875 2IS CODE FOR WIND LOADS

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875 2IS CODE FOR WIND LOADS

875 2IS CODE FOR WIND LOADS

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  • 1. IS : 875 ( Part 2 ) - 1987 (Reaffirmed 1997) Indian Standard CODE OF PRACTICE FORDESIGN LOADS (OTHER THAN EARTHQUAKE) FOR BUILDINGS AND STRUCTURES PART 2 IMPOSED LOADS (Second Revision) ~- Sixtll Reprint JUNE 1998 UDC 624~042.3 : 006.76 @ Copyright 1989 BUREAU OF INDIAN STANDARDS MANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARG NEW DELHI 110002Gr 8 March 1989
  • 2. IS : 875 ( Part 2 ) - 1987 .I Indian Standard CODEOFPRACTICEFORDESIGNLOADS(OTHERTHANEARTHQUAKE) FORBUILDINGSANDSTRUCTURES PART 2 IMPOSED LOADS (Second Rev’sion) Structural Safety Sectional Committee, BDC 37 Chairman RepresentingBRIG L. V. R AMAKRISHNA Engineer-in-Chief’s Branch, Army Headquarters, New Delhi MembersD R K. G. BHATIA Bharat Heavy Electricals Ltd ( Corporate, Research & Development Division ), HyderabadS HRI M. S. BHATIA In pe;rs;;l) capacity ( A-2136, Sa/darjmg Enclave, NewSHRT N. K. BHATTACHARYA Engineer-in-Chief’s Branch, Army Headquarters, New De Ihi SHRI S. K. MA L H O T R A (Alternate )DR S. C. C HAKRABARTI Central Building Research Institute ( CSIR ), Roorkee SHKI A. D A T T A ( AIIernare )C HIEF E NGINEER ( NDZ ) II Central Public Works Department, New Delhi S U P E R I N T E N D I N G S URVEYOR OF W O R K S ( NDZ ) II ( Alternate )D R P. DA Y A R A T N A M Indian Institute of Technology, Kanpur D R A. S. R. SAI ( Alternate )D E P U T Y M U N I C I P A L COMMISSIOKER ( EN G G ) Municipal Corporation of Greater Bombay, Bombay C ITY E NGINEER ( Alternate )D IRECTOR ( CMDD-I ) Central Water Commission, New Delhi D EPUTY D IRECTOR ( CMDD-I ) ( Alternate )M A J- GEN A. M. GOGLEKAR Institution of Engineers ( India ), Calcutta P ROF D. N. T RIKHA ( Alternate )SHRI A. C. GUPTA National Thermal Power Corporation Ltd, New DelhiSHRI P. SEN G U P T A Stewarts and Lloyds of India Ltd, Calcutta S HRI M. M. GHOSH ( Alternate )SHRI G. B. J A H A G I R D A R National Industrial Development Corporation Ltd, New DelhiJ OINT D IRECTOR S T A N D A R D S ( B & S ), CB Ministry of RailwaysS HRI S. P. JOSHI Tata Consulting Engineers, New Delhi S HRI A. P. M ULL ( Alternate )S HRI S. R. KUI.KARNI M. N. Dastur & Co, Calcutta S HRI S. N. PAL ( Alternate )S HRI H. N. MI S H R A Forest Research institute and Colleges, Dehra Dun SHRI R. K. PUNHANI ( Alternate )S HRI T. K. D. MU N S H I Engineers India Ltd. New DelhiD R 6. RA J K U M A R National Council for Cement and Building Materials, New DelhiD R M. N. KESHWA RA O Structural Engineering Research Centre ( CSIR ), Madras S HRI S. GO M A T H I N A Y A G A M ( Alternate )D R T. N. S UBBA R A O Gammon India Ltd, Bombay DR S. V. L O N K A R ( AIfernafe )S HRI P. K. RA Y Indian Engineering Association, Calcutta S HRI P. K. M UKHERJEE ( Alternate )SHRI S. SE E T H A R A M A N Ministry of Surface Transport ( Roads Wing ), New Delhi S HRI S. P. C HAKRABORTY ( Alternate ) ( Continued on page 2 ) 0 Copyright 1989 BUREAU OF INDIAN STANDARDS This publication is protected under the Indian Cop.vright Act ( XIV of 1957) and reproduction in whole or in part by any means except with written permission of the publisher shall be deemed to be an infringement of copyright under the said Act.
  • 3. IS : 875 ( Part 2 ) - 1987( Continuedfrom page 1 ) Members RepresentingSHRI M. C. SHARMA India Meteorological Department, New DelhiSHRI K. S. SRINIVASAN National Buildings Organization, New Delhi SHRI A. K. LAL ( Alternate )S HRI SUSHJL KLIMAR National Building Construction Corporation, Limited, New DelhiSHRI G. RAMAN, Director General, BIS ( Ex-officio Member ) Director ( Civ Engg ) Secretary S HRI B. R. NARAYANAPPA Deputy Director ( Civ Engg ), BIS Panel on Loads ( Other than Wind Loads ), BDC 37 : P3 ConvenerD R T. N. SUBBA RA O Gammon India Limited, Bombay D R S. V. LONKAR ( Alternate ) MembersD R T. V. S. R. APPA RA O Structural Engineering Research Centre, CSIR Campus, Madras D R M. N. KESHAVA R AO ( Alternate )SHRI S. R. KULKARNI M. N. Dastur & Co Ltd, CalcuttaSHRI M. L. MLHTA Metallurgical & Engineering Consultants ( India ) Ltd. Ranchi SHRI S. K. DATTA ( Alternate )D R C. N. SRINIVASAN M/s C. R. Narayana Rao, MadrasSUPERINTENDING E NGINEER ( D ) Central Public Works Department ( Central Designs Organization ), New Delhi E XECUTIVE E NGINEER ( D ) VII ( Alternate )DR H. C. V ISVESVARAYA National Council for Cement and Building Materials, New Delhi
  • 4. IS : 875 ( Part 2 ) - 1987 CONTENTS Page0. FOREWORD ... *.. ... ... ... 41. SCOPE ... ... ... ... ... 52. TERMINOLOGY ... ... ... ... ... 53. IMPOSED LOADS ON FLOORS D UE TO USE AND O CCUPANCY ... ... 63.1 Imposed Loads ... ... ... ... 6 3.1.1 Load Application ... ... ... .., 12 3.1.2 Loads Due to Partitions ... ... ... ... 123.2 Reduction in Imposed Loads on Floors ... ... ... 123.3 Posting of Floor Capacities ... ... ... ... 134. IMPOSED LOADS ON ROOFS ... ... ... .,. 134.1 Imposed Loads on Various Types of Roofs ... ... ... 134.2 Concentrated Load on Roof Coverings ... ... ... 134.3 Loads Due to Rain ... ... ... ... 134.4 Dust Load ... ... ... ... 134.5 Loads on Members Supporting Roof Coverings ... .,. 135. IMPOSED HORIZONTAL LOADS ON PARAPETS AND BALUSTRADES ... ... 13 6. LOADING EFFECTS DUE TO IMPACT AND VIBRATION ... ... 14 6.1 Impact Allowance for Lifts, Hoists and Machinery ... .I 14 6.2 Concentrated Imposed Loads with Impact and Vibration .,* . . . 15 6.3 Impact Allowances for Crane Girders ... ... . . . 15 6.4 Crane Load Combinations ... ... ... . . . 16 7. OTHER LOADS ... ... ... f.. . . . 16 APPENDIX A ILLUSTRATIVE EXAMPLE SHOWING REDUCTION OF UNIFORMLY DISTRIBUTED 17 IMPOSED F LOOR L OADS IN M U L T I- STOREYED B UILDINGS FOR D ESIGN OF C OLUMNS
  • 5. IS : 875 ( Part 2 ) - 1987 Indian Standard CODE OF PRACTICE FOR DESIGN LOADS (OTHER THAN EARTHQUAKE) FOR BUILDINGS AND STtiUCTURES PART 2 IMPOSED LOADS (Second Revision) 0. FOR E W O R D0.1 This Indian Standard ( Part 2 ) ( Second 0.3.1 With the increased adoption of the Code,Revision ) was adopted by the Bureau of Indian a number of comments were received on the pro-Standards on 31 August 1987. after the draft visions on live load values adopted for differentfinalized by the Structural Safety Sectional Com- occupancies. Simultaneously live load surveysmittee had been approved by the Buildmg Divi- have been carried out in America and Canada tosion Council. arrive at realistic live loads based on actual deter-0.2 A building has to perform many functions mination of loading ( movable and immovable )satisfactorily. Amongst these functions are the in different occupancies. Keeping this in viewutility of the building for the intended use and other developments in the field of windand occupancy, structural safety, fire safety; engineering, the Sectional Committee responsibleand compliance with hygienic, sanitation, venti- for the preparation of the Code has decided tolation and day light standards. The design of prepare the second revision of IS : 875 in thethe building is dependent upon the minimum following five parts :requirements prescribed for each of the above Part 1 Dead loadsfunctions. The minimum requirements pertaining Part 2 Imposed loadsto the structural safety of buildings are beingcovered in this Code by way of laying down Part 3 Wind loadsminimum design loads which have to be assumed Part 4 Snow loadsfor dead loads, imposed loads, snow loads and Part 5 Special loads and load combinationsother external loads, the structure would berequired to bear. Strict conformity to loading Earthquake load is covered in a separatestandards recommended in this Code, it is hoped, standard, namely IS : 1893-1984* which shouldwill not only ensure the structural safety of the be considered along with above loads.buildings which are being designed and construct- 0.3.2 This Code ( Part 2 ) deals with imposeded in the country and thereby reduce the hazards loads on buildings produced by the intendedto life and property caused by unsafe structures, occupancy or use. In this revision, the followingbut also eliminate the wastage caused by assuming importalit changes have been made:unnecessarily heavy loadings. a) The use of the term ‘live load’ has been0.3 This Code was first published in 1957 for the modified to ‘imposed load’ to cover notguidance of civil engineers, designers and archi- only the physical contribution due totects associated with the planning and design of persons but also due to nature of occu-buildings. It included the provisions for the basic pancy, the furniture and other equipmentsdesign loads ( dead loads, live loads, wind loads which are a part of the character of theand seismic loads ) to be assumed in the design occupancy.of buildings. In its firs! revision in 1964, the b) The imposed loads on floors and roofswind pressure provisions were modified on the have been rationalized based on thebasis of studies of wind phenomenon and its codified data available in large numbereffects on structures, undertaken by the special of latest foreign national standards, andcommittee in consultation with the Indian other literature. Further, these valuesMeteorological Department. In addition to this, have been spelt out for the major occu-new clauses on wind loads for butterfly type pancies as classified in the Nationalstructures were included; wind ,pressure coeffi- Building Code of India as well as thecients for sheeted roofs, both curved and sloping, various service areas appended to the majorwere modified; seismic load provisions were delet- occupancies.ed ( separate code having been prepared ) andmetric system of weights and measurements was *Criteria for earthquake resistant design of structuresadopted. (fourth revision ). 4
  • 6. IS : 875 ( Part 2 ) - 1987 C) The reduction of imposed loads for the prevailing practices in regard to loading design of vertical supporting members standards followed in this country by the various in multi-storeyed b u i l d i n g s h a s b e e n municipal authorities and has also taken note of further increased from 40 to 50 percent. the developments in a number of countries abroad. 4 Provision has been included for sign In the preparation of this Code, the following posting of loads on floors in view of national standards have been examined : the different loadings specified. for a) BS 6399 : Part 1 : 1984 Design Loading for different occupancies and to avoid possi- Buildings Part I: Code of Practice for ble misuse in view of conversion of Dead and Imposed Loads. British Stand- occupancies. ards Institution. e) The value of loads on parapets and b) AS : 1170, Part 1-1983 - SAA Loading balustrades have been revised with its effect taken both in the horizontal and Code, Part I Dead and Live Loads. vertical directions. Australian Standards Institution. f> In the design of dwelling units planned c) NZS 4203-1976 New Zealand Standard and executed in accordance with General Structural Design and Design IS : 8888-1979*, an imposed load of 1.5 Loading for Building. Standards Associa- kN/m* is allowed. tion of New Zealand. g> SI Units have been used in the Code. d) ANSI. A 58.1 - 1982American Standard Building Code Requirements for Minimum 0.3.3 The buildings and structural systems shall Design Loads in Buildings and Otherprovide such structural integrity that the hazards Structures.associated with progressive collapse such as thatdue to local failure caused by severe overloads or e) National Building Code of Canada ( 1977 )abnormal loads not specifically covered therein Supplement No. 4. Canadian Structuralare reduced to a level consistent with good Design Manual.engineering practice. f ) DIN 1055 Sheet 3 - 1971 Design Loads 0.3.4 Whenever buildings are designed for future for Buildings - Live Load ( West Germanadditions of floor at a later date, the number of Loading Standards ).storeys for which columns/walls, foundations, etc,have been structurally designed may be posted in !?I IS0 2103-1986 Loads due to use anda conspicuous place similar to posting of floor occupancy in residential and public build-capacities and both could be placed together. ings.0.4 The Sectional Committee responsible for the h) IS0 2633-1974 Determination of Impos-preparation of this Code has taken into account ed Floor Loads in Production Buildings- - and Warehouses. lnternational Organiza- *Guide for requirements of low income housing. tion for Standardization.1. SCOPE 2.1 Imposed Load - The load assumed to be produced by the intended use or occupancy of a1.1 This standard ( Part 2) covers imposed loads* building, mcluding the weight of movable parti-( live loads ) to be assumed in the design of build- tions, distributed, concentrated loads, load dueings. The imposed !oads, specified herein, are to impact and vibration, and dust load but ex-minimum loads which should be taken into con- cluding wind, seismic, snow and other loads duesideration for the purpose of structural safety of to temperature changes, creep, shrinkage, differ-buildings. ential settlement, etc.1.2 This Code does not cover detailed provisions 2.2 Occupancy or Use Group - The principalfor loads incidental to construction and special occupancy for which a building or part of a build-cases of vibration, such as moving machinery, ing is used or intended to be used; for the pur-heavy acceleration from cranes, hoists and the pose of classification of a building according tolike. Such loads shall be dealt with individually occupancy, an occupancy shall be deemed toin each case. include subsidiary occupancies which are contin- gent upon it. The occupancy classification is given from 2.2.1 to 2.2.8.2. TERMINOLOGY 2.2.1 Assembly Buildings - These shall include2.0 For the purpose of this Code, the following any building or part of a building where groupsdefinitions shall apply. of people congregate or gather for amusement, recreation, social, religious, patriotic, Civil, travel *The word ‘imposed load’ is used through out instead and similar purposes, for example, theatres,of ‘live load’ which is synonymous. motion picture houses, assembly halls, city halls, 5
  • 7. IS : 875 ( Part 2 ) - 1987marriage halls, town halls, auditoria, exhibition provided for normal residential purposes with orhalls, museums, skating rinks, gymnasiums, without cooking or dining or both facilitiesrestaurants ( also used as assembly halls ), places ( except buildings under 2.2.5). It includes oneof worship, dance halls, club rooms, passenger multi-family dwellings, apartment housesstations and terminals of air, surface and other phats ), lodging or rooming houses, restaurants,public transportation services, recreation piers hostels, dormitories and residential hotels.and stadia, etc. 2.2.7.1 Dwellings - These shall include any 2.2.2 Business Buildings - These shall include building or. p;i:t occupied by members of single/any building or part of a building, which is used for multi-family units with independent cookingtransaction of business ( other than that covered facilities. These shall also include apartmentby 2.2.6 ); for the keeping of accounts and records houses ( flats ).for similar purposes; offices, banks, professionalestablishments, court houses, and libraries shall 2.2.8 Storage Buildings - These shall includebe classified in this group so far as principal func- any building or part of a building used primarilytion of these is transaction of public business for the storage or sheltering of goods, wares orand the keeping of books and records. merchandize, like warehouses, cold storages, freight depots, transity sheds, store houses, gara- 2.2.2.1 Ofice buildings - The buildings ges, hangers, truck terminals, grain elevators,primarily to be used as an office or for office pur- barns and stables.poses; ‘office purposes’ include the purpose ofadministration, clerical work, handling money, 3. IMPOSED LOADS ON FLOORS DUE TOtelephone and telegraph operating and operating USE AND OCCUPANCYcomputers, calculating machines; ‘clerical work’includes writing, book-keeping, sorting papers, 3.1 Imposed Loads - The imposed loads to betyping, filing, duplicating, punching cards or assumed in the design of buildings shall be thetapes, drawing of matter for publication and the greatest loads that probably will be produced byeditorial preparation of matter for publication. the intended use or occupancy, but shall not be less than the equivalent minimum loads specified 2.2.3 Educational Buildings - These shall in Table 1 subject to any reductions permittedinclude any building used for school, college orday-care purposes involving assembly for instruc- by 3.2.tion, education or recreation and which is not Floors shall be investigated for both thecovered by 2.2.1. uniformly distributed load ( UDL ) and the cor- responding concentrated load specified in Table 1 2.2.4 Industrial Buildings - These shall include and designed For the most adverse effects butany building or a part of a building or structure in they shall not be considered to act simultaneously.which products or materials of various kinds and The concentrated loads specified in Table 1 mayproperties are fabricated, assembled or processed be assumed to act over an area of 0.3 x 0.3 m.like assembly plants, power plants, refineries, gasp!ants, mills, dairies, factories, workshops, etc. However, the concentrated loads need not be considered where the floors are capable of 2.2.5 Institutional Buildings - These shall include effective lateral distribution of this load.any building or a part thereof, which isused for All other structural elements shall be investi-purposes, such as medical or other treatment in gated for the effects of uniformly distributed loadscase of persons suffering from physical and mental on the floors specified in Table 1.illness, disease or infirmity; care of infants, con-valescents of aged persons and for penal or cor- N OTE 1 - Where in Table 1, no values are given forrectional detention in which the liberty of the concentrated load, it may be assumed that the tabula-inmates is restricted. Institutional buildings ted distributed load is adequate for design purposes.ordinarily provide’ sleeping accommodation for N OTE 2 - The loads specified in Table I are equiva-the occupants. It includes hospitals, sanitoria, lent uniformly distributed loads on the plan area andcustodial institutions or penal institutions like provide for normal effect of impact and acceleration. They do not take into consideration special concentra-jails, prisons and reformatories. ted loads and other loads. 2.2.6 Mercantile Buildings -These shall include N OTE 3 - Where the use of an area or floor is notany building or a part of a building which is used provided in Table 1, the imposed load due to the use and occupancy of such an area shall be determinedas shops, stores, market for display and sale of from the analysis of loads resulting from:merchandise either wholesale or retail. Office,storage and service facilities incidental to the sale a! weight of the probable assembly of persons;of merchandise and located in the same building b) weight of the probable accumulation of equipmentshall be included under this group. and furnishing; 2.2.7 Residential Buildings - These shall include 4 weight of the probable storage materials; andany building in which sleeping accommodation is 4 impact factor, if any. 6
  • 8. IS : 875 ( Part 2 ) - 1987 TABLE 1 IMPOSED FLOOR LOADS FOR DlFFERENT OCCUPANCIES (Clauses 3.1, 3.1.1 and4.1.1 )SL OCCYJPANCY CLASSIFICATION U NIFORMLY C ONCENTRATEDNo. DISTRIBUTED LOAD L OAD ( UDL )(1) (2) (3) (4) kNlma kNi ) RESIDENTIAL BUILDINS a) Dwelling houses: 1) All rooms and kitchens 2’0 1’8 2) Toilet and bath rooms 2’0 - 3) Corridors, passages, staircases 3.0 4.5 including tire escapes and store rooms 4) Balconies 3.0 1’5 per metre run concen- trated at the outer edge b) Dwelling units planned and execut- cd in accordance with IS : 888S- 1979* only: 1) Habitable rooms, kitchens, I.5 1’4 toilet and bathrqoms 2) Corridors, passages and stair- 1.5 1’4 cases including fire escapes 3) Balconies 3.0 1.5 per metre run concen- trated at the outer edge C) Hotels, hostels, boarding houses, lodging houses, dormitories, residential clubs: 1) Living rooms, bed rooms and 2’0 1.8 dormitories 2) Kitchens and laundries 3.0 4.5 3) Billiards room and public loun- 3.0 2.7 gcs 4) Store rooms 5.0 4.5 5) Dining rooms, cafeterias and 4.0 2.7 restaurants 6) Oflice rooms 2.5 2.7 7) Rooms for indoor games 3.0 1.8 8) Baths Lind toilets 2’0 - 9) Corridors, passages, staircases 3’0 4.5 including fire escapes, lobbies -- as per the floor serviced ( excluding stores and the like ) but not less than 10) Balconies Same as rooms to which 1.5 per metre run concen- they give access but with trated at the outer edge a minimum of 4’0 d) Boiler rooms and plant rooms - to 5’0 6.7 be calcuiated but not less than ( Continued ) 7
  • 9. IS : 875 ( Part 2 ) - 1987 TABLE 1 IMPbED FLOOR LOADS FOR DIFFERENT OCCUPANCIES - ConrdSL O CCUPANCY C LASSIFICATION UNSFORMLY CONCENTRATEDNo. DISTRIBUTED LOAD L OAD ( UDL )(1) (2) (3) (4) kN/ms kN e) Garages: Garage floors ( including park- 2.5 9.0 ing area and repair workshops ) for passenger cars and vehicles not exceeding 2’5 tonnes gross weight, including access ways and ramps - to be calculated but not less than Garage floors for vehicles not 5’0 9.0 exceeding 4.0 tonnes gross weight ( including access ways and ramps ) - to be calculated but not less than ii) EDUCATIONAL BUILDINGS a) Class rooms and lecture rooms 3’0 2.1 ( not used for assembly purposes ) b) Dining rooms, cafeterias and 3.0t 2.7 restaurants 4 Offices, lounges and staff rooms 2.5 2.7 d) Dormitories 2.0 2.7 e) Projection rooms 5’0 - f1 Kitchens 3.0 4.5 Lx) Toilets and bathrooms 2.0 - h) Store rooms 5.0 45 3 Libraries and archives: 1) Stack room/stack area 6’0 kN/ms for a minimum 4’5 height of 2’2 m + 2’0 kN/m* per metre height beyond 2.2 m 2) Reading rooms ( without sepa- 4’0 4.5 rate storage ) 3) Reading rooms ( with separate 3.0 4.5 storage k) Boiler rooms and plant rooms - to 4.0 45 be calculated but not less than ml Corridors, passages, lobbies, stair- 40 4.5 cases including fire escapes - as per the floor serviced ( without account- ing for storage and projection rooms ) but not less than n) Balconies Same as rooms to which 15 per metre run concen- they give access but with trated at the outer edge a minimum of 4.0 iii) INSTITUTIONAL BUILDlNGS a) Bed rooms, wards, dressing rooms, 2’0 1.8 dormitories and lounges b) Kitchens, laundries and labora- 3.0 45 tories ( Continued ) 8
  • 10. IS : 875 ( Part 2 ) - 1987 TABLE 1 IMPOSED FLOOR LOADS FOR DIFFERENT OCCUPANCIES - CodSL O CCUPANCY C LASSIFICATION UNIFORMLY C ONCENTRATEDNo. DISTRIB UTED LOAD L OAD ( UDL )(1) (2) (3) (4) kN/m’ kN c) Dining rooms, cafeterias and 3.0t 2.7 restaurants d) Toilets and bathrooms 2.0 - e) X-ray rooms, operating rooms, 3’0 4’5 general storage areas -to be cal- culated but not less than f) Office rooms and OPD rooms 2’5 2’7 g) Corridors, passages, lobbies and 4’0 45 staircases including fire escapes - as per the floor serviced but not less than h) Boiler rooms and plant rooms - to 5’0 4.5 be calculated but not less than j) Balconies Same as the rooms to 1’5 per metre run concen- which they give access but trated at the outer edge with a minimum of 4.0iv) ASSEMBLY BUILDINGS a) Assembly areas: 1) with fixed seatsz 4’0 - 2) without fixed seats 5’0 3.6 b) Restaurants ( subject to assembly ), 4.0 4.5 museums and art galleries and gymnasia c) Projection rooms 50 - d) Stages 5’0 4.5 e) Office rooms, kitchens and laundries 3’0 4.5 f) Dressing rooms 2’0 1’8 g) Lounges and billiards rooms 2.0 2.7 h) Toilets and bathrooms 2.0 - j) Corridors, passages, staircases 4’0 4.5 including fire escapes k) Balconies Same as rooms to which 1.5 per metre run concen- they give access but with trated at the outer edge a mintmum of 4.0 m) Boiler rooms and plant rooms 7’5 4’5 including weight of machinery n)- Corridors, passages subject to loads 5’0 4.5 greater than from crowds, such as wheeled vehicles, trolleys and the like. Corridors, staircases and pas- sages in grandstandsv) BUSINESS AND OFFICE BUILDINGS ( see ulso 3.1.2 ) a) Rooms for general use with separate 2’5 2’7 storage b) Rooms &thout separate storage 4.0 4.5 I Continued ) 9
  • 11. IS : 875 ( Part 2 ) - 1987 TABLE 1 IMPOSED FLOOR LOADS FOR DIFFERENT OCCUPANCIES - ContdSL O CCUPANCY C LASSIFICATION UNTFORMLY CONCENTRATEDNo. D ISTRIBUTED LOAD L OAD ( UDL ) (1) (2) (3) (4) kN/m’ kNe c) Banking halls 3’0 2.7 d) Business computing machine rooms 3’5 4.5 ( with fixed computers or similar equipment ) e) Records/files store rooms and 5’0 4.5 storage space f) Vaults and strong room - to be 5’0 4.5 calculated but not less than g) Cafeterias and dining rooms 3.0t 2.7 h) Kitchens 3.0 2.7 j) Corridors, passages, lobbies and 4.0 4.5 staircases including fire escapes - as per the floor serviced (excluding stores ) but not less than k) Bath and toilet rooms 2.0 .-. m) Balconies Same as rooms to which I.5 per metre run concen- they give access but with trated at the outer edge a minimum of 4.0 n) Stationary stores 4’0 for each metre of storage height p) Boiler rooms and plant rooms - to 5’0 be calculated but not less than q) Libraries see Sl No. ( ii ) vi) MERCANTILE BUILDINGS a) Retail shops 4.0 3.6 b) Wholesale shops - to be calculated 6’0 4.5 but not less than c) Office rooms 2’5 2’7 d) Dining rooms, restaurants and cafe- 3’0t 2.7 terias e) Toilets 2.0 - f) Kitchens and laundries 3’0 4’5 g) Boiler roooms and plant rooms - 5’0 6.7 to be calculated but not less than h) Corridors, passages, staircases 4.0 4.5 including fire escapes and lobbies j) Corridors, passages, staircases sub- 5.0 4.5 ject to loads greater than from crowds, such as wheeled vehicles, trolleys and the like k) Balconies Same as rooms to which 1.5 per metre run concen- they give access but with trated at the outer edge a minimum of 4.0 10
  • 12. IS : 875 ( Part 2 ) - 1987 TABLE 1 IMPOSED FLOOR LOADS FOR DIFFERENT OCCUPANCIES - ContdSL O CCUPANCY C LASSIFICATION U NIFORMLY C ONCENTRATEDNo. DrsTRleUTED LOAD LOAD ( UDL ) (1) (2) (3) (4) kN/ma kNvii) INDUSTRIAL BUILDTNGS a) Work areas without machinery/ 2.5 4.5 equipment b) Work areas with machinery/equip- ments 1) Light duty 1 To be calcula- 5’0 4.5 2) Medium duty > ted but not 7.0 4.5 3) Heavy duty J less than 10.0 4.5 d Boiler rooms and plant rooms - to 5.0 6.7 be calculated but not less than 4 Cafeterias and dining rooms 3.0t 2.7 e) Corridors, passages and staircases 4.0 4.5 including fire escapes f) Corridors, passages, staircases sub- 5.0 4.5 ject to machine loads, wheeled vehicles - lo be calculated but not less than 9) Kitchens 3.0 4.5 h) Toilets and bathrooms 2’0viii) STORAGE BUILDINGS /I Storage rooms ( other than cold 2.4 kN/m* per each 7.0 storage ) warehouses - to be calcu- metre of storage height lated based on the bulk density of with a minimum of materials stored but not less than 7.5 kN/ma b) Cold storage -- to be calculated 5.0 kN/m2 per each 9.0 but not less than metre of storage height w i t h a minimum of 15 kN/m* cl Corridors, passages and staircases 4.0 4.5 including fire escapes --~ as per the floor serviced but not less than d) Corridors, passages subject to loads 5.0 4.5 greater than from crowds, such as wheeled vehicles, trolleys and the like e) Boiler rooms and plant rooms 7.5 4.5 *Guide for requirements of low income housing. tWhere unrestricted assembly of persons is anticipated, the value of UDL should be increased to 4.0 kN/m*. $‘With fixed seats’ implies that the removal of the seating and the use of the space for other purposes isimprobable. The maximum likely load in this case is, therefore, closely controlled. §The loading in industrial buildings ( workshops and factories ) varies considerably and SO three loadingsunder the terms ‘light’, ‘medium’ and ‘heavy’ are introduced in order to allow for more economical designs butthe terms have no special meaning in themselves other than the imposed load for which the relevant floor is design-ed. It is, however, important particularly in the case of heavy weight loads, to assess the actual loads to ensurethat they are not in excess of 10 kN/m*; in case where they are in excess, the design shall be based on the actualloadings. i/For various mechanical handling equipment which are used to transport goods, as in warehouses, workshops,store rooms, etc, the actual load coming from the use of such equipment shall be as-ertained and design shouldcater to such loads. 11
  • 13. IS : 875 ( Part 2 ) - 1Yar N OTE 4 - While selecting a particular loading, the weight per metre run of finished partitions, possible change in use or occupancy of the building subject to a minimum of 1 kN/m2, provided total should be kept in view. Designers should not neces- sarily select in every case the lower loading appropriate weight of partition walls per square metre of the to the first occupancy. In doing this, they might intro- wall area does not exceed 1.5 kN/m2 and the duce considerable restrictions in the use of the build- total weight per metre length is not greater than ing at a later date and thereby reduce its utility. 4.0 kN. N OTE 5 - The loads specified herein which are based on estimations, may be considered as the 3.2 Reduction in Imposed Loads on Floors characteristic loads for the purpose of limit state method of design till such time statistical data are 3.2.1 For Floor Supporting Structuraal Members - established based on load surveys to be conducted in Except as provided for in 3.2.1.1, the following the country. reductions in assumed total imposed loads on N OTE 6 - When an existing building is altered by floors may be made in designing columns, load an extension in height or area, all existing structural bearing walls, piers, their supports and founda- parts affected by the addition shall be strengthened, where necessary, and all new structural parts shall be tions. designed to meet the requirements for building there- after erected. Number of Floors ( In&d- Reduction in Total N OTE 7 - The loads specified in the Code does not ing the Roof) to be Carried Distributed Imposed include loads incidental to construction. Therefore, by Member under Load on all Floors to close supervision during construction is essential to Consideration eusure that overloading of the building due to loads be Carried by the by way of stacking of building materials or use of Member under equipment ( for example, cranes and trucks ) during Consideration construction or loads which may be induced by floor to ( Percent ) floor propping in multi-storeyed construction. does not occur. However: if construction loads were of short duration, permissible increase in stresses in the case of 1 0 working stress method or permissible decrease in load 2 10 factors in limit state method, as applicable to relevant design codes, may be allowed for. 3 20 N OTE 8 - The loads in Table 1 are grouped together 4 30 as applicable to buildings having separate principal occupancy or use. For a building with multiple occu- 5 to 10 40 pancies, the loads appropriate to the occupancy with Over 10 50 comparable use shall be chosen from other occupancies. N OTE 9 -- Regarding loading on machine rooms inc!uding storage space used for repairing lift 3.2.1.1 NO reduction shall be made for any machines, designers should go by the recommendations plant or machinery which is specifically allowed of lift manufacturers for the present. Regarding the for, or in buildings for storage purposes, ware- loading due to false ceiling the same should be con- sidered as an imposed load on the roof/floor to which houses and garages. However, for other buildings it is fixed. where the floor is designed for an imposed floor load of 5.0 kN/m” or more, the reductions shown 3.1.1 Load Application - The uniformly distri- in 3.2.1 may be taken, provided that the loadingbuted loads specified in Table 1 shall be applied assumed is not less than it would have been if allas static loads over the entire floor area under the floors had been designed for 5.0 kNjmZ withconsideration or a portion of the floor area which- no reductions.ever arrangement produces critical effects on thestructural elements as provided in respective N OTE -In case if the reduced load in the lowerdesign codes. floor is lesser than the reduced load in the upper floor, then the reduced load of the upper floor will be In the design of floors, the concentrated loads adopted.are considered to be applied in the positions whichproduce the maximum stresses and where deflec- 3.2.1.2 An example is given in Appendix Ation is the main criterion, in the positions which illustrating the reduction of imposed loads in aproduce the maximum deflections Concentrated multi-storeyed building in the design of columnload, when used for the calculation of bending and members.shear are assumed to act at a point. When usedfor the calculation of local effects, such as crush- 3.2.2 For Reams in Each Floor Level - Whereing or punching, they are assumed to act over an a single span of beam, girder or truss supportsactual area of application of 0.3 x 0.3 m. not less than 50 m2 of floor at one general level, the imposed floor load may be reduced in the 3.1.2 Loads Due to Light Partitions - In office design of the beams, girders or trusses by 5 per-and other buildings where actual loads due to cent for each 50 ma area supported subject to alight partitions cannot be assessed at the time of maximum reduction of 25 percent. However, noplanning, the floors and the supporting structural reduction shall be made in any of the followingmembers shall be designed to carry, in addition to types of loads:other loads, a uniformly distributed load persquare metre of not less than 339 percent of a) Any superimposed moving load, 12
  • 14. IS : 875 ( Part 2 ) - 1987 b) Any actual load due to machinery or where it is ensured that the roof coverings would similar concentrated loads, not be transversed without suitable aids. In any case, the roof coverings shall be capable of carry- c) The additional load in respect of partition ing the loads in accordance with 4.1,4.3, 4.4 and walls, and snow load/wind load. 4 Any impact or vibration. 4.3 Loads Doe to Rain - On surfaces whose posi- N OTE - The above reduction does not apply to tioning, shape and drainage systems are such as to beams, girders or trusses supporting roof loads. make accumulation of rain water possible! loads due to such accumulation of water and the Impos-3.3 Posting of Floor Capacities - Where a floor ed loads for the roof as given in Table 2 shall beor part of a floor of a building has been designed considered separately and the more critical of the .to sustain a uniformly distributed load exceeding two shall be adopted in the design.3.0 kN/m2 and in assembly, business, mercantile,industrial or storage buildmgs, a permanent notice 4.4 Dust Load - Jn areas prone to settlementin the form as shown in the label, indicating of dust on roofs ( example, steel plants, cementthe actual uniformly distributed and/or concentrat- plants ), provision for dust load equivalent toed loadings for which the floor has been structu- probable thickness of accumulation of dust mayrally designed shall be posted in a conspicuous be made.place in a position adjacent to such floor or onsuch part of a floor. 4.5 Loads on Members Supporting Roof Cover- ings - Every m e m b e r o f t h e supporting structure which is directly supporting the roof covering(s) shall be designed to carry the more DESIGNED IMPOSED FLOOR LOADING severe of the following loads except as provided in 4.5.1 : DISTRIBUTED. . . . . . . . . . . ..kN/mZ a) The load transmitted to the members CONCENTRATED, . . . . kN from the roof covering(s) in accordance with 4.1, 4.3 and 4.4; and b) An incidental concentrated load of 0.90 L-ABEL INDICATING D ESIGNED I MPOSED F L O O R kN concentrated over a length of 12.5 cm LOADING placed at the most unfavourable positions on the member. N OTE 1 - The lettering of such notice shall be embossed or cast suitably on a tablet whose least N OTE - Where it is ensured that the roofs would be dimension shall be not less than 0’25 m and located not traversed only with the aid of planks and ladders cap- less than 1.5 m above floor level with lettering of a able of distributing the loads on them to Iwo or more minimum size of 25 mm. supporting members, the intensity of concentrated load indicated in (b) may be reduced to 0.5 kN with N OTE 2 - If a concentrated load or a bulk load has the approval of the Engineer-in-Charge. to occupy a definite position on the floor, the same could also be indicated in the label above. 4.5.1 In case of sloping roofs with slope greater t h a n lo”, members supporting the roof purlins,4. IMPOSED LOADS ON ROOFS such as trusses, beams, girders, etc, may be desig- ned for two-thirds of the imposed load on purlins4.1 Imposed Loads on Various Types of Roofs - or roofing sheets.On flat roofs, sloping roofs and curved roofs, theimposed loads due to use or occupancy of the 5. IMPOSED HORIZONTAL LOADS ONbuildings and the geometry of the types of roofs PARAPETS AND BALUSTRADESshall be as given in Table 2. 5.1 Parapets, Parapet Walls and Balustrades - 4.1.1 Roofs of buildings used for promenade or Parapets, parapet walls and balustrades togetherir.cidental to assembly purposes shall be designed with the members which give them structuralfor the appropriate imposed floor loads given ih support shall be designed for the minimum loadsTable 1 for the occupancy. given in Table 3. These are expressed as horizon- tal forces acting at handrail or coping level. These4.2 Concentrated Load on Roof Coverings - To loads shall be considered to act vertically also butprovide for loads Incidental to maintenance, unless net simultaneously with the horizontal forces.otherwise, specified by the Engineer-in-Charge, all The values given in Table 3 are minimum valuesroof coverings ( other than glass or transparent and where values for actual loadings are available,sheets made of fibre glass ) shall be capable of they shall be used instead.carrying an incidental load of 0.90 kN concen-trated on an area of 12.5 cm* so placed as to fire- 5.2 Grandstands and the Like-Grandstands,duce maximum stresses in the covering, The stadia, assembly platforms, reviewing stands andintensity of the concentrated load may be reduced the like shall be designed to resist a horizontalwith the approval of the Engineer-in-Charge, force applied to seats of 0.35 kN per linear metre 13
  • 15. IS : 875 ( Part 2 ) - 1987along the line of seats and O-15 kN per linear factors, lateral and longitudinal braking forcesmetre perpendicular to the line of the seats. acting across and along the crane railsThese loadings need not be applied simultaneously. respectively.Platforms without seats shall be designed to resista minimum horizontal force of O-25 kN/m’ of 6.1 Impact Allowance for Lifts, Hoists and Machi-plan area. nery - The imposed loads specified in 3.1 shall be assumed to include adequate allowance for ordi-6. LOADING EFFECTS DUE TO IMPACT nary impact conditions. However, for structures AND VIBRATION carrying loads which induce impact or vibration,6.0 The crane loads to be considered under impos- as far as possible, calculations shall be made fored loads shall include the vertical loads, eccentri- increase in the imposed load, due to impact orcity effects induced by vertical loads, impact vibration. In the absence of sufficient data for TABLE 2 IMPOSED LOADS ON VARIOUS TYPES OF ROOFS ( Clause 4.1 ) SL T YPE OF R OOF U NIFORMLY D ISTRIBUTED M INIMUM IMPOSED L OAD No. IMPOSED LOAD M EASUKED M EASURED ON P LAN ON P LAN AREA (1) (2) (3) (4) i) Flat, sloping or curved roof with slopes up to and includ- ing 10 degrees a) Access provided 1’5 kN/m’ 3.75 kN uniformly distributed over any span of one metre width of the roof slab and 9 kN uniformly distributed over the span of any beam or truss or wall b) Access not provided 0.75 kN/m2 1.9 kN uniformly distributed except for maintenance over any span of one metre width of the roof slab and 4.5 kN uniformly distributed over ths span of any beam or truss or wall ii) Sloping roof with slope greater For roof membrane sheets or pur- Subject to a minimum of than 10 degrees lins-0.75 kN/mZ l e s s 0.02 kN/m’ 0.4 kN,W for every degree increase in slope over 10 degrees iii) Curved roof with slope of line ( O;le; 0.52 ya ) kN/m” Subject to a minimum of obtained by joining spring- 0.4 kN/m* ing point to the crown with y = h/l the horizontal, greater than h = the height of the highest 10 degrees point of the structure measured from its spring- ing; and I = ;hord width of the roof singly curved and shorter of the two sides if doubly curved Alternatively, where structural analysis can be carried out for curved roofs of all slopes in a simple manner applying the laws of statistics, the curved roof shall be divided into minimum 6 equal segments and for each segment imposed load shall be calculated appropriate to the slope of the chord of each segment as given in ( i ) rind ( ii ) above N OTE 1 - The loads given above do not include loads due to snow, rain, dust collection, etc. The roof shall be designed for imposed loads given above or for snow/rain load, whichever is greater. N OTE 2 - For special types of roofs with highly permeable and absorbent material, the contingency of roof material increasing in weight due to absorption of moisture shall be provided for. 14
  • 16. IS : 875 ( Part 2 ) - 1987 TABLE 3 HORIZONTAL LOADS ON PARAPETS, PARAPET WALLS AND BALUSTRADES ( Cfause 5.1 ) SL U SAGE A R E A INTENSITY OF HORIZONTAL No. LOAD, kN/m RUN (2) (3) Light access stairs-gangways and the like not 0.25 more than 600 mm wide ii) Light access stairs. gangways and the 0.35 like, more than 600 mm wide: stairways, landings, balconies and parapet walls ( private and part of dwellings ) iii) All other stairways, landings and balco- 0.75 nies, and all parapets and handrails to roofs except those subject to overcrow- ding covered under ( iv ) iv) Parapets and balustrades in place of 2’25 assembly, such as theatres, cinemas, churches, schools, places of entertain- ment. sports, buildings likely to be over- crowded NOTE - In the case of guard parapets on a floor of multi-storeyed car park or crash barriers provided in certain buildings for fire escape, the value of imposed horizontal load ( together with impact load ) may be determined.such calculation, the increase in the imposed loads 6.2 Concentrated Imoosed Loads with Imuact andshall be as follows: Vibration - Concentrated imposed loads with impact and vibration which may be due to instal- Structures Impact led machinery shall be considered and provided Allowance for in the design. The impact factor shall not be Min less than 20 percent which is the amount allow- For frames supporting lifts 100 percen able for light machinery. and hoists For foundations, footings 40 percent 6.2.1 Provision shall also be made for carrying and piers supporting lifts any concentrated equipment loads whiIe the and hoisting apparatus equipment is being installed or moved for servic- For supporting structures 20 percent mg and repairing. and foundations for light machinery, shaft or motor 6.3 Impact Allowances for Crane Girders - For units crane gantry girders and supporting columns, the For supporting structures 50 percent following allowances shall be deemed to cover all and foundations for reci- forces set up by vibration, shock from slipping or procating machinery or slings, kinetic action of acceleration, and retarda- power units tion and impact of wheel loads : Type of Load Additional Load a) Vertical loads for electric overhead cranes 25 percent of maximum static loads for crane girders for all classes of cranes 25 percent for columns supporting Class IJI and Class IV cranes 10 percent for columns supporting Class I and Class II cranes No additional load for design of founda- tions b) Vertical loads for hand operated cranes 10 percent of maximum wheel loads for crane girders only (Continued) 15
  • 17. IS : 813 ( rart L ) - 1Y17 c) Horizontal forces transverse to rails: 1) For electric overhead cranes with -10 percent of weight of crab and the trolley having rigid mast for suspen- weight lifted by the cranes, acting on any sion of lifted weight ( such as soaker one crane track rail. acting in either direc- crane, stripper crane, etc ) tion and equally distributed amongst all the wheels on one side of rail track For frame analysis this force shall be applied on one side of the frame at a time in either direction 2) For all other electric overhead cranes -5 percent of weight of crab and the weight and hand operated cranes lifted by the cranes, acting on anyone crane track rail, acting in either direction and equally distributed amongst the wheels on one side of rail track For the frame analysis, this force shall be applied on one side of the frame at a time in either direction d) Horizontal traction forces along the -5 percent of all static wheel loads rails for overhead cranes, either electri- cally operated or hand operated Forces specified in ( c ) and ( d ) shall be accommodated on the span but withoutconsidered as acting at the rail level and being taking into account overloading accordingappropriately transmitted to the supporting sys- to 6.3( a ) to give the maximum effect.tem. Gantry girders and their vertical supports 6.4.2 Lateral Surge - For design of columnsshall be designed on the assumption that either of and foundations, supporting crane girders, thethe horizontal forces in ( c ) and ( d ) may act at following crane combinations shall be considered:the same time as the vertical load. a) For single-bay frames - Effect of one NOTE-&e IS : 807-l!%+ for classification ( ClaSSeS crane in the bay giving the worst effect 1 to 4 ) of cranes. shall be considered for calculation of surge 6.3.1 Overloading Factors in Crane Supporting force, andSttu twes - For all ladle cranes and charging b) For multi-bay frames - Effect of twocranes, where there is possibility of overloading cranes working one each in any of twofrom production considerations, an overloading bays in the cross-section to give the worstfactor of 10 percent of the maximum wheel load- effect shall be considered I‘or calculationing shall be taken. of surge force.6.4 Crane Load Combinations - In the absenceof any specific indications, the load combinations 6.4.3 Tractive Forceshall be as indicated in the following sub-clauses. 6.4.3.1 Where one crane is in operation with 6.4.1 Vertical Loads - In an aisle, where more no provision for future crane, tractive force fromthan one crane is in operation or has provision only one crane shall be takenfor more than one crane in future, the followingload combinations shall be taken for vertical 6.4.3.2 Where more than one crane is inloading: operation or there is provision for future crane, tractive force from two cranes giving maximum a) Two adjacent cranes working in tandem effect shall be considered. w i t h f u l l l o a d a n d w i t h overloadmg according to 6.3( a ); and N OTE - Lateral surge force and longitudinal trac- tive force actingacross and along the crane rail respec- tively, shall not be assumed to act simultaneously. b) For long span gantries, where more than However, if there is only one crane in the bay, the one crane can come in the span, the girder lateral and longitudinal forces may act together simul- shall be designed for or.e crane fully loaded taneously with vertical loads. with overloading according to 6.3(a) plus as many loaded cranes as can be 7. OTHER LOADS- 7.1 Dead Load - Dead load includes the weight *Code of practice for design, manufacture, erectionand testing ( structural portion ) of cranes and hoists of all permanent components of a building includ-(first revision ). ing walls,partitions, columns, floors, roofs, finishes 16
  • 18. IS:875(Part2)-1987and fixed permanent equipment and fittings that IS : 1893-1984*.are an integral part of the structure. Unit weightof building materials shall be in accordance with 7.4 Snow Load - Snow loading on buildingsIS : 875 ( Part 1 )-1988: shall be in accordance with IS : 875 ( Part 4 )-I 988.7.2 Wind Load -- The wind load on buildings/ 7.1 Special Loads and Load Combinations-structures shall be in accordance with IS : S75 Special loads and load combinations shall be i n( Part 3 )-1988. accordance with 1s : 875 ( Part 5 )-1988.7.3 Seismic I;;;;t dfeismic load on buildings/ *Criteria for eartnquake resistant design of structuresstructures , in accordance with ( fc;ur/h revision ). APPENDIX A ( Clause 3.2.1.2 ) ILLUSTRATIVE EXAMPLE SMOWING REDUCTION OF UNIFORMLY DISTRIBUTED IMPOSED FLOOR LOADS IN MULTI-STOREYED BUII,DINGS FOR DESIGN OF COLUMNSA-l. ‘I he total imposed loads from different floor Floor loads do.not exceed 5-O kN/m’.levels ( including the roof) coming on the centralcolumn of a multi-storeved building ( with mixed A-l.1 Applying reduction coefficients in accor-occupancy ) is shown in Fig. I. Calculate the dance with 3.2.1, total reduced floor loads on thereduced imposed load for the design of column column at different levels is indicated along withmembers at different floor levels as given in 3.2.1. Fig. 1. 17
  • 19. IS:875(Part2)-1987 Floor Actual Floor No. from Load Coming onTop ;zfd;ng Columns at Different Floors, kN Loads for which Columns are to be Designed, kN ( 30 + 40 t- 50 ) (1 - 0.2 ) = 96 (30$4O$50$50)(1-Oo’3)=119 ( 3F2Z- 4O + 50 + 50 t 40 ) ( 1 - 0 4 ) = (3~~50+50+50+40+45)(1-o~4) ( 30 + 40 + 50 + 50 c 40 + 45 + 50 ) ( l - 0 . 4 ) = 183 ( 30 + 40 + 50 + 50 + 40 f 45 + 50 t so) ( i -- 0.4) = 213 ( 30 + 40 $- 50 + 50 + 40 + 45 + 50 + 50 + 40 ) ( 1 - 0.4 ) = 237 ( 30 + 40 + 50 + 50 + 40 + 45 + 50 + 50 + 40 -+ 40 ) ( 1 - 0.4:) = 261 (30+40+5O+50+40+45+50+50 +40+40+40)(1-O.5)=237’5< 261 :. adopt 261 for design (30+40+50+50+40+45+50+50 -t40+40+40+55) ( l - 0 5 ) = 2 6 5 ( 30 + 40 + 50 + 50 + 40 + 45 + 50 + 50 H02-y0+40+55+55)(1-O~5) ( 30 + 40 + 50 t 50 + 40 + 45 I- 50 t 50 -I- 40 + 40 + 40 + 55 + 55 + 70 ) ( 1 -05 ) = 327.5 ( 30 + 40 + 50 t 50 + 40 + 45 + 50 + 50 +40+40-t-40+55+55+70+80) ( 1 - 0.5 ) - 367’5 F:G. 1 LOADING D E T A I L S 18
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