ROADSIDE SIGN

INSTALLATION AND MAINTENANCE

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ROADSIDE SIGN INSTALLATIONAND MAINTENANCE

Importance of Signs

Roadway signs give information on highwayroutes, directions, destinations and points ofinterest , and are especially helpful for thedriver who is unacquainted with the highwayand the area. To be effective, signs must bein good repair, properly placed and visibleboth day and night. Timely and correctmaintenance of traffic signs is cri t ical .Damaged, obscured, or missing signs may failto provide needed information to a driver andcan contribute to a crash. When properlyinstalled and maintained they can make a bigcontribution to the safety of the highwaysystem.

Common Deficiencies

The most common signing deficiencies aremissing signs, signs that cannot be seen dueto faded sheeting or hidden by trees, andimproperly installed breakaway posts.

Inspections

Inspections should be made at least once peryear to check for damage, visibil i ty, properbreakaway device operation, and generalcondition. Inspections should be made bytrained and qualified personnel and is easierif two persons make the inspections so thatnotes can be taken without interfering withdriving. Warning lights should always beused on the vehicle for safety. In addition toregular inspections, maintenance personnelshould be alert during normal travel toobserve signs for legibil i ty and damage.Other employees who frequently travel thehighways should also be instructed to reportany obscured, damaged or missing signs.Corrective action should be taken

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immediately. Sometimes damaged signs canbe replaced at a better location, but crewsshould never move or take down a signunless someone with the appropriate -authority has approved the change. Nightinspections should be made at least once peryear to check for reflectivity of the signface.

Breakaway Post Installation andMaintenance

Roadside signs can be a severe roadsidehazard if they are not correctly installed andregularly maintained. The followingguidance is to help field crews in their jobof installing and maintaining the breakawayfeatures on roadside signs. Severalbreakaway types are commonly used,depending on size of sign, etc:

Large Sign Breakaway Bases

• 4-bolt Slip Base• 4-bolt Shear Connector

Large roadside signs may use either theslip-base design (Figure 1) or the shearconnector type (Figure 2), but the slip-basetype is most commonly used in SaudiArabia. The 4-bolt slip-base and the 4-boltshear connector types both work on theprinciple of having the signpost release atground line when hit by a vehicle. The postthen rotates up and out of the vehicle path(Figure 3). To safely do this a hinge point isrequired just below the sign face (Figure 4).

A. Slip-Base Breakaway:

When hit from the front the four boltsclamping the two slip-base plates togetherare pushed out of the slotted holes as theupper post slides away from the fixed stub

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plate. Although the slip-base can breakaway when struck from either the front orback, it works best when hit from the front(sign face) side. It will not work if hit fromthe side, so this type should not be used inintersections, etc., where side hits arelikely.

Slip-bases are normally used on multi-postlarge signs, and as a general rule the postsshould be spaced at least 2.4 m apartwhenever possible so that only one post islikely to be hit during a crash. The bottomof the sign should also be at least 2.1 mabove the ground to avoid having the signpanel hit the top of the car during a crash.

Another very critical i tem is how far thestub posts are exposed above ground line.Many times these stub posts are much toohigh, either from poor installation practicesor from erosion around the foundation. Thestub posts should never be exposed morethan 100 mm.

Because of its design, the torque (tension)in the high-strength bolts on the slip-base isEXTREMELY CRITICAL for properoperation. These high-strength bolts shouldbe loosened and re-torque at least once peryear so that wind vibration does not loosenthe bolts causing the sign to collapse. Athin sheet metal bolt retainer (30-gauge)placed between the slip-base plates willhelp keep any loose bolts in place until thenext inspection and re-torquing. Figure 8shows details of a 4-bolt slip-base andtorque requirements.

As previously mentioned, a hinge point isrequired on the posts just below the signface, to allow the post to rotate awayfrom an impacting vehicle and to allow itto pass under the sign. Without a hinge,the sign panel binds the post and preventsit from

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easily swinging out of the way of thevehicle. Figure 9 shows details at a hingejoint and the bolt torque requirement.

B. Shear Connector Breakaway:

Although not as commonly used, these typesof breakaway supports may be encountered.These are specialized designs that must beinstalled and repaired according to themanufacturer 's instructions. (TranspoIndustries is the supplier.) The StandardDrawings should be referred to as well asthe manufacturer 's installation procedures.This type base will work when hit from anydirection and there are no bolt torquerequirements. Both of these features makethis a desirable design. As previously noted,the stub post must not be installed too high;height above ground line must not be morethan 100 mm. This design also uses hingesand fuse plates just below the sign face, andsince it can function when hit from anydirection, fuse plates should be used onboth front and back sides of the posts.

Small Sign Breakaway Bases

Small signs are usually placed on either aslip-base (3-bolt) or a threaded pipecoupling type breakaway base.

A. 3-Bolt Slip Base:

This design is excellent since it will workwhen hit from any direction, and isespecially well suited for intersectionsalthough it can be used anywhere a smallsign is needed. The base is triangular inshape (see Figure 6) and has 3 bolts withwashers between the plates. The bolts mustnot be overtightened. See the torque table inFigure 8 for slip-bases. This type baseshould be used to replace any of the oldertype inclined (angled) slip bases due to

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being able to function when hit from anydirection.

B. Threaded Pipe Coupling:

This small sign breakaway base type is alsouseful, and is simple to maintain. Thecoupling is simply threaded onto the stubpost at ground line and the sign post isthreaded into the coupling. When hit , thepost usually shears off just above thecoupling or the coupling breaks, soreplacement of the post may only requirereplacement of coupling. Sometimes thepost can be reused. It is very important thatthe stub post and coupling be located atground line (see Figure 7), not above it .

Important Points to Remember(See Figures 8 & 9)

1. Keep the stub post height close to groundline (max 100mm), so the impactingvehicle does not hit i t .

2. Slip-base designs must have correct bolttorque. Many times the bolts are tootight from vibrating out.

3. Use a bolt retainer plate (30-gaugemetal) on slip-base designs to preventloose bolts from vibrating out.

4. Washers must be placed between theslip-base plates to prevent excessfriction.

5. When a sign is severely damaged andmust be completely replaced, considerrelocating it further from the roadway.Large signs can be moved outward up to10 m without reducing their visibility,and they are seldom hit when placed thatfar out from the roadway.

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6. Before starting any work, place all necessarywarning devices so that the work can be donesafely. Park all work vehicles away from trafficwhen not needed. Refer to the Ministry's pocketmanual on work zone traffic control.

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8

BOLTING PROCEDURE FOR ASSEMBLY OFBASE CONNECTION:

1. ASSEMBLE SIGN POST, BOLT KEEPER PLATE AND STUB POST WITH BOLTS AND THREE FLAT WASHERS PER BOLT AS SHOWN. 2. SHIM AS REQUIRED TO PLUMB POST.3. TIGHTEN ALL BOLTS THE MAXIMUM POSSIBLE WITH A 305 TO 381 MM WRENCH TO CLEAN BOLT THREADS AND TO BED WASHERS AND SHIMS.4. LOOSEN EACH BOLT IN SEQUENCE AND RETIGHTEN BOLTS IN A SYSTEMATIC ORDER TO THE PRESCRIBED TORQUE. DO NOT OVER TIGHTEN. 5. TO PREVENT NUT LOOSENING, BURR THREADS OF BOLT AT JUNCTION WITH NUT USING A CENTER PUNCH.6. SEE BASE CONNECTION TABLE BELOW FOR BOLT TORQUE REQUIREMENTS.

FOUNDATION FLUSHWITH GROUND

STUB POST

W.P.

40 D

ESI

RA

BL

E10

0 M

AX

IMU

M

H.S. HEX HEAD BOLT, HEX NUT,AND THREE WASHERS EACH BOLT.SEE BASE CONNECTION DATA TABLEAT RIGHT FOR BOLT TORQUE. DO NOTOVER TIGHTEN.

SEE BOLTING PROCEDURE FORASSEMBLY OF BASE CONNECTION.

WASHER

BOLT KEEPERPLATE (30 GA)

REMOVE ALLGALVANIZINGRUNS OR BEADSIN WASHER AREA

STIFFENER PLATE

SIGN POST

1/2"

t1 (T

yp.)

POST

LE

NG

TH

(SE

E P

RO

JEC

T P

LA

NS)

W1

W2

TYP.6(1/2 t )

AA

varie

s

varies varies

SEE NOTE BELOW

NOTE:(MAY BE CUT AS SHOWN, OR MAY BERECTANGULAR & SIZED TO FIT POST.

BREAKAWAY SLIP BASE CONNECTION DETAIL

BASE CONNECTIONPOST SIZE BOLT SIZE

& TORQUE

16 Ø X 70 50 NM

85 NM19 Ø X 90

W6X9

W6X12

W6X15

W6X18

W8X21

W10X22

W10X26

W12X26

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MINISTRY OF COMMUNICATIONSKINGDOM OF SAUDI ARABIA

DATEDRAWING NUMBER121 A SS-3J 6/1418

Figure 5Breakaway Sign Posts

(Page 2 of 1)

FUSE PLATE BOLT TORQUE1. ALL FUSE PLATE BOLTS SHALL BE TIGHTENED IN THE SHOP TO PRODUCE THE REQUIRED MINIMUM TENSION IN CONFORMATION WITH ASTM - A325 OR THE EQUIVALENT TORQUE AS SHOWN IN THE TABLE BELOW. AFTER POSTS ARE SHIPPED AND ERECTED AT THEIR SITES. THE NUTS SHALL BE LOOSENED AND RE-TORQUED TO THEIR PROPER VALUE.2. AFTER BEING RE-TORQUED TO THE SATISFACTION OF THE ENGINEER. THE NUTS, BOLTS AND WASHERS SHALL BE FREED OF RUST. CLEANED AND GIVEN A HEAVY AND THOROUGH COAT OF ZINC - RICH PAINT.

BOLT SIZE TORQUE MIN. RESIDUAL TENSION

13 Ø 135 NM 54 KN

16 Ø 270 NM 85 KN

480 NM19 Ø 126 KN

715 NM22 Ø 175 KN

1070 NM25 Ø 229 KN

1835 NM29 Ø 251 KN

BREAKAWAY CONNECTION DETAIL(SEE SHEET SS-3J)

SECTION A-A

Sign Panel

50 45°

100

Back Plate(if used)

Saw Cut3 (Max)

Flat Washers

H.S. BoltsFuse Plate

(treated with slotstowards base)

Sign Post

Directionof Traffic

40 Desirable100 Max

Washers (3)Base

Bolt Keeper Plate

H.S. Bolts

Stub Post

CL

CL

Directionof Traffic

Washer

Washer

Washer

Bolt Keeper Plate

See Bolt Torque forBase Connection(page 2)

Stub Post

Back Plate(if used)

Sign Post

Fuse Plate

See Bolt Torque at left

Dir

ectio

nof

Tra

ffic

Top 45° Bevel Optional

FGL

A A

MINISTRY OF COMMUNICATIONSKINGDOM OF SAUDI ARABIA

DATEDRAWING NUMBER121 B

Figure 6Breakaway Sign Posts

(Page 1 of 2)

SS-3K 6/1418

GENERAL NOTES:

1. SUPPORT AND DESIGN SHALL CONFORM WITH CURRENT AASHTO STANDARD SPECIFICATIONS FOR STRUCTURAL SUPPORTS OF HIGHWAY SIGNS, LUMINAIRES AND TRAFFIC SIGNALS WITH A DESIGN WIND SPEED OF 100 KMPH.2. STEEL PIPE SHALL BE GALVANIZED IN ACCORDANCE TO ASTM DESIGNATION A123.3. WHERE SOLID ROCK IS ENCOUNTERED AT GROUND LEVEL, THE FOUNDATION SHALL BE A MINIMUM DEPTH OF 450mm WHEN SOLID ROCK IS ENCOUNTERED BELOW GROUND LEVEL, THE FOUNDATION SHALL EXTEND INTO THE SOLID ROCK A MINIMUM DEPTH OF 450mm OR PROVIDE A MINIMUM FOUNDATION DEPTH OF 750mm ONLY CONCRETE FOUNDATION SHALL BE USED IN ROCK.4. UNLESS OTHERWISE SHOWN ALL DIMENSIONS ARE IN MILLIMETERS.

TRIANGULAR SLIP BASE NOTES:

1. THE LIFTING RAMP MAY CONSIST OF WELDED RAMPS OR A CONICAL SHAPE FORMED INTO THE CENTER OF THE STUB POST BASE PLATE.2. THE SIGN POST BASE PLATE OF THE TRIANGULAR SLIP BASE SHALL HAVE THE SAME EXTERIOR DIMENSIONS AS THE BOTTOM PLATE. THE LIFTING RAMP SHALL BE A PART OF THE STUB POST BASE PLATE ONLY. A HOLE EQUAL TO THE INSIDE DIAMETER OF THE SIGN POST BASE PLATE WITH THE HOLE EDGE BEVELED AS DETAILED.3. THE BASE PLATES AND LIFTING RAMP SHALL CONFORM WITH THE REQUIREMENTS OF ASTM A36 OR A572 GRADE 50.4. ALL STRUCTURAL STEEL SHALL BE GALVANIZED IN ACCORDANCE WITH ASTM A123. THE ENTIRE SUPPORT SHALL BE GALVANIZED FROM THE TOP DOWN TO A MINIMUM DEPTH OF 150mm INTO THE FOUNDATION. ALL NUTS, BOLTS, AND WASHERS SHALL BE GALVANIZED IN ACCORDANCE WITH ASTM DESIGNATION B695 CLASS 50 OR A153 CLASS C OR D.5. ALL HIGH STRENGTH BOLTS SHALL CONFORM TO ASTM A325 (ASTM A449 MAY BE SUBSTITUTED FOR ASTM A325 PROVIDED PROPER BOLT HEAD, NUT AND/OR WASHER CLEARANCES ARE MAINTAINED) ALL HIGH STRENGTH NUTS SHALL BE OF SUCH CAPACITY AS TO DEVELOP THE BOLT STRENGTH.

BOLTING PROCEDURE FOR ASSEMBLING OF BASE CONNECTION:

1. ASSEMBLE SIGN POST, BOLT KEEPER PLATE AND STUB POST WITH BOLTS AND THREE FLAT WASHERS PER BOLT AS SHOWN.2. SHIM AS REQUIRED TO PLUMB THE POST.3. TIGHTEN ALL BOLTS THE MAXIMUM POSSIBLE WITH A 300 TO 400mm WRENCH TO CLEAN BOLT THREADS AND TO BED WASHERS AND SHIMS.4. LOOSEN EACH BOLT IN SEQUENCE AN RETIGHTEN BOLTS IN A SYSTEMATIC ORDER TO THE PRESCRIBED TORQUE OF 50 NM DO NOT OVER TIGHTEN .5. TO PREVENT NUT LOOSENING, BURR THREADS OF BOLT AT JUNCTION WITH NUT USING A CENTER PUNCH.BREAKAWAY TRIANGULAR SLIP BASE

DETAIL 'A'

BREAKAWAY PIPE COLLAR COUPLING BREAKAWAY TRIANGULAR SLIP BASE

BOLT KEEPER PLATESIGN POST & STUB POSTSECTION A-A

44

22

44

22

21 DSHIM

FURNISH TWO 0.3 THICKAND TWO 0.8 THICKSHIMS PER POST. SHIMSSHALL BE FABRICATED FROMBRASS SHIM STOCK OR STRIPCONFORMING TO ASTM B36.

32

264

76 76

18 DIA. HOLES51

264

30°30°

DIA. 108

NOTE: BOLT KEEPER PLATE SHALL BE 30 GAUGE GALVANIZED STEEL.

264

76 76

32

264

5130°30°

104

60°60°

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PROVIDE 13 DIA. (MAX)HOLE IN THE STUB POST BASEPLATE WITHIN THE INSIDE RADIUSOF THE STUB POST FORGALVANIZED DRAINAGE.

PLUG WELD

6 TYP.

6

TYP. SEAL WELD ATENDS-GROUND SMOOTH

THE BEVEL END SHALL BE TANGENT TOTHE BOLT HOLE. ANY MISALIGNMENTSHALL BE CORRECTED BY GRINDING.FACE OF BEVEL SHALL BE FINISHEDTO A MINIMUM SMOOTHNESSOF f=500

TRIANGULAR SLIP BASE SHALL BE USED FOR SIGNSSUPPORTED ON 76mm DIAMETER AND LARGER PIPE POSTS

30

150

For 7

6 an

d 89

dia

. pip

e10

00 fo

otin

g de

pth

40 TO 100

PermissibleShop Splice

380

Min

.

Non-reinforcedConcrete Footing

SEE DETAIL 'A'

Triangular Slip Base

Sign Cross-arm(s)

TRIANGULAR SLIP BASE SHALL BE USED FOR 76mAND LARGER PIPE POSTS. THE CROSS-ARM(S) SHOULD BEPARALLEL TO ONE SIDE OF THE TRIANGULAR SLIP BASE.

Triangular slip base(SEE DETAILS THIS DRAWING)

Sign Cross-arm(s)

Tack weld

Tack weldStandardthreaded pipecollar coupling

Sign post

Sign cross-arm(s)

30615

0

For 5

1 an

d 64

dia

. pip

e75

0 Fo

otin

g D

epth

PermissibleShop splice

380

Standard threaded pipecollar coupling

Non-reinforcedconcrete footing

Coupling shall beflush or projecteda max. 6mmabove top of foundation

159

76 or 88Nominal dia.

pipe(galvanized)

Sign postBase plate

Washer

SEE NOTE 1

BOLT KEEPER PLATE

Lifting Ramp

25 159

Stub postbase plate

16 Ø x 70 H.S. Hex Bolt(3 required, with 3 washer each)

TOP OF CONCRETE FOOTINGTO MATCH GROUND LINE

40 T

YP.

(100

MA

X)

WASHER6

6

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MINISTRY OF COMMUNICATIONSKINGDOM OF SAUDI ARABIA

DATEDRAWING NUMBER110-E

Figure 7Breakaway Sign Details

For Small Roadside Signs

SS-1Q Jumada, 1 - 1418

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