8/11/2019 2911 Draft -Part2

1/35

For Comments only Doc: CED 43(7283)

BUREAU OF INDIAN STANDARDS

DraftIndian Standard(Not to be reproduced without the permission of BIS or used as Standard)

DESIGN AND CONSTRUCTION OF PILE FOUNDATIONS CODE OFPRACTICE

PART 1 CONCRETE PILES

SECTION 2 BORED CAST IN SITU CONCRETE PILES[Second Revision of IS 2911 (Part 1/Section 2)]

------------------------------------------------------------------------------------------------------------Soil and Foundation Engineering Last Date of Receipt ofSectional Committee, CED 43 Comments : 31032005------------------------------------------------------------------------------------------------------------

FOREWORD((Formal clauses will be added later)

This standard was originally published in 1964 and subsequently revised in 1979.It included provisions regarding driven cast-in-situ piles, precast concrete piles,bored cast-in-situ piles, under reamed piles and load testing of piles. It hasnow been felt that the provisions regarding the different types of piles should befurther revised for ease of reference and to take into account the recentdevelopments in this field. This revision has been brought out to incorporatethese developments. This standard has been published in the following sections.

Section 1 Driven cast-in-situ concrete pilesSection 2 Bored cast-in-situ concrete pilesSection 3 Driven precast concrete pilesSection 4 Precast piles in prebored holes

In the present revision following major modifications have been made:

a) Definitions of various terms have been modified as per the prevailingpractice in the country. Procedures for calculation of bearing capacity,structural capacity, factor of safety, lateral loads capacity, overloading etc.have also been modified to bring them at par with the present practices.

8/11/2019 2911 Draft -Part2

2/35

2

b) Design parameters with respect to adhesion factor, earth pressurecoefficient, subgrade modulus etc. have been revised to make themconsistence with the outcome of modern research and constructionpractices.

c) Minimum grade of concrete to be used in pile foundations has been

revised to M25.

1. SCOPE

1.1 This standard (Part 1/Sec 2) covers the design and construction of boredcast in-situ concrete piles which transmit the load to the soil by resistancedeveloped either at the pile tip by end-bearing or along the surface of the shaft byfriction or by both.

1.2 This standard does not cover the use of bored cast-in-situ concrete pilesfor any other purpose, for example, temporary or permanent retaining structure.

2. REFERENCES

The Indian Standards given in Annexure A contain provisions which throughreference in this text, constitute provisions of this standard. At the time ofpublication, the editions indicated were valid. All standards are subject torevision, however, from time to time and parties to agreements based on thisstandard are advised to apply the most recent editions of the standards.

3. TERMINOLOGY

For the purpose of this standard, the following definitions shall apply.

3.1 Bored Cast-in-situ pile

Piles formed by boring a hole in the ground by percussive or rotary method withthe use of temporary/permanent casing or drilling mud and subsequently fillingthe hole with reinforced concrete.

3.2 Batter Pile (Raker Pile)

The pile which is installed at an angle to the vertical using temporary orpermanent liner.

3.3 Load Bearing Pile

A pile formed in the ground for transmitting the load of a structure to the soil bythe resistance developed at its tip and/or along its surface. It may be formedeither vertically or at an inclination (batter pile) and may be required to resistuplift forces.

If the pile supports the load primarily by resistance developed at the pile tip orbase it is called End Bearing Pile and, if primarily by friction along its surface,then Friction Pile.

8/11/2019 2911 Draft -Part2

3/35

3

3.4 Anchor Pile

A pile meant for resisting pull or uplift forces.

3.5 Small and large diameter piles

Piles of 600mm or less in diameter are commonly known as small diameter pileswhile piles greater than 600mm dia are called large diameter piles. The followingnominal diameters (in mm) are commonly used in piling:

450, 500, 600, 750, 800, 900, 1000, 1100, 1200 and upto 2000 mm.

3.6 Ultimate Load Capacity

The maximum load which a pile can carry before failure, i.e., when the soil failsby shear as evidenced from the load settlement curve or the pile fails as astructural member.

3.7 Allowable Load

The load which may be applied to a pile after taking into account its ultimate loadcapacity, pile spacing, the allowable settlement, negative skin friction and otherrelevant loading conditions.

3.8 Safe Load

It is the load derived by applying a factor of safety on the ultimate load capacityof the pile or as determined from load test.

3.9 Working Load

The load assigned to a pile as per design.

3.10 Factor of Safety

It is the ratio of the ultimate load capacity of a pile to the safe load on the pile.

3.11 Gross Displacement

The total movement of the pile top under a given load.

3.12 Elastic Displacement

This is the magnitude of displacement of the pile head after rebound on removalof a given test load. This comprises two components:

a) Elastic displacement of the soil participating in the load transfer, andb) Elastic displacement of the pile shaft

8/11/2019 2911 Draft -Part2

4/35

4

3.13 Net Displacement

The net vertical movement of the pile top after the pile has been subjected to atest load and subsequently released.

3.14 Test Pile

A pile which is selected for load testing and which is subsequently used as a partof the foundation. The test pile may form a working pile itself, if subjected toroutine load test up to one and one-half times the safe load.

3.15 Working Pile

A pile forming part of the foundation system of a given structure.

3.16 Trial Pile

One or more piles, which are not working piles, may be installed if required to

assess the load-carrying capacity of a pile. These piles are tested either to theirultimate load capacity or to twice the estimated safe load.

3.17 Cut Off Level

It is the level where a pile is cut-off to support the pile caps or beams or any otherstructural components at that level.

4. NECESSARY INFORMATION

4.1 For the satisfactory design and construction of driven cast in-situ piles thefollowing information would be necessary:

a) Site investigation data as laid down under IS 1892, or any other relevantIS Code. Sections of trial boring, supplemented, wherever appropriate, bypenetration tests, should incorporate data/information sufficiently belowthe anticipated level of founding of piles but this should generally be notless than 10 metres unless bed rock or firm strata have been encountered.

b) The nature of the soil both around and beneath the proposed pile shouldbe indicated on the basis of appropriate tests of strength, compressibilityetc. Ground water level and artesian conditions, if any, should also berecorded. Results of chemical tests to ascertain the sulphate, chloride

and any other deleterious chemical content of soil and water should beindicated.

c) For piling work in water, as in the case of bridge foundation, data on highflood levels, water level during the working season, maximum depth ofscour, etc, and in the case of marine construction, data on high and lowtide level, corrosive action of chemical present and data regarding flow ofwater should be provided.

8/11/2019 2911 Draft -Part2

5/35

5

d) The general layout of the structure showing estimated loads and moments

at the top of pile caps but excluding the weight of the piles and capsshould be provided. The top levels of finished pile caps shall also beindicated.

e) All transient forces due to seismic, wind, current etc are to be indicatedseparately.

4.2. As far as possible all information in 4.1 shall be made available to theagency responsible for the design and/or construction of piles and/or foundationwork.

The design details of pile foundation shall give the information necessary forsetting out and layout of piles, cut-off levels, finished cap level, layout andorientation of pile cap and the safe capacity of each type of pile, etc.

5. EQUIPMENT AND ACCESSORIES

5.1 The equipment and accessories would depend upon the type of bored cast-in-situ pile chosen for a job after giving due consideration to the subsoilstrata, ground water condition, and the required penetration therein.

5.2 Among the commonly use plants, tools and accessories, there exist a largevariety: suitability of which depends on the subsoil conditions and manner ofoperations, etc.

5.3 Boring operations are generally done by percussion or rotary type rigs withDirect Mud Circulation of Reverse Mud Circulation methods to bring thecuttings out. In soft layers and loose sands, bailers and chisel methodshould be used with caution to avoid the effect of suction.

5.4 Drilling mud should be used for stabilizing the side of bore holes wherestabilization is not done by casing.

5.5 Standard augur boring without proper stabilization of borehole by drillingmud or casing should not be used for bored piling work.

5.6 Kentledge Dead weight used for applying a test load on a pile.

5.7 Pile Rig A movable steel structure for driving piles in the correct position

and alignment by means of a hammer operating in the guides of the frame.

6 DESIGN CONSIDERATIONS

6.1 General

Pile foundations shall be designed in such a way that the load from the structurecan be transmitted to the soil without causing any soil failure and without causingsuch settlement, differential or total, under permanent/transient loading whichmay result in structural damage and/or functional distress. The pile shaft should

8/11/2019 2911 Draft -Part2

6/35

6

have adequate structural capacity to withstand loads (vertical, axial or otherwise)and moments which are to be transmitted to the subsoil.

6.2 Adjacent Structures

6.2.1 When working near existing structures care shall be taken to avoid damage

to such structures. IS 2974 (Part 1) may be used as a guide for studyingqualitatively the effect of vibration on persons and structures.

6.2.2 In case of deep excavations adjacent to piles, proper shoring or othersuitable arrangement shall be made to guard against undesired lateral movementof soil

6.3 Pile Capacity

The bearing capacity of a pile depends on the properties of the soil in which it isembedded. Axial load from a pile is normally transmitted to the soil through skinfriction along the shaft and end bearing at its tip. A horizontal load on a vertical

pile is transmitted to the soil primarily by horizontal subgrade reaction generatedin the upper part of the shaft. Lateral load-bearing capacity of a single piledepends on the soil reaction developed and the structural capacity of the shaftunder bending. It would be essential to investigate the lateral load capacity ofthe pile using appropriate values of horizontal modulus of the soil.

6.3.1 The ultimate bearing capacity of a pile may be estimated by means ofstatic formula based on soil test results. Pile capacity should preferably beconfirmed by initial load tests on trial piles tested to its ultimate level particularlyin locality where experience of piling is not available.

The settlement of pile obtained at safe load/working load from load-test resultson a single pile shall not be directly used for estimating the settlement of astructure. The settlement may be determined on the basis of subsoil data andloading details of the structure as a whole using the principles of soil mechanics.

6.3.2 Static formula

The ultimate load capacity of a single pile may be obtained by using staticanalysis, the accuracy being dependent on the reliability of the soil properties forvarious strata. When computing capacity by static formula, the shear strengthparameters obtained from borehole and laboratory test data should besupplemented, wherever possible, by in-situ shear strength obtained from field

tests if borehole / laboratory test data are found inadequate. The two separatestatic formulae, commonly applicable for cohesive and non-cohesive soil areindicated in Annexure B. Other alternative formulae may also be applicabledepending on the subsoil characteristics. Such formula using static conepenetration data and standard penetration resistance are given in Annexure 3details of which are given in Sections B-3 and B-4 of Annexure B.

6.3.3 Uplift Capacity

The uplift capacity of a pile is given by sum of the frictional resistance and theweight of the pile (buoyant or total as relevant). The recommended factor of

8/11/2019 2911 Draft -Part2

7/35

7

safety is 3.0 in the absence of any pullout test results and 2.0 with pullout testresults. Uplift capacity can be obtained from static formula (Annexure B) byignoring end bearing but adding weight of the pile (buoyant or total as relevant).

6.4 Negative Skin Friction or Dragdown Force

When a soil stratum, through which a pile shaft has penetrated into a underlyinghard stratum, compresses as a result of either it being unconsolidated or it beingunder a newly placed fill or as a result of remoulding during driving of the pile, adragdown force is generated along the pile shaft up to a point in depth where thesurrounding soil does not move downward relative to the pile shaft. Existence ofsuch a phenomenon shall be assessed and suitable correction shall be made tothe allowable load where appropriate.

Note Estimation of this dragdown force is still under research. Although a few empiricalapproaches are available they are still under revision and therefore no definite proposal isembodied in this standard.

6.5 Structural Capacity

The piles shall have necessary structural strength to transmit the loads imposedon it, ultimately to the soil.

6.5.1 Axial Capacity

Where a pile is wholely embedded in the soil its axial carrying capacity is notlimited by its strength as a long column. Where piles are installed through veryweak soils, special considerations shall be made to determine whether the shaftwould behave as a long column or not; if necessary, suitable reductions shall bemade for its structural strength following the normal structural principles covering

the buckling phenomenon.

When the finished pile projects above ground and is not secured against bucklingby adequate bracing, the effective length will be governed by the fixity imposedon it by the structure it supports and by the nature of the soil into which it isinstalled. The depth below the ground surface to the lower point of contraflexurevaries with the type of the soil. In good soil the lower point of contraflexure maybe taken at a depth of 1 metre below ground surface subject to a minimum of 3times the diameter of the shaft. In weak soil such as soft clay or soft silt, thispoint may be taken at about half the depth of penetration into such stratum butnot more than 3 metres or 10 times the diameter of the shaft whichever is less.The degree of fixity of the position and inclination of the pile top and the restraint

provided by any bracing shall be estimated following accepted structuralprinciples.

The permissible stress shall be reduced in accordance with similar provision forreinforced concrete columns as laid down in IS 456.

8/11/2019 2911 Draft -Part2

8/35

8

6.5.2 Lateral Load Capacity

A pile may be subjected to transverse force for a number of causes, such aswind, earthquake, water, current, earth pressure, effect of moving vehicles orships, plant and equipment, etc. The lateral load-carrying capacity of a singlepile depends not only on the horizontal subgrade modulus of the surrounding soil

but also on the structural strength of the pile shaft against bending, consequentupon application of a lateral load. While considering lateral load on piles, effectof other co-existent loads, including the axial load on the pile, should be takeninto consideration for checking the structural capacity of the shaft. Arecommended method for the pile analysis under lateral load in given inAnnexure D. Other accepted methods such as the methods of Reese andMatlock or Broms may also be used.

6.5.2.1 Because of limited information on horizontal modulus of soil, andpending refinements in the theoretical analysis, it is suggested that the adequacyof a design should be checked by an actual field load test.

6.5.2.2 RakerPiles

Raker piles are normally provided where vertical piles cannot resist the appliedhorizontal forces. Generally the rake will be limited to 1 horizontal to 6 vertical inthe preliminary design the load on a raker pile is generally considered to be axial.The distribution of load between raker and vertical piles in a group may bedetermined by graphical or analytical methods. Where necessary, dueconsideration should be made for secondary bending induced as a result of thepile cap movement, particularly when the cap is rigid. Free-standing raker pilesare subjected to bending moments due to their own weight, or external forcesfrom other causes. Raker piles, embedded in fill or consolidating deposits, maybecome laterally loaded owing to the settlement of the surrounding soil. Inconsolidating clay, special precautions, like provision of permanent causing,should be taken for raker piles.

6.6 Spacing of Piles

The center to center spacing of piles is considered from two aspects, viz.,

a) practical aspects of installing the piles; and

b) the nature of the load transfer to the soil and possible reduction in thebearing capacity of piles group.

6.6.1 In case of piles founded on hard stratum and deriving their capacity mainlyfrom end bearing the minimum spacing shall be 2.5 times the diameter of thecircumscribing circle corresponding to the cross-section of the shaft. In case ofpiles resting on rock, the spacing of two times the said diameter may be adopted.

6.6.2 Piles deriving their bearing capacity mainly from friction shall be spacedsufficiently apart to ensure that the zones of soils from which the piles derive theirsupport do not overlap to such an extent that their bearing values are reduced.Generally the spacing in such cases shall not be less than 3 times the diameterof the shaft.

8/11/2019 2911 Draft -Part2

9/35

9

6.6.3 In case of loose sand or filling closer spacing may be possible sincedisplacement during the piling may be absorbed by vertical and horizontalcompaction of the strata. Minimum spacing in such strata may be two times thediameter of the shaft.

NOTE In the case of piles of non-circular cross-section, diameter of the circumscribing circleshall be adopted.

6.7 Pile Groups

6.7.1 In order to determine the bearing capacity of a group of piles a number ofefficiency equations are in use. However, it is difficult to establish the accuracyof these efficiency equations as the behaviour of pile group is dependent onmany complex factors. It is desirable to consider each case separately on itsown merits.

6.7.2 The bearing capacity of a pile group may be equal to or less than the

bearing capacity of individual piles multiplied by the number of piles in the group.The former holds true in case of piles, cast or driven into progressively stiffermaterials or in end-bearing piles. For driven piles in loose sandy soils the groupcapacity may even be higher due to the effect of compaction. In such cases aload test should be made on a pile in the group after all the piles in the grouphave been installed.

6.7.3 In case of piles deriving their support mainly from friction and connected bya rigid pile cap, the group may be visualized as a block with the piles embeddedwithin the soil. The ultimate capacity of the group may then be obtained byconsidering block failure taking into account the frictional capacity along theperimeter of the block and end bearing at the bottom of the block using the

accepted principles of soil mechanics.

6.7.4 When the cap of the pile group is cast directly on reasonably firm stratumwhich supports the piles, it may contribute to the bearing capacity of the group.This additional capacity along with the individual capacity of the piles multipliedby the number of piles in the group shall not be more than the capacity workedout as per 6.7.3.

6.7.5 When a pile group is subjected to moment either from superstructure or asa consequence of inaccuracies of installation, the adequacy of the pile group inresisting the applied moment should be checked. In case of a single pilesubjected to moment due to lateral forces or eccentric loading, beams may beprovided to restrain the pile effectively from lateral or rotational movement.

6.7.6 In case of a structure supported on single piles/group of piles resulting inlarge variation in the number of piles from column to column it may result in largedifferential settlement. Such differential settlement should be either catered for inthe structural design or it may be suitably reduced by judicious choice ofvariations in the actual pile loading. For example, a single pile cap may beloaded to a level higher than that of the pile in a group in order to achievereduced differential settlement between two adjacent pile caps supported on anumber of piles.

8/11/2019 2911 Draft -Part2

10/35

10

6.8 Factor of safety

6.8.1 Factor of safety should be chosen after considering:

a) the reliability of the estimated value of ultimate bearing capacity of a pile,

b) the types of superstructure and the type of loading, and

c) allowable total/differential settlement of the structure.

6.8.2 When the ultimate bearing capacity is determined from either static formulaor dynamic formula, the factor of safety would depend on the reliability of theformula and the reliability of the subsoil parameters used in the computation.The minimum factor of safety on static formula shall be 2.5. The final selection ofa factor of safety shall take into consideration the load settlement characteristicsof the structure as a whole at a given site.

6.8.3 Higher value of factor of safety for determining the safe load on piles maybe adopted where:

a) settlement is to be limited or unequal settlement avoided,

b) large impact or vibrating loads are expected,

c) the properties of the soil may deteriorate with time

6.9 Transient Loading

The maximum permissible increase over the safe load of a pile, as arising out ofwind loading, is 25 percent. In case of loads and moments arising out ofearthquake effects, the increase of safe load on a single pile may be limited tothe provisions contained in IS 1893. For transient loading arising out ofsuperimposed loads, no increase is allowed.

6.10 Overloading

When a pile in a group, designed for a certain safe load is found, during or afterexecution, to fall just short of the load required to be carried by it, an overload upto 10 percent of the pile capacity may be allowed on each pile. The totaloverloading on the group should not, however, be more than 10 percent of the

capacity of the group subject to the increase of the load on any pile being notmore than 25 percent of the allowable load on a single pile.

6.11 Reinforcement

6.11.1 The design of the reinforcing cage varies depending upon the driving andinstallation conditions, the nature of the subsoil and the nature of load to betransmitted by the shaft - axial, or otherwise. The minimum area of longitudinalreinforcement of any type or grade within the pile shaft shall be 0.4 percent of thesectional area calculated on the basis of outside area of the casing or the shaft.

8/11/2019 2911 Draft -Part2

11/35

11

6.11.2 The curtailment of reinforcement along the depth of the pile, in general,depends on the type of loading and subsoil strata. In case of piles subject tocompressive load only, the designed quantity of reinforcement may be curtailedat appropriate level according to the design requirements. For piles subjected touplift load, lateral load and moments, separately or with compressive loads, itwould be necessary to provide reinforcement for the full depth of pile. In soft

clays or loose sands, or where there may be danger to green concrete due todriving of adjacent piles, the reinforcement should be provided up to the full piledepth, regardless of whether or not it is required from uplift and lateral loadconsiderations. However, in all cases, the minimum reinforcement specified in6.11.1 should be provided for the full length of the pile.

6.11.3 Piles shall always be reinforced with a minimum amount of reinforcementas dowels keeping the minimum bond length into the pile shaft below its cut-offlevel and with adequate projection into the pile cap, irrespective of designrequirements.

6.11.4 Clear cover to all main reinforcement in pile shaft shall be not less than

50mm. The laterals of a reinforcing cage may be in the form of links or spirals.The diameter and spacing of the same is chosen to impart adequate rigidity ofthe reinforcing cage during its handing and installations. The minimum diameterof the links or spirals shall be 6mm and the spacing of the links or spirals shall benot less than 150mm. Generally a spacing of 300mm is considered moreappropriate and practical.

6.12 Design of Pile Cap

6.12.1 The pile caps may be designed by assuming that the load from column isdispersed at 450from the top of the cap to the mid-depth of the pile cap from thebase of the column or pedestal. The reaction from piles may also be taken to bedistributed at 450 from the edge of the pile, up to the mid-depth of the pile cap.On this basis the maximum bending moment and shear forces should be workedout at critical sections. The method of analysis and allowable stresses should bein accordance with IS 456. Other rational methods as agreed between theconcerned parties may also be used.

6.12.2 Pile cap shall be deep enough to allow for necessary anchorage of thecolumn and pile reinforcement.

6.12.3 The pile cap should be rigid enough so that the imposed load could bedistributed on the piles in a group equitably.

6.12.4 In case of a large cap, where differential settlement may be occurbetween piles under the same cap, due consideration for the consequentialmoment should be given.

6.12.5 The clear overhang of the pile cap beyond the outermost pile in the groupshall a minimum of 150mm.

6.12.6 The cap is generally cast over a 75mm thick leveling course of concrete.The clear cover for main reinforcement in the cap slab shall not be less than60mm.

8/11/2019 2911 Draft -Part2

12/35

12

6.12.7 The pile should project 500mm into the cap concrete.

6.12.8 The design of grade beam if used shall be as given in IS 2911 (part 3).

7 MATERIALS AND STRESSES

7.1 Cement

The cement used shall be any of the following :

a) 33 Grade Ordinary Portland Cement conforming to IS 269b) 43 Grade Ordinary Portland Cement conforming to IS 8112c) 53 Grade Ordinary Portland Cement conforming to IS 12269d) Rapid Hardening Portland Cement conforming to IS 8041e) Portland Slag Cement conforming to IS 455f) Portland Pozzolana Cement (fly ash based) conforming to IS 1489 (Part 1)g) Portland Pozzolana Cement (calcined clay based) conforming to IS 1489

(Part 2)h) Hydrophobic cement conforming to IS 8043j) Low heat Portland Cement conforming to IS 12600, andk) Sulphate resisting Portland Cement conforming to IS 12330

7.2 Steel

Reinforcement steel shall be any of the following:

a) Mild steel and medium tensile steel bars conforming to IS 432 (Part 1)b) High strength deformed steel bars conforming to IS 1786, andc) Structural steel conforming to IS 2062

7.3 Concrete

7.3.1 Consistency of concrete to be used for bored cast in-situ piles shall beconsistent with the method of installation of piles. Concrete shall be so designedor chosen as to have a homogeneous mix having a slump/workability consistentwith the method of concreting under the given conditions of pile installation.

7.3.2 The minimum slump should be 125mm when the concrete in the pile is notcompacted. The slump should not exceed 180mm.

7.3.3 The minimum grade of concrete to be used for piling shall be M-25. Forconditions under which the concrete is not exposed to sulphate attack, theminimum cement content shall be 300 kgf/m3 (see Annexure E). For concreteexposed to sulphate attack the minimum cement content shall be in accordancewith IS 456. When under water concreting 10 percent additional cement overthat required for the designed mix of concrete for the required slump shall beused subject to a minimum of 370 kgf/m3. For subaqueous concrete therequirements specified in IS 456 shall be followed.

8/11/2019 2911 Draft -Part2

13/35

13

7.3.4 Clean water, free from acids and other impurities, shall be used in themanufacture of concrete.

7.3.5 The average compressive stress under working load should not exceed 25percent of the specified works cube strength at 28 days calculated on the totalcross-sectional area of the pile. Where the casing of the pile is permanent, of

adequate thickness and of suitable shape, the allowable compressive stress maybe increased.

7.4 Drilling Mud (Bentonite)

The drilling mud to be used for stabilizing the borehole in bored piling workshould conform to the specifications given in Annexure C.

8 WORKMANSHIP

8.1 Control of Pilling Installation

8.1.1 Bored cast-in-situ piles should be installed by installation technique,covering

a) the manner of borehole stabilization, that is use of casing and / or useof drilling mud

b) Manner of concreting, i.e., direct pouring or by use of tremie and

c) Choice of boring tools in order to permit satisfactory installation of apile at a given site. Detailed information about the subsoil conditions isessential to predetermine the details of the installation technique.

8.1.2 Control of Alignment Piles shall be installed as accurately as possible asper the design and drawing either vertically or to the specified batter. As a guide,a deviation of 1.5% in alignment for vertical piles and a deviation of 4% for rakerpiles should not be exceeded.

Piles less than 600mm in diameter should not deviate more than 75mm or D/whichever is less. For piles having diameter more than 600mm this deviationshould not be greater (75mm or D/10, whichever is more) from their designedpositions at the working level. In the case of single pile under a column thepositional deviation should not be more than 75mm or D/6 whichever is less.

8.1.3 A minimum length of two metres of temporary casing shall be provided foreach bored pile unless otherwise specifically desired. Additional length ortemporary casing may be used depending on the condition of the strata, groundwater level, etc.

8.1.4 For aggressive action of ground water or for marine situations, piles maybe formed with permanent liner. Where the permanent liner is used and the boreis filed with water or bentonite fluid, the pile should be concrete fully by usingtremic method.

8/11/2019 2911 Draft -Part2

14/35

14

8.2 Use of Drilling Mud

8.2.1 In case a borehole is stabilized by use of drilling mud, the specific gravityof the mud suspension should be determined at regular intervals by a suitableslurry sampler. Consistency of the drilling mud shall be controlled throughout theboring as well as concreting operations in order to keep the hole stabilized as

well as to avoid concrete getting mixed up with the thicker suspension of themud. A specification of the bentonite to be used stabilizing boreholes is given inAnnexure C.

8.2.2 The concreting operations should not be taken up when the specificgravity of bottom slurry is more than 1.12. Concreting shall be done by tremiemethod in all such cases. The slurry should be maintained at 1.5m above theground water level.

8.3 Cleaning of borehole

8.3.1 If a borehole is stabilized by drilling mud the bottom of the hole shall be

cleaned of all loose and undesirable materials before commencement ofconcreting:

a) Boring done with normal bailor and chisel with temporary /permanent liner. First heavier material will be removed withcleaning too such as smaller diameter bailor. Then reinforcementcage will be lowered and the tremie pipe insisted with waterpressure through tremie pipe.

b) Boring done with bentonite slurry. Borehole shall be flushed withfresh bentonite solution under pressure through tremie pipe.

c) Boring done by rotary drilling rigs. Cleaning bucket attached to thekelly shall be used for cleaning the bore. Wherever bentonitesolution is used, after using cleaning bucket, the bore shall beflushed with fresh bentonite solution.

In case of flushing with water or bentonite solution the pump capacity shall besuitably decided depending on depth and diameter of bore so that sufficientpressure is built to lift the material up along with the fluid. Flushing should becontinued till coarse materials cease to come out with the overflowing fluid. Thefiner materials will normally remain suspended in the fluid but they do not poseany problem. Normally a flow of fluid about 1 to 2 times the volume of pilebore is sufficient to clean the bore under pressure.

8.4 Tremie Concreting

Concreting under water shall be done by tremie method. The followingrequirements are particularly to be followed for tremie concrete work

a) The concrete should be coherent, rich in cement (not less than 400 kg/m3)and of slump between 150 to 200mm

b) The tremie should be water tight throughout its length and have a hopperattached to its head by a water tight connection.

8/11/2019 2911 Draft -Part2

15/35

15

c) The tremie pipe should be large enough in relation to the size of theaggregate. For 25mm down aggregate, the tremie pipe should have adiameter not less than 200mm. For 20mm down aggregate, tremie pipeshould be of diameter not less than 150mm. All piling above 600mmdiameter, should, however be done with 200mm diameter tremie pipe.

d) A steel plate or a ball is placed at the bottom of the hopper and the hopperfilled with concrete. The first charge of concrete is sent down the tremieby removal of this plate or ball. Additional concrete is then added into thehopper and by surging action is pushed down the tremie and into the pilebore to the bottom of the pile. Theoretically, a small part of the first chargewhich gets contaminated is supposed to be the top of the rising concretewithin the bore.

e) The tremie pipe should always be kept full of concrete and should alwaysremain at least one meter into the concrete in the bore hole with adequatemargin against accidental withdrawal if the pile.

f) The pile should be concreted wholly by tremie and the method ofdeposition should not be changed midway to prevent laitance from beingentrapped within the pile.

g) All tremie pipes should be scrupulously cleaned before use.

8.4.1 Normally concreting of the piles should be uninterrupted. In exceptionalcases of interruption of concreting, it shall be resumed within 1 or 2 hours, butthe tremie shall not be taken out of the concrete. Instead it shall be raised andlowered from time to time to prevent the concrete around the tremie from setting.

8.4.2 In case of withdrawal of tremie out of the concrete, either accidentally or toremove a choke in the tremie, the tremie may be introduced 60cm to 100cm inthe old concrete and concreting resumed as mentioned in 8.4.1. The freshconcrete will emerge out of the tremie displacing the laitance and scum andprevent impregnation of laitance of scum in the fresh concrete.

8.4.3 The top of concrete in a pile shall be brought above the cut-off level topermit removal of all laitance and weak concrete before capping and to ensuregood concrete at the cut-off level for proper embedment into the pile cap.

8.4.4 Where cut-off level is less than 2.5metre below the ground level concreteshall be cast to a minimum of 600mm above cut-off level. For each additional

0.3m increase in cut-off level below the working level additional coverage of50mm minimum shall be allowed. Higher allowance may be necessarydepending on the length of the pile. When concrete is placed by tremie method,concrete shall be cast upto the ground level to permit overflow of concrete forvisual inspection or to a minimum of one metre above cut-off level. In thecircumstances where cut-off level is below ground water level the need tomaintain a pressure on the unset concrete equal to or greater than waterpressure should be observed and accordingly length of extra concrete above cut-off level shall be determined.

8/11/2019 2911 Draft -Part2

16/35

16

8.5 Defective Pile

8.5.1 In case, defective piles are formed, they shall be left in place. Additionalpiles as necessary shall be provided.

8.5.2 Any deviation from the designed location, alignment or load capacity of apile shall be noted and adequate measures taken well before the concreting ofthe pile cap and planth beams.

8.5.3 While removing excess concrete or laitance above the cut-off levelchipping by manual or pneumatic tools shall be permitted seven days after pilecasting. Before, chipping/breaking the pile top, a 40mm deep groove shall bemade manually all round the pile at the required cut-off level.

8.5.4 After concreting the actual quantity of concrete shall be compared with theaverage obtained from observations made in the case of a few piles already cast.If the actual quantity is found to be considerably less, the matter should be

investigated and appropriate measures taken.

8.6 Recording of Data

8.6.1 A daily site record shall be maintained for the installation of piles and shallcontain the number and dimension of the pile, depth bored (including depth insoft / hard rock, time taken for boring, concreting and empty boring (cut-off level),chiseling and whether the pile is wet or dry. Sample bore log in the initial stageor when major variation occur should be shown. When drilling mud is used,specific gravity of the fresh supply and contaminated mud in the bore hole beforeconcreting shall be checked regularly.

8.6.2 Typical data sheet for facility of recording pilling data is shown inAnnexure F

8/11/2019 2911 Draft -Part2

17/35

17

Annexure A(Clause 2)

LIST OF INDIAN STANDARDS

IS 269: 1989 Specifications for ordinary and low heat Portland cement(fourth revision)

IS 432 (Part I): 1982 Specification for mild steel and medium tensile steel barsand hard drawn steel wire for concrete reinforcement:Part I Mild Steel & Medium Tensile Steel Bars(third revision)

IS 455: 1989 Specifications for Portland slag cement (fourth revision)

IS 1489 Specification for Portland pozzolona cement

Part 1: 1991 Fly Ash Based (third revision)Part 2: 1991 Calcined clay based (third revision)

IS 1786:1985 Specification for cold, worked steel, high strength deformed barsfor concrete reinforcement (third revision)

IS:1892:1979 Code of practice for sub-surface investigation for foundations(first revision)

IS:1893:1984 Criteria for earthquake resistant design of structure (fourth revision)

IS 2062:1999 Steel for general structural purposes Specification (fifth revision)

IS:2720 (Part V):1985 Methods for test of soils: Part V Determination of Liquidand Plastic Limits (second revision)

IS:2911 (Part 1/Sec I):1979 Code of practice for design and construction of pilefoundation: Part I Concrete piles. Sec 1 Driven cast-in-situpiles

IS:2911 (Part 3): 1980 Code of practice for design and construction of pilefoundations : Part 3 Under reamed pile (first revision)

IS:2911 (Part 4): 1985 Code of practice for design and construction pilefoundations : Part 4 Load test on piles (first revision)

IS:4091:1979 Code of practice for design and construction of foundations fortransmission line towers and poles (First revision)

IS:4651 (Part I):1974 Code of practice for planning and design of ports andharbours. Part 1 Site Investigation (first revision)

8/11/2019 2911 Draft -Part2

18/35

18

IS:4968 Method for sub-surface sounding for soils (first revision)

Part 1:1976 Dynamic method using 50mm cone without bentonite slurry (firstrevision)

Part 2:1976 Dynamic method using cone and bentonite slurry (first revision)

Part 3:1976 State cone penetration test (first revision)

IS:6403:1981 Code of practice for determination of bearing capacity of shallowfoundations (first revision)

IS: 6909:1990 Specification for super sulphated cement.

IS 8041:1990 Specification for Rapid Hardening Portland Cement (secondrevision)

IS 8043:1991 Specification for Hydrophobic Portland Cement (second revision)

IS 8112:1989 Specification for 43 Grade Ordinary Portland Cement (firstrevision)

IS 12269:1989 Specification for 53 Grade Ordinary Portland Cement

IS 12330:1988 Specification for Sulphate resisting Portland Cement

IS 12600:1989 Specification for Low Heat Portland Cement

8/11/2019 2911 Draft -Part2

19/35

19

Annexure B

(Clause 6.3.2)

LOAD CARRYING CAPACITY OF PILES - STATIC ANALYSIS

B-1 PILES IN GRANULAR SOILS

B-1.1 The ultimate bearing capacity (Qu) in kN of piles granular soils is given bythe following formula.

Qu= Ap( D /N+ PDNq) + =

n

i 1Ki Pditan iAsi (1)

where the first part gives the end bearing resistance and the second part givesthe skin friction resistance.

Ap = cross sectional area of pile toe in m2

B = stem diameter of pile in m/ = effective unit weight of the soil at pile toe kN/m3

N& Nq= bearing capacity factors depending upon the angle of internal friction/at pile toePD = effective overburden pressure at pile toe in kN/m

2(see note 5 below)

=n

i 1= summation for layers 1 to n in which pile is installed and contribute to

positive skin frictionKi = coefficient of earth pressure applicable for i

thlayer (see note 3 below)Pdi = effective overburden pressure in kN/m

2for the ith layer

i = angle of wall friction between pile and soil for the ithlayerAsi = surface area of pile stem in m

2in the ithlayer

Note 1 Nfactor can be taken for general shear failure according to IS: 6403

Note 2 Nq factor will depend on the nature of soil, type of pile, the L/B ratio and itsmethod of construction. The values applicable for driven piles are given in Figure B-1.

Note 3 Ki, the earth pressure coefficient depends on the nature of soil strata, type of pile,spacing of piles and its method of construction. For bored piles in loose to dense sand

with varying between 250and 40

0Kivalues in the range of 1 to 1.5 may be used.

Note 4 , the angle of wall friction may be taken as of the friction angle of the soil

around the pile stem.

Note 5 In working out pile capacity by static formula, the maximum effective overburdenat the pile tip should correspond to the critical depth, which may be taken as 15 times the

pile diameter for 300and increasing to 20 times for 40

0.

Note 6: For piles passing through cohesive strata and terminating in a granular stratum,a penetration of at least twice the pile diameter should be given into the granular stratum

8/11/2019 2911 Draft -Part2

20/35

20

Fig. B-1 Bearing Capacity Factor Nqfor Drive Piles

B-2 PILES IN COHESIVE SOILS

B-2.1 The ultimate bearing capacity (Qu) in kN of piles in cohesive soils is givenby the following formula.

Qu= ApNccp+ =n

i 1i ci Asi

(2)

where

the first part gives the end bearing resistance and the second part gives the skinfriction resistance.

Ap = cross sectional area of pile toe in m2

Nc = bearing capacity factor, may be taken as 9

cp = average cohesion at pile toe in kN/m2

=n

i 1= summation for layers 1 to n in which pile is installed and contribute to

positive skin friction

8/11/2019 2911 Draft -Part2

21/35

21

i = adhesion factor for the ithlayer depending on the consistency of soil

ci = average cohesion for the ithlayer in kN/m2

Asi = surface area of pile stem in the ithlayer in m2

The value of adhesion factor idepends on the undrained shear strength of theclay and may be obtained from Fig.

Fig. Variation of with Cu

B-3 USE OF STATIC CONE PENETRATION DATA

B-3.1 When static cone penetration data are available for the entire depth, thefollowing correlation may be used as a guide for the determination of ultimatecapacity of a pile.

B-3.2 Ultimate end bearing resistance (qu) in kN/m2may be obtained as

qu= 22

2

10

c

cc qqq

++

where,

qc0 = average static cone resistance in kN/m2 over a depth of 2D below the

pile toe

qc1 = minimum static cone resistance in kN/m2 over the same 2D below the

pile toe

8/11/2019 2911 Draft -Part2

22/35

22

qc2 = average of the envelope of minimum static cone resistance values overthe length of pile of 8B above the pile toe

B = diameter of pile

B-3.3 Ultimate skin friction resistance can be approximated to local side friction

(fs) in kN/m2

obtained from static cone resistance as:

Type of soil Local side friction fs(kN/m2)

qcless than 1000 kN/m2

Clay

Silty clay and silty sand

Sand

Coarse sand and gravel

qc/30 < fs< qc/10

qc/25 < fs< 2qc/25

qc/100 < fs< qc/25

qc/100 < fs< qc/50

< fs< qc/150

Where qcis the cone resistance in kN/m2

B-3.4 The correlation between standard penetration resistance N (blows/30cm)and static cone resistance qcin kN/m

2given below may be used for working outthe end bearing resistance and skin friction resistance of piles. This correlation

should only be taken as a guide and should, preferably be established for a givensite as they can vary substantially with the grain size, Atterberg limits, water tableetc.

Soil type qc/N

Clay

Silt, sandy silt and slightly cohesive silt-sand mixtures

Clean fine to medium sand and slightly siltysand

Coarse sand and sand with little gravel

Sandy gravel and gravel

150 200

200 250

300 400

500 600

800 1000

8/11/2019 2911 Draft -Part2

23/35

23

B-4 MEYERHOFS FORMULA FOR COHESIONLESS SOIL

B-4.1 The correlation suggested by Meyerhof using standard penetrationresistance N in saturated cohesionless soil to estimate the ultimate capacity ofdriven pile is given below. The ultimate capacity of pile (Qu) in kN is given as

Qu= 40 NBL Ap+

50.0

sAN ..(3)

where

the first part gives the end bearing resistance and the second part gives thefrictional resistance.

N = average N value at pile toe

L = Length of penetration of pile in the bearing strata in m

B = Diameter or minimum width of pile in m

Ap = cross sectional area of pile toe in m2

N = average N along the pile shaft

As = surface area of pile stem in m2

Note: The end bearing resistance should not exceed 400 NAp

B-4.2 The non plastic silt or very fine sand the equation has been modified as:

Qu= 30 NBL Ap+

60.0

sAN ..(4)

The meaning of all terms are same as for equation 3.

B-5 Factor of Safety

The minimum factor of safety for arriving at the safe pile capacity from theultimate capacity obtained by using static formulae should be 2.5.

B-6 Pile in Stratified Soil

In stratified soil / C- soil the ultimate bearing capacity of piles should bedetermined by calculating the skin friction and end bearing in different strata byusing appropriate expressions given in clause C-1 and C-2.

B-7 Piles in Sound Rock

B-7.1 Piles resting directly on sound rock may be loaded to their safe structuralcapacity. It is however recommended that a keying of 150mm for small diameterpiles and 300mm for large diameter piles be provided.

8/11/2019 2911 Draft -Part2

24/35

24

B8 Piles in Weathered / Soft Rock

For pile founded in weathered/soft rock different empirical approaches are usedto arrive at the socket length necessary for ultilising the full structural capacity ofthe pile.

Since it is difficult to collect cores in weathered/soft rocks, the method suggestedby Cole and Stroud using N values is more widely used. The allowable load onthe pile, by this approach, is given by

Qa =s

u

s

cuF

BLc

F

BNc

..

4.

2

2

1 +

Where cu1= shear strength of rock below the base of the pile in kN/m2. Refer

Table 1.

Nc = bearing capacity factor taken as 9.Fs = Factor of safety usually taken as 3.

= 0.3 (recommended value)cu 2= average shear strength of rock in the socketted length of pile

(Refer Table 3)B = diameter of pile in m.L = length of socket in m.

(Note : - For N 60, the stratum is to be treated as weathered rock ratherthan soil).

Table .3:Consistency and Shear strength of weathered rock

Shear strengthkN/m

2

ApproxN value

Strength/Consistency

Grade Breakability Scratch

40000 -Very Strong

A Difficult to breakagainst solid object

with hammer

Cannot be scratchedwith knife

20000-

Strong B Broken against solidobject with hammer

Can just be scratchedwith knife

10000 - Moderatelystrong

4000 - Moderatelyweak C Broken in hand byhitting with hammer Can just be scratchedwith thumb nail

2000 - weak D Broken by leaning onsample with hammerwith knife

No penetration whenscratched with thumbnail

1000 - weak E Broken by hard Penetration of about5mm with knife

8/11/2019 2911 Draft -Part2

25/35

25

ANNEXURE C

(Clause 5.3)

SPECIFICATIONS OF DRILLING MUD (BENTONITE)

C 1. PROPERTIES

C 1.1 The bentonite suspension used in bore holes is basically a clay ofmontmorillonite group having exchangeable sodium cations. Because of thepresence of sodium cations, bentonite on dispersion will break down into smallplate like particles having a negative charge on the surfaces and positive chargeon the edges. When the dispersion is left to stand undisturbed, the particlesbecome oriented building up a mechanical structure of its own. This mechanicalstructure held by electrical bonds is observed as a thin jelly like mass or

membrane. When the jell is agitated, the weak electrical bonds are broken andthe suspension becomes fluid again.

C 2 FUNCTIONS

C 2.1The action of bentonite is stabilizing the sides of bore holes is primarilydue to thixotropic property of bentonite. The thixotropic property of bentonitesuspension permits the material to have the consistency of a fluid whenintroduced into a trench or hole. When left undisturbed it forms a jelly likemembrane on the borehole wall and when agitated it becomes a fluid again.

C 2.2 In the case of a granular soil, the bentonite suspension penetrations intosides under positive pressure and after a while forms a jelly. The bentonitesuspension then gets deposited on the sides of the hole and makes the surfaceimpervious and imparts a plastering effect. In impervious clay, the bentonite doesnot penetrate into the soil, but deposits only as thin film on the surface of hole.Under such condition, stability is derived from the hydrostatic head of thesuspension.

C 3. SPECIFICATION

C 3.1 The bentonite powder and bentonite suspension used for piling work-shall satisfy following requirements:-

a) The liquid limit of bentonite when tested in accordance IS:2720 (Part V)shall be 400% or more.

b) The bentonite suspension shall be made by mixing it with fresh waterusing a pump for circulation. The density of the freshly prepared bentonitesuspension shall be between 1.03 and 1.10g/ml depending upon the piledimensions and the type of soil in which the pile is to be bored. Thedensity of bentonite after contamination with deleterious material in thebore hole may rise upto 1.25g/ml and should be brought down to at least1.12g/ml by flushing before concreting.

8/11/2019 2911 Draft -Part2

26/35

26

c) The marsh viscosity of bentonite suspension when tested by a marshcone shall be between 30 to 60 seconds; in special cases it may beallowed upto 90 seconds.

d) The pH value of the bentonite suspension shall be between 9 and 11.5.

8/11/2019 2911 Draft -Part2

27/35

27

ANNEXURE D

(Clause 6.5.2)

ANALYSIS OF LATERALLY LOADED PILES

D-1 GENERAL

D-1.1 The ultimate resistance of a vertical pile to a lateral load and the deflectionof the pile as the load builds up to its ultimate value are complex mattersinvolving the interaction between a semi-rigid structural element and soil whichdeforms partly elastically and partly plastically. The failure mechanisms of aninfinitely long pile and that of a short rigid pile are different. The failuremechanisms also differ for a restrained and unrestrained pile head conditions.

Because of the complexity of the problem only a procedure for an approximate

solution that is adequate in most of the cases is presented here. Situations thatneed a rigorous analysis shall be dealt with accordingly.

D-1.2 The first step is to determine if the pile will behave as a short rigid unit oras an infinitely long flexible member. This is done by calculating the stiffnessfactor R or T for the particular combination of pile and soil.

Having calculated the stiffness factor, the criteria for behaviour as a short rigidpile or as a long elastic pile are related to the embedded length L of the pile. Thedepth from the ground surface to the point of virtual fixity is then calculated andused in the conventional elastic analysis for estimating the lateral deflection andbending moment.

D-2 STIFFNESS FACTORS

D-2.1 The lateral soil resistance for granular soils and normally consolidatedclays which have varying soil modulus is modeled according to the equation.

y

p= hz

where,p = lateral soil reaction per unit length of pile at depth z below ground level

y = lateral pile deflectionh= coefficient of modulus variation for which the recommended values of are

given in Table D-1

8/11/2019 2911 Draft -Part2

28/35

28

D-2.2 The lateral soil resistance for preloaded clays with constant soil modulusis modeled according to the equation,

y

p= Ki

where,

Ki= k1/1.5B, where k1 is Terzaghis modulus of subgrade reaction asdetermined from load deflection measurements on a 30cm square plateand B is the width of pile. The recommended values of k1are given inTable D-2

Table D-1 Values of coefficient of modulus variation hin kN/m3

hkN/m3x 103Soil Type N

(Blows /30 cm) Dry Submerged

Very loose sand

Loose sand

Medium sand

Dense sand

Very loose sand

0 4

4 - 10

10 - 35

> 35

0.4

2.5

7.5

20.0

-

-

1.4

5.0

12.0

0.4

Note: The hvalues may be interpolated for intermediate relative densities

Table D-2 Values for subgrade modulus k1in kN/m3for cohesive soil

Soil consistency Unconfinedcompression strength

qukN/m2

Range of k1kN/m3x 103

Soft

Medium stiff

Stiff

Very stiff

Hard

25 to 50

50 to 100

100 to 200

200 to 400

> 400

4.5 to 9.0

9.0 to 18.0

18.0 to 36.0

36.0 to 72.0

>72.0

Note: for quless than 20, k1may be taken as zero, which implies that there is nolateral resistance

8/11/2019 2911 Draft -Part2

29/35

29

D-2.3 Stiffness Factors

D-2.3.1 Granular Soil:

Stiffness factor T in m = 5b

EI

Where,

E = Youngs modulus of pile material in MN/m2I = Moment of inertia of the pile cross section in m4b= Coefficient of modulus variation in MN/m

3from Table D-1

D-2.3.2 For Cohesive Soils:

Stiffness factor R in m = 4KB

EI

Where,

E = Youngs modulus of pile material in MN/m2I = Moment of inertia of the pile cross section in m4K = 1.5 k1, the values of k1in MN/m

3from Table D-2B = The width of pile shaft in m

D-3 Criteria for Short Rigid Piles and Long Elastic Piles

D-3.1 Having calculated the stiffness factor T or R, the criteria for behaviour as ashort rigid pile or as a long elastic pile are related to the embedded length L asfollows.

Soil ModulusPile Type

Linearly increasing Constant

Rigid free head L 2T L 2R

Elastic freehead

L 4T L 3.5R

Note: The intermediate L shall indicate a case between rigid case and an elasticcase

8/11/2019 2911 Draft -Part2

30/35

30

D-4 Deflection and Moments in Long Elastic Piles

D-4.1 Equivalent cantilever approach gives a simple procedure for obtaining thedeflections and moments due to relatively small lateral loads. This requires thedetermination of depth of virtual fixity, zf.

The depth to the point of fixity may be read from the plots given in Figure D-1. eis the effective eccentricity of the point of load application obtained either byconverting the moment to an equivalent horizontal load or by actual position ofthe horizontal load application. R and T are the stiffness factors describedearlier.

D-4.2 The pile head deflection y shall be computed using the following equations

Deflection y =( )EI

zeH f

3

3+

x 103 .for free head pile

Deflection y =( )

EI

zeH f

12

3+

x 103 .for fixed head pile

where,

H = Lateral load in kNy = Deflection of pile head in mmE = Youngs modulus in kN/m2of pile materialI = Moment of inertia in m4of the pile cross sectionzf= Depth to point of fixity in me = Cantilever length in m above ground/bed to the point of load application

D-4.2 The fixed end moment of the pile for the equivalent cantilever may be

determined from the expressions below.

Fixed end moment MF= )fzeH + .for free head pile

=2

fzeH +

.for fixed head pile

The fixed head moment MFof the equivalent cantilever is higher than the actualmaximum moment M in the pile. The actual maximum moment may be obtainedby multiplying the fixed end moment of the equivalent cantilever by a reductionfactor, m, given in Figure D-2.

8/11/2019 2911 Draft -Part2

31/35

31

Fig. D1 DEPTH OF FIXITY

Fig.D2 DETERMINATION OF REDUCTION FACTORS FOR COMPUTATIONOF MAXIMUM MOMENT IN PILE

8/11/2019 2911 Draft -Part2

32/35

32

ANNEXURE E(Clause 7.3.3)

Classification of sulphates in soils affecting concrete in piled foundations andrecommended precausions

Concentration of sulphate expressed as SO3 Types of cement limiting mix proportions for fullycompacted concrete and other protective measuresfor

Classification

Total SO3% in soil

SO3in 2:1AqueousExtract ofsoil

In GroundWater ppm

Concrete placed in thin steelshells in dry conditions

1.

Reinforced concrete in pile capsand ground beams

2

Concrete indriven cast-in-situ and boredcast-in-situ piles

3

1 Less than0.2

- Less than300

a: Above highest water levelOPC: Min = 300kgf/m

3

b: In contact with fluctuating waterlevel OPC: Min = 310 kgf/m

3

Max w/c ratio = 0.55

a: Above highestwater level OPC:Min=330 kgf/m

3

b: In contact withfluctuating water

labelOPC: Min=370kgf/m

3

Max w/cratio=0.55

2 0.2 0.5 - 300-1200 a: Above highest water levelOPC: Min = 330 kgf/m

3

b: In contact with fluctuating waterlevel OPC: Min = 350 kgf/m

3

Or SRPC: Min = 310 kgf/m2

Max w/c ratio = 0.50

a: Above highestwater level OPC:Min=370 kgf/m

3

b: In contact withfluctuating waterlevel.OPC: Min=380kgf/m

3or SRPC:

Min=340 kgf/m3

Max w/cratio=0.50

3 0.5 1.0 1.9 3.1 1200-2500 a: Above highest water levelOPC: Min = 400 kgf/m

3Or SRPC:

Min = 350 kgf/m3

b: In contact with fluctuating waterlevel. SRPC: Min = 390 kgf/m

3

Max w/c ratio = 0.50

a: Above highestwater level OPC:Min=400 kgf/m

3

Or SRPC:Min=350 kgf/m

3

b: In contact withfluctuating waterlevel.SRPC: Min=340kgf/m

3

Max w/cratio=0.50

4 1.0 2.0 3.1 5.6 2500-5000 a: Above highest water levelOPC: Min = 400 kgf/m

3Or SRPC:

Min = 350 kgf/m3

Max w/c ratio = 0.45b: In contact with fluctuating watertable as for pre-cast concrete butexternal

a: Above highestwater level andsoil free fromseepage waterSRPC: Min=400kgf/m

3

b: In contact withfluctuating waterlevel in lowerrange of SO3

8/11/2019 2911 Draft -Part2

33/35

33

and favourablecations useSRPC: Min=390kgf/m

3Max w/c

ratio = 0.45For Higher rangeof SO3and

unfavourablecations, placeconcrete indurable metal orplastic sleeveleft left in place

5 Over 2.0 Over 5.6 Over 5000 a: Above highest water levelOPC: Min = 400 kgf/m

3or SRPC:

Min=350 kgf/m3

b: In contact with fluctuating waterlevel. SRPC: Min=390 kgf/m

3with

permanent external sheathing asabove. Max w/c ratio = 0.40

a: Above highestwater level andsoil free fromseepage SRPC:Min=390 kgf/m

3.

Max w/cratio=0.40

b. Cast-in-situpiles areunsuitable forinstallationbelow the watertable

Note - Wherever high chloride is present along with high sulphate content as inthe case of sea water, Pozzolana Portland cement is to be preferred.

8/11/2019 2911 Draft -Part2

34/35

34

8/11/2019 2911 Draft -Part2

35/35

ANNEXURE F(Clause 8.9.2)

Typical Data Sheet for Recording Installation of Driven-Cast-in-Situ Pile

(Name of Piling Agency)PILE INSTALLATION RECORD

Name of Work : Name of Client :Drawing No : Date/Shift :

Pile Serial No : Time of start of drivingPile location : Time of end of driving :

Pile No : Time of start of concrete :Diameter of pile : Time of end of concrete :

Actual ground level : Time of extraction of tube :Cut off level : End of extraction of tube :

Main tube length :

Follower length : DEPTH BLOWS CUM DEPTH

0.00 13.00Total length of tube : 0.50 13.50

Type of hammer : 1.00 14.00Weight of hammer : 1.50 14.50Stroke/Drop of hammer : 2.00 15.00

2.50 15.50Type of shoe used : 3.00 16.00

3.50 16.50Tube length above GL :Total length driven from GL: 4.00 17.00Length driven from cut-off: 4.50 17.50

5.00 18.00Total number of blows : 5.50 18.50

Set for last 10 blows :Repeat set for 10 blows

*: 6.00 19.00

Repeat set for 10 blows*: 6.50 19.50

7.00 20.00Concrete mix/grade : 7.50 20.50Slump of concrete : 8.00 21.00No. of cubes cast : 8.50 21.50No. of cement bags used :Theoretical cement consumption: 9.00 22.00Actual cement consumption: 9.50 22.50

10.00 23.00*if necessary 10.50 23.5011.00 24.0011.50 24.5012.00 25.0012.50 25.50