2974_1_macine foundation design & cons_reciprocating type

8/12/2019 2974_1_Macine Foundation Design & Cons_Reciprocating Type

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IS : 2974 Part I ) - 1982lndian Standard

CODE OF PRACTICE FORDESIGN AND CONSTRUCTIONMACHINE FOUNDATIONS OF

PART I FOUNDATION FOR RECIPROCATINGTYPE MACHINES

Second RevisionSecond Reprint MAY 1993

UDC 62415911 : 6219-12

0 Copydghf 1982BUREAU OF INDIAN STANDARDSMANAK BHAVAN, 9 BAHADUR SHAH ZAPAR MAIt0

NEW DELHI 110002Gr 6 December 1982

( Reaffirmed 1998 )


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IS : 2974 Part I ) - 1982Indian Standard

CODE OF PRACTICE FORDESIGN AND CONSTRUCTION OF

MACHINE FOUNDATIONSPART I FOUNDATION FOR RECIPROCATINGTYPE MACHINES

Second RevisionFoundation Engineering Sectional Committee, BDC 43

ChairmanPROS DINESH MOHAN

MWLhSDg R. K. BHANDA~I

RepresentingCentral Building Research Institute ( CSIR ),RoorkeeCentral Building Research Institute ( CSIR ),RoorkeeSHR~ DEVENDRA SHA~~IA ( AltcrnatsCHIEF ENQINFERSrrnl S. Guna ( Ahrnatr ) Calcutta Port Trust, CalcuttaSHRI M. G. DANDAVATE

S HI&IN. C. DUGWAL ( Alternate)The Concrete Association of India, Bombay

SHRIA.G. DASTIDAR In personal capacity ( 5 Hungerford Court, 12X,SHRI V. C. DESRPAI~DE Hungerford Street. Calcutta )SPRI A. G, OS-AL The Pressure Piling Co (I) Pvt Ltd, BombayDIRECTOR ( CSMRS ) Stup Consultants Limited, BombayCentral Soil & Material Research Station,New DelhiDY DIRECTOR (CSMRS ) ( Alternate )SHRI A. H. DIVANJ I Asia Foundations and Construction Pvt L td,

SHRI A. N. J +NOLE (Alternate ) BombaySRRI R. K. DAS GUPTA Simp Tcu:;xrete Piles ( India ) Private L imited,aSI~RI H. GURA BISWAS ( AZternatc )D~J A~DIS~I NARAIN Indian Geotechnical Society, New DelhiPI ~OFSWAMI SARAN (Alternate )SRR~ G. S. J AIN G. S. J ain & Associates, RoorkeeSHRT AWOX KUMAR AI N ( Alternate )SARI N. J AQANNATHSARI A. K. MITRA ( Alternate ) Steel Authority of India, Bokaro( Con&wed on pop 2 j

9 Gqyri~ht 1982BUREAU OF INDIAN STANDARDS

This publication is protected under the In&cm Coeyricht ,461( XIV of 1957 ) andreproduction in whole or in part by any mrans except with written permission of the~ publisher shall be deemed to be an infringeTnt of conyright under the -aid Act.


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IS : 2971 Part I ) - 1982Continuedrompage1 )

Members RepresentingJ OWT DIRECTOR ( DESIGNS) National Buildings Organisation, New DelhiSHRI SUNIL BERY ( Alternate )J OIN P Dr IlECToR RESEAROR Ministry of Railways

( GE )-I, RDSOJ .)INT DIRECTOR RESEARCH( B & S ), RDSO ( Alteraatc )DR R. K. KATTI Indian Institute of Technology, BombaySHRI S. R. K ULKARNI M. N. Dastur & Co Pvt Ltd, CalcuttaS HRI S. ROY ( Alternate )SERI 0. P. MALHVTRA Public Works Department, Chandigarh Administ-SHRI A. P. MATHURSHRI V. B. M~THURSHRI T. K. D. MUNSI

rationCentral Warehousing Corporation, New DelhiMachenzies Limited, BombayEngineers India Limited, New DelhiSHRI M. IYENQAR (Alternate ) _SERI B. K. P%NTRAKY The Hindustan Construction Co Ltd, BombaySHRI V. M. MAD~E ( Ahernate )SHRI M. R. PUNJA Cemindia Co Ltd, BombaySHRI S. MUKHERJ EE ( Alternate )SHRI N. E. V. RA~HVAN The Braithwaite Burn & J essop ConstructionCompany L imited, CalcuttaPROF GOPAL RANJ AN University of Roorkee, RoorkeeDR V. V. S. RAO Nagadi Consultants Private Ltd. New DelhiSHRI T. N. SUBBA RAO Gammon India Limited, BombaySHRI S. A. REDDI ( Alternate )SHRIARJUNRIJHSINCJHANI Cement Corporation of India, New DeIhiSARI 0. S. SRIVASFAVA (Alternate )DR A. SAR~UNAN College of Engineering, GuindySHRI S. BOMMI NATRAN Alternate )Sanr K. R. SAXENA Engineering Research Laboratories, Government ofAndhra Pradesh, HyderabadBRIG OXBI~~ SINQH Engineer-in-Chiefs Branch, Army Headquarters,New DelhiLT-COL K. P. ANAND ( Alternate )SHRI N. SIVA~URU Ministry of Shipping and Transport, New DelhiSHRI K. P. SARKAR (Alternate )SUPERINTENDINQ ENGINEER Central Public Works Department, New Delhi( DESIGNS )EXECUTIVE ENQTNEER( D~~IQNS ) V ( Affernate )SHRI M. D. TAMBEKAR Bombay Port Trust, BombayDR A. VaRAoARhJAN Indian Institute of Technology, New DelhiD,c. R. KANIRAJ ( Alternate )

SEW G. RAM.~N, Director General ISI ( Ex-ojicio Member )Director ( Civ Engg )Secretary

SHRI K. M. MATHURDeputy Director ( Civ Engg ) ISI,

( Continued n puge 22 )2


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IS : 2974 Part I ) - 1982Indian Seandard

CODE OF PRACTICE FORDESIGN AND CONSTRUCTlON OF

MACHINE FOUNDATIONSPART I FOUNDATION FOR RECIPROCATINGTYPE MACHINES

Second Revision0. FOREWORD

0.1 This Indian Standard ( Part I ) ( Second Revision ) was adopted bythe Indian Standards Institution on 26 July 1982, after the draft finalizedby the Foundation Engineering Sectional Committee had been approvedby the Civil Engineering Division Council.0.2 Installation of heavy machinery has assumed increased importancein the wake of the vast programme of industrial development in thecountry. Foundations for these machines have to be specially designedtaking into consideration the impact and vibration characteristics of theload and the properties of soil under dynamic conditions. While manyof the special features relating to ;he design and construction of suchmachines foundations will have to be as advised by the manufacturersof these machines, still a large part of the details will have to be accord-ing to certain general principles of design covering machine foundations.This standard is intended to lay down these general principles.This part, which is the first of a series of standards relating tomachine foundations, deals with machines of the reciprocating type forwhich rigid-block type foundations are generally used. This standard wasfirst published in 1964 and revised in 1969. In this revision, the principalmodifications made are in respect to providing additional information ofpile foundation, grouting and inclusion of guidelines for installation ofanti-vibration mountings and testing and measurement of vibration.0.3 For the purpose of deciding whether a particular requirement of thisstandard is complied with, the final value, observed or calculated, ex-pressing the result of a test or analysis, shall be rounded off in accordancewith IS : 2-1?60*. The number of significant places retained in therounded off value should be the same as that of the specified value in thisstandard.

*Rules for rounding off numerical values ( reoised.3


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IS : 2974 Part I ) - 19821. SCOPE1.1 This standard covers the design and construction of foundations formachines of the reciprocating type which normally generate steady statevibration and is of a size for which a rigid block type foundation isnormally used.2. TERMINOLOGY2.0 For the purpose of this standard, the definitions of the following termshall apply ( see Fig. 1 ).

Lateral p.Longitudinal PVVertical p 0 = Combined Centroid of Foundationand Machinery SystemPitching MaRocking MU C = Cefitroid of Bearing SurfaceYawing M.

FIG 1 AXES AND CO-ORDINATES4


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IS : 2974 Part I ) - 19822.1 Supporting Ground - That part of the ground carrying loadarising from the machine and foundation.2.2 Foundation - The part of the structure in direct contact with,and trammilting loads to the supporting ground.2.3 Forces -and Couples

2.3.1 Ext er nal For ces - The unbalanced part of the periodic inertiaforces caused by the acceleration and deceleration of reciprocating parts.The primary inertia force has one complete cycle and the secondaryinertia force two cycles per revolution of the crank shaft.2.3.2 Ver ti cal For ce - An unbalanced force at machine operationfrequency or twice the operationdirections of axis 5. frequency, or both, acting in the2.3.3 H or izontal Force - An unbalanced force at machine operationfrequency or twice machine operation frequency, or both acting in thedirections of axis X.2.3.4 Ext ehzal Coupl e - A moment which occurs when one inertia forceis balanced by another but in a separate line of action. For foundationdesign it is usually necessary to consider only the primary and secondaryvertical and horizontal couples.2.3.5 Ver ti cal Coupl e - An unbalanced couple at machine operation

frequency or twice the machine operation frequency, or both acting inthe planes of axes Y


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IS : 2974 Part I ) - 19822.6.1 Damping Constant ( C ) - Constant of proportionality relatingforce of damping with instantaneous velocity of motion.2.6.2 Gitical Damping ( C, ) - Th e magnitude of damping at which themotion of the system changes from periodic to aperiodic.

where Cc = 2,/Kk for single degree of freedom system2.6.3 Damping Factor - The ratio of the damping constant ( C ) to thecritical damping ( Cc ) of the system.

2.7 Amplitude of Motion - The distance that a body moves from itsposition of rest when subjected to vibration.2.8 Frequency - The number of times a periodic motion repeats itselfexpressed in revolutions or cycles per minute (f ).

2.8.1 Operation Frequency - The rotating speed of the main drive incycles per second or the frequency of the periodic force acting on thesystem.

NOTE - System meant the machine, the foundation block and soil.2.8.2 Angular Frequency ( w ) - The frequency expressed in radians persecond.2.8.3 Natural Frequency ( fn ) - The frequency of free vibration of abody.2.8.4 Pisturbing Frequency - The frequency of a periodic force.2.8.5 Limiting F-eqnencies - If a system possesses n degrees of freedomhaving n natural frequencies f,,_ f3, f4, .._.. _._. ._ fn, the minimumand maximum of such frequencies, f ,,,i,,and f maz re known as limitingfrequencies of the system.2.8.6 Evquenry Ratio (f/f ) - Th e ratio of the operating frequency tothe natural frequency.

2.9 Degrees of Freedom of a System - The degree of freedom of asystem is defined as the number of coordinates required to describe thedisplaced position of the system ( see Fig. 2 ).2.10 Reasonance - When the frequency of the forced vibration( ope,ating frequency of the machine ) equals the natural frequency ofthe foundation soil system the condition of resonance is reached.2.11 Mass Moments of Inertia - The resistance of a mass to rotationand equal to its mass times the radius of gyration squared.

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IS : 2974 ( Part I ) - 1982IERTICALZw

YAWING

TC HING

Lateral PZ Pitching & ILongitudinal PV Rocking WVVertical PC Yawing %z

The axis TT is parellel to the crank shaft.FIG. 2 SYSTZM OF AXES AND THE SIX DEGREES OF FREEDOM

2.12 Mass-Spring Syste?2.12.1 Single M ass Spri ng System - A rigid body supported by a numberof springs, such a system has six natural frequencies, three of them beingtranslational or three Cartesian, co-ordinate axes and the other three beingrotational on three planes in a Cartesian co-ordinate system.2.12.2 M ult i pl e M ass-Spri ng System -A number of rigid bodies connect-ed by a series of relatively flexible springs. The natural freqencies dependon the number of degrees of freedom being defined as the number ofco-ordinates required to identify a point on the rigid body.

2.13 Fatigue Factor or Fatigue Coefficient - The factor of safetyutilized to obtain equivalent static force for a dynamic force so as to takecare of reduction in the strength of the concrete and steel due to repeatedloading. The factor should be assumed as 3 unless otherwise specified.


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IS : 2974 Part I ) - 19823. N OTATIO%3.1 The notations given in Appendix A shall apply.4. NECESSARY DATA4.1 Data to be Provided by Machine Manufacturer - The manu-facturer should provide information as outlined in 4.1.1 to 4.1.3.

4.1.1 Generala) Description of driving and driven machinery,b) Operating speed or speed ranges,c) Number and arrangement of cylinders,d) Distance between axis of main shaft of the machine and the topface of foundation,e) Maximum rated output,f ) Gear box ratio where applicable, andg) Maximum operating temperature in the bases of the machine.

4.1.2 For Static Design4.1.2.1 A detailed loading diagram comprising plan, elevation andsection showing details of communication and point of all loads onfoundation.4.1.2.2 A detailed drawing showing the position and sire of mount-

ing feet and details of holding down bolts.4.1.3 For Dynamic Design

4.1.3.1Details of out of balance forces and couples shall be given,together with associated frequencies for all possible moc es of vibrationfor driving and driven machinery. These include the following:a) External forces,b) External primary couples,c) External secondary couples, andd) Harmonic torques.4.1.3.2 Mass moments of inertia of driving and driven machineabout three principal axes shall be indicated.4.1.3.3 Additional information relating to specific machines, as givenbelow, shall be provided where necessary:a) Loads due to dynamic short circuit conditions, andb) Loads due to an abnormal sudden stoppage.

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IS : 2974 ( Pzrt I ) - 19524.1.3.4 Where it is founrl necessary to use anti-vibration mountings,the type and positions be indicated.

4.2 Data 8x1Ground and Site Conditions - The following soil datashall be known:a) Soil profile an,1 soil charactrri.tics up to a cepth at least threetimes the expected mean plan ciin,ension of the fount ation whichcan be taken as the square root of t :e expected area, or hardstrata.b) Soil investi,gation to the extent necessary in accordance withIS : 1892-1979* and for the determination of dynamic p:ope;tiesof soil in accordance with IS : 524%1977t.c) The relative position of the water table be ow ground at differenttimes of the year.

5. DESIGN CRITERIA5.1 General

5.1.1 The fou:l(lation structure of machine shai be iso a[etl at alllevels from the main bt~i ling and frorn other foundations as far aspossible.5.1.2 Overhanging cantilevers where unavoidable shall he c esigned toensure rigid,ity against vibt ation.5.1.3 All machine foundations shall saticfy two fundamental criteria;that resonance does not occur between the frequencie of the l.~u ~atingloads and natural frequency of foundation/soil system an also theamplituc e of vibration does not exceed safe limits. Design critrria basedon frequency and amplitude limits c,nn be classed as follows:

a) Limits set by the possibility of damage or uneconomic ivear tomachinery or associated equipment or both,b) Limits set by the porsibility of damage to building structuics,c) Limits of structural borne vibrations to ensure confort of person,andd) Limits set by possibility of disturbance of ground resulting inunacceptab e settlement of foundation.

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IS : 2974 Part I ) - 19825.2 Frequency Ratio - Wherever possible the natural frequency ofthe foundation soil-system shall be higher than the highest disturbingfrequency and the frequency ratios shall not be rormally less than 0.4.Where this is not po;sible, the natural frequency of the foundation-soilsystem shall be kept lower than the IoweGt disturbing f equency. The fre-quency ratios in such ca;es shall not be lower than l-50. While the abovecriteria shall be applie-l to all possible modes of vibration, it may be per-mtted to operate machines closer to the resonance in certain modes ofvibration provided the resulting amplitudes do not exceed the permissiblelimit.

NOTE - Even though machine may be balanced, minor disturbing forces canoccur due to manufacturinq tolerances and other causes, for sensitive installations,the frequencies arising from these may have to be considered.5.3 Permissible Amplitudes

5.3.1 Limitationsof Vibration Amplitude to Avoid Damage to Machinery - Thisshall be specified by the manufacturer and shall in no cases be exceeded.Where no specific limit has been stated by the manufacturer, it may betaken that foundation satisfying the following amp itude criteria shallprovide a satisfactory base for machinery.5.3.2 Limitations of Vibration Amplitude to Avoid Damage to Machinery -The clamage in neighbouring buildings due to resonance will be neqligi-ble if the amplitude vibration of the foundation is less than 200 microns

at frequencies below 20 Hz, where the disturbing frequency exceed 20 Hz,a lower amplitude may be necessary for certain installation;, when avalue corresponding to the frequency may be read off line ADD ofFig. 3.5.3.3 Limitation of Vibration AmplitudG to Alsoid Discomfort of Persons -For low speed machines, it is unlikely that foun lations which satisfy5.3.2 will produce vibrations of sufficient amplitude to be disturbing topersons. In special cases where there are particular reasons to avoirlc i\cornfort to personnel, a low permissible amplitude corresponding to

operating frequency of machine can be read off from FL;. 3.5.3.4 Limitutions of Amplitude to Avoid Settlemant - For most soil types,foundttions for low speed machines designed to limiting amr)liturleot 200 microns will not suffer un-lue settlement due to dynamic loads.In ca;e of some soils like loose sanls an1 silts in conjunction with highwater table, there is a possibility of significant settlement to occur. Inall such cases, it shall be preferable to consolidate the soil unclerneaththe fo ln:lation.

1


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IS : 2974 ( Part I ) - 19822502001501007550

+4J;; 205g 150 103 7*5

0*25 L 3 5 1 20 30 50 100 160 (Hz 1DISTURBING FREQUENCY

Line ZDD Limit to Avoid Damage to BuildingsLine ACC Limit to Avoid Serious Discomfort to PersonsLine ABB Limit to Ensure Rearonshle Comfort to PwsonT

NUTE - IIese Limits do not include any factor of safety.FIG. 3 ~PLITUDE IJMITS OF FOUNGATION I $LOCK


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IS : 2974 Part I ) - 19825.4 Concrete Foundation Design

5.4.1 General Conditions - Normally concrete block foundations aredesigned for reciprocating machires. Both the foun:lations and machinesare usually taken as a single body resting on an elastic bedding. ( Sub-soil or resilient mounting ). The foundation is subject to oscillations atdeterminable frequencies in six degrees of freedom ( Fig. 2 ).Pile foundations may be used in cases where the soil conditions areunsuitable to support block foundation or when natural frequency of theblock foundation< needs to be raised in cases where it is impossible toalter dimensions or when amplitudes or settlement or both need to bereduced.Cellular foundations may be used in special cases where it isnecessary to maintain the rigidity of a block foundation but with masssaving of concrete. Wherever possible provision shall be made incellular foundations to acid mass by filling the voids to adjust the naturalfrequency of foundation block provided this does not result in additionalsettlement.

5.4.2 Dimensions of Concrete Foundation Blocks - For initial dimensioningof the concrete foundation blocks, the following empirical rules may beallowed.5.4.2.1 Mass of the foundation shall be greater than that of themachine.5.4.2.2 The eccentricity of foundation syctem along axis XX/Ushall not exceed 5 percent of the length of the corresponding side ot thecontact area. In addition, centre of gravity of machine and foundationshall be if possible below the cop of foundation block.5.4.2.3 To ensure reasonable stability in the case of verticalmachines, the total width of the foundation ( measured to right anglesto shaft ) shall be at least equal to the distance from the centre of theshaft to the bottom of the foundation. In case of horizontal machines,where cylinders are arranged laterally the width shall be ,greater.5.4.2.4 The proportion of foundation block shall be such to ensurestability.

5.4.3 Final Desi,qn of Foundation Blocks - The final dimenr-ions of aconcrete foundation shall be derived from vibration calculations andshall consider:a) The dimensions of foundations by empirical rules,b) The bearing pressure due to dead and imposed load,c) lhe natural frequencies of the system for six modes of vibrations,

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4e)f 1

IS : 2974 Part I ) - 1982The relationship between the exciting frequency and naturalfrequency of the foundation-soil system,Calculated amplitudes in the various modes of vibration, andInfluence of water table specially when at a high level.

Appendix B aives the design procedure for an unlamped system.However, damping can also be considered in certain cases.5.4.3.1 Full value of permissible stresses for steel and concrete asspecified in IS : 456-1978 shall be allowed if dynamic loads areconsidered in detailed design by applying suitable dynamic and fatiguefactors.5.4.3.2 The following dynamic elastic modulus of concrete may beused in design:

Grades of Concrete Dy namic El ast i c M oduluskgf/cm

M 15 250 000M 20 300 000M 25 340 000M 30 370 000

5.4.3.3 The soil stress below the foundations shall not exceed80 percent of the allowable stress under static loading determined inaccordance with IS : 6403-1981;. When seismic force: are consideredallowable stress in the soil shall be increased as specified in IS : 18.+3-19751.5.4.4 Supporting foundation blocks on end-bearing or friction pilesshall be considered in cases where there is need to make a signifi-antchange in frequency in one or more modes of vibration or dead loads.

Pile caps where used as a foun.-lation block shall be of such a size asLOmeet all design criteria, and be not less than 60 cm thick.5.4.4.1 Rrqui remsnt of pil cdfoundati ons - The most usual reasons foradoption of piled foundation are as follows:a) When pressure on the soil under the block exceeds the permissiblebearing pressure;

*Code of practice for plain and reinforced concrete ( third revi si on .tCode of practice for determination of bearing capacity of shallow foundations( Jirstreuirion.$Cri eria for earthquake resistant design of structures ( f&d revision ).


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IS : 2974 Part I ) - 1982b)

4

When a foundation is found to be subject to resonance, or whenan increase in the mass of the block is either unduly wasteful inmaterial or ineffective due to the danger of rescnance in othermodes;When a block foundation i s low tuned by one mode and hightuned by other and desirable or specified frequency ratioscannot be maintained simultaneously;When the amplitudes of movement of a block foundation are inexcess of their permissible values;Piled foundation shall be used when a raft foundation is liable tosuffer a differential settlement exceeding the permissible limit; andPiles may be used to minimize the effect of ground bornevibration on surrounding foundations and equipment.

3.4.4.2 Eualuati on of pil e soil sti ffness - Pile soil stiffness factors bothin vertical and horizontal ( see IS : 9716-1581* ) modes of vibration shallPreferably be determined by conducting in sit u test on piles. In cases,where it becomes difficult to conduct this test, the values can be takenfrom some standard publications. The centre of gravity of the system,that is, foundation and machine shall be located within 5 percent of thelength of foundation to concerned axis with respect to the centre ofgravity of the pile group.

5.4.4.3 Design considerationsa)

b)

4

Pile-soil stiffness factors both in vertical and horizontal modesof vibration shall be determined by conducting in sit u dynamictests on piles. For preliminary design however the computativemethod of estimation of pile-soil stiffness can be adopted.Usually in sit u dynamic tests are conducted on single pile withfree head condition. In actual practice the pile shall be used ina group with pile heads largely restrained by the pile cap.Allowance shall be made for these factors in evaluation of pile-soil stiffness to be adopted for design. Failure to take account ofthese factors will lead to error in estimating stiffness of the system.After evaluating the pile-soil stiffness, the design shall becarried out in the same way as for the block foundation restingdirectly on soil.

*Guidelines for lateral dynamic load test on piles.


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IS : 2974 Part I ) - 19825.45 M in im um Rein forcement n Bl ock Foundat i ons

5.4.5.1 Minimum reinforcement in the concerete block shall be notless than 25 kg/ms. For machine; requiring special design conGderationsof foundatron3, like machines numpin g explosive gases the reinforcementshall be not less than 40 kg/ma.

5.4.5.2 The minimum reinforcement in the block shall usuallycon,iist of 12 mm bars space1 at 200/230 mm centre to centre extendingboth vartically and horizontally near all the faces of the foundationblock.5.4.5.3 The following points shall be considered while arranging thereinforcements:a) The ends of mild steel ( if used ) shall always be hookedirrespective of whether they are designed for tension or com-pression,b)c>(0

Reinforcement shall be used at all faces,If the height of foundation block exceeds one metre, shrinkagereinforcement shall be placed at suitable spacing in all threedirections, andReinforcemc,it shall be provided around all pits and openingsand shall be equivalent to 0.50 to 0.75 percent of the cross-sectional area of the opening.

5.4.6 Ant i -Vibrat ion Mount ings5.4.6.1 Where it is found to be impracticable to design a foundationconsisting of a simple concrete block resting on the natural soils to givesatisfactory dynamic characteristics , it may be posible to reduce thetransmiitcd vibrations to acceptable levels by means of anti-vibrationmounting.5.4.6.2 Depending upon the nature of the machinery and theinstallation, the anti-vibration mounting may be used:a) Between machinery and foundation, andb) between a foundation block and a supporting system.

6. CONSTRUCTION6.1 Concrete - Concrete strength shall be specified on the basis of28-day cube strength. The concrete grade shall be at least M-15( according to IS : 456-1978* ).


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IS : 2974 Part I ) - 19826.2 Continuity of Work - Foundation block shall preferably be castin single continuous operation. In case of vpry thick blocks ( exceedingabout 5 m ) if needed, construction joints can be provided. In such aevent construction joint shall be suitably designed by the design#engineer and shown in working drawing. In the event of an unforseeninterruption in concrete, the resulting unavoidable joint shall beconsidered as a construction joint and treated in the same way as cons-truction joints.6.3 Cement Grout

6.3.1 Cement grout used for fitting or embedding shall consist of onepart of Portland cement and two parts of clean sharp sand mixed to amoist consistency sufficient to facilitate the grout being fully workedunder all seatings. Quick setting cement shall not be used.6.3.2 Additives may be employed to give non-shrink properties tocement grout. In this case the ratio of cement and sand may be variedaccording to the instruction of manufacturer.6.3.3 Cement grout shall be placed within a period commensurate

w i th cement type but not later than one hour from the time of mixing.6.4 Grouting

6.4.1 All metallic and concrete surfaces shall be thoroughly cleanedand washed to clean all dirt, oil, grease, loose particles and cementlaitance. The concrete surfaces shall be roughened and saturated withclean water and kept wet for at least 24 hours and all surplus waterremoved and surfaces cleaned, oil free with compressed air if requiredbefore commencement of grouting.

6.4.2 Provision shall be made if required to avoid trapping air. Airrelief holes shall be provided, if necessary.6.4.3 Forms shall be high enough to provide a head of the grout onall sides which shall be about 150 mm high on side from which cementgrout is to be poured. Forms shall be placed with sufficient clearanceto the edges of the bases to enable the grout to be properly worked into

position.6.4.4 Forms shall be strong and secure and well covered to preventleakage. The cement grout shall be poured from one side to avoidforming air pockets and be carried out continuously without interruptionso that\filling is continuous and dense.6.4.5 On completion of the curing of the grout underfill the machineshall be finally checked to ensure that its alignment is acceptable.6.4.6 Exposed surfaces of grout and concrete shall be prepared andgiven two coats of an oil and alkali resistant coating.

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IS : 2974 ( Part I ) - 19827. TESTING AND MEASUREMENT OF VIBRATION7.1 General - Testing of a foundation block prior to the initialrunning of the machinery may, where warranted be carried out todetermine the natural frequencies in various modes of vibration and theamplitudes due to dynamic forces likely to occur either during normalrunnin,g or during emergency or adverse running conditions of themachine. The observation can also be made during the operation ofmachines.7.2 Excitation - In case where blocks are to be tested prior to therunning of machines, foundation blocks may be excited either by anelectromagnetic or hydraulic vibrator. The block shall be excited insame modes of vibration as is expected from the operating machinery.The amplitudes of motion which can be induced with a scale downdisturbing force may be significantly smaller than those expected in theoperation of machine. Allowance may have to be made for the n-n-linearity of soil response.7.3 Measurements

7.3.1 The vibrations shall be measured by transducers having a linearresponse over the range 2 to 200 Hz. The accuracy of transducers shallbe better than 10 percent and they shall respond to a uniaxial motionwith more than 10 percent cross sensitivity.7.3.2 The transducers shall be preferably piezo electric type or geo-phones meeting the requirements as in 7.3.1.7.3.3 The transducers shall be mounted firmly to the foundation. Thetransducers shall not be merely rested on the foundation or held withhand.7.3.4 Transducers shall preferably be placed on extremities of theupper-most surface of the block and as near as possible to the axis of Xand Y ( see Fig. 1 ).7.3.5 In order to gain full picture of the behaviour of a block, it shallbe desirable to use a multiple channel recorder with filter, singlechannel recorder can also be used in small installations.7.3.6 It shall be preferable to use Vibration Analyser which canmeasure frequency and amplitude of vibrationsimultaneously.


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IS : 2974 Part I ) - 1982APPENDIX A

Clause 3.1 )NOTATIONS

SYMBOL DESCRIPTIONA Area of foundation in contact with soilAa Horizontal amplitude of foundation subjected tohorizontal force P, and moment M LAZ Vertical amplitude of foundation subjected tovertical force PzA4 Rotational amplitude of foundation subjected tohorizontal force Pa and moment M iC Damping constant

Critical dampingCoefficient of elastic uniform compression of SoilCoefficient of elastic uniform shear of soilCoefficient of elastic non-uniform compressionof soilEccentricity of eccentric weight of rotating parts

J Frequencyfn Natural frequency_fk&2 First and second natural frequencies of founda-tion subjected to horizontal vibrationf,,l,f,,2,f,,3 First, second and third natural frequencies offoundation when centre of gravity of mass ofmachine and foundation and the centroid ofthe founcation contact area with soil lies onvertical plane but not on the same verticallinef nz

nz

Horizontal resonance frequency of foundationand soil systemVeL tical resonance frequency of foundationand soil system

UNITcm2cmcm

radiandimension-lesskg-s/cmkg/cm3kg/cm3kg/cm3cmC/SC/Sc/s

c/s

c/sc/s


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IS : 2974 Part I ) - 1982SYMBOLfn4h

I

kL

M iMVS

mm.

PWE

W

w n

DESCRIPTIONRotational resonance frequency of foundationand soil systemHeight of the top surface of the foundationabove the centre of gravity of the found-ation and machineMoment of inertia of contact area with res-pect to the axis of rotation passing throughthe centroid of the areaStiffness of springDistance from mass centre of gravity of thevibrating system with respect to the axis ofrotationDynamic momentMass moment of inertia of the vibrating systemwith respect to the axis of rotation passingthrough C G of the systemMass moment ofinertia of the vibrating systemwith respect to the axis of rotation passingthrough centroid of contact area of founda-tion with soilMass of vibrating systemMass of eccentric weight of rotating partsOscillating force applied at the centre ofgravity of vibrating massWeight of foundation and machineEccentric distance from centroid of contactarea of foundation with soil to the C G ofmass of machine and foundationCircular frequencyCircular natural frequency

UNIT

CIScm

cm4

kg/cmcm

kg/cmkg-cm-s2

kg-cm-s2

kg-s2/cmkg -sz/cmkgkgcm

radian/sradian/s


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IS : 2974 Part I ) - 1982APPENDIX B

( Clause 5.4.3 )ANALYSIS FOR THE DETERMTNATPOM OF NATURALFREQUENCIES AND AMPLITUDES OF FOUNDATIONSACCOMPANIED BY SIMULTANEOUS ROTATPON,SLIDING AND VERTICAL DISPLACEMENT MASSSPRING ANOLOGY )

B-l. Limiting Natural Frequencies - Tllc limiting naluralfrequencies shall be calculated as follows:

a l l t , fz CTn5 - -4x mB-2. Check on DesignB-2.1 When the centre of gravity of mass of n:achinc and founrationand centroid of contact area of foundation lie on the same vertical line,the vertical vibralion of foundaticn is independent of vibrations inhorizontal direction and rotation about the horizontai axis. The naturalfrequencies should be calculated as follows:

where Y = M,/Mmo.Amplitudes are calculated as follows:

nzoe oJ2


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IS : 2974 Part I ) - 1982I-,WL+GAL2 - M,,,d ) Pz f CrALMiAx = 16 n4m MnL (_,ft --f 2


23/25


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BUREAU OF INDIAN STANDARDSHeadquartersManak Bhavan, 9 Bahadur Shah Zafar Marg, NEW DELHI 110002Talephones : 331 01 31, 331 13 75 Telegrams : Manaksanrtha( Common to all offices )Regional Oflces TelephonesCentral : Manak Bhevan, 9 Behedur Sh8h Zafar Mrrg,NEW DELHI-1 10002 [ 331 01 31331 1375*Eastern : l/l 4 C.I.T. Scheme VII M, V. I. P. Road,Maniktola, CALCUTTA 700054Northern : SC0 445-446, Sector 35-C,CHANDIGARH 160036Southern : C. I. T. Campus, MADRAS 600113Western : Manakalaya, E9 MIDC, Marol, Andheri (East),BOMBAY 400093Branch OfjlcesPushpak Nurmohamed Shaikh Marg, Khanpur,AHMEDABAD 380001SPeenya industrial Area, 1 st Stage, Bangalore Tumkur RoadBANGALORE 560058Gengotri Complex, 5th Floor, Bhadbhada Road, T. T. Nagrr,BHOPAL 462003Plot No. 82/83, Lewis Rocld, BHUBANESHWAR 7510025315, Ward No. 29, R. G. Barua Road, 5th Byelene,GUWAHATI 7810035-6-56C L. N. Gupta Marg ( Nampally Station Road),HYDERABAD 500001R14 Yudhlster Marg, C Scheme, JAIPUR 302005117/418 B Sarvodaya Nagar, KANPUR 208005Patliputra Industrial Estate, PATNA 800013T.C. No. 14/l 421, University P.O., Palayam .TRIVANDRUM 695035lnspecflon Olflce (With Sale Point) :Pushpanjali, 1st Floor, 265-A West High Court Road,Shankar Nagar Square, NAGPUR 440010Institution of Engineers ( India ) Building, 1332 Sliivaji Nwar.PUNE 411005

*Soles Off~cen Calcutta is at 5 Chowrlnghsr Approach, P.O. PrlncspStreet, Calcutta 700072fSales Office in Bombay Is at Novelty Chambers, Grant Road,Bombay 400007

36 24 99

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[ 263482 63 49E384955.38 49 56

667165 36 273 31 77

23 1083

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27 63 0039 65 29


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AMENDMENT NO. 1 NOVEbi BER 1985TO

I S: 2974 Part l ) - 1982 CODE OF PRACTICE FOR DESIGNAND CONSTRUCTI ON OF MACHI NE FOUNDATI ONSPART 1 FOUNDATI ON FOR RECI PROCATI NG TYPE MACHI NES

Second evision)Corrbendum- - - - -

Page 1, ckzuse B-2.4) Delete the last sentenceA typical........ ig. 2 .

(Em 43)Printed at Simco Printing Press Delhi, India

2974_1_macine foundation design & cons_reciprocating type

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