula.
12. Road Reconnaissancea. Road reconnaissance is reconnaissance made to
obtain information about existing roads, primarilyto permit establishment of a route. It is concernedwith the conditions of existing roads for immediateuse and not for maintenance operations. The infor-mation obtained is used to estimate the quantity andkind of traffic and loads that a route can accommo-date in its present condition. Road reconnaissancemay also include estimates of the practicability ofimprovement and the engineer work involved inconditioning a route to accommodate specified trafficand loads.
b. Information required for the reconnaissancereport of an existing road includes the following:
(1) Local name of the road.
19
(2) Local road designation and number.(3) Location of the road by map grid reference.(4) The length of the road between specified
and readily identifiable points.(5) The normal width of' the road:
(a) Between fences.(b) Between drainage ditches.(c) Between edges of pavement; that is,
traveled way.(6) Alinement of the road.(7) Drainage, including culverts.(8) Foundation.(9) Surface.(10) Obstructions, including kinds and locations.
(Obstructions include, but are not limitedto, underpasses, fords, large tree limbs,craters, projecting buildings, etc.)
(11) Reductions in width.(12) Excessive gradients; locations and grades
of all over 6 percent.(13) Sharp curves; location and radius of all
shorter than 150 feet.(14) Bridge locations. (Bridge reconnaissance
is described in paragraph 18.)(15) Underpass locations together with their
limiting lengths, limiting widths, and limit-ing heights.
(16) Tunnel locations together with their limit-ing lengths, limiting widths, and limitingheights.
(17) Ford locations. (Ford reconnaissance isdescribed in paragraph 24.)
20
(18) Ferry locations. (Ferry reconnaissance isdescribed in paragraph 26.)
(19) Snow shed locations and estimated coverage.(20) Snow gallery locations together with their
limiting lengths, limiting widths, and limit-ing heights.
c. The radii of short radius curves may be esti-mated by using a cord to swing an arc. This methodis shown in figure 5. The curves are staked as arcs
Pi
PC
200' CORD PT
& CenterlinePC Point of curvaturePI Point of intersectionPT Point of tangency
Figure 5. A curve staked by using a cord.
of circles by swinging an arc with tracing tape orcord from the experimentally determined center of acircle which is tangential to the relatively straightapproaches to the curve being measured. The lengthof the tape or cord from the center of the circle toits circumference is the radius of the curve. Thismethod is practical for curves having a radius up to250 feet and located on relatively level ground.
21
d. A more practical method for measuring theradii of curves in any type of terrain, especiallyrough wooded or built-up areas, is based on theformula--
C= 2 /m (2R- m)
where: C = length of a chord subtended by an arcof a circle
m = the perpendicular distance from centerof chord to the circle or centerline ofthe road, and
R = the radius of the circle.This method is illustrated in figure 6.Solving for R the above formula becomes-
R= C2/8m+m/2
By fixing m at any convenient distance, such as5 feet, the formula becomes-
R= C2/40+2.5
In the practical application of the formula, m ismeasured from the centerline of the curve towardthe estimated center of the circle and then C is
R\ I
Figure 6. Measuring a curve using R=C2 /8m+m/2.
22
measured perpendicularly to m, making sure that Cis centered on m.Example: If C is measured to be 58 feet, fromformula-
R=C2 /40+2.5, thenR=86.6 feet
Note that when m equals 5 feet and R equals 150feet, C must equal 77.46 feet. Thus when measur-ing C any value greater than 77.46 feet will give avalue of R greater than 150 feet and therefore thecurve need not be reported.
13. Road Reconnaissance Report
a. The Standard Road Reconnaissance Report,(DA Form 1248) (fig. 7) is used to report all roadinformation. Short forms or work sheets for rapidfield work may be designed and produced by theunit making the reconnaissance.
b. Method of Use. All of the blank spaces on DAForm 1248 are to be filled in. When it is impossibleto determine any item required by the report, theappropriate space should be marked NOT KNOWN.If the width of the roadway varies, paragraph 4 ofthe form should indicate the lower and upper limitsof the width and the stretches of roadway of differentwidths should be indicated on the mileage chart.Similarly, if the data for items 9, 10, 11, and 12 ofthe form are different for various stretches of road,they should be so indicated by placing the appropri-ate road classification fraction (par. 14b) on themileage chart opposite the stretch of road to whichthe classification applies. Obstructions are listedand described in section III of the form, and indi-
23
STANDARD ROAD RE NcAISSANCE REPORT I2 s Ryt./953
s-a, /I5"'fC8 4rZ L/ #8 //sLC 8SECTIOH i CENERAI YoiD IINFO .DIA IFermD .Tlnw
--a -- w~ Al.PR/, qs--F, -EAr R.. , f
6 . ......... .r . .......e... ...../0 tJt LY ltS3laroo-h-o
SETION ETIL R INF... ..a l.. I ....... .. ll .....
.DA .,R 1248
1 Front of form
Figure 7. Exanple of a Standard Road Reconnaissance Report.
24
SECTION IV. MILEAGE CHART
O TE _CAL T
_OAN INroRaETlOI | IIRANC | ROAND IOlRo.AATION
,I0ES · _ KILO.ETI .S
670 - IM^; w st C.ALF.Eb
| .;LT .f' ReNR (foa Rco iA )
ADFS a6FTI IRb
V ~3.55 -° ~TNCT h R ONCT 417
-,M
__es - (A4cc7A o)
40. 70
Or -· o L --FA;FAK - NK RaouTK /0C31
2 Back of form
Figure 7-Continued.
25
cated on the map or overlay by appropriate symbols(fig. 2). The mileage chart is on the reverse side ofDA Form 1248. This chart is used to show thelocation of the salient features and classificationelements of the road, starting at the bottom of thepage and proceeding up the chart at the desired scale.If the English system of measurement (miles, yards,feet) is used, the opposite metric side of the chartmay be used for additional information.
14. Road Classification
a. Characteristics Considered in Road Classification.The classification of a road considers two groups ofcharacteristics. The first group, called elements,consists of alinement (A), drainage (D), foundation(F), and surface (S). Rating of elements used inroad classification is given in table I. The secondgroup, called attributes, consists of the length of thestretch of road to be classified, the width of thetraveled way at its narrowest point, the type ofsurface material, the presence of gradients in excessof 6 percent, and the presence of obstructions.Symbols for the length and width of the road, and fortypes of road surfaces are given in table II.
b. Road Classification Fraction. Road classifica-tion is determined from general or hasty reconnais-sance and is expressed in the form of a fraction. Theroad classification fraction is used on maps, overlays,and mileage charts for convenience and readyreference in preparing a hasty reconnaissance.The more deliberate reconnaissance is performedwhen time and the availability of qualified personnelpermits. The resulting detailed information is
26
00,
ce
0 .0 0
~~~~~
z : Z : = ®
'0 /.-o 0 1
E-- Cl
oo~- e
~F 1)000 O2 EIaa / o 0 .11
0 0
G ~ ~ ~~~~~~~ =d 8 o~'0~~~~ 0' · 0 0
'o'o
-c~ ~~~~~~-.3 C
R :5- 13_ - ~; O3 .
a a c3 G~~n U t ceC ~~~~
27
V ofo u~ "P0
0 0 c ~ .0 5.2 . O-0 ' B 0- 0 ,
d' 71 ~X 52 O ~ 12
12122~' C. O o
6~ ~~~ I I II
Ie" I I I_ vi i
IS O I I I Ia~~~ I" I
12 ~ ~ I I I0 I , ~
a:~~~ 0 c ~ Od 0 S~· 0, a ~ES %~~~2
Table II. Symbols for Length and Width of Road, and for Typesor Road Surfaces
Symbol Meaning
mi Preceded by a numeral, indicates length of road inmiles between two points identified by dots onthe map or overlay.
km Preceded by a numeral, indicates length of road inkilometers.
ft Preceded by a numeral, indicates width of traveledway in feet at the narrowest point.
m Preceded by a numeral, indicates width of traveledway in meters.
k Concrete.b Bituminous surface treatment. The symbol "b"
may be used with any of the other surfacesymbols to denote a waterproof bituminousskin. For example: kb-bituminous concrete.
p Paving brick or stone.r Crushed rock, coral, or waterbound macadam.gl Gravel or lightly metaled surface.n Natural or stabilized soil, sand-clay, shell, cinders,
disintegrated granite, or other selected material.v Various other types not itemized above (to be
described in reconnaissance report).
recorded on the road reconnaissance report describedin paragraph 13. The position of the symbols (aabove) for the elements in the road classificationfraction indicates their rating. Elements which arerated good, have their symbols placed in the numera-tor. Elements which are rated fair or bad, havetheir symbols placed in the denominator. Thenumerator contains, in addition to the "good"elements, the road width and the surface type; andthe denominator contains the "fair" or "bad"elements and the road length, as shown below:
28
"good" elements, road width, surface type
"fair" elements or "bad" elements, road length
(1) An example of a classification fractionfollows:
FD 20 ft rbAgc S 6.4 mi
This fraction describes a stretch of road 6.4miles long and 20 feet wide at the narrowestpoint in the traveled way. The road hasa good foundation and drainage system, butbad alinement, with grades in excess of 6percent and sharp curves with radii lessthan 150 feet. The road also has a bitu-minous macadam surface in bad condition.
(2) When factors cannot be determined, theirsymbols are omitted.
(3) Electric transmittal of the road classificationfraction requires that the numerator beseparated from the denominator by a slant,for example-
FD 20 ft rb/Agc S 6.4 mi
c. Obstructions. Obstructions which affect thetraffic capacity of the road are not shown in theclassification fraction, but are indicated on a map oroverlay by the appropriate symbols selected fromfigure 2 and by placing a comprehensive descriptionof them in section III of DA Form 1248 (fig. 7).Obstructions to be indicated in the road reconnais-sance report include the following:
(1) Overhead obstructions-bridges, wires, over-hanging buildings, or similar obstructionshaving a vertical clearance of less than 14feet.
29
(2) Reductions in width such as craters, narrowbridges, archways, underpasses, and build-ings projecting into the roadway.
(3) Steep gradients-in excess of 6 percent.(4) Sharp curves which large combination vehi-
cles may have difficulty negotiating-radiusless than 150 feet.
(5) Fords.d. Shoulders. Where shoulders are of appreciable
width and usable in an emergency, they are coveredby a separate note in the road report, giving width,type of surface (grass, gravel, etc.), and generalcondition.
e. Responsibility .for Road Classification. Roadclassification is a responsibility of the engineer staffat the headquarters which arranged the requiredroad reconnaissance.
15. Road SignsRoad signs are classified according to use as stop,
warning, regulatory, and guide. Their sizes, shapes,colors, and markings are summarized in table III.Some of their applications are listed in table IV.
Table III. Road Signs-Shapes and Colors
Color
Type Shape Position Back- Legendground syor
symbol
Stop -.. ....... Octagonal.- Upper and lower sides of Yellow._ Black.octagon horizontal.
Warning .------ Square ..-... One diagonal vertical- Yellow.- Black.Regulatory -... Rectangular_ Long axis vertical Whit.. Black.Guide .-.. .... Rectangular Long axis horizontal White__. Black.
Note. Sizes of signs must be sufficiently large to be easilyread under adverselight conditions.
30
Table IV. Road Signs--Applications
Type Application
Stop ----------- All vehicles stop.
Warning -------- Advance warning of stop signs and trafficsignals.
Bumps.Changes in road width.Cross road.Curves.Danger or hazard.Dangerous corner.Dips.Junction T.Junction Y.Level railroad crossing, advance warning.Men working.Railroad crossing.Road construction or repairs.Road narrows.Slippery road.Steep grades.Steep hill.Turns.
Regulatory ----- No entry.One way.Parking restriction.Specific regulations for vehicles.Speed limit.
Guide --------- Detour.Detour begins.Detour ends.Directions.Distances.Information to help driver.Locations.Route number.
31
a. Stop Signs. Stop signs (fig. 8) are octagonalin shape and require all vehicles to stop. They havea yellow background, on which the word "stop" issuperimposed in black. The letters should be atleast one-third the height of the sign. They areerected so that the upper and lower sides of theoctagon are horizontal.
Figure 8. Stop sign.
b. Warning Signs. Warning signs (fig. 9) are usedto indicate traffic hazards. They are square in shapeand are erected on a diagonal. They have a yellowbackground on which the legend or symbol is super-imposed in black. They are used to indicate turns,curves, intersections, steep grades, bumps, changesin road widths, railroad crossings, and other roadhazards.
c. Regulatory Signs. Regulatory signs (fig. 10)are used to regulate and control traffic by legal au-thority. They are rectangular in shape and areplaced with the long axis vertical. They have awhite background on which the legend or symbol is
32
superimposed in black. They are used to indicatespeed limits, one way, parking restrictions, and otherspecific regulations for vehicles except bridge clas-sifications, which are discussed in paragraph 21.
d. Guide Signs. Guide signs (fig. 11) are used toindicate locations, distances, directions, route num-bers, and similar information of help to drivers. Inorder to distinguish road guide signs from routeguide signs (par. 9a), the road signs are rectangularin shape and are placed with the long axis horizontalto the ground. They have a white background onwhich the legend or symbol is superimposed in black.
e. Exceptions. Exceptions to the signs describedabove include directional disks (par. 16), alternativeroute signs (fig. 4), and bridge markings (par. 21).
f. Night Signing. Night signing is not standardized.Each army provides lighting or reflecting deviceswhere deemed necessary. Only the most importantsigns, or those indicating extremely hazardous con-ditions, should be lighted.
g. Road Signs in Arctic Regions. Arctic conditionsrequire special attention to posting road signs.Permanent routes are designated by durable markers.In open country, poles about 8 feet high with direc-tion markers, snow markers, wisps of straw, brush-wood, rock cairns, or flags serve the purpose. Num-bering the markers sequentially and placing them atequal distances from each other on tangents, withcloser spacing on curves, are effective safety meas-ures. Markers should be erected at least 3 feet offthe traveled road to avoid damage by the traffic. Ifcomplete road marking is impossible, arrow signposts should be erected at prominent points to indi-
332944 0--55----3 33
CURVE TO RIGHT SHARP CURVE TO RIGHT
WINDING CURVES RAILROAD CROSSING
T-JUNCTION PRIMARY ROAD CROSSINGSECONDARY ROAD
Figure 9. Warning sign examples.
34
STEEPWIDNHILL ROAD
ROUGH ONELANEOAD NROAD
SLIPPERYMEWHENWOKNWET WORKI
Figure 9-Continued.
35
~~~~L ~ I
C4LLI N LLN
tr3,
w ~ ~ ~~ !.-
e ~~~~LLIc Ir
C= CM~~I LL C-uJ
36 -J
36
TRAFFIC BRIDGE ROADSIGNALAHEAD OUT CLOSED
END (3 NDETOUR DETOUR 604
FRANKFURT
PARIS f 3564ORLEANS ORD. MAM CO
Figure 11. Guide sign examples.
37
cate the direction of the road or the route and thedistance to the objective. Road markers used forlong periods in arctic regions are checked frequentlybecause their positions can be altered readily by anenemy.
h. Responsibility for Road Signs. Design and speci-fications for materials of road signs are responsibili-ties of the Chief of Engineers. Making road signs isan engineer responsibility. Posting road signs is anengineer responsibility coordinated with the appro-priate provost marshal and the highway traffic regu-lation officer of the Transportation Corps regardinglocation and the number used. Operational responsi-bility for road signing is a command function.
16. Directional Disks
a. Directional disks (fig. 12) are used to supplementother guide signs to indicate the direction of a route.In addition they are used as an appendage to anymajor unit or formation sign indicating the route tothat unit.
b. Details of the directional disk are as follows:(1) The disk is a circle with a minimum dia-
meter of 1 foot. The normal disk consistsof a fixed black arrow on a white back-ground. The disk used on detours has afixed white arrow on a red background.
(2) The disk has eight equally spaced holesaround the edge of the circumference toallow it to be erected with its surface verticaland with the arrow pointing in the appro-priate direction.
38
STRAIGHT ON TOWARD THE FRONT STRAIGHT ON AWAY FROM THELINE FRONT LINE
TURN RIGHT TURN LEFT
FORK RIGHT FORK LEFT
SHARP TURN TOWARDS RIGHT SHARP TURN TOWARDS LEFTREAR REAR
Figure 12. Directional disk markings.
39
c. Restrictions on the use of the directional disk areas follows:
(1) The directional disk is restricted for use onmain supply routes, lateral routes, and mainaxes. Battalions and lower units are notpermitted to erect directional disks on theirown initiative. The object of this restric-tion is to insure that minor units do notmake indiscriminate use of directional disksbecause of the resulting confusion whichmight occur.
(2) Units not allowed to erect directional diskscan use arrow signs, providing they are ofdifferent coloring and shape from direc-tional disks.
d. Application of directional disks is given in figure12. These applications in no way supersede the useof regulatory signs listed in paragraph 15c.
40
SECTION IV
BRIDGES AND OTHER CROSSINGMEANS
17. Generala. Crossing Means. Crossing means discussed in
section IV are as follows:(1) Bridges. A highway bridge (fig. 13) is a
structure erected over a river, a chasm, ora gorge, which carries a roadway for ve-hicular or foot traffic. (Railway bridgesare often decked over to serve as highwaybridges.) Bridge reconnaissance is dis-cussed in paragraph 18, and bridge clas-sification is described in paragraph 19.Bridges generally consist of three elements,as follows:
(a) Spans. Types of spans are illustrated inappendix III. They are classified asslab, beam (stringer, either simple or con-tinuous), girder, truss, cantilever, arch,suspension, or ponton (floating). Ifmovable, spans are further classified asswing, bascule, retractile, or lift.
(b) Intermediate supports. Intermediate sup-ports are illustrated in appendix IV.They are classified by types as trestle
41
CUT---
- APPROACH -iI APPROACH
kBRIDGP-1 ROADWAY
a
k APPROACHa - APPROACH SPANS
b b
ABUTMENT ABUTMENT
PIER
'\ I / ir
b-b OVERALL LENGTHc-c LENGTH, BEARING TO BEARING
d LENGTH, ABUTMENT TO ABUTMENT
1 Typical bridge with fill approach at one end and cut ap-proach at other end
2 Typical bridge with approach spans at one end3 Typical bridge, consisting of two spans and a pier support,
illustrating length measurement bases
Figure 13. Typical bridge approaches, abutments, and pier.
42
bents, pile bents, crib piers, and solidpiers.
(c) Abutments. Abutments are the groundsupports at each end of a bridge. Theyare illustrated in appendix V. Abut-ments are classified as straight, wing,U-type, and T-type. Construction ofapproaches to these abutments variesfrom simple fill method to detailed bridgetype construction.
(2) Tunnels. Tunnels are illustrated in ap-pendix VI. Their reconnaissance and re-lated details are discussed in paragraph 22and appendix VI. Tunnels are classified,by types of bore, as semicircular, eliptical,horseshoe, and square with arched ceiling.
(3) Causeways, snowsheds, and galleries. Cause-ways, snowsheds, and galleries are crossingmeans which may be less frequently en-countered in route reconnaissance thanothers discussed in this section. Eachshould be judged on its own merits, as tothe necessity of making a report on recon-naissance of the structure.
(4) Fords. Fords are classified by their traffica-bility for personnel, trucks, and tanks.Their reconnaissance and associated detailsare discussed in paragraph 24.
(5) Crossings on ice. In estimating the load-carrying capacity of ice, for use as a streamcrossing, both the thickness and the condi-tion of the ice must be taken into considera-
43
tion. This is discussed in further detail inparagraph 25.
(6) Ferries. Ferries are classified as poweredferries, cable ferries, or current operatedferries. Their reconnaissance and asso-ciated details are discussed in paragraph 26.
b. Bypass Information. For the purpose of routereconnaissance information, bypasses are divided intofour categories. These categories, together withtheir symbols, are discussed in detail in paragraph 27.They are as follows:
(1) Bypass exists.(2) Bypass readily constructed.(3) Bypass difficult.(4) Bypass impossible.
c. Administrative Procedure and Traffic Control.Responsibility for the various procedures involvedin the marking of bridges and other crossing meansis discussed in paragraph 28. Traffic control includesthe supervision of special crossings of bridges or othercrossing means. Traffic control responsibility andspecial crossings are discussed in detail in para-graph 29.
18. Bridge Reconnaissance
a. The purpose of bridge reconnaissance is todetermine limiting features of a bridge used as aportion of a route. These limiting features includelimiting width, overhead clearance, length (if abottleneck), load-carrying capacity, traffic move-ment possibilities, estimated amount of repair orreinforcement required, and posting needs. Thereare two approaches to bridge reconnaissance, depend-
44
ing upon the amount of time and qualified personnelavailable for the reconnaissance.
(1) Hasty reconnaissance. Hasty reconnais-sance is made to determine the immediatetrafficability of the bridge. The infor-mation to be obtained from this type ofreconnaissance is similar to that for delib-erate reconnaissance, except that time andother limitations preclude a complete cover-age. Therefore, hasty reconnaissance at-tempts only to gain exact informationnecessary to allow immediate use of thebridge with reasonable safety. A tempo-rary bridge classification may be computedfrom the information obtained by hastyreconnaissance by the use of appendix VIII.
(2) Deliberate reconnaissance. Deliberate re-connaissance is made when time and quali-fied personnel are available to determine allof the features necessary to a thoroughanalysis and classification or to determinenecessary repairs or demolition procedures.The information to be obtained by deliber-ate reconnaissance is detailed. It includesthe approach roadway, the identification ofthe bridge by its name or number, class,name of the geographical feature it crosses,its location by highway number, and otherdistinguishing details. It includes also adescription of the bridge by type, its prin-cipal dimensions, its general condition, and,where required, sufficient detailed dimen-sions to permit calculating its load-carrying
45
capacity. It finally includes site features;bypass information; the repairs and rein-forcement needed; a rough estimate of thetime, labor, and material needed to effectthe repairs and the reinforcement; and ademolition estimate. Sketches of sufficientdetail to illustrate the written report shouldbe included.
b. The Bridge Reconnaissance Report (DA Form1249) is used to report bridge information. Theinstructions for making the reconnaissance shouldindicate the amount of detail required so as to guidethe reconnaissance party. Short forms or worksheets for rapid field work may be designed and pro-duced by the unit making the reconnaissance.
c. Details to be entered on DA Form 1249 in theorder of items follow:
(1) Identification (items 1-11). Enter all datawhich establish positive identification of thebridge by reference to route, map sheet,grid reference, bridge name or number,class, geographic location, and crossing.
(2) General reconnaissance (Section I, items12-17). Record the temporary class (app.VIII), roadway width, overhead clearance,condition, total length, and bypass informa-tion.
(3) Detailed reconnaissance (Section II, items18-20). Enter the principal dimensions ofthe bridge as indicated in table V, the sitefeatures, and the condition of approaches.In item 18c, circle appropriate letters(NESWN) to indicate location of each
46
abutment, i. e., NE for northeast, S forsouth, etc.
(4) Remarks (item 21). Note any additionalpertinent data, not specifically covered else-where on the report.
(5) Estimate of repair and/or demolition (item22). Record, where necessary, the repairsand reinforcement needed. Give a roughestimate of the time, labor, and materialneeded to effect the repairs and reinforce-ments. Include a demolition estimate.
(6) Sketches (item 23). Make two-dimensionalsketches of the bridge, consisting of a sideelevation, a cross section of the criticalspan, a cross section of the critical member,and a site plan.
(a) The side elevation shows the generalfeatures of the structure including thenumber of spans, piers, abutments, andtheir types. Dimensions, such as spanlength, height above streambed, waterlevel, and panel length, are also noted onthe side elevation.
(b) The cross section of the critical span showssufficient information regarding the de-tail of construction to allow calculationsfor its classification, maintenance, rein-forcement requirements, and destruction.This includes items such as: width ofspan, type of construction, and designdetail. Tables V and VI outline neces-sary dimension requirements for eachtype of bridge.
47
BRIDGE RECONNAISSANCE REPORT 0 o P 1954
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48
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332944 0-55----4 49
(c) The cross section of the critical membershows sufficient dimensions to allowmathematical development of its strength.Detailed dimensions are furnished tomeet the requirements for any given typeof bridge, as indicated in table VI.
(d) The site plan sketch shows location,length, and width of the bridge; thedimension and gradient of the roadwayapproach and departure from the struc-ture; terrain topography of sufficientdetail to trace waterways; fording possi-bilities; and other pertinent details.
(7) Computation of bridge class (item 2). Usingthe information obtained above, com-pute the bridge classification by methodsdescribed in appendixes VII, VIII, andIX, or in TM 5-260.
(8) Photographs. Wherever possible, photo-graphs should be included to show sideview, view from traveled way, and aview underneath the deck, where appli-cable.
19. Bridge Classificationa. Bridge classification is the military method of
grouping bridges by their safe load-carrying capacityunder normal crossing conditions. For normal mili-tary convoy movements within the United States itis not necessary to establish bridge classes, becausethe approval of the appropriate state highway de-partment must be obtained prior to the movementof vehicles which exceed the legal load limit. In a
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state of emergency, bridge classes are established bythe engineer of the command that is to use the bridge.
b. The bridge class number is a whole numberranging from 4 to 150. It is determined by an en-gineering analysis according to principles describedin TM 5-260 and is placed on a standard sign usedto mark a bridge. Methods of determining a tem-porary classification number are given in appendixVIII. The bridge class number may be either singleor dual.
(1) A single class number is the bridge classnumber that will permit the crossing ofeither wheeled or tracked vehicles whosevehicle class numbers are equal to or lessthan the bridge class number.
(2) A dual class number is a dual number whichindicates one normal class number forwheeled vehicles and another normal classnumber for tracked vehicles. Dual classnumbers may be used only when the spanlength is approximately 95 feet or less, andwhen the bridge is capable of carryingtracked vehicles whose vehicle class num-bers are 50 or larger. Typical dual classnumbers are: 70/50, 80/60, 100/60, and50/70. The wheeled vehicle class numberis always shown above the tracked vehicleclass number. A bridge may be postedwith a single class number even though adual class number is authorized.
c. The normal bridge class number is a whole num-ber which represents the highest class vehicle per-mitted to cross the bridge under normal crossing
54
conditions; that is, vehicles maintain a 30-yard con-voy spacing, for floating bridges speed is limited to25 miles per hour, and sudden stopping or accelera-tion is not permitted. If the class number is notdual, the number is the maximum class for wheeledvehicles or the maximum class for tracked vehicles,whichever is the smaller. If the bridge class numberis a dual class number, wheeled and tracked vehiclesare considered separately and both numbers areposted. The normal class number of a multilanebridge may be a combination of class numbers indi-cating the normal class for two lane traffic and thecomputed class number for one-way traffic using twolanes without the restrictions imposed by controlledcrossing rules (par. 29b(1)).
d. A special class number is a number which repre-sents the load-carrying capacity of a bridge underspecial crossing conditions. Under exceptional oper-ating conditions in the field, the theater commanderor local civil authorities, in areas under their control,may authorize vehicles to cross bridges when thebridge classification number is less than the vehicleclassification number. Special class numbers arenever posted on standard bridge marking signs, butmay be posted on supplementary signs. Specialclass numbers may be for either controlled, caution,or risk crossings (par. 29b).
(1) A controlled class number is the number ob-tained, for multilane bridges only, by mul-tiplying the normal class number (eithersingle or dual) of the weakest lane of themultilane bridge by the factor 1.5.
(2) A caution class number is the number ob-
55
tained by multiplying the normal single lanecrossing class number of either a single laneor multilane nonstandard bridge by 1.25.For standard prefabricated bridges, thecaution class number is obtained from ap-pendix IX or the appropriate technicalmanual.
(3) A risk class number is a number which per-tains only to standard prefabricated fixedor floating bridges and is obtained fromclassification data given in appendix IX andappropriate technical manuals.
e. Computation of bridge class numbers is de-scribed in appendixes VII, VIII, and TM 5-260.For each standard class, both a bending momentclass curve and a shear class curve have been drawn.All bending moments have been computed in mil-lions of inch-pounds. The curves were determinedhy plotting the maximum bending moment and themaximum shear force, induced in simple spans, bythe hypothetical vehicles, representative of actualmilitary vehicles of the United States and NATOnations, against the span length in feet. In com-puting the bending moment curves and the shearclass curves, no allowance was made for impact, andit was assumed that all vehicles would maintain thenormal convoy distance of thirty yards from therear of one vehicle to the front of the followingvehicle.
f. Assumptions made in calculating bridge classnumbers include working stresses for timber, steel,and concrete; impact; and widths of roadway betweencurbs.
56
(1) The working stresses are shown in para-graphs 164, 180c, and 189, FM 5-35.
(2) The lateral distribution factor of 1.5 is takenfrom paragraph 156a, FM 5-35.
(3) The allowance for impact is 15 percent ofthe live load stresses for steel superstruc-tures. No allowance is made for impact intimber structures (par. 159, FM 5-35).
(4) Computations and classifications are basedon minimum widths of roadway betweencurbs, as given in table VII. Single-lanebridges with less roadway width than thatgiven in the table must be posted with ap-propriate warning signs (par. 21b(2)), butdo not require reduction in bridge class.The multilane class number will be re-duced when the lane width required is notavailable.
Table VII. Minimum Widths of Bridges Used in BridgeClass Computations
Minimum width between curbsBridge class range
One lane (ft) Two lane (ft)
4-30-- - - - - - 11 1831-60 -------------------- 13 . 2461-100 -------------------- 15 27
(5) The minimum vertical clearance above thebridge deck is 14 feet for bridges of class 70and below, and 15 feet 6 inches for bridgesabove class 70. Less headroom does not
57
require reduction of bridge class, but doesrequire marking with telltales, as describedin paragraph 21b(2) (b).
(6) Bridges with spans of less than 25 feet,require special attention during classifica-tion if the computed class, due to shear, ishigher than the computed class due tobending moment (TM 5-260).
g. Masonry, brick, and concrete arch bridgeclassifications are determined in accordance with theprocedures given in appendix VII and TM 5-260.
h. Foreign civilian and foreign military bridgesrequire classification in accordance with the proce-dures given in TM 5-260.
20. Responsibility for Bridge Classificationa. Standard equipment bridges, intended for
vehicular use, are classified by the Chief of Engineers.b. Classes of standard equipment bridges for
normal, caution, and risk crossings are given inappendix IX and appropriate technical manuals.
c. A bridge designed in the field is classified by theengineer unit which designed it.
d. Existing domestic bridges, foreign civilianbridges, and foreign military bridges are classified bythe engineer unit supporting the units using thebridges.
21. Bridge Markinga. Purpose. Bridge marking provides a con-
venient means for indicating the bridge class and forgiving other limiting information about the bridge todrivers and others (fig. 15).
58
FLOATING B
2 For floating bridge
I I -
0 0
1 For single lane fixed bridge2 For floating bridge3 Indicating the limiting vehicle classes of a two lane
bridge when used as a two lane bridge or as a singlelane bridge
Figure 15. Typical bridge class and information signs.
b. Types. The two general types of bridge signsare circular signs and rectangular signs.
(1) Circular signs. The bridge classification isinscribed on circular signs. Such signs are
59
placed at all bridges to indicate the bridgeclassification. These signs have a yellowbackground with a 1s-inch black border,and the bridge classification and appro-priate symbols are inscribed thereon inblack. The legend should be as large asthe diameter of.the sign permits. Circularbridge signs with a single class number (fig.15 (O and O) have a minimum diameter of16 inches, and those with dual class numbers(fig. 15 ()) have a minimum diameter of 20inches. The bridge class number may beeither a single lane, multilane, dual class ormultilane dual class number or combinationof numbers. Bridges which do not requirea dual classification are marked with signsas shown in figure 15 O and ®. A multi-lane single class bridge sign has the normalclass number for two lane traffic on the left,and has on the right the computed classnumber for one-way traffic centered overtwo lanes (fig. 15 (). A typical dual classsign is shown in figure 16 (. Figure 16 )illustrates the combination of dual class andtwo-way bridge class signs. In this applica-tion the wheeled vehicle sign will be placedabove or to the left of the tracked vehiclesign. A multilane bridge having lanes ofdifferent classes will be posted with aseparate class sign for each lane (fig. 17).
(2) Rectangular signs. Additional instructionsand technical information are inscribed onrectangular signs. Such signs are placed
60
~ 80
~6
1 Indicating the limiting wheeled vehicle class and thelimiting tracked vehicle class
2 Indicating combination of dual class and two-way bridgeclass signs
Figure 16. Typical dual class bridge signs.
at all bridges where additional restrictionsand certain technical information are needed.Their size is a minimum of 16 inches inheight or width, but at least as wide as thecircular bridge sign with which they areassociated. They have a yellow back-
61
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ii
6 2
62
ground with a 1 h-inch black border. Theappropriate inscription on the sign shouldbe as large as the dimensions of the signpermit, but the letters of the inscriptionmust be at least 4 inches high. Separaterectangular signs are used to give certaintechnical information, except where existingcivilian bridge signs are sufficiently clear.The rectangular signs include the followingdata:
(a) Width limitations for abnormally narrowbridges. The inscription on the rectan-gular sign consists of two horiozntalarrows with the limiting width given infeet.
(b) Height limitation for every bridge whichhas overhead bracing, trolley wires, orother features which limit the vehicleclearance to less than 14 feet for bridgesof class 70 and below, and 15 feet 6inches for bridges above class 70. Theinscription on the rectangular sign con-sists of two vertical arrows with thelimiting height given in feet. In addi-tion, a telltale, usually a piece of timbersuspended above the roadway at aheight of 3 inches less than that of thebridge, is provided on the approach road,well in advance of the bridge (fig. 18).Vehicles which touch the telltale arediverted before reaching the bridge.
c. Location. Bridge signs are positioned so as tofacilitate maintaining an uninterrupted flow of
63
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traffic over the bridge. The locations of circularand rectangular bridge signs and appropriate warningsigns are as follows:
(1) Bridge classification (circular) signs (fig.15 ()) are placed at both ends of eachbridge in such a position as to be clearlyvisible to the drivers of all oncoming traffic.
(2) Bridge information (rectangular) signs areplaced immediately below the bridge classi-fication (circular) signs (fig. 15 ().
(3) Bridge guide signs, such as the ones infigure 11, are placed at approaches to thebridge and at appropriate distances fromthe bridge, as required.
d. Examples. Example of bridge marking andguide signs are given in illustrations as follows:
(1) Typical bridge class and information signsare shown in figure 15.
(2) Typical dual class bridge sign for thelimiting wheeled vehicle class and for thelimiting tracked vehicle class is shown infigure 16 0.
(3) Typical dual class bridge signs indicatingcombination of dual class and two-waybridge class signs are shown in figure 16 ).
(4) Typical use of single lane bridge class andinformation signs and road guide signs isillustrated in figure 18.
(5) Typical use of two lane bridge class andinformation signs and road guide signs isillustrated in figure 19.
(6) Typical bridge class and road regulatorysigns for multilane bridges are illustrated infigure 17.
332944 0-55 5 65
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66 ~i
22. TunnelsA tunnel is an underground passageway which is
approximately horizontal and is open at both ends,providing for a road, a railroad, or a canal. Thediscussion of tunnels in this paragraph is confined totheir reconnaissance and marking.
a. Tunnel Reconnaissance.(1) The purpose of tunnel reconnaissance is to
determine the limiting features of a tunnelused as a portion of a route and sometimesused for storage purposes.
(2) Information to be obtained by tunnel recon-naissance is detailed. It includes theapproaches, the identification of the tunnelby its map location, its name, the name ofthe terrain feature it passes, its location byhighway name and number or by railroadline, and other distinguishing features. Itincludes also a description of the tunnel bytype of cross section of its bores, the borelining, the portals, the kind of earth or rockthrough which it passes, its principal andalso its limiting dimensions, and the clear-ance. It finally includes a description of itsphysical condition, and repairs if any neededfor its effective use.
b. Tunnel Reconnaissance Report. DA Form 1250(fig. 20) Tunnel Reconnaissance Report is usedto report tunnel information. The instructions formaking the reconnaissance should indicate theamount of detail required so as to guide thereconnaissance party. Short forms or work sheetsfor rapid field work may be designed and produced
67
TUNNEL RECONNAISSANCE REPORT | Aug, 54
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6868
· X F S ^.L .ZSCUAE . .F m F m m _ ri CTU^ I
2 Back of form
Figure 0--Continued.
69
by the units making the reconnaissance. Unlessotherwise directed, data are entered on the tunnelreconnaissance form as follows:
(1) Identification (items 1-11). Enter all infor-mation which establishes positive identifica-tion of the tunnel by route number, routelocation, map series and sheet numbers, gridreference, tunnel number, type of tunnel,and geographic reference name.
(2) Dimensions (items 12-17). Enter overalltunnel dimensions as indicated in figure21. Design characteristics and guides formeasuring tunnel dimensions are given inappendix VI.
(3) Specifications (items 18-21). Enter the typeof lining material, type of portal material,type of ventilation, and drainage means.
(4) Special considerations (items 22-29). Enterhere whether the tunnel is chambered fordemolition, the date of completion of thetunnel, and its present condition. Enteralso bypassability; opportunities for alter-nate crossing; the gradient and passabilityof the approaches; in-tunnel restrictions;and any geologic data pertinent to mainte-nance, improvement, or safety.
(5) Sketches (items 30-32). Draw a plan andprofile, a portal view, and a cross section ofthe bore.
(a) The plan includes geographic positioningof the tunnel, approach and departureroutes, and terrain features in the imme-diate area of the tunnel with emphasis on
70
special features which may affect alter-nate crossings. Tunnel alinement mustbe shown, including straight sections,angles, and curves. The profile showsthe gradient to and from the tunnel, thegradient of the tunnel floor (designatingany change in grade), and the relation ofthe tunnel to the terrain through whichit passes.
(b) The portal view shows the mouth of thetunnel, the material of which it is con-structed, and its position in relation tothe surrounding terrain. It further showsa limited section of the approachingroute.
(c) The cross section of the tunnel lJore showsdetailed information regarding the allow-able traffic width, the shape of the boreas it may affect load heights and widths,and possible manmade or natural obstruc-tions.
(6) Remarks (item 33). Include here any perti-nent information not covered above andattach photograph.
c. Tunnel Marking. Marking of tunnels is donein accordance with the appropriate and applicableinstructions for marking bridges as given in para-graph 21.
23. Causeways, Snowsheds, and GalleriesCauseways, snowsheds, and galleries are not
usually encountered as often in route reconnaissanceas other crossing means discussed in this section.
71
a~ -""'"1~
|I \ / PLAN
PROFILE 66
a4
Figure 21. Standard dimensional data for tunnels.
72
EXPLANATION SHEET
I - Portal-to-portal length of tunnel.
la - Centerline distance of tunnel.
2 - Effective width of the roadway, curb-to-curb.
3 - Horizontal clearance, being the minimum width of the
tunnel bore measured at least four feet above the
roadway.
4 - Vertical clearance, being the distance between the
top of the roadway and the lower edge of the tunnel
ceiling or any obstruction below the ceiling, such as
trolley wires or electric light wires.
4a - Rise of tunnel arch (radius of curved portion)
5 - Radius of curvature of the roadway
either measured or estimated.
6 - Gradient, being the percentage of rise
of the roadway between portals.
6a - Change in gradient within the tunnel (percentage of
rise each way from break of grade).
Figure 21 -Continued.
73
When such structures constitute an obstruction tothe movement of traffic along the route, a reconnais-sance report is made. Data required for such areport is limited to clearances and load-carryingcapacity. The data are supported by photographsor a sketch of each structure. Sufficient descriptiveinformation is also included in the reconnaissancereport, if accomplished, to permit an evaluation ofthe structures in respect to their strengthing orremoval.
a. A causeway is a raised way across wet orunstable ground. When a causeway is consideredan obstruction, reconnaissance is reported as outlinedabove.
b. A snowshed is a shelter to protect from snow,as a long structure over an exposed part of a roador railroad. A reconnaissance report, when necessary,is completed as detailed above.
c. A gallery is any sunk or cut passageway coveredoverhead as well as at the sides. A gallery may, insome cases, constitute an obstruction to the move-ment of traffic along the route; and, if so, a recon-naissance report should be made as specified above.However, in the combat area, a gallery may becomeimportant not because it is an obstruction but forthe additional protection it may afford.
24. FordsA ford is a shallow place in a stream where the
bottom permits the passage of personnel and vehicles.a. Ford Reconnaissance.
(1) Traficability. Fords are classified accordingto their passability for foot traffic (pedes-
74
trians), wheeled vehicles (trucks), andtracked vehicles (tanks). Their traffic-ability is established from the data givenin table VIII.
Table VIII. Trafficability of Fords
Fordable Minimum MaximumType of traffic depth width Type bottom allowable
(feet) (feet) spproaes
3- (single file) Firm enough toFoot ..-..... ..... 33j -..... 7- (column of prevent sink- 1:1
3's). ing.
Trucks ......-... 2-....... 12 ... |........ 3:1
Light tank ...- i..... 1 to 3.... 14 ...--- 2:1_- Firm and
Medium tanks .-... 2 to 4 ..-- 14 ...-...... smooth. 2'1
Heavy tanks.....-.. 4 to 6 .. 14 ........ 2 1
*Basedonharddrysurface. Ifwetandslippery, slope must be less.
(2) Approaches. Approaches may be pavedwith concrete or a bituminous surface mate-rial but are usually unimproved, consistingof sand and gravel. The composition andthe slope of the approaches to a ford shouldbe carefully noted to permit a determina-tion of its trafficability in bad weather.
(3) Stream bottom. The composition of thestream bottom of a ford determines itspassability. It is important, therefore, toindicate if it is composed of sand, gravel,silt, clay, rock, or other material.
(4) Ford bottom. In some cases, the naturalriver bottom at a ford has been paved to
75
2b HIGH WATR MAiRK
NORMALWATER LEVEL- | --
=PPROACH ELEVATION5b=APPROACH DISTANCE5 ==SLOPE OF APPROACH (I:5 )
Figure 22. Standard dimensional data for fords.
improve its load-bearing capacity, and toreduce the depth of the water. Improvedfords may have gravel or concrete floors,layers of sand bags, steel mats, or woodenplanking.
(5) Climatic conditions. Seasonal floods, ex-cessive dry seasons, freezing, and othersuch extreme weather conditions materiallyaffect the fordability of a stream. For thisreason the effect of climatic conditions on aford should be recorded.
(6) Current. The swiftness of the current andthe presence of debris are recorded in order
76
EXPLANATION SHEET
I - The width of stream bed from bank to bank.
2 - The actual width of the water measured at normal stage. In
addition, maximum width (2a) and minimum width (2b) are
estimated, based on local observations or records of high
water and low water, and then recorded.
3 - The actual depth of the stream at normal water level.
3a - Estimated maximum water depth based on local observations
or records.
3b - Estimated minimum water depth based on local observations
or records.
4 - The width of the approach. It is the effective width of the
traveled way of the roads leading to the ford.
5 - The slope of the approaches. It is the shape of the stream
banks throu:gh which the approach roads are cut. This is
expressed as the ratio between elevation (Sa) and distance
(Sb). For example, a slope of 1:1 means that the approach
road drops one foot for every foot of length.
Figure 22-Continued.
to determine their effect on the conditionand passability of the ford. The speed ofthe current is estimated as swift, moderate,or slow.
(7) Dimensions. The standard dimensionaldata used in describing fords are illustratedin figure 22.
77
1 Typical fordFigure 23. Ford crossing
(8) Photographs. Whenever a ford is recon-noitered, it is photographed. Photographsshould show the banks, the approaches,and the stream, in one view. The photo-graph should be taken while a vehicle,preferably a military vehicle, is crossing, togive an indication of water depth and thelocation of the ford (fig. 23).
b. Ford Reconnaissance Report DA Form 1251.A report of each ford reconnaissance will be made onDA Form 1251, (fig. 24). Short forms or worksheets for rapid field work may be designed andproduced by the unit making the reconnaissance.
78
2 Typical reconnaissance photograph of a ford
Figure 23--Continued.
Details to be entered on the Ford ReconnaissanceReport form follow:
(1) Identification kitems 1-10). Enter all datawhich will establish positive identificationof the ford as to route, map sheet, gridreference, ford number, geographic loca-tion, and name of stream or crossing.
(2) Characteristics of crossing (item 11). Recordthe width and depth of the crossing and the
79
velocity of the stream at present water leveland at low, mean, and high level. Alsogive date, season, or month(s) for each ofthese. Figure 22 indicates the dimensionsto be recorded at each water level.
(3) Description (items 12-17). Record the com-position of the stream bottom, compositionand slope ratio of approaches, type of pave-ment (if any) of approaches and ford, us-able width of approaches and ford, andany hazards, such as flash floods or quick-sand, which would affect the trafficabilityof the ford. Figure 22 illustrates themethod of computing slope ratio of ap-proaches.
(4) Remarks (item 18). Enter here any otherpertinent data not recorded elsewhere onthe report. This should include descrip-tion of approach roads, guide markers,depth gages, and any other informationwhich may assist in the trafficability classi-fication of the ford.
(5) Sketches (items 19 and 20). Draw militarysketches of the ford, showing both a profileand a site plan.
(a) The profile sketch indicates the waterlevel and the elevation of the stream bot-tom and approaches.
(b) The site plan gives the alinement of theford and its approaches, with appropriatedimensions. Terrain and other site fea-tures in the immediate area of both banksshould be shown. Also indicate the
so
north arrow and the direction of flow ofthe stream.
(6) Remarks (%tem 21). Attach photographs,as specified in a(8) above, to the FordReconnaissance Report.
c. Ford Marking. Marking of fords is done inaccordance with the appropriate and applicableinstructions for marking bridges as given in para-graph 21. In addition, the width of the ford ismarked by suitable posts erected on the shores athigh water level on both sides of the stream. Max-imum depth of the ford should also be posted on bothshores. Warning signs are erected on both shoresto remind drivers that the brakes of vehicles driventhrough the ford are wet and must be appropriatelydried.
25. Crossings on Icea. Conditions Governing Crossings on Ice. Cross-
ing a stream on ice depends on settled weather andabsence of enemy opposition. Sudden rises in tem-perature may weaken the ice. Enemy artillery fireor bombing may break the ice. However, underfavorable conditions, crossing streams on ice ispracticable, and can be successful for large bodies oftroops and for heavy equipment.
b. Load-Carrying Capacity of Ice. The load-carry-ing capacity, or bearing power, of ice varies with itsthickness and its condition. Clear, newly frozenice is stronger than old, porous ice. Ice coatingsare stronger when the ice is in intimate contact withthe water underneath. Warm weather quickly re-duces the carrying capacity of an ice layer, even
332944 0-55 6 81
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Figure 24--Continued.
83
though the thickness remains the same. The warmweather makes the ice layer porous and lowers itsbearing capacity. Estimates of the loads which canbe supported by undamaged ice layers in direct con-tact with the water beneath are presented in table IX.
Table IX. Estimated Load-Carrying Capacity of Ice Layersin Direct Contact With Water Beneath
Thickness of Estimated load-carrying capacityice layer (in.)
1l -. ....... Individual soldiers.2 --------- Infantry in open order.6- ------- Infantry in march column with light motor
transport.8 --------- 4-ton wheeled vehicles.
Maximum axle load-7 tons.Minimum distance between vehicles-65 feet.
12 -------- 10-ton wheeled vehicles.Maximum axle load-7 tons.Minimum distance between vehicles-65 feet.
14 -------- 20-ton wheeled vehicles.Minimum distance between vehicles-65 feet.
26. Ferries
a. General. A ferry site is a place or passage wheretraffic and cargo are conveyed across a river or otherwater obstacle by a water vehicle which is called aferry or ferryboat. Ferries encountered in routereconnaissance may vary widely in physical appear-ance and capacity, depending upon the width, depth,and current of the stream or body of water, and thecharacter of the traffic to be moved. Propulsion offerries may be by oars, by poles, or by steam, gaso-
84
line, or diesel engines. They may also be propelledby a cable stretched across the stream or body ofwater, by hand, or by power-operated winches. Atrail ferry consists of a cable stretched across thestream and properly anchored on each bank. Theassembly includes necessary hauling and maneuveringlines. The raft or rafts to be ferried are attached tothe ferry cable, usually by a bicycle traveler, for easeand safety of movement. The method of construc-tion and operation of a trail ferry is illustrated infigure 25. Construction of ferryboats varies throughwide limits. They may be made of wood or metal,and range from expedient rafts to ocean-going vessels.A flying ferry is a current-operated ferry held in thestream by an anchor well upstream from the crossingsite; as the ferry moves from shore to shore it de-scribes an arc of a circle, the center of which is theanchor.
b. Ferry Reconnaissance.(1) The capacity of a ferryboat is given in tons
and in the total number of passengers andvehicles it can safely transport. Whenmore than one ferryboat is employed for agiven route, the capacity of each is givenindividually.
(2) Climatic conditions, from season to season,have a marked effect on ferry operations.Fog and ice substantially reduce the totaltraffic-moving capacity of the ferry route.Therefore, data on tide fluctuations, freez-ing periods, floods, excessive dry spells, andtheir effects on ferry operation are ascer-tained and recorded.
85
TO DEADMEN
FERRY CABLE TRAVELER
SNATCH BLOCK
MANEUVER LINES \ HAULING LINE34 -IN.ROPE (I-IN.ROPE)
CURRENT
\ HAULING LINEATTACGHED TO
MANEUVER LINESATTACHED TOTREADWAYSPACING-HOOK
OUTBOARDMOTORS
Figure 25. Trail ferry.
(3) Ferry slips, or piers, are provided at landingplaces on the shore to permit easy loadingof passengers, cargo, and vehicles. Theslips may vary from simple log or plankpiers on wooden piles or trestle bents toelaborate terminal buildings, constructed ofconcrete or masonry and containing facilities
86
such as ticket offices, waiting rooms, andcargo and freight-handling equipment. Thedistinguishing characteristic of a ferry slipis the floating pier which can be quicklyadjusted to the height of the ferryboat deckabove the stream surface. This permitsprompt loading and unloading of the ferry-boat. The load-carrying capacity of theferry slip determines the maximum weightof individual loads that can be moved acrossit and onto the ferry boat.
(4) Approach roads to ferry slips have an im-portant bearing on the use of the ferryroute. Therefore, the carrying capacityand condition of the approach roads mustbe ascertained and recorded.
(5) Dimensions of certain limiting features offerries are necessary for adequate recon-naissance.
(a) Width of the stream or body of waterfrom bank to bank at normal water level,is ascertained and recorded. In caseswhere the ferryboat does not cross at thenarrowest point, the distance in milestraveled by the ferryboat from the ferryslip on one side to the ferry slip on theother side is ascertained and recorded.
(b) Depth of the stream at estimated normalwater level at each ferry slip is ascertainedand recorded.
(c) Width of traveled way of approach roadsis measured and recorded.
(6) Photographs are taken of all ferries recon-
87
noitered. These photographs should in-clude the ferry site, the ferry slips, the ferry-boats, and the approach roads. If theferryboats are not self-propelled, the photo-graphs should include auxiliary equipmentsuch as cables, towers, and winches. Ifphotographic equipment is not available,sketches showing the same items are made.
c. Ferry Reconnaissance Report DA Form 1252.For each ferry reconnoitered a DA Form 1252 iscompleted (fig. 26). Short forms or work sheets forrapid field work may be designed and produced bythe unit making the reconnaissance. Details to beentered on DA Form 1252 follow:
(1) Identification (items 1-11). Enter all infor-mation which establishes positive identi-fication of the ferry by route, map sheet,grid reference, ferry number, class, geo-graphic location, and the name of the streamor body of water the ferry crosses.
(2) Limiting features (item 12). Enter any lim-iting features which would affect ferryoperations, such as condition of vessels,terminals, floods, low water, freezing andtides. Also give seasons and dates for anysuch limiting climatic conditions.
(3) Description (items 13-15). Record the depthof the stream or body of water at low, mean,and high water levels; the crossing time;and the length of the course.
(4) Vessel features (item 16). Record the per-tinent design features of the vessel(s) used.This information includes the number and
88
construction type of units, the method andpower of propulsion, length, beam, draft,gross net tonnage, and capacity.
(5) Terminal features (item 17). Designate thegeographic direction of the banks by cir-cling the appropriate letters (NESWN).Enter the name, the dimensions of the slips,and specific docking facilities. For highwayapproaches, note the type of surface, thenumber of lanes leading into the slip, andthe class. Enter any additional pertinentinformation in item 18. For railroad ap-proaches, give the number of tracks ap-proaching the slip and the number of sidings.Facilities for transferring freight and de-tailed information, in exceptional caseswhere railroad cars are loaded directly onthe ferry, should be given in item 18.
(6) Remarks (item 18). Use this space to am-plify details given in paragraphs above.Note obstructions, navigational aids, andany other pertinent data not recorded else-where. Where special facilities are avail-able, it is important to emphasize theirpresence for use in logistical planning.
(7) Sketches (items 19 and 20). Draw a sketchshowing the route alinement plan and twosketches showing terminal views on bothsides of the crossing.
(a) The route alinement plan indicates thegeographical course of the ferry, terminalsand approaches to the slips. Particularcare is taken in recording obstructions.
89
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Figure 26. Ferry Reconnaissance Report form.
90
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Figure 6--Continued.
91
Navigational aids such as buoys andlights are shown. The position of thehighway or rail approaches, includingsurrounding terrain features, should beincluded in this sketch.
(b) Two separate sketches are made showingeach terminal. These sketches show thegeographical position of each bank andinclude details of the slips, ramps, andbumper piles.
(8) Remarks (item 21). In addition to photo-graphs of vessels called for in item 16 ofthis form, any other photographs whichillustrate details given in the report shouldbe attached.
d. Ferry Marking. Marking for ferries is doneaccording to the appropriate and applicable instruc-tions for marking bridges, as given in paragraph 21.Stop, warning, regulatory, and guide signs, as appro-priate and applicable, are posted on approach roadsand at ferry slips.
27. Bypass InformationA bypass, for the purpose of route reconnaissance
information, is a local detour required to circumventan obstruction to military traffic along the normalcourse of a route. Bypasses are classified as: bypasseasy, bypass difficult, and bypass impossible.
a. Bypass Easy. The bypass easy classification(indicated by BPE) requires consideration of threedistinct types of conditions:
(1) A normal bypass is considered in existenceif a detour can be made by all types ofvehicles in less than 15 minutes at an aver-
92
age rate of speed, utilizing any of the follow-ing means:
(a) Alternate route including alternate bridge.(b) Offroad movement including alternate
bridge.(c) Alternate roads and ford or ferry.(d) Offroad movement and ford or ferry.
(2) An emergency bypass assumes alternatebridges have been destroyed and alternateroads are not usable. Therefore an emer-gency or combat bypass is considered toexist if a detour can be made in the immedi-ate vicinity by all types of vehicles, utilizingany of the following means:
(a) Existing tracks or trails and ford.(b) Offroad movement and ford.(c) Offroad movement and dry crossing.
(3) A readily constructed bypass is said to existwhenever it is possible to construct a bypassor local detour in four hours or less, using oneengineer platoon and its organic equipment.
b. Bypass Difficult. The bypass difficult classi-fication (indicated by BPD) is used when construc-tion of a bypass or local detour will take more thanfour hours, using one engineer platoon and its organicequipment. If it is determined that the constructionof a bypass will be difficult, reconnaissance partiesdetermine the necessary requirements to bypass theobstruction.
c. Bypass Impossible. The bypass impossibleclassification (indicated by BPI) is used when anyone of the following conditions prevails:
(1) Terrain absolutely prohibits offroad move-ment.
93
(2) Width and depth of the stream to be spannedabsolutely prohibits fording or the con-struction of temporary crossing means.
(3) Depth or slope of the gorge or chasm abso-lutely prohibits construction of temporaryapproaches to the crossing site.
(4) No alternate road or railroad bridge existswithin a reasonable distance.
d. Limiting Bypass Factors. Limiting bypassfactors must be considered. These include:
(1) Condition of the terrain.(2) Ability of bypass, without improvement, to
sustain heavily loaded military vehiclesover a considerable length of time.
(3) Ability of bypass to sustain only a fewvehicles, before becoming impassable.
(4) Effects of climatic or seasonal changes (rain,freezing, snow, etc.) on cross-country move-ment.
28. Administrative Proceduresa. Design and specifications for materials of signs
for bridges and other crossing means are responsi-bilities of the Chief of Engineers. The supply ofsigns for marking bridges and other crossing means isan engineer responsibility. Posting signs, regardinglocation and the number to be used, for bridges andother crossing means is an engineer responsibilitycoordinated with the appropriate provost marshaland the highway traffic regulation officer of theTransportation Corps. Operational responsibilityfor the marking of bridges and other crossing meansis a command function.
94
29. Traffic Control Over Bridges and Other CrossingMeans
Traffic control over bridges and other crossingmeans is needed to prevent failure of bridges andferries and the blocking of tunnels, fords, causeways,snowsheds, and galleries.
a. Traffic Control Responsibility.(1) Engineer responsibility for traffic control
over bridges and other crossing means islimited to the supply and posting ofappropriate markings after the completionof the necessary reconnaissance and theresulting evaluations.
(2) Provost marshal responsibility for trafficcontrol over bridges and other crossingmeans includes the following:
(a) Establishment of traffic control policies.(b) Performance of traffic control reconnais-
sance.(c) Establishment of traffic control posts.(d) Operation of traffic control posts.(e) Enforcement of traffic regulations.(f) Local rerouting in emergencies.
(3) Military police responsibility for trafficcontrol over bridges and other crossingmeans includes the following:
(a) Enforcing traffic regulations.(b) Enforcing speed regulations.(c) Enforcing vehicle interval limits.(d) Enforcing crossing limitations such as
weight of vehicles, lanes to be used,priority on crossing single lane bridges,priority on crossing two lane bridges
95
when a single lane crossing is required byvehicle weight.
(e) Supervising special crossings described inb below.
b. Special Crossings. Special crossings are classi-fied as controlled crossings, caution crossings, andrisk crossings. A special crossing may be authorizedunder exceptional operating conditions in the field bythe theater commander or local civil authorities topermit a vehicle to cross a bridge or other crossingmeans whose class number is less than that of thevehicle.
(1) A controlled crossing is a crossing over amultilane bridge in which the vehicle classifi-cation number is not more than 50 percentgreater than the bridge classification num-ber for one lane and where the vehicle mustbe centered over two or more lanes carryingone-way traffic. When the bridge classnumber is not the same for all lanes so used,the lane with the lowest bridge class numberdetermines the controlled rating. The sub-ject of a controlled class number is discussedin paragraph 19d(1).
(2) A caution crossing is a bridge crossing wherevehicles with a classification up to 25percent above the posted bridge loadingare allowed to proceed cautiously acrossthe span. A caution class number is thenumber obtained by multiplying the normalcrossing class number of either a single laneor multilane nonstandard bridge by 1.25.For standard prefabricated bridges, the
96
vehicle class number must not exceed thepublished caution bridge class number.The caution class number is obtained fromappendix IX or the appropriate technicalmanual. Caution crossings apply to singlelane bridges and to multilane bridges whenthe vehicle remains on the centerline of thebridge, maintains a 50-yard distance fromthe vehicle in front, does not exceed a speedlimit of 8 miles per hour, does not stop, isnot accelerated, and does not have its gearsshifted on the bridge or other similarcrossing means.
(3) A risk crossing may be made only on pre-fabricated fixed and floating bridges. Riskcrossings may be made only in the gravestemergencies where excessive losses willotherwise result and where the vehicle re-mains on the centerline of the bridge, doesnot exceed a speed limit of 3 miles per hour,is the only vehicle on the span, does notstop, is not accelerated, and does not haveits gears shifted. Tanks, on risk crossings,must be steered by using their clutches only.Risk crossings, under these conditions, arepermitted only if the vehicle class numberdoes not exceed the published risk class.The subject of a risk class number is dis-cussed in paragraph 19d(3).
c. Examples of Special Crossings.(1) A tracked vehicle with classification 73 ap-
proaches the bridge shown in figure 16,which has a tracked vehicle classification of
33R2944 0--55--7,' 97
60. The vehicle is allowed to cross, usingthe bridge as a single lane bridge, being cen-tered on the two lanes.
(2) A tracked vehicle with classification 73 ap-,proaches an aluminum deck-balk fixedbridge, components of which are found inthe M4 floating bridge sets and in the air-borne 50-ton divisional floating bridge sets.The overall span of the bridge is 30 feet.The normal crossing classification is 60.The caution crossing classification is 80.Therefore, the vehicle is allowed to cross;but it must remain on the centerline of thebridge, must not exceed a speed limit of 8miles per hour, must not be stopped or ac-celerated, and must not have its gearsshifted while on the bridge.
(3) A tracked vehicle with classification 73 ap-proaches a bridge with classification 50. Itis allowed to cross, using the bridge as asingle lane bridge under the conditions of29b(1) above.
(4) A tracked vehicle with classification 73 ap-proaches an 80-foot span panel bridge,Bailey type, M2 with 150-inch roadway.The risk crossing classification of this bridgeis 75. The vehicle may be allowed to crossthis bridge in a grave emergency if the ve-hicle remains on the centerline of thebridge, does not exceed a speed of 3 milesper hour, is the only vehicle on the span, isnot stopped or accelerated, does not haveits gears shifted while on the bridge, and issteered by the use of its clutches.
98
SECTION V
VEHICLE CLASSIFICATION
30. Generala. The basis of the vehicle classification system is
the effect a vehicle has on a bridge while crossing thebridge. The effect is the result of a combinationof factors which includes the gross weight of thevehicle, the distribution of this weight, the speed atwhich the vehicle crosses the bridge, and the re-sulting impact on the bridge. The excessive loadscommon to military vehicles, such as heavy artil-lery, tanks, and heavy engineer equipment, makevehicle classification an extremely important factorin determining the suitability of a given route.These critical loads are applicable not only to indi-vidual wheeled vehicles, but involve also considera-tion of track-laying vehicles, towed vehicles, andvehicles being moved by transporter. In order tocompute the total classification of some of these com-binations, each separate vehicle must be evaluated.
b. Classification numbers assigned to vehicles arewhole numbers ranging from 4 to, and including, 150.These classification numbers have been developedfrom studies of hypothetical vehicles having charac-teristics approximately the same as those of actualUnited States and NATO nations military vehicles.
c. Narrow vehicles having an outside-to-outside
99
tire width, or track width, narrower than that ofthe hypothetical vehicles of the classes which wouldotherwise apply are given a higher vehicle classifi-cation.
d. Unloaded vehicles are sometimes given tempo-rary classification numbers. Unloaded combinationvehicles, where the payload is a substantial amountof the vehicle weight, may also be given a temporaryclassification number.
31. Vehicles Which are Classifieda. Standard military vehicles include all items of
equipment which habitually move on land and whichare mounted on wheels, tracks, or combinations ofwheels and tracks. Therefore, military vehicles arefurther described as wheeled, tracked, or halftracked.For classification purposes, military vehicles aredivided into two categories: single vehicles andcombination vehicles.
(1) A single vehicle is any military vehiclewhich has only one frame or one chassis.Examples include prime movers, tanks,halftracks, full trailers, and gun carriages.
(2) A combination vehicle is a military vehicleconsisting of two or more single vehicles,space less mtlan 30 yards apart, whichmove as one unit. Examples include primemovers pulling semitrailers supported onthe "fifth wheel" of the prime mover,prime movers or trucks towing full trailers,gun carriages, and tongue or pole trailers;or any single vehicle towing any othersingle vehicle at a distance of less than 30yards apart.
100
b. Classification numbers are assigned to all singlevehicles in military use which have a gross weightexceeding 3 tons, and to all trailers in military usewhich have a rated payload exceeding 1Y tons.
(1) Separatclassification numbers aUassignedto each' ngle vehicle wfi one towsanother, unlesS the dist ce between themis less than 30 r and both are on onebridge span at e neame time. In such acase the fe classe as a combinationvehiclj and the class of Th combination isthsum of the classificatio numbers of
e two vehicles. t / d W S 5a.(2) Temporary classification numbers may be
assigned under special conditions.(a) When two single vehicles, one towing the
other, are classed as a combinationvehicle ( (1) above), a temporary classifi-cation sign is then carried by the leadingvehicle.
(b) When cargo vehicles used exclusively onhighways are permitted increased pay-loads (TM 9-2800-1), the commanderauthorizing the increased loads is re-sponsible for replacing the vehicle classi-fication signs with temporary vehicleclassification signs which increase theclassification number by the amount ofthe authorized overload in tons. Forexample, a 252-ton truck with classifica-tion number 8, carrying an authorizedon-highway load of 4Xh tons, has a 2-tonoverload and is therefore given a tempo-rary classification number 10.
101
(c) Unloaded single vehicles may be given atemporary classification number. It iscomputed by subtracting the rated pay-load in tons from the normal classifica-tion number. For example, a 6-tontruck with classification number 16 isgiven a temporary' classification number10 when unloaded.
(d) Combination vehicles, where the payloadis a substantial part of the gross weight,are assigned unloaded classification num-bers (Table X). The unloaded classifi-cation number is shown on a detachableclassification sign (par. 33b(1)) when thecombination is unloaded.
(3) Optional classification numbers may be as-signed to baggage and other pole typetrailers with a rated payload capacity of1 Y tons or less, although the gross weightsof such trailers are usually combined withtheir respective towing units for vehicleclassification purposes.
32. Data Required For Vehicle Classification
a. The single vehicle dimensional data required forvehicle classification are indicated in figure 27 ().Dimensional data required for both single wheeledvehicles and single tracked vehicles are shown.
b. The trailer dimensional data required for vehicleclassification are indicated in figure 27 (®). Onlywheeled trailers are shown.
102
33. Marking of Vehiclesa. The purpose of marking vehicles is to afford
immediate recognition of the classification of eachvehicle in order to aid in traffic control at bridgesand other crossing means (par. 29).
b. Marking of vehicles is accomplished by trontvehicle classification signs and by side vehicle classi-fication signs (fig. 28). These signs have a yellowbackground with black numerals.
(1) Front vehicle classification signs are cir-cular and are 9 inches in diameter (fig.29 (). The numerals are as large as thediameter of the sign will permit. The frontvehicle signs are placed above the vehiclebumper to the driver's right and below hisline of vision. Heavy, cargo carryingvehicles, having a standard vehicle classifi-cation number larger than 30, carry also areadily detachable front vehicle classifica-tion sign inscribed with the unloaded classi-fication number of the vehicle. Frontvehicle classification signs are placed oneach single vehicle with a gross weight ex-ceeding 3 tons. Front vehicle -classifica-tion signs of combination vehicles aremarked with the letter C, in red, above theclassification number. When it is not pos-sible to determine the classification numberof a combination vehicle from the tables orby computation, a safe field method ofclassifying the combination is to add theclass numbers of the towing and the towedvehicles. The sum is the temporary classi-
103
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CLASS NUMBER (BLACK) YELLOW BACKGROUND
Figure 28 Typical vehicle classification sign.
fication number of the combination and isto be placed on the front sign.
(2) Side vehicle classification signs are circularand are 6 inches in diameter (fig. 29 ().They have a yellow background with blacknumerals superimposed, and are locatedwhere normal use of the vehicle will notconceal them from view. Side vehicle signsare placed on each trailer having a ratedpayload or capacity exceeding 12 tons.
c. Other uses of front and side vehicle classificationsigns include the marking of combination vehicles,towed vehicles, and special purpose vehicles.
106
(1) For combination vehicles, each leadingvehicle in the combination carries a frontvehicle classification sign. It is inscribedwith the classification number of the com-bination with the letter C in red above theclassification number (fig. 30 (i). In addi-tion, each vehicle in the combinationcarries a side vehicle classification sign in-scribed with its classification as a singlevehicle (fig. 30 ®).
(2) For towed vehicles, each vehicle is classed
:1 QIA.DA
WHEELED VEHICLES TRACKED VEHICLES
TRAILERS
1 Front vehicle classification signs2 Side vehicle classification signs
Figure 29. Markings and typical locations of classificationsigns for single vehicles.
107
COMBINATION X
I 65
2 Side classification signs for combination vehicle3 Classification signs for towed vehicleFigure 30. Markings and typical locations of classification
signs for combination towed vehicles.
as a separate vehicle unless both are on onebridge span at the same time and the dis-tance between them is less than 30 yards.In such a case they are classified as a com-bination vehicle, and the classification of
108
Figure 31. Location of classification sign on grader, road,motorized.
the combination is the sum of the classifi-cation numbers of the separate vehicles.This combination classification number isshown on a temporary front sign (fig. 30 ().
(3) Special purpose vehicles are equipped withfront classification signs or side classifica-tion signs, depending upon their means ofpropulsion. The locations of classificationsigns on several special purpose vehiclesare shown in figures 31, 32, and 33.
34. Responsibility for Vehicle Classificationa. Standard Army vehicles are classified by the
Chief of Engineers. Their classifications are givenin paragraph 36.
b. Nonstandard vehicles, which include enemyvehicles and other nonstandard vehicles obtained inthe field, are classified by the engineer of the nearestdivision or higher headquarters.
109
Figure 32. Location of classification sign on roller, road,engine-driven.
Figure 33. Location of classification sign on scraper, road,- motorized.
c. Temporary classification of a vehicle, in anemergency, may be made by the using unit. This isdone by comparing the gross weight, axle loads, anddimensions of the unclassified vehicle with those of asimilar classified vehicle and applying, temporarily,the classification number thus obtained. At the same
110o
time the using unit initiates the classificationprocedure in b above.
35. Administrative Proceduresa. Design and specification for materials of vehicle
classification signs are responsibilities of the Chiefof Ordnance.
b. Initial application or attachment of vehicleclassification signs is a responsibility of the Chief ofOrdnance.
c. Procurement of vehicle signs is on a regularordnance item-of-supply basis.
d. Maintenance of vehicle classification signs andmarking of them is a command responsibility.
e. Replacement of lost or destroyed vehicle classi-fication signs is governed by existing supply andmaintenance regulations, as most of them are detach-able. However, this does not relieve the commanderof the responsibility for maintaining vehicle classifi-cation signs for all vehicles in his command. There-fore, use of expedient materials and local fabricationof expedient signs may become necessary.
36. Classification of Standard Military VehiclesThe classification of standard military vehicles is
given in table X, as follows:a. Single vehicles.
(1) Wheeled.(2) Tracked.(3) Halftracked.(4) Trailers, wheeled, full.(5) Trailers, tracked.
d. Combination vehicles.(1) Wheeled.(2) Tracked.(3) Semitrailer.
111
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APPENDIX I
REFERENCES
1. Field Manuals5-5-Engineer Troop Units5-6-Operations of Engineer Troop Units5-9-Elementary Bridging5-10-Routes of Communication5-34-Engineer Field Data5-35-Engineers' Reference and Logistical Data19-5-Military Police19-25-Military Police Traffic Control20-100-Army Aviation21-30- Military Symbols25-10-Motor Transport30-5-Title Classified31-71-Operations in the Arctic100-5-Field Service Regulations; Operations100-10-Field Service Regulations; Administra-
tion101-5-Staff Officers' Field Manual; Staff Organi-
zation and Procedure101-10-Staff Officers' Field Manual; Organiza-
tion, Technical, and Logistical Data
2. Technical Manuals5-240-Aerial Photography30-246-Tactical Interpretation of Air Photos
157
5-260-Principles of Bridging9-2800--Military Vehicles9-2800-1-Military Vehicles (Ordnance Corps Re-
sponsibility)
3. Other Military PublicationsTB 5-253-1--Soil Testing Set No. 1 and Expedi-
ent TestsSR 320-5-1 Dictionary of United States Army
Terms
4. U. S. Department of CommercePublic Roads Administration. Manual on Uniform
Traffic Control Devices for Streets and highways.G. P. O., 1948.
158
APPENDIX II
GUIDES FOR DETERMINING LOAD-BEAR-ING CAPACITY OF ROADS.
1. Generala. Guides for determining the load-bearing capac-
ity of roads require an elementary knowledge of thestructure and the design of roads.
b. A road is an open way provided for the con-venient passage of personnel, vehicles, and animals.It usually consists of a surface or pavement, a basecourse, and a subgrade or foundation.
c. The load-bearing capacity of a road is its abilityto support traffic. It is expressed in the same mannerthat vehicle classification numbers are expressed.
2. RoadsThe component parts of a road are usually a
pavement or surface, a base course, and a subgrade(fig. 34).
a. The surface or pavement of a road is the topportion of the road structure. It comes into directcontact with the wheel load or tracked load. It isintended to resist traffic wear and dusting and toprevent surface water from infiltrating into the roadstructure. It may consist of-
(1) Earth,(2) Sand-clay,
159
WHEEL LOAD
':' ':'~ PAVEMENTOR SURFACE
AREA OFTIRE CONTACT
SUBGRADESUPPORT
SUBGRADE
LOW BEARING RATIO SUBGRADE
Figure 34. Section of road and wheel looding.
(3) Gravel,(4) Bituminous mixes,(5) Concrete, or(6) Paving brick, block, or stone.
b. The base course of a road is the intermediateportion of a road structure which distributes theinduced stresses from the wheel or tracked load sothat they will not exceed the strength of the sub-grade. Base courses are usually made from selectedgravel or crushed rock.
160
c. The subgrade is the foundation of a road struc-ture. It supports the load placed upon the surfaceof the road. Improved roads usually have a subgradecomposed of selected material found in the immediatevicinity of the road.
3. Surfaces
Surfaces of roads may be flexible or rigid.a. Flexible road surfaces may be composed only
of the natural earth material of which the road isconstructed; may be composed of this earth materialstabilized with oil, cement, or other material; ormay be a bituminous pavement.
b. Rigid road surfaces are usually made of portlandcement concrete. Brick, block, and stone may alsobe considered rigid surfaces.
4. Soils
Soils form the basis for the vast majority of roads.Elevated roadways are a notable exception. Soils,briefly, are considered here according to their type,their classification, and their allowable foundationbearing pressure. Soil types are listed and describedin table XI. A soil classification chart is given intable XII. Allowable foundation bearing pressuresfor various kinds of soil under specified conditions aregiven in table XIII.
332944 0-55 11 161
Table XI. Principal Soil Types
Name Description
Gravel ------ A mass of detached rock particles, generallywater-worn, ranging in size from 14 inch toabout 4 inches.
Sand -------- Granular material composed of rock particlesranging in diameter from 0.25 inch to 0.002inch which will not pass through a No. 270sieve. It is difficult to distinguish sandfrom silt when the particles are uniformlysmall. Dried sand, however, differs fromsilt in that it has no cohesion and feelsgritty.
Silt --------- A fine granular material composed of par-ticles ranging in diameter from 0.002 inchto 0.0002 inch. It will pass through aNo. 270 sieve. It lacks plasticity and haslittle dry strength. To identify: preparea pat of wet soil and shake it horizontallyin the palm of the hand. With typicalinorganic silt, the shaking action causeswater to come to the surface of the sample,making it appear glossy and soft. Repeattest with varying moisture contents.Squeezing the sample between the fingerscauses the water to disappear from thesurface and the sample quickly stiffensand finally cracks or crumbles. Allowsample to dry, and test its cohesion andfeel by crumbling with the fingers. Typicalsilt shows little or no dry strength and feelssmooth in contrast to the grittiness of finesand.
162
Table XI. Principal Soil Types-Continued
Name Description
Clay -------- Extremely fine-grained material composedof particles smaller than 0.0002 inch indiameter. To identify: work a samplewith the fingers, adding water when stiff-ness requires. Moist sample is plasticenough to be kneaded like dough. Makefurther test by rolling ball of kneaded soilbetween palm of hand and a flat surface.Clay can be rolled to a slender thread,about Y inch in diameter, without crum-bling; silt crumbles, without forming athread. Measure hardness of dry clay byfinger pressure required to break a sample.It requires much greater force to breakdry clay than dry silt.
Organic ------ Soil composed of decayed or decaying vege-tation; sometimes mixed with fine-grainedmineral sediments, such as peat or muskeg.Identified by coarse and fibrous appearanceand odor. Odor may be intensified byheating. Plastic soils containing organicmaterial can be rolled into soft, spongythreads.
163
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165
Table XIII. Allowable Foundation Bearing Pressures
Soil Safeallowablepressure
General description Classi- Condition (lb perfication sq ft)
Fine grained soils ...-----............- - Soft, unconsolidated, hav- 1,000ing high moisture con-tent.
Clay, silts, very fine sands MH, CH Stiff, partly consolidated, 4, 000or mixtures of these con- OH, ML medium moisture con-taining a few coarse tent.particles of sand or ___gravel. CL, OL Hard, well consolidated, 8, 000
low moisture content,slightly damp or dry.
Sands and well-graded SW, SC Loose, not confined -.---- 3, 000sandy soils, containingsome silt and clay. SP Loose, confined .--------- 5,000
SF Compact -..------- ------- 10, 000
Gravel and well-graded GW Loose, not confined . . ... 4,000gravelly soils contain-ing some sand, silt, and GC Loose, confined -.-. --- 6,000clay.
GP Compact ----------------- 12, 000
GF Cemented sand and gravel_ 16, 000
Rock .------------------- -------------- Poor quality rock- soft 10, 000and fractured, also hard-pan.
Good quality; hard and 1 20,000solid.
I Minimum.
5. Load-Bearing Capacitya. The load-bearing capacity of a road, considered
by itself, is measured in pounds of allowable wheelload. It is expressed in a series of whole numbersbetween 4 and 150 in the same manner that vehicleclassification numbers are expressed. These num-bers and their significance are given in table XIV.
166
Table XIV. Hypothetical Vehicle Classification Numbers andTheir Significance
Maximum MaximumHypothetical vehicle classification number single axle single wheel
load (tons) load (pounds)
4 --------------------. 2.5 2, 5008 -..---- ---- ---- ---- ---- ---- 5.5 5, 50012 ----------------------------- 8.0 8, 00016 --------------------------- - 10.0 10, 00020-i- ------------------ 11. 0 11,00024 ------------------------- 12.0 12, 00030 ------------------------- 13 5 13, 50040 ----------------------------- 17.0 17, 00050 -------------------------- 20.0 20, 00060 ------------------------------ 23.0 23, 00070 ---------------------. 25.5 25, 50080 ------------------------------ 28.0 28, 00090 ------------------------------ 30.0 30, 000100 ----------------------------- 32.0 32, 000120 ------------------.-.-.------- 36.0 36, 000150 -....... 42.0 42, 000
b. An approximation of the load-bearing capacityof a road with a flexible pavement may be obtainedfrom the data in figure 35.
c. Computation of the approximate load-bearingcapacity of a road, considered by itself, can be madefrom a determination of the thickness of the surfacecourse or pavement, the thickness of the base course,and the type of subgrade material. By applying thisinformation to tables XI, XII, and XIII and thecurves in figure 35, the approximate load-bearingcapacity is obtained. The accuracy of this method isentirely dependent on the experience and judgmentof the reconnaissance personnel.
167
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d. An example of the computation of the load-bearing capacity of a road follows.
(1) By field inspection, it is determined that theroad has a 10-inch compacted gravel basecourse and a 3-inch bituminous surfacecourse or pavement. This is a combinedthickness of 13 inches. By use of theidentification method given in table XI it isdetermined that the subgrade consists ofwell-consolidated, fairly dry clay.
(2) Fairly dry clay, well-consolidated, is shown intable XII to be in the ML-CL range of soilgroupings.
(3) Experience with similar soils indicates that asafe CBR (California Bearing Ratio) valueis approximately 8 percent.
(4) Reference to figure 35 shows that for a 13-inch combined thickness of pavement andbase course the permissible wheel load isabout 13,000 pounds.
(5) Reference to table XIV shows that this wheelload corresponds to a vehicle classificationnumber 30.
(6) The road is given a classification number 30.e. Limitation of the load-bearing capacity of a high
type road is the classification of the weakest bridgein the route.
169
APPENDIX IIIBRIDGE SPANS
1. GeneralBridge spans may be divided into two general
classes: fixed bridges and movable bridges, asenumerated below:
a. Fixed bridge spans (fig. 36) are further dividedinto eight types, according to structure design.
SLAB STEEL STRINGER GIRDER
T I z 1 , , 1 I I I
TRUSS .ARCH (Open Spandrel) ARCH (Closed Spandrel )
CANTILEVER SUSPENSION
Figure S6. Classification of fixed bridges by type of fixed struc-ture.
170
These types, which are discussed in more detail inparagraphs 2 through 9 of this appendix, are canti-lever, slab, beam (simple or continuous stringer),truss, girder, arch, suspension, and ponton (floating).
b. Movable bridges are discussed in paragraph 10of this appendix.
c. Principal bridge span dimensional data are
CLEARANCE
HORIZONTAL |CLEARANCE -
WI__D OTH OF t-DC ZFLOORC SYSTM
3. AX- 3.. 3 .
DIMENSION 3 -HEIGHT ABOVE STREAMBED (GROUND)DIMENSION 3a -HEIGHTABOVE NORMAL WATER LEVEL
I Measuring width of roadway and clearances2 Measuring height above stream bed and normal water level
Figure 37. Principal bridge span dimensional data.
171
illustrated in figure 37, and principal dimensionalrequirements are given in table V.
d. Capacity dimension data requirements arepresented in table VI.
2. Cantilever Bridges
A cantilever bridge is one in which two self-supporting beams, or trusses, project from pierstoward each other, with no intermediate support.These beams are either joined directly to one anotheror are connected by a suspended span. Figure 38illustrates a cantilever bridge and designates itssections.
3. Slab Bridgesa. Slab bridges are short span bridges consisting
primarily of a reinforced concrete slab resting directlyon the abutments or intermediate supports. Awearing surface of bituminous material, gravel, orwooden planks is usually laid over the concrete, butsometimes the upper side of the slab is the wearingsurface.
b. A standard dimension data guide for concretebridges is given in figure 39. A typical concreteslab bridge is illustrated in figure 40.
4. Beam Bridges
a. The majority of all bridges with short spans aresimple stringer bridges. Stringers are generally con-structed of steel, concrete, or wood. A standarddimension data guide for simple stringer bridges isgiven in figure 41. The most common types ofstringers are as follows:
172
C:4
z
N~dS ~o 2 _
u3N---0......L.I
0.
2~~~~~~~~~~~F4~~~~
0
z~~~"r'~~~
U
l__.
z '7
U31N33 z P4
173
w I vI I
W
z;9
I~~~~~~~~~~7
A
A
CONCRETE CONCRETET-BEAM SLAB
SECTION A-A
Figure 39. Standard dimension data guide for concrete bridges.
Figure 40. Typical concrete slab bridge.
(1) Wooden stringers.(a) Rectangular timber (fig. 42).
(b) Log (fig. 43).
174
SPAN , IPAN
(jb C
Figur e 41. Standard dimension data guide for simple strinaer bridges.
332944 0 - 55 (Face p. 174)
Figure 42. Simple stringer bridge with rectangular timberstringers.
(2) Steel stringers.(a) I-beam (figs. 44 and 45).(b) Wide flange (WF) beam.(c) Channel.(d) Rail.
b. Beam span bridges are reinforced concretebridges in the form of slabs resting on a series ofrectangular beams. Beams and slabs are pouredintegrally. The beams may be reinforced withstandard rods, steel T-beams, I-beams, or channels.The wearing surface of the roadway may consist ofbituminous material or wooden planking laid on topof the concrete slab. A standard dimension dataguide for concrete bridges is given in figure 39.Typical single span and multispan concrete bridgesare illustrated in figures 46, 47, and 48.
175
Figure 43. Simple stringer bridge with log stringer.
5. Truss Bridges
a. Truss span bridges are used for spans whichare too long for simple stringer or girder bridges.The truss is a compound beam in which the parts arearranged to form one or more triangles in the sameplane. It carries the roadway loads, transmittedfrom the bridge flooring to the abutments and inter-mediate supports. Trusses are usually constructedof steel, although wood truss bridges are found in ornear areas where timber is abundant.
b. A standard dimension data guide for trussbridges is given in figure 49.
c. Classification of truss types, by the position ofthe roadway (fig. 50), follows:
(1) Deck truss. The roadway is located aboveor on the top chord.
176
Figure 44. Simple stringer bridge with steel I-beams and timberflooring.
Figure 45. Simple stringer bridge with steel I-beams and con-crete slab flooring.
(2) Through truss. The roadway is situatednear the bottom chord, and overhead brac-ing (crosswise) is frequently provided.
(3) Pony (half-through) truss. The roadway islocated close to the top chord, and no over-head bracing (crosswise) is provided.
332944 0-55 12 177
Figure 46. Typical single span concrete bridge.
Figure 47. Typical concrete bridge.
178
Figure 48. Typical multispan concrete T-beam bridge.
d. Common types of bridge trusses are illustratedin figure 51, but it is not generally necessary to in-clude their names in bridge reconnaissance reports.
e. Typical truss bridges are illustrated as follows:(1) Typical steel deck truss bridge (fig. 52).(2) Typical timber truss bridge (fig. 53).(3) Typical steel through truss bridge (Warren
type) (fig. 54).(4) Typical steel pony truss span on combina-
tion streetcar and highway bridge (fig. 55).
6. Girder Bridges
a. Girder span bridges are composed of girdersand a floor system. The girder is a compound steelbeam, built up of plates, shapes (such as angles,channels, and Z-sections), lattice work, bars, andother elements, which transmits the roadway loadsto the intermediate supports and abutments. The
179
I~~~~~~~~~~~~~~~I
a.~~~~~~~- cn -~~~~~~~~~~~~~~~~~~~~a
180~l
DECK TYPE
THROUGH TYPE
HALF-THROUGH OR PONY TYPE
Figure 50. Classification of truss types by position of roadway.
floor system is composed of stringers, floor beams,flooring, and a roadway. Normally, girder spansare constructed of steel, but occasionally they aremade of prestressed concrete.
b. A standard dimension data guide for plategirder spans is given in figure 56.
c. Identification of girder bridges is difficult.They may be mistaken for truss bridges or simplestringer bridges. Therefore, it is important to makeclose inspection of girder bridges and to identifytheir component parts accurately when capacity
181
I~~~~~
CD
2 2W w cn
xo 4 C
Wa
> co
z ~ ~~0 0VW 0
cc
a
z Ia
4 I-c
3 I-C I. "I *,Ia a 3c
a I
3 5~I- 0 ~~ ~~~~~~~~~~~~~0 0
a o~~~~~~~~~~~~~~~~Io C.) I- I0 ..
t o
Z~~~~~~~~~~~~~
a -Ia~~~
Ia2
o IaIL) a7 w
a caIn 3I- 0Wc 0
0. 0: 2
2 Ia
CD a in30
I-2
182
Figure 52. Typical steel deck truss bridge.
Figure 53. Typical timber truss bridge.
183
Figure 54. Typical steel through truss bridge (Warren type).
calculations are involved. The common types ofplate girders are single plate or box type girders.The bridges constructed of these girders are deckplate girder bridges or through plate girder bridges.
(1) Plate girder span. The plate girder span isthe most common type. The roadway isusually located above the top flange plateof the girder. A typical multispan plategirder bridge is illustrated in figure 57.
(2) Through type girder span. If the floor sys-tem is carried at or near the level of thelower chords so that the traffic passes be-tween or through the girder, the structureis called a through type girder bridge.This type is illustrated in figure 58.
7. Arch Bridges
a. Arch span bridges are constructed in manytypes and variations. Basically, an arch bridgeconsists of an arch (including an arch ring), a crown,a fill and hinges, and a floor system. A standard
184
AZ
1 Pony truss and through truss forming combination bridge
2 Pony truss highway bridge
Figure 55. Typical pony truss spans.
dimension data guide for arch bridges is given infigure 59. Common types of arch construction usedin bridges are illustrated in figure 60. Nomenclatureof arch bridges is given in figure 61.
b. Classification of arch spans, for reconnaissancereport purposes, may be given as follows:
(1) Masonry arch (solid earth-filled and deckltype (fig. 62)). Appendix VII describes in
185
Figure 57. Typical multispan plate girder bridge.
Figure 58. Through type girder bridge.
detail the requirements for classifyingmasonry arch bridges.
(2) Concrete arch, either solid (earth-filled) oropen (spandrel) type, with the roadwayusually supported above the arch ring by aseries of columns, posts, or small arches(figs. 63 and 64).
(3) Steel arch, either deck type with the road-way resting on the top (horizontal) member
186
a
PLATE GIRDERFigure 56. Standard dimension data guide for plate girder bridges.
332944 0 - 55 ( Face p. 186)
[SI] ~ ~ ~ ~ ~ ~
ai~ ~~ I -\
I6~~~i
18
4i C,\
B~~~~- =
I :E~~~~~~~~~~~~~
P; I~~~~~~
if a I~~~~~~~~
188~~~
ROADWAY ROADWAY ROADWAY
SPANDREL-BRACEDSTEEL ARCH
b- SPANDREL COLUMNS a-SPANDREL ARCHES
ROADWAY
TRUSSED ARCHES
OUTER RING EXTRADOS
PARAPET WALL
------- " SPANDREL WALL, SPRING LINE
INNER RING INTRADOS
BUUTMENTABUTMENT FOOTING
Figure 61. Nomenclature of arch bridges.
of a trussed steel arch, or through type (tiedarch) with the roadway suspended from thearched member (truss or beam) by a seriesof bars, I-beams, or webbed (latticed)vertical members (figs. 65, 66, and 67).
189
Figure 62. Typical solid masonry arch bridge.
8. Suspension Bridges
a. Suspension spans have the bridge roadwaysuspended by means of vertical cables or ropes fromtwo or more suspension cables, which pass overtowers and are anchored at the ends. Suspension
190
Figure 63. Typical solid concrete arch bridge.
Figure 64. Typical open type (spandrel) concrete arch bridge.
bridges are usually employed where the constructionof intermediate supports is impracticable due to thedepth of the bridge gap, or where navigation mustpass under the bridge.
b. A standard dimension data guide for suspensionbridges is given in figure 68. Typical suspensionbridges are illustrated in figures 69, 70, and 71.
191
Figure 65. Parallel curve, steel rib, arch bridge.
Figure 66. Steel trussed deck arch bridge.
9. Ponton (Floating) Bridges
A ponton (floating) bridge (fig. 72) is a temporarybridge which is supported by low, flat-bottomedboats or other floating structures. The major com-ponents are the floats, saddle assembly, and thesuperstructure which carries the roadway. Some
192
Figure 67. Steel tied arch bridge, through type.
types of military bridges are provided with a rampor trestle to facilitate the approach. Ponton bridgesshould be replaced as soon as possible by more perma-nent structures. Although they are essentiallyfixed bridges of a temporary nature, they may bereleased at one end to allow passage of ships.
10. Movable Bridgesa. Movable bridges (fig. 72) may be classified as
follows:(1) Swing bridges.(2) Lift bridges.(3) Bascule bridges.(4) Retractile bridges.
b. Reconnaissance of movable bridges requires theassignment of a special engineer detail.
332944 0-55 13 193
I - -
I e
Figure 68. Standard dimension data guide for suspensionbridges
194
Figure 69. Suspension bridge with steel cable, timbe? reinforcingtruss, steel floor beams, and external sway bracing.
195
Figure: 7 Baile ty s
Figure 70. Bailey type suspension bridge.
Figure 71. Steel suspension bridge.
196
SWING BRIDGES
a -TRUNNIONb-COUNTERWEIGHT
SINGLE LEAF, TRUNNION TYPE
BASGULE BRIDGE DOUBLE LEAF, TRUNNION TYPE
BASCULE BRIDGE
FLOATING BRIDGE ROLLING LIFT TYPEBASCULE BRIDGE
Hn n C rVERTICAL LIFT BRIDGE
Figure 72. Classification of movable bridges (by type of movablestructure) and ponton (floating) bridge.
197
APPENDIX IV
BRIDGE INTERMEDIATE SUPPORTS
Intermediate supports for bridges are ground sup-ports between abutments. They may be log trestlebents (fig. 73), timber trestle bents (fig. 74), cribpiers (fig. 75), masonry piers (fig. 76), prefabricatedsteel trestle piers (fig. 77), open type concrete piers(fig. 78), or solid concrete piers (fig. 79).
Figure 73. Typical log trestle bent.
198
- -A
CAPTRANSVERSEBRACING
SILL
Figure 74. Shaped timber trestle bent.
Figure 75. Typical crib pier.
199
Figure 76. Typical masonry pier.
Figure 77. Typical prefabricated steel trestle pier.
200
a oror1 -dz ' 1-
... uC-,,-. .-.. _kv
Figue 78. Typical open type concrete pier.
201
Figure 79. Typical solid concrete pier.
202
APPENDIX V
BRIDGE ABUTMENTS
Bridge abutments (fig. 80) are the ground supportsat the shore ends of a bridge. They may be con-structed of concrete, masonry, or earth with a wooden
STRAIGHT ABUTMENTBOX -ABUTMENT
WING ABUTMENT U-ABUTMENT
OF BRIDGE
SHOREWARD SUPPORTPIER OF APPROACH SPAN
T-ABUTMENT PIER ABUTMENT
Figure 80. Types of common abutments.
203
end wall and abutment sill. Typical abutments areas follows:
a. Straight abutment (fig. 81).b. T-type abutment (fig. 82).c. U-type abutment (fig. 83).d. Wing type abutment (fig. 84).e. Earth abutment, with timber abutment sill and
end wall (fig. 85).f. Pier abutment (fig. 80).,g. Box abutment (fig. 80).
Figure 81. Typical straight abutment.
204
Figure 82. Typical T-type abutment.
Figure 83. Typical U-type abutment.
205
Figure 84. Typical wing type abutment.
END WALLABUTMENT SILL
FOOTINGS
_- nABUTMENT WALL
Figure 85. Typical earth abutment, with timber abutment silland end wall.
206
APPENDIX VITUNNELS
A tunnel consists of a bore, a tunnel liner, and aportal. Common shapes of tunnel bores (fig. 86)are semicircular, elliptical, horseshoe, and square
SEMI-CIRCULAR ELLIPTICAL
HORSE-SHOE SQUARE WITHARCHED CEILING
Figure 86. Common types of tunnel bores or cross sections.
207
. ....
Figure 87. Typical unlined tunnel.
Figure 88. Typical masonry lined tunnel.
208
with arched ceiling. Tunnels may be unlined(fig. 87), masonry lined (fig. 88), and concrete lined(fig. 89). Portals may be made of masonry (fig. 90)or of concrete (fig. 91). Alinement of tunnels maybe straight (fig. 92) or curved (fig. 93).
Figure 89. Typical concrete lined tunnel.
332944 0-55 14 209
Figure 90. Typical masonry tunnel portal.
-.. -
r mm
Jr~~~~~~;r
:~~~~~~~~~~~~~~~~~~~~~i
Figure 90. Typical masonry tunnel portal.
,_f
Figure 91. Typical concrete tunnel portal.210
Figure 92. Tunnel with straight horizontal alinement.
Figure 93. Tunnel with curved horizontal alinement.211
APPENDIX VIIDETAILED REQUIREMENTS FOR CLASSIFI-CATION OF MASONRY ARCH BRIDGES
1. Measurement and InspectionThere are two things to be done:a. Measure the leading dimensions of the bridge.b. Examine the bridge to determine its condition,
construction, and the state of the abutments.
2. MeasurementThe following dimensions must be measured (fig.
94):The span (clear span) ---------- (®) feet
Note. In the case of skew spans, measure parallel tothe axis of the roadway.
The rise of the arch ring at the crown ---- k feetThe thickness of the arch ring at the crown_ _j feetThe depth of fill between the road surface and the
arch ring at the crown ------------------ b feetThe width of the bridge between parapets (road-
way width) -..---------------------- () feet
Figure 94. Measurement of masonry arch bridge.212
3. Inspectiona. Normally, only outward appearances can be
examined. Probing into the construction will benecessary only on important routes where thestrength of the bridge is in doubt.
b. Visible signs can be misleading, for the followingreasons:
(1) The thickness of the arch ring under theparapet can be measured, but it does notfollow that this thickness obtains under theroadway.
(2) Some old bridges have been strengthenedby removing the fill and replacing it withconcrete.
(3) The depth and nature of the backfill to theabutment plays a large part in the stabilityof the arch.
(4) The arch ring may have dropped away fromthe fill, so that the latter alone carries theload.
c. Attention must be paid to the following:(1) The arch ring.
(a) Nature and condition of the brickwork ormasonry.
(b) Thickness of the joints.(c) Condition of the mortar.(d) Deformation of the arch ring from its
original shape.(e) Presence of cracks-their width, length,
number, and position.(2) Parapet and spandrel walls.
(a) Sagging of the parapet.(b) Cracks.
213
(c) Outward movement of the parapet rela-tive to the arch ring.
(3) Abutments.(a) Failure of the abutment walls by crack-
ing, settlement, or movement.(b) Adequacy of the abutments to resist
horizontal arch thrust.(c) Adequacy of the wing walls to restrain
the spread of the backfill.(d) Nature of the backfill. This can be dis-
covered only by probing.(e) Nature of the foundation-discovered
only by probing.
4. Classification Procedure
A provisional load class based solely on span andthickness of the crown is first obtained. This isthen modified by various factors, selected in accord-ance with the dimensions, construction, and condi-tion of the bridge. The result, termed the adjustedload class, is modified to the nearest standard loadclass to give the final load class.
5. Provisional Load Class
Refer to the nomograph figure 95. Mark thebridge span (1) on column A and the total crownthickness (j+b=ring+fill) on column B. Linethrough these points to column C, and read off theprovisional load class.
6. Profile FactorsFlat arches are not so strong under a given loading
as those of steeper profile. A very large rise, how-
214
A cARCH SPAN BRIDGE
FEET B-60 TOTAL CROWN
b+j IS150INCHES FEET 140
72 B
100-
.so
215330
54-0100--
I0-
Figure 95. Nomograph for determining the provisional loadclassification of masonry arch bridge.
215
PROFILE FACTOR
1.0 -
0.9 \\
as II0.8 - iJ- l__ -
0.7 -
0 .64 \
4 5 6 7 a
SPAN / RISE RATIO
Figure 9fi6. Profile factors for masonry arch bridges.
216
ever, does not necessarily add to the strength, asfailure can occur through the crown of the arch,acting as a smaller arch of flatter rise. For thisreason, a span-rise ratio of 4 and less is assumed togive optimum strength, and has a profile factor of 1.When the span-rise ratio is greater than 4, referenceis made to figure 96, which gives the appropriateprofile factor for the different ratios.
7. Material FactorsTo determine material factors (table XV), the
following must be noted:a. The material used for the ring.b. The type of construction-i. e., whether the
voussoirs are in courses or laid at random.c. The condition of the material-i. e., whether
there is much spalling, and whether the voussoirs aresound or deteriorating due to weathering.
d. Examine the soflit, and look for signs of disin-tegration and cracks. Usually the first signs offailure occur at the quarter-points on the intrados.
Table XV. Material Factors for Masonry Arch Bridges
Condition Material factor
1. Granite, whinstone, and built-in-course ma-sonry with large shaped voussoirs -------- 1. 5
2. Concrete or blue engineering bricks ---------- 1. 23. Limestone, good random masonry, and build-
ing bricks in good condition ----------- 1. 04. Masonry of any kind or brickwood in poor
condition (many voussoirs flaking or badlyspalling, shearing, etc.). Some discretionis permitted if the dilapidation is only mod-erate --------- ------------------------ 0. 7-0. 5
217
8. Joint FactorsThe strength and stability of the arch ring depend
to a large extent on the size and condition of thejoints. In this connection, it is necessary to dis-tinguish between cement and lime mortar as a joint-ing material (table XVI). Lime mortar is commonlyused in brick construction, particularly on oldbridges, and although it is softer than cement mor-tar and has less strength, this is compensated for bybetter joint-filling properties and good distributingpower under load. Partially-deteriorated cementmortar must not be confused with lime mortar ingood condition.
Table XVI. Joint Factors for Masonry Arch Bridge
Type of joint Joint factor
1. Thin joints, fio inch or less in width --------- 1. 252. Normal joints, with width up to /% inch, regular,
straight with mortar in good condition andwell pointed ------------------------------ 1. 00
3. Ditto, but with mortar unpointed .--- .904. Wide joints, generally over %f inch wide and
usually irregular; mortar in good condition_ .805. Ditto, but with mortar containing voids deeper
than one-tenth of the ring thickness .-- .706. Very wide joints, lo inch or more in width, with
poor mortar having voids deeper than one-tenth of the ring thickness, and so deterio-rated that it has the properties of sand alone . 50
9. Crack Factorsa. General. The age of cracks is of great impor-
tance. Old cracks no longer operating, and which
218
probably occurred soon after the bridge was built,can be ignored. Recent cracks, on the other hand,usually show clean faces, with perhaps small loosefragments of masonry. Although cracks may appearas shear of the bricks or masonry, they normallyfollow an irregular line through the mortar; caremust be taken to observe whether they are cracksand not merely deficiencies of the pointing material.
b. Types of Cracks. Crack factors are given intable XVII. The following are the more importanttypes:
(1) Longitudinal cracks within 2 feet of theedge of the arch, caused by lateral spreadof the fill, producing an outward force onthe parapet walls and pushing the outerportion of the ring away from the centerportion (fig. 97).
Table XVII. Crack Factors in Masonry Arch Bridges
Type of crack Crack factor
1. Small longitudinal cracks within 1.0.2 feet of the edge of the arch,i. e., less than %{ inch in widthand less than one-tenth of thespan in length.
2. Large longitudinal cracks within 1.0.2 feet of the edge of the arch,i. e., greater than ¼f inch inwidth and longer than one-tenth of the span in length: Forbridges having widths greaterthan 20 feet.
219
Table XVII. Crack Factors in Masonry Arch Bridges-Con.
Type of crack Crack factor
3. Longitudinal cracks within the 0.9-0.7.center third of the bridge.
a. One small crack less than 1.0.hfi inch in width andless than one-tenth ofthe span in length.
b. One large crack greater 0.5.than }/4 inch in widthand longer than theabove.
c. Several narrow cracks- 0.5.i. e., three or more.
4. Small lateral and diagonal cracks, 1.0.i. e., less than }/s inch in widthand shorter than one-tenth ofthe arch width.
5. Large lateral and diagonal cracksgreater than % inch in width Maximum load class:and longer than the above. 12; or the figure
derived by calcula-tion, using the otherfactors, whichever
6. Cracks between the arch ring and is the less.parapet wall greater than one- 0.9.tenth of the span, due to lateralspread of the fill.
7. Cracks between the ring andspandrel, due to a dropped ring. Reclassify from the
nomograph, on theassumption that thecrown thickness isthat of the ringalone.
220
CRACKS DUE TO CRACKS DUE TO VARYINGSPREAD OF FILL SUBSIDENCE ALONG LENGTHPORTION OF RING OF ABUTMENT. (THE DOWNWARDAND PARAPET WALL DETO DISPLACEMENT MAY NOT BEOUTWARDS. LATERA SRED NOTICEABLE. ONLY THE CRACKS)
Figure 97. Longitudinal cracks in arch ring.
(2) Longitudinal cracks within the center thirdof the bridge, due to varying amounts ofsubsidence in different places along thelength of the abutment. These are danger-ous if large, because they indicate that thering has broken up into narrower independ-ent rings (fig. 97).
(3) Lateral cracks, usually found near thequarter-points, due to permanent deforma-tion of the arch, which may be caused bypartial collapse of the arch or movement atthe abutments.
(4) Diagonal cracks, normally starting near thesides of the arch at the springing andspreading towards the center of the bridgeat the crown. They are probably due tosubsidence at the sides of the abutment, andindicate that the bridge is in a dangerousstate.
(5) Cracks between the arch ring and thespandrel or parapet walls. These are dueto two causes:
(a) Spread of the fill, so that the parapet wallis pushed out relative to the arch ring(fig. 98).
(b) Movement of a flexible ring away from astiff fill, so that the two act independently.
221
CRACKS DUE TOSPREAD OF FILLPUSHING PARAPETWALL OUTWARDS FILL
RING
LATERAL MOVEMENT -r---
Figure 98. Cracks between arch ring and parapet wall.
CRACKS
Figure 99. Movement of arch ring away from stiff fill.
This type of failure frequently producescracks in the spandrel wall near thequarter-points (fig. 99).
10. Deformation Factors
a. General. Failure of the arch ring is observed inthe ring itself, and is frequently accompanied by asag of the parapet over approximately the samelength (fig. 100). Deformation of the arch ring maybe due to two causes:
(1) Partial failure of the arch ring.(2) Movement at the abutment.
b. Deformation Factors. Deformation factors aregiven in table XVIII.
222
SAGGING PARAPET
Figure 100. Deformation of arch ring.
Table XVIII. Deformation Factors for Masonry Arch Bridges
Degree of deformation Deferred factor
1. Deformation limited so Discard profile factor alreadythat the rise over the calculated and apply span-affected portion is always rise ratio of affected por-positive. tion to the whole arch.
2. Distortion so that there is Maximum load class: 12.a flat section of profile.
3. Large deformation so that Maximum load class: 5;a portion of the ring is but only if fill at crownsagging. exceeds 18 inches.
11. Abutment Factors
a. General. In the assessment of the abutments itis necessary to apply two factors. The first takesaccount of the size and shape of the abutment asan adequate support for the arch, and alwaysapplies. The second applies to faults in the abut-ment, i. e., cracks, movements, etc.
b. Abutment Size Factors. Abutment size factorsare given in table XIX. One or both of the abutments
223
may be considered inadequate to resist the fullthrust of the arch. This may occur when:
(1) The bridge is on a narrow embankment,particularly if the approaches slope downsteeply from the bridge;
(2) The bridge is on an embanked curve;(3) The abutment wing walls are very short
and suggest little solid fill behind the arch;(4) In the case of multispan bridges, each span
is considered separately and abutmentfactors are applied in accordance withwhether the arch is supported on one abut-ment and one pier, or on two piers.
c. Abutment Fault Factors. Abutment fault factorsare given in table XX.
Table XIX. Abutment Size Factors for Masonry Arch Bridges
Condition Abutmentsize factor
1. Both abutments satisfactory ---------------- 1.002. One unsatisfactory abutment .-............ . 953. Both abutments unsatisfactory ----------- . 904. Both abutments massive, but a clay fill is
suspected --------------------------- - . 705. Arch supported on one abutment and one pier_ .906. Arch supported on two piers .--------------- 80
224
Table XX. Abutment Fault Factors.for Masonry Arch Bridges
Nature of fault Abutment fault factor
1. Inward movement of one abutment, 0.75-0.50 (dependingshown by hogging of the arch on degree). Notring and the parapet at the more than class 30crown, and, possibly, open or class 12, accord-cracks in the intrados between ing to degree.the quarter-point and the spring-ing. Old movement, with a ell-
consolidated fill and slight hog-ging of the ring.
2. Outward spread of abutments. Thisusually causes change in the pro-file. If the movement has notbeen excessive and appears tohave ceased, determine thenature of the fill behind theabutments and allow factorsvarying from 1 to 0.5, accordingto the nature and condition ofthe fill.
3. Vertical settlement of one abutment.Investigate the ground undereach abutment, and apply fac-tors ranging from 0.9 for slightmovement to 0.5 where the ma-terials under each abutment aredissimilar.
12. Application of the Factors
The profile, material, and joint factors, togetherwith the abutment size factor, are applied in everycase. The remaining three factors, namely thosefor cracks, deformation and faults in the abutments,
3:2944 0-5,5--15 225
are applied with discretion. Clearly, if the arch hasdeformed and cracked due to a fault in the abut-ments, it is unrealistic to downgrade the bridge forall three of the latter factors operating together. Insuch a case, the load class is worked out by applyingthese factors in turn to the provisional load class (asmodified by the first four factors) and adopting thelowest figure so obtained. After applying the variousfactors to the provisional load class, the figureobtained is rounded off to the nearest standard loadclass, to give the final classification.
13. Two-Way ClassificationBridges which are wide enough to accept two lanes
of traffic may be given a two-way load class equal to0.9 of the one-way class.
14. Examplea. Data.
Span -.............. 40 feetRise -. ............... 8 feetArch ring thickness-.. ... 18 inchesDepth of fill at crown ---- 12 inchesWidth between parapets__ 15 feetMaterial - . ......... Limestone in good condition.Joints - ............... Mortar, with some deteri-
oration and small voids;close joints.
Cracks - .......... There is a large longitudinalcrack in the arch underone parapet wall.
Abutments - . ........ One approach is uip a narrowembankmenlt.
b. Provisional Load Class.Mark span 1=40 feet on column A, figure 95.Total crown thickness (ring + cover) = 2.5 feet.Mark this on column B, figure 95.
226
Line through these two points across column C, andread off the provisional load class, which in thisinstance is 34.
c. Adjusted Load Class. The provisional class isnow amended by the various factors, as follows:
(1) Profile factor.
Span-rise ratio= 4 =5.
From figure 96 the profile factor is 0.86.(2) Material factor. From table XV, for lime-
stone in good condition, the material factoris 1.0.
(3) Joint factor. From table XVI, the jointfactor is between 0.80 and 0.70 -say 0.75.
(4) Crack factor. From table XVII, the onelarge longitudinal crack at the edge of thering, for a bridge of this width, gives acrack factor of 0.9.
(5) Abutment .factor. One abutment is con-sidered unsatisfactory, owing to the narrowand steep approach. From table XIX,this gives a factor of 0.95.Hence,
Adjusted load class=34 x 0.86 x 1.0 x 0.75 x0.90 x 0.95
=19 for one-way traffic.and 19 x 0.9=17 for two-way traffic.
d. Summary. From figure 95, column D, thenearest bridge classes are 16 and 20, and it is reason-able to say that the bridge is class 20 for one-waytraffic, and class 16 for two-way traffic.
227
APPENDIX VIIIANALYSIS OF SUPERSTRUCTURE BY A
NOMOGRAPHIC METHOD
1. GeneralDetermination of bridge class numbers for simple
span timber or steel stringer bridges is made by useof the chart in figure 101. By the application ofspecial empirical formulae, this method is also appliedto simple span reinforced concrete bridges. Lateraldistribution, dead load, and impact have been takeninto account. The maximum lane width which isconsidered effective for a one-way crossing of a two-lane bridge, or for a single-lane bridge, is 15 feet.The determination of the class number per lane of atwo-lane bridge is based on a lane width equal to one-half the roadway width up to a maximum of 15 feet.
2. Class Determinationa. Steel Stringers. The span length in feet, number
of stringers per lane, and the section modulus ininches, of one stringer is needed to enter on thechart. Knowing the beam depth (in inches) and theflange width (in inches), the section modulus may bepicked from table XXI. Where measured dimensionsfall between two given sizes, always use the lightersection. The values in this table are for the lightestU. S. sections for the given dimensions. Values forheavier U. S. sections are found in the A. I. S. C.Handbook. FM 5-35 gives values for common U. S.and foreign shapes. To use the chart (fig. 101), lineup a straightedge through the values for number of
228
Nuwnbr of Steel Stringer Per Lane
o 0 a a 0 a 0 0
Number of Inches of Width of Timber Stringers Per Lon
Section Modulus (S) of Steel Stringers in Inches
_ .J J { , I , i I a l I jIlI, I I I I I [llJJ llh~&l]Jll) )a f O *I I I o i I
Depth of Timber Stringern in Inches
Total Resisting Moment (MR) Per Lone-in ft. lips
0 -_ 8' o08. o ,:n g g 'd 8 u e
Figre 101. Nomograph for determining b)ridge rlaso nlnyw er.
II Io C
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229
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231
steel stringers per laxte and section modulus of onesteel stringer in inches (table XXI, col. 4). Notethe point where the straightedge intersects the linelabeled "Total Resisting Moment per Lane-in footkips." From this latter point, follow across hori-zontally on the chart on the line representing thetotal resisting moment until it intersects the value forthe span length-in feet of the bridge. This point isthe class number of the bridge. If the point does notfall on a class curve, the value may be interpolatedbetween the curves by estimation.
b. Timber Stringers. The span length in feet,depth of timber stringers in inches, and the numberof inches of width per lane is needed to use the chart.The number of inches of width per lane is the sumof the widths of all the stringers in the lane. Touse the chart, line up a straightedge through thevalues for "Number of Inches of Width of TimberStringers per Lane" and "Depth of Timber Stringersin Inches." Note the point where the straightedgeintersects the line labeled, "Total Resisting Momentper Lane-in foot kips." From this latter point,follow across horizontally on the chart on the linerepresenting this total resisting moment until itintersects the value for the span length-in feet. Ifthe point does not fall on a class curve, the value maybe interpolated between the curves by estimation.
c. Reinforced Concrete. The capacity of reinforcedconcrete spans may be determined from the chartin figure 101 when the total resisting moment perlane, in foot kips, and span length in feet are known.The total resisting moment is estimated by use ofthe following formulas:
232
a.
· t~ ~ 8 <10dr~~~C =
S 4O) C) + C. m
+ i i E : -' a
+ - - ,a ~ E2;
"Bs- . o . s
C ¢O2m 1
Enter the right-hand chart of figure 101 with the"Total Resisting Moment per lane in ft kips" andthe "Span Length in feet." Intersect the spanlength with the resisting moment and read the classnumber directly from the chart. When the pointdoes not fall on a class curve, the value may beinterpolated between the curves by estimation.
3. Posting the Bridge
a. Single-Lane Bridge. By use of the nomographfor a single-lane bridge, the single-lane class numberis determined, as in 2 above. This is posted as infigure 15 or as a dual class number, figure 16. Todetermine the dual class number, see c below.
b. Multilane Bridge. For a multilane bridge, themultilane class number is determined by use of thenomograph. This allows for normal operation forall the bridge lanes. This number is posted on theleft-hand side of the bridge sign (fig. 15()). Asingle-lane class number is posted on the right-handside of the bridge sign. It is computed consideringonly the number of stringers effective under a 15-footwidth of roadway. A simple method is as follows:The value of total resisting moment per lane (MR),as used in the initial class determination, is read fromthe chart. This is multiplied by 15 feet times thenumber of lanes and divided by the roadway widthin feet.
MR() MRX15XN N=number of lanesR() W W= roadway width in feet
The single lane class number is then determinedfrom the chart (fig. 101), using the single-lane
234
resisting moment (MR(s)) and the span length in feet.c. Dual Class Numbers. A dual class number
indicates one class number for wheeled vehiclesposted above another class number for tracked ve-hicles (fig. 160)). If the span length is 95 feetor less, and if the bridge class number is 50 or above,then a dual class number is determined from the dualclassification curves (TM 5-260). (This step is notmandatory, even if the bridge class number is 50or above, since a dual class number need not neces-sarily be used even though authorized.) Enter thedual classification curves with the span length infeet, proceed up the span length line to the classvalue for tracked vehicles (solid lines) that is equalto the bridge class determined from the nomograph(fig. 101). This point of intersection represents thebridge under consideration. Using the dashed lines(wheeled vehicle class curves), read the wheeledvehicle class at this point. If this point does not fallon a wheeled vehicle class curve, the value may beinterpolated between the curves by estimation.
235
APPENDIX IX
CLASSIFICATION TABLES FOR STANDARDPREFABRICATED RAFTS, FIXED BRIDGES,AND FLOATING BRIDGES
Table XXII Floating Bridge ClassificationTable XXIII Raft ClassificationTable XXIV Classification of Panel Bridge, Bailey
Type, M2, (150-inch roadway)Table XXV Classification of Portable Steel High-
way Bridge, H20Table XXVI Classification of Steel Treadway
Fixed Bridges, M2 and Widened
236
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Table XXV. Classification of Portable Steel Highway Bridge,H0O
1 2 3 4 5 7 8 9 10
2-truss construc- 3-truss construe- 4-truss construc-tion tion tion
Span in feet --
Nor- Canu- Risk Nor- Cau- Risk Nor- Cau- Riskmal tion mal tion mal tion
37.5 ---- - 70 80 90 80 80 90 80 80 9050 - . ............. 55 65 75 60 80 90 75 80 9062.5 ---- - 45 55 65 60 65 75 65 75 8575 3--............. 50 50 60 55 60 70 60 70 8087.5 3-- - 40 45 55 50 55 65 55 65 75100 ---------------- 35 40 50 45 50 60 50 60 70112.5 -- - 30 35 40 40 45 55 50 55 65125 3--------------- 20 24 30 35 40 50 45 50 60137.5 --- - 16 20 24 30 35 45 35 40 50150 ..-.....-. 12 16 20 24 30 35 30 35 40
242
Table XX VI. Classification of Steel Treadway Fixed Bridges,M2 and Widened
1 2 3 4 5 1
Num- Classber of Clear
Type tread-ways in n Nor- Cau-
span mal tion
1 Widened bridge -.....-.-. . .2 20 90 b 110 b 14022 80 95 b120
3 24 70 80 b10026 60 70 9028 55 60 8030 50 55 7532 45 50 6534 40 45 55
2 Plywood treadwaylane (spans .-------.- --.-- 16 18 24up to 34 feet) ..............
3 M2 bridge .- ........... 4 36 30 35 5038 27 30 4540 25 28 4042 23 26 4044 21 24 3546 20 23 35
5 48 19 22 3050 18 21 3052 18 20 2854 17 19 2756 16 18 2558 16 18 24
For 2-treadway span bridges without transverse stiffeners use 0.8 of classgiven in table.
b Width controls.
243
APPENDIX X
GLOSSARY
Abutment. The support at each end of a bridgewhich supports the dead weight of the bridgeand prevents lateral movement of the earthembankment.
Aggregate. Natural or processed material, such ascrushed rock, gravel, slag, and shell, used withor without artificial binder as material for thesubbase, base, or wearing course of a road.Aggregate, in a surface course, is often calledroad metal.
All-weather road. Any road which, with reasonablemaintenance, is passable throughout the year toa volume of traffic never appreciably less thanits dry-weather capacity. This type of road hasa waterproof surface and is only slightly affectedby rain, frost, thaw, or heat. At no time is itclosed to traffic by weather effects other thansnow blockage. Included in this category areconcrete, bituminous surface, brick, or stonepavement.
Approach. Applies generally to the immediate sec-tion of roadway leading to a bridge. It isconstructed to provide access to a bridge, as afill that rises to a bridge or a cut that slopesdown to a bridge. The term is also used in
244
describing the relative direction or ease of ap-proach, though no special structure or con-struction is required for that purpose. Forexample, "a direct approach," or "right-angleapproach."
Approach span. That portion of the roadwayapproach to a bridge which is supported onpiers.
Arch bridge. A haunched structure (arch) whichspans an opening and which transmits any loadplaced on it in the form of an inclined thrust tothe supports (piers, abutments).
Arch culvert. An arched structure through a railroador highway embankment to carry a small streamor provide for the passage of water; under itsown load, and all loads imposed upon it, itproduces an inclined thrust at the supports.
Attachable vehicle (class) classification sign. Frontvehicle (class) sign for use on cargo-carryingvehicles having a standard vehicle classificationnumber larger than 30, which gives the unloadedclassification number of the vehicle.
Bascule bridge. A movable span bridge in whichthe movable span moves in a vertical plane,rotating about a horizontal axis (trunnion type),or rolling back from the opening in the bridge(rolling lift type).
Base course. The portion of a road structure betweenthe subgrade and the surface course or pavementwhich distributes the induced stresses from thewheel load or tracked load to the subgrade.
Feam. A horizontal load-bearing member of astructure, long in proportion to its thickness.
245
Beam bridge. A short span bridge, always decktype, with steel, concrete, or timber beams,extending between abutments or piers.
Box culvert. A culvert with a rectangular waterpassage.
£ri~dge. A structure erected over a river, chasm, orgorge, which carries a roadway for vehicular orfoot traffic. Bridges are classified, accordingto structure, as follows:
a. Cantilever.b. Slab.c. Beam.
(1) Simple stringer.(2) Concrete.
d. Truss.e. Girder.f. Arch.g. Suspension.h. Ponton (floating).i. Swing.j. Lift.k. Bascule.1. Retractile.
See also Arch bridge; Bascule bridge; Beam bridge;Cantilever bridge; Deck bridge; Dual classbridge; Ferry bridge; Floating bridge; Girderbridge; Half-through bridge; Lift bridge; Mov-able bridge; Multilane bridge; Retractile bridge;Single lane bridge; Skew bridge; Slab bridge;Stringer bridge; Suspension bridge; Swing bridge;T-beam bridge; Through bridge; Treadwaybridge; Trestle bridge; Truss bridge; Two lanebridge.
246
Bridge (class) classification number. Number whichrepresents the safe load-carrying capacity of abridge under normal crossing conditions.
Bridge length. The length of a bridge is expressed asthe distance between the extreme ends (overalllength) of the bridge. This should not be con-fused with span length which is defined in termsof the distance between bearings.
Bypass. A local detour required to circumvent anobstruction to military traffic along the normalcourse of a route.
California bearing ratio (CBR). A measure of theshearing resistance of a soil under carefully con-trolled density and moisture conditions, whichis used with empirical curves for designing flex-ible road pavements. It is expressed as a ratioof the unit load required to force a piston intothe soil to the unit load required to force thesame piston the same depth into a standardsample of crushed stone.
Cantilever bridge. A bridge in which two self-supporting beams or trusses, projecting frompiers toward each other, are either joined directlyor connected by a suspended span.
Causeway. A raised way across wet or marshyground, or across water.
Caution crossing. A crossing for which the vehicleclass number is no more than 25 percent greaterthan the bridge single lane class number.Caution crossings require that the vehicle re-mains on the centerline of the bridge, maintainsa 50-vard distance from the vehicle in front, doesnot exceed the speed limit of 8 miles per hour,
247
and does not stop, accelerate, or shift gears onthe bridge.
Clay. A soil which contains colloidal scale-likeparticles which are the cause of plasticity. Itis plastic when moist but permanently hardwhen baked or fired.
Clear span. The distance, face to face, of the sup-ports (piers or abutments) of a bridge at meanwater level.
Clearance. The clear space (horizontally or vertical-ly) available in a structure such as a bridge or atunnel to permit passage through; also the spacebetween the water level and the under side of abridge (under-bridge clearance).
Combination vehicle. A military vehicle consistingof two or more single vehicles, spaced less than30 yards apart, which move as one unit.
Concrete. Artificial stone made by mixing cementand sand with gravel, broken stone, or otheraggregate. The materials are mixed with suf-ficient water to cause the cement to set andbind the entire mass.
Controlled crossing. A crossing over a multilanebridge for which the vehicle classification num-ber is not more than 50 percent greater than thebridge classification number for one lane, andwhere the vehicle must be centered over two ormore lanes carrying one-way traffic, with alimitation of one vehicle on each span of thebridge. When the bridge class number is notthe same for all lanes so used, the lane with thelowest bridge class number determines the con-trolled rating.
248
Critical span. Ii a multispan bridge, with individualspans of various dimensions or of different con-struction or material, the span with the leastcapacity.
Culvert. A structure through a railroad or highwayembankment to carry a small stream or providefor the passage of water. The simplest form ofculvert is a pipe. See also Arch culvert; Boxculvert.
Deck bridge. A bridge in which the floor system issupported on or near the top chord (line of topmembers) of the bridge trusses or girders withno more than a guardrail at the sides.
Directional disc. A circular sign, used to supplementother road guide signs, which indicates the direc-tion of a route. The disc is a circle having aminimum diameter of 1 foot. The normaldirectional disc has a fixed black arrow on awhite background. The directional disc usedon detours has a fixed white arrow on a redbackground. The disc has eight equally spacedholes around the edge of the circumference toallow the disc to be placed in a vertical planewith the disc arrow pointing in the appropriatedirection.
Dual class bridge. A bridge having one class numberfor wheeled vehicles and another class numberfor tracked vehicles.
Engineer information. Information on topographyand resources of the area in which operationsare being or may be conducted and informationof enemy installations and activities which mayaffect engineer operations.
249
Engineer reconnaissance. The operation of searchingfor engineer information in the field.
Fair-weather road. A road which quickly becomesimpassable in bad weather and which cannot bekept open by normal maintenance. This typeof road is so seriously affected by rain, frost, orthaw, that traffic is brought to a complete haltfor long periods. Examples of this category are:natural soil, stabilized soil, sand-clay, shell,cinders, and disintegrated granite.
Ferry. A barge, boat, or other water vehicle usedto convey traffic and cargo across a river orother water obstacle. Also called ferry boat orferry craft.
Ferry bridge. A movable car, at roadway level,which is suspended from, and which moves backand forth under, an overhead fixed bridge sup-ported on towers, the overhead portion beinghigh enough above water level to afford adequateclearance for navigation.
Ferry site. A place or passage where traffic andcargo are conveyed across a river or other waterobstacle by a water vehicle.
Ferry slip. The shore side of a ferry to facilitate theloading and unloading of ferry craft.
Floating bridge. A ponton bridge or any temporarybridge that is supported by low flat-bottomedboats or other floating structures.
Ford. A shallow place in a stream where the streambottom permits the passage of personnel andvehicles.
Front vehicle classification sign. A circular sign whichis 9 inches in diameter with black numerals, as
250
large as the sign will permit, on a yellow back-ground, and which is placed on the vehicle abovethe bumper to the driver's right and below hisline of vision.
Gallery. Any sunk or cut passageway covered over-head as well as at the sides.
Girder. A steel beam made in a single piece (I-beam) or built up of plates and shapes (angles,channels, Z-sections, etc.). The term also ap-plies to reinforced concrete members which actas girders.
Girder bridge. A bridge with a structure composedof girders.
Gravel. A mass of detached rock particles, generallywater-worn, ranging in size from 3% inch to about4 inches.
Gross weight of a vehicle. The weight of the vehiclewhen fully equipped and serviced for operations,including the crew and the rated payload ofcargo and personnel for cross-country (off-high-way) operation.
Guide sign. A rectangular highway sign erected ina vertical plane, with its long axis horizontal toindicate locations, distances, directions, routenumbers, and other information of help todrivers.
Half-through bridge. A bridge which is shallow orwhose floor is so near to the top chord that nooverhead bracing can be used.
I-Iatracked vehicle. A combination wheeled andtracklaying vehicle in which the rear end issupported by a complete band track and thefront end is supported on wheels. It is driven
251
by the track alone or by the wheels and tracktogether.
Hazard sign. See Warning sign.Headroom. The desirable minimum vertical clear-
ance in a bridge structure, a tunnel, or anunderpass.
Intermediate support of a bridge. A bent or pierbetween the abutments of a multispan bridgewhich supports the ends of two adjacent spans.
Lift bridge. A bridge of which a span can be raisedhorizontally.
Limited all-weather road. A road which, with reason-able maintenance, can be kept open in badweather to a volume of traffic which is consider-ably less than its dry-weather capacity. Thistype of road does not have a waterproof surfaceand is considerably affected by rain, frost, orthaw. Traffic on it is completely halted forshort periods of a day or so at a time. Heavyuse during adverse weather conditions may leadto a complete collapse of the road. Examplesare crushed rock or waterbound macadam,gravel or lightly metaled surface.
Military sketch. A hasty map or sketch of an area,especially one prepared in the field for a specialtactical purpose.
Military vehicle. Any item of equipment whichhabitually moves on land and which is mountedon wheels, tracks, or combinations of wheels andtracks.
Movable bridge. A bridge of which one or more spanscan be moved from their normal position toprovide unobstructed passage for vessels.
252
Multilane bridge. A bridge with a roadway wideenough to pass two or more lanes of trafficsimultaneously.
Normal crossing. A crossing in which the vehicleclassification number is equal to or less thanthe bridge classification number, and where thevehicles maintain a 30-yard convoy spacing.For normal crossing on floating bridges the speedis restricted to 25 miles per hour without suddenstopping or acceleration.
Obstruction. Any obstacle that stops or slows downan advance. Obstructions may be natural(deserts, rivers, swamps, or mountains); or theymay be artificial (barbed-wire, entanglements,pits, concrete or metal antimechanized traps).
Organic matter. Soil composed of decayed or de-caying vegetation, sometimes mixed with fine-grained mineral elements. Examples are peatand muskeg.
Overpass. In common usage, a structure erected topermit a road or railroad route to pass overanother route. However, in order to simplifystructure numbering and identification, thisterm will not be used in route or road recon-naissance. Instead, any structure, along thecourse of a route, erected to permit crossingover another route will be designated as abridge.
Pavement of a road. The top portion of a roadstructure, which comes into direct contact withthe wheel load or the tracked load. It is in-tended to resist traffic wear and dusting, and toprevent surface water from infiltration into theroad structure.
253
Payload of a military vehicle. The total load avehicle is rated to carry, exclusive of the crew.
Pony truss. A half-through bridge truss.Posting a sign. Erecting a highway sign at a desig-
nated location.Prime mover. A vehicle possessing military charac-
teristics, designed primarily for towing heavywheeled weapons and frequently providingfacilities for the transportation of the crew of,and ammunition for, the weapon.
Raft. The term used to describe the individualfloating bays which are to be incorporated intoa continuous bridge.
Rated payload of a military vehicle. The total loada vehicle is rated to carry exclusive of the crew.
Reconnaissance. A directed effort in the field togather information of the enemy, terrain, orresources, which is undertaken by an appropri-ate element of the armed forces. Not to beconfused with espionage.
Regulatory sign. A rectangular highway sign,erected in a vertical plane with its long axisvertical, which indicates speed limit, one-waypassage, parking restrictions, and other specificregulations for vehicles.
Retractile bridge. A bridge which is supported onwheels resting on tracks on shore, and which isrolled horizontally back from the opening. Thisterm is applicable to short spans only.
Risk crossing. A crossing over a prefabricated fixedor floating bridge, permitted only in the gravestemergency where excessive losses will otherwiseresult, and where the vehicle remains on the
254
centerline of the bridge, does not exceed a speedlimit of 3 miles per hour, is the only vehicle onthe span, and does not stop, is not accelerated,or does not have its gears shifted. Tanks mustbe steered by using clutches only. A crossing ispermitted under these conditions only if thevehicle classification number does not exceed thepublished risk classification number of thebridge.
Road. An open way provided for the convenientpassage of personnel and vehicles.
Road classification. The detailed classification of aroad, mainly for engineer purposes. It includeswidth, length, alinement, drainage, foundation,surface, and any particular obstruction butexcludes bridge classification.
Road classification fraction. The presentation of roadclassification information, excepting obstruc-tions, by symbols arranged as a fraction, withsymbols for elements rated "good" and symbolsdenoting road width and road surface beingplaced in the numerator, and symbols for thoseelements rated "fair" or "bad" and symbols forroad length being placed in the denominator.For example-
"good" elements, road width, surface type"fair" or "bad" elements, road length
Road Reconnaissance Report. The report of roadreconnaissance containing the detailed informa-tion necessary for the classification of a road.
Road sketch. A military sketch of a road which hasbeen reconnoitered.
255
Route. The road, or roads, including tracks andbridges, used when moving from one place toanother.
Route classification. The simple classification of aroute to assist staff officers in planning a normalroad movement. It includes width of roads,types of roads, load-carrying capacity of roads,load-carrying capacity of bridges, and the pres-ence of obstructions and other limiting factors.
Route classification formula. Route classificationsymbols arranged in order as follows: width ofroad, type of road, load-carrying capacity.
Route sign. A highway warning, regulatory, or guidesign.
Sand. Soil consisting of mineral grains varying fromabout 4 inch to 0.002 inch.
Semitrailer. A vehicle designed to be towed by andattached to a tractor truck by means of a fifthwheel device, a portion of its weight being car-ried by the tractor truck. It is equipped withretractable gear to support the front end whendetached.
Side vehicle (class) classification sign. A circular signwhich is 6 inches in diameter with black numer-als, as large as the sign will permit, on a yellowbackground, and which is placed on the rightside of the vehicle in such a position that normaluse of the vehicle will not conceal it from view.
Silt. Soil consisting of natural mineral grains smallerthan 0.002 inch which lack plasticity and havelittle or no dry strength.
Single lane bridge. A highway bridge having a road-way of insufficient width to accommodate more
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than one line of vehicular traffic of the classindicated by the bridge classification number.
Single vehicle. Any military vehicle which has onlyone frame or chassis, such as trucks, primemovers, tanks, halftracks, full trailers, and guncarriages.
Skew bridge. A bridge with one or both abutmentsplaced at other than a right angle to the lengthof the bridge. If the piers and abutments are atright angles to the line of the bridge, the bridgeis not skew, even though oblique to the line ofthe stream.
Slab bridge. A short-span bridge, always deck type,consisting of a reinforced concrete slab restingon abutments.
Snowshed. A shelter to protect from snow, as a longstructure over an exposed part of a road orrailroad.
Soil. The solid particles produced by mechanical andchemical disintegration of rocks with an ad-mixture of organic matter and soluble salts.
Span. The center-to-center distance between sup-ports (centers of bearing) of a bridge.
Standard vehicle. An item of equipment which habit-ually moves on land, and is mounted on wheels,tracks, or halftrack and wheels.
Stringer. A basic bridge member, usually a longhorizontal beam which connects uprights andsupports a floor.
Stringer bridge. A bridge designed with a stringersystem, which is composed of longitudinalmembers (stringers) supported by and spanning
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the distance between the transverse (intermedi-ate) supports or end supports (abutments).
Subgrade. The foundation which supports the loadplaced upon a road surface.
Substructure. All of that part of the structure belowthe bridge seats or below the springing line ofarches.
Superstructure. All of that part of the structureabove the bridge seats or above the springingline of arches, or above the caps of timber trestlebents.
Surface course. The top portion of a road structure,which comes into direct contact with thewheeled load or tracked load. It is intendedto resist traffic wear and dusting, and to preventsurface water from infiltration into the roadstructure.
Suspension bridge. A bridge which has its roadwaysuspended from two or more cables usuallypassing over towers and securely anchored atthe ends.
Swing bridge. A bridge which revolves horizontallyabout a vertical axis, and generally consists oftwo or more plate girders or trusses supportedon a pier in such a manner that they can berotated on a circular track or pivot resting onor attached to the pier.
T-beam bridge. A short span bridge, always decktype, consisting of a reinforced concrete deckslab constructed as a monolith with supportingreinforced concrete beams. The slab and beamsare thoroughly tied together by means of stir-rups and bent-up bars. For this reason, part
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of the slab acts to assist the upper part of thebeams in resisting compressive stress.
Through bridge. A bridge in which the floor is onilor near the bottom chord (line of bottom mem-bers), and which is provided with overheadbracing.
Towed vehicle. A single vehicle towed by anothersingle vehicle.
Tracked 'vehicle. A single vehicle having tracks inplace of wheels.
Tracklaying vehicle. A vehicle which travels upontwo endless tracks, one on each side of themachine. Tanks are one type of tracklayingvehicle.
Tractor truck. A vehicle designed to tow a semi-trailer by means of a fifth wheel attachment.
Trafic lane. A width of roadway or bridge assignedto a single line of vehicular traffic.
Trailer. A vehicle designed to be towed, and pro-vided with a suitable drawbar or tongue forattachment to a pintle or other suitable couplingmounted on the towing vehicle.
Treadway bridge. A bridge whose roadway is formedby two tracks or treadways.
Trestle. A braced framework of timbers, poles, orsteelwork. Used alone, the term is ambiguous.It should be expressed as a trestle bent ortrestle bridge.
Trestle bent. A transverse frame which supportsthe ends of the stringers in adjacent spans of atrestle bridge. A trestle bent consists of ver-tical members, called posts; a top member whichsupports the superstructure, called a cap; a
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bottom horizontal member, called a sill; andbracing.
Trestle bridge. A beam bridge commonly used inrailroad construction. The spans are bridgedwith beams (stringers) on which the deck orties are laid directly.
Truss. A structural element that acts like a beam,and is composed of a system of membersjointed together at their ends to form a seriesof triangles, each member carrying primarilyaxial loads.
Truss bridge. A bridge in which the roadway loadsare transmitted from the floor system to thebridge abutments or piers by means of trusses(generally one along each side).
Two lane bridge. A highway bridge having a road-way of sufficient width to simultaneously ac-commodate two lines of vehicular traffic of theclass indicated by the bridge classificationnumber.
Underpass, highway. A structure which permits ahighway to pass below another road or arailroad route.
Vehicle. A general military term embracing allwheeled, tracklaying, combined wheeled andtracklaying equipment and chassis powered bya self-contained power unit, bicycles, andtrailers or semitrailers towed by vehicles. Seealso Combination vehicle; Halftracked vehicle;Military vehicle; Semitrailer; Single vehicle;Standard vehicle; Towed vehicle; Trackedvehicle; Tracklaying vehicle; Tractor truck;Trailer; Wheeled vehicle.
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Vehicle (class) classification number. A whole num-ber which represents the effect a vehicle has ona bridge in crossing it. This effect dependsupon the gross weight of the vehicle and itsweight distribution to the axles or tracks.
Vehicle (class) classification sign. A sign placed ona classified vehicle to show its (class) classifica-tion number.
Viaduct. A term applied to multispan structuresconsisting of narrow reinforced concrete ormasonry arches, or short steel spans supportedon high towers or piers of concrete, masonry,or steel, for carrying a road or railroad overa valley.
Warning sign. A square highway sign with its diag-onal in a vertical plane to indicate road hazardsand conditions requiring special precaution.
Wheeled vehicle. A vehicle mounted on wheels asopposed to a full or partial tracklaying vehicle.
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APPENDIX XI
TABLES
PageI. Ratings of Elements Used in Road Classifica-
tion ---------------------------------- 27II. Symbols for Length and Width of Road, and
for Types of Road Surfaces ------------- 28III. Road Signs-Shapes and Colors ----------- 30IV. Road Signs-Applications -------------... 31V. General Dimension Data Required for Each
of the Seven Basic Types of Bridges ----- 51VI. Capacity Dimension Data Required for Each
of the Seven Basic Types of Bridges ----- 52VII. Minimum Widths of Bridges Used in Bridge
Class Computations -.------------------- 57VIII. Trafficability of Fords -................. 75
IX. Estimated Load-Carrying Capacity of IceLayers in Direct Contact With WaterBeneath ------------------------------ 84
X. Vehicle Classification Data ---------------- 112XI. Principal Soil Types -------------- 162
XII. Soil Classification Chart ----------------- 164XIII. Allowable Foundation Bearing Pressures ---- 166XIV. Hypothetical Vehicle Classification Numbers
and Their Significance ------------------ 167XV. Material Factors for Masonry Arch Bridges__ 217
XVI. Joint Factors for Masonry Arch Bridge ----- 218XVII. Crack Factors in Masonry Arch Bridges ---- 219
XVIII. Deformation Factors for Masonry ArchBridges ------------------------------- 223
XIX. Abutment Size Factors for Masonry ArchBridges -............................ 224
262
Page
XX. Abutment Fault Factors for Masonry ArchBridges ------------------------------- 225
XXI. Properties of Steel Beams ----------------- 229XXII. Floating Bridge Classification ------------- 237
XXIII. Raft Classification ----------------------- 238_XXIV. Classification of Panel Bridge, Bailey Type,
M2, (150-Inch Roadway) --------------- 240XXV. Classification of Portable Steel Highway
Bridge, H20 -------------------------- 242XXVI. Classification of Steel Treadway Fixed
Bridges, M2 and Widened -------------- 243[AG 253 (2 Aug 54)]
263
BY ORDER OF THE SECRETARY OF THE ARmY:
M. B. RIDGWAY.General, United States Army,
OFFICIAL: Chief of Staff.JOHN A. KLEIN.
Major General, United States Army,The Adjutant General.
DISTRIRUTION:Active Army:
G1, G2, G3 (2) Cml Co (1)DEP LOG (2) Med Co (1)Tee Svc, DA (1) QM Co (1)COFENGRS (10) SigC Co (1)Tec Svc Bd (2) Engr Co (3)AFF (10) FA Btry (3)Army AA Comd (2) Inf Co (3)OS Maj Comd (25) Ord Co (3)OS Base Comc (2) Armd Co (3)Log Comd (2) AAA Btry (3)MDW (1) TC Co (3)Armies (5) Ft & Cp (2)Corps (5) IUSMA (10)Div (5) FA Sch (100)Engr Brig (3) InS Sch (100)Engr GP (3) Armd Sch (100)Cml Bn (1) TC Sch (100)Med Bn (1) Engr Seh (135)QM Bn (1) CGSC (10)SigC Bn (1) PMST Engr ROTC units (2)Rngr Bn (3) Engr Div (1)FA Bn (3) Engr Dist (1)Inf Bn (3) Mil Dist (2)Ord Bn (3) Units organized under follow-Armc Bn (3) ing TOE's:AAA Bn (3) 7-11, Inf Regt (2)TC Bn (3) 17-51, Armd Cav Regt (2)NO: None.USAR: None.Unless otherwise noted, distribution applies to ConUS and o'erseas.For explanation of abbreviations used, see SR 320-50-1.
264 u. s. GOVERNMENT PRINTING OFFICE: 1955 0-332944
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