1888_method of load test on soils

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( Reaffirmed 1997 )


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IS:1888 - 1982Indian Standard

METHOD OF LOAD TEST ON SOILSSecond Revision )

Soil Engineering and Rock Mechanics Sectional Committee, BDC 23Chairman

DR JAGDISH NARAINMembers

RepresentingUniversity of Roorkee, Roorkee

SFiRI P. D. AoARWAI, Public Works Department, Government ofUttar Pradesh, LucknowDa B. L. DHAWAN ( Afternaie )Da ALAM SINQH University of Jodhpur, JodhpurCHlEB l&arEE~n ( RCD ) Irrigation Department, Government of Punjab,( IPRI ) ChandigarhSHKI P. S. GOSAL Alternate )SHRI M. C. DAN~AVATE Concrete Association of India, BombaySRRI N. C. DUC+~AL( Alternate )In personal capacity ( 5 Hungerford Court, 12/l,Hungerford Street, Calcutta )SHRIA. G. DMTIIMRDR G. S. DHILL~NDIRBXIYOIL Indian Geotechnical Society, New DelhiCentral Soil and Material Research Station,New DelhiDEPUTY DIRECTOR Alternate )DIRECTOR 11~1 Irrigation Department, Government ofUttar Pradesh, Roorkee\ Asia Foundations and Construction (P) Ltd, BombayHRI A. I-1. DIVANJ ISHIEI A. N J ANCLP, Alternate )Dn GOPAL R.YJ .*N Institution of Engineers ( India), Calcutta; a.ldUniversity of Roorkee, RoorkeeSHIL I S. GUPT~ Cemindia Company Limited, BombayScar N. V. De-Sousa ( &ernnle )SHRI ASHOK I . J OIN G. S. Jain & Associates, RoorkeeSHRI VIJ AY IL J OIN illterrzate )J OIFT DIXACTOR REsEAxif Ministry of Railways( G.E.-I ), RDSOJ OINT DIRXCTOR RESEARCH

G. E.- II ) ;llternnle )

@ Copyright 1983INDIAN STANDARDS INSTITUTION

This publication is protected under the Indian Coprright Act XIV of 1957 ) andreproduction in whole or in part by any means except with written permission of thepublisher shall be deemed to be an infringement of copyright under the said Act.


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Continued j?om page 1 )Members Representing

LT-COL V. K. KANITKARSHRI 0. P. MALHOTRASHRI D. R. NARAHARI

Ministry of Defence ( Engineer-in-Chiefs Branch )Public Works Department, Chandigarh Administra-tion, ChandigarhCentral Building Research Institute ( CSIR ),RnorkeeSHRI V. S. AoARWAL ( Alternate )SHRI T. K. NATRAJ AN Central Road Research Institute ( CSIR 1,New Delhi

SHRI RdNJ IT SINoH Ministry of Defence ( R D )SHRI V. B. GHORPADE ( Alternate )DR G. V. RAO Indian Institute of Technology, New DelhiDR K. K. GUPTA ( Alternate )RESEARCH OFFICER ( B RRL ) Public Works Department, Government of Punjab,ChandigarhSHRI K. R. SAXEN. Engineering Research Laboratories, Government ofAndhra Pradesh, HyderabadSECRETARY Central Board of I rrigation Power, New Delhi

DEPUTY SECRETARY ( Alternate )SHRI N. SIVACURU Roads Wing ( Ministry of Shipping and Transport )SHRI P. R. KALRA ( Alternate )SHRJ K. S. SRINIVASAN National Buildings Organization, New DelhiSHRI SUNIL BERRY ( Alternate )SHRI N. SUBRAMANYAM Karnataka Engineering Research Station, Govern-ment of Karnataka, KrishnarajasagarSUPERTNTENDINCE N a I N E E R Public Works Department, Government Of Tamil

(P D) Nadu, MadrasEXECUTIVE ENGINEER( SMRD ) ( Alternate )SHRI H. C. VERM_~ All India Manufacturers Dealers Association,BombavSHRI H. K . GUHA ( Alternate )SHHI G. RAMAN, Director General, IS1 (Ex-o o Member )Director ( Civ Engg )

SfxretarySHRJ K. M. MATHURDeputy Director ( Civ Engg ), IS1

Site Exploration Investigation for Foundations Subcommittee,BDC 23 : 2Members

SHRI P. D. ACoARWAL Public Works Department, Government ofUttar Pradesh, LucknowSHRI V. S. AooARWAL Central Building Research Institute ( CSIR ),Roorkee

SHRI M. P. J AIN ( Alternate )Continued on page l2 )

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IS : 1888 1982

I ndian StandardMETHOD OF LOAD TEST ON SOILS

( Second Revision0. FOREWORD

0.1 This Indian Standard (Second Revision ) was adopted by the IndianStandards Institution on 30 November 1982, after the draft finalized bythe Soil Engineering and Rock Mechanics Sectional Committee had beenapproved by the Civil Engineering Division Council.0.2 Visual examination of the soil exposed in suitably located trial pits atthe site, combined with the already established data for different types ofsoils is commonly used for deciding on the safe bearing capacity. Whilethis procedure may be adequate for light or less important structuresunder normal conditions, relevant laboratory tests or field tests areessential in the case of unusual soil types and for all heavy and importantstructures. This standard covers plate load test method for determinationof ultimate bearing capacity of soil in place which assumes that soil stratais reasonably uniform. The load test included in the standard is alsoused to find modulus subgrade reaction useful in the design of raftfoundation -and in the design of pavements.0.3 Plate load test, though useful in obtaining the necessary informationabout the soil with particular reference to design of foundation has somelimitations. The test results reflect only the character of the soil locatedwithin a depth of less than twice the width of the bearing plate. Since thefoundations are generally larger than the test plates, the settlement andshear resistance will depend on the properties of a much thicker stratum.Moreover this method does not give the ultimate settlements particularlyin case of cohesive soils. Thus the results of the test are likely to bemisleading, if the character of the soil changes at shallow depths, whichis not uncommon. A satisfactory load test should, therefore, includeadequate soil exploration ( see IS : 1892-1979* ) with ~due attention beingpaid to any weaker stratum below the level of the footing.0.4 Another~limitationsis the concerning of the effect of size of foundation.For clayey soils the bearing capacity ( from shear consideration ) for alarger foundation is almost the same as that for the smaller test plate.- -__-__

*Code of practice for sub-surface investigation for foundations ( jrsl revision ).3


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IS a88 1982But in dense sandy soils the bearing capacity increases with the size ofthe foundation. Thus tests with smaller size plate tend to give conser-vative values in dense sandy soils. Tt may, therefore, be necessary to testwith plates of at least three sizes and the bearing capacity resultsextrapolated for the size of the actual foundation ( minimum dimensionsin the case of rectangular footings ).0.5 This standard was first published in lC62 and subsequently revisedin 1971. In the present revision, the use of apparatus has been generalizedand also specific sizes of plates have been mentioned for the differenttypes of soils, besides incorporating zero correction which was present in1971 version and prescribing log log scale for cohesionless and partiallycohesive soils.0.6 For the purpose of deciding whether a particular requirement of thisstandard is complied with, the final value, observed or calculated,expressing the result of a test or analysis, shall be rounded off in actord-ante with IS : 2-1960*. The ~number of significant places retained in therounded off value should be the same as that of the specified value inthis standard.

1. SCOPEi.1This standard lays down the method for conducting load test forestimation of bearing capacity of soils and its settlement.2. TERMINOLOGY2.1 For the purpose of this standard, the definitions given in 18 : 280%1972t and IS : 6403-1981 shall apply.3. APPARATU3.1 Loading platform truss of sufficient size and properly designedmembers soas to estimate load reaction Tor conducting the test shall beused. The typical set up used for gravity loading is given in Fig. 1, forieaction loading in Fig. 2 and for loading truss in Fig. 3.3.2 Hydraulic jack of required capacity with properly calibrated loadmeasuring device, such as pressure gauge, electronic load cell, or proving,ring shall be used.3.3 Bearing Plates - Circular or square bearing plates of mild steel,not less than 25 mm in thickness and varyingin size from 300 to 750 mm

*Rules for rounding off numerical values ( revised ).Glossary of terms and symbols relating to soil engineering ( jirst revision ).Code of practice for determintaion of allowable bearing pressure on shallowfoundations ( first reuision ) .

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WOODEN JO STS OFSUITABLE SIZE WOODEN PLANKS

WOODEN JOISTS0F SUITABLE SIZE

15 cm LOADING COLUMN(WITH PLUM BOB ARRAN

LE IRON STAKESODEN GUIDE JOISTS

TEST PLATE

NOTE - Ctamp could also be at 2ower level.FIG. 1 TYPICAL SET UP FOR GRAVITY LOADING PLATFORM

6ALL AND SOCKARRANGEMENHEAD ROOM FORPERSON TO -SITAND OBSERVE

IF NECESSARYNOTE Dial gauge fixturemay be on the form clamp also.

FIG. 2 TYPICAL SET UP I;OR REACTION LOADING PLATFORM


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CROSS BARCHANNELSPIKEH.,,,RSf I-J

FIG. 3 TYPICAL SET UP FOR LOADING TRUSS


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IS : 1888 - 19824.4 Size and Shape of Plate - Except in case of road problems andcircular footing;, square plates may be adopted. For clayey and siltysoils and for loose to medium dense sandy soils with N < 15, a 450 mmsquare plate or concrete blocks shall be used. In the case of dense sandyor gravelly soils ( 15 < N < 30 ) three plates of sizes 300 mm to 750 mmshall be used depending upon practical considerations of reaction loadingand maximum grain size. The side of the plate shall be at least fourtimes the maximum size of the soil particles present at the test location.

NOTE - N is the standard penetration resistance value determined in accordancewith IS : 2131-l%l*.4.5 Test Arrangement

4.5.1 The loading platform shall be supported by suitable means atleast 2.5 m from the test area with a height of 1 m or more above thebottom of the pit to provide sufficient working space. No support ofloading platform should be located within a distance of 3.5 times size oftest plate from its centre.4.5.2 The test plate shall be placed over a fine sand layer of maximumthickness 5 mm, so that the centre of plate coincides with the centre ofreaction girder/beam, with the help of a plumb and bob and horizontallylevelled by a spirit level to avoid eccentric loading. The hydraulic jackshould be centrally placed over the plate with the loading column inbetween the jack and reaction beam so as to transfer load to the plate.A ball and socket arrangement shall be inserted to keep the direction of

the load vertical throughout the test. A minimum seating pressure of70 g/cm2 shall be applied and removed before starting the load test.4.5.3 The two supports of the reference beam or datum rod shall beplaced over firm ground, fixed with minimum two dial gauges resting atdiametrically opposite ends of the plates. The dial gauges shall be soarranged that settlement is measured continuously without any resettingin between.

4.6 Load Increments - Apply the load to soil in cumulative equalincrements up to 1 kg/cm2 or one-fifth of the estimated ultimate bearingcapacity, whichever is less. The load is applied without impact,fluctuation or eccentricity and in case of hydraulic jack load is measuredover the pressure gauge, attached to the pumping unit kept over thepit, away from the testing plate through extending pressure pipes.4.7 Settlement and Observation - Settlements should. be observedfor each increment of load after an interval of 1, 2.25, 4, 6.25, 9, 16 and

*Method for standard penetration test for soils (.first revision ).8


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IS : 1888 - 1982Continued from page 2 )

Members RepresentingDRALAM SUCH University of Jodhpur, JodhpurDIRECTOR Central SoilNew Delhi & Material Research Station,

DIWUTY Drn~~~ox ( CSMRS ) ( Alternate )E x E c u T I v E E N c I N E E n Central Public Works Department, New DelhiDESIGNS ) VE x E c TJ T I v E E N a I N R E n Public Works Department, Government of(SM&RD) Tamil Nadu, MadrasEXECUTIVE ENGINEER ( CD ) ( AlternateTOINT DIREC~COR RESEAILCH Ministry of Railways ( G.E.-II ) RDSODEPUTY DJRECT~R ( G.E.-II )RDSO ( Altermzle

SHRI M. D. Nara Associated Instruments Manufacturers (I) Pvt Ltd,New DelhiPROF T. S. N.~GARAJ ( Alternate )SHRI T. K. NATIEJAN Central Road Research Institute ( CSIR ), New DelhiLT-COL I(. M. S. SAnASI Engineer-in-Chiefs Branch ( Ministry of Dt,fence )SHRI A. K. ClI_4TURVEDI ( ~h%Ut~ )SHRI S. K. SHOM~ Geological Survey of India, Calcutta

SHRI P. N. M~XTA ( Alternate)SHRI N. SIVAoUaU Roads Wing ( Ministry of Shipping and Transport )SHKI P. K. THOMAS ( Alternate )SUPERINT~NIJINO EN~INREIL ( IC ), Irrigation Department, Government of Maharashtra,NAUPUR Bombay

*Acted as Convener.12

1888_method of load test on soils

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