Multi-Storied Public Buildings Rules 1973

8/10/2019 Multi-Storied Public Buildings Rules 1973

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The Multi-Storied and Public Buildings

Rules, 1973

(G.O. Ms. No.1769, Rule Development and LocalAdministration, dated 24thAugust, 1973)

(Published in the Tamil Nadu Government Gazette PartV. page 1345, dated 7thNovember, 1973)

S.R.O.A-914 of 1973 - In exercise of the powers conferred by section 191and sub-section (1) of section 303 of the Tamil Nadu District Municipalities Act,

1920 ( Tamil Nadu Act V of 1920) the Governor of Tamil Nadu hereby makes thefollowing special rules.

RULES

1. Short title: -

(1) These rules may be called The Multi Storied and public Building Rules1973.

2. Definit ion: -

In these rules there is anything repugnant in the subject or context " Multi-storied Building" means and include all buildings 1[with more than four floors(including ground floors)] or whose height is 15 meters or more,

3. Application of rules: -

Every person intending to construct, re-construct, add to or alter any multi-storied building in addition to the general requirements laid down in the rules,shall also comply with the following special rules.

4. Area for the construction: -

(a) Any construction, re-construction, alteration or addition of or for amulti-storied building, shall be permitted only within the area approved for theconstruction of multi-storied buildings in a Town Planning Scheme made underthe Tamil Nadu Town Planning Act, 1920, or in a development plan under theTamil Nadu Town and Country Planning Act, 1971, or declared by a SpecialResolution by the council with the approval of the Director of Town Planning for


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such purpose and shall not exceed the maximum number of store's or maximumheight prescribed for the individual area.

(b) The minimum extent of site for construction of multi-storied buildingshall be not less than 4 grounds in extent and should have the shortest side not

less than 24-50 meters (80 feet) and shall about on a street not less than 12-25meters (40 feet) in width.

(c) In so far as the determination of sufficiency of all aspects of structuraldesign, building, plumbing, fire protection, construction practices and safety, thespecifications, standards and codes of practice recommended un thespecifications, standards and codes of practice recommended in the NationalBuilding Code of India, 1970 shall be fully confirmed to, besides those prescribedin these rules and any breach thereof shall be deemed to be a breach of therequirements under these rules.

5. Engineer's approval: -

The Engineers shall while according his approval or permission follow thecode of practice and standard requirements recommended in the NationalBuilding code of India, 1970.

6. Site plan, streets and spaces: -

The site plan to be submitted in triplicate under the rules, shall also showthe following,

(a) The existing and proposed building in relation to the boundaries of thesite and in relation also to all adjacent streets, building (with number of storeysand height) and premises within a distance of 15 meters (50 feet) of the site.

(b) The means, of access from the street or streets to all buildings existingand proposed in the site, to the parking spaces and facilities provided in the sitewithin or outside the buildings and for scavenging and fire protection.

(c) The spaces to be left about the building for circulation, air, light access,parking and amenity; and

(d) The general layout of the columns and load bearing walls showing theestimated loads including moments and torques coming on the foundation units.


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7. Building plans: -The building plans to be submitted in triplicate under the rules

shall also show,

(a) Floor plans of all floors and covered area, indicating clearly the size

and size and arrangements or rooms and the position of staircases, ramps andlift walls.(b) Longitudinal and cross sections of the buildings to show size of

footings, basement and superstructure, framing members and details of buildingand room heights and of staircases etc.

(c) In the case of constructions using steel structures complete designdrawings, showings sizes sections and relative location of the various steelmembers, floor levels, column centers and offsets;

(d) In the case of Prefabricated building drawings, describing the elementsof the structure or assembly including all data or physical properties ofcomponent materials with details of joints to an enlarged scale, site or shop

location of services such as installation of piping, wiring or other accessories andprefabricated elements; and(e) Plans and sectional details or water supply and seware system for the

building.

8. Specifications: -

The following detailed specification shall be furnished with the applicationfor permission under these rules:-

(a) General and detailed specifications, giving and grade of materials to beused.

(b) Detailed computations, stress diagrams to show the sufficiency andcorrectness of the design; and

(c) Type and condition of soil or rock to which the foundation transfers theloads.


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9. Floor Area Ration and maximum plot coverage:-

The maximum Floor Area Ratio and Maximum Permissible plot coveragefor different occupancies shall be as in the following table

THE TABLE

Floor Area Ratios and maximum plot coverage for different Building Types.

S.No Build ing type Floor Area ratio Plot coverage

1 Residential 150 35

Commercial-

(a)George Town and otherSpecial areas declaredby council with the approvalOf Director of Town Planning.

120 502

(b) Other areas of the City 160 40

Public and industrial-

(a) George Town and otherSpecial areas declaredBy council.

150 503

(b) Other areas of the city 100 50

Explanation (1)-

The Floor Area Ratio specified in the Tables may be increased by 20 percent for the following services

(a) A basement or cellar and space under a building constructed on stiltsand used as parking space, store room and air - conditioning plant room used asnecessary to the Principal one.

b) Electric cabin or sub - station, watchman's booth, pump house andgarage stilts. And

c) Staircase room and lift rooms above the common storey, architecturalfeatures, and chimneys.


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Explanations (2)-The maximum plot coverage specified in the Table includes 5 per cent for

covered parking another 5 percent may be allowed for covered garages for carand cycle parking. This area for parking in ground floor will not be taken intoconsideration for calculation floor Area Ratio, but the space above it in first and

upper floors will be counted.

10. Structural suff iciency: -

(1) Foundations: -

(a) Every wall, column post and beam of building shall be supportedadequately by foundations of concrete or reinforced concrete, Plies, pires,caissers or other foundations of such thickness and projection as will benecessary to safety sustain and consult all the dead and superimposed loadwithout exceeding the limitations of permissible stresses shrinking and swelling,characteristics, such as clavey soils.

(b) The structural design of the foundations shall be determined as per therecommendations in the National Buildings Code of India, 1970 to ensuresufficiency and safety of the structures and to keep the stresses of the foundationmaterials and supporting soils within permissible limits prescribed in these rules.

(c) Piles either friction piles or end bearing piles may be used for thefoundations of a building when soil condition are suitable and their design, useand spacing shall conform to the recommendations in Part VI - Section 2 of theNational Building Code.

(d) All piles used to support any structure or part thereof shall be driven,jetted or otherwise embedded to such depth as is necessary to secure adequatesoil or rock bearing capacity and in such a manner as not to impair their strengthand shall be of sufficient strength to withstand also all stresses resulting from thehandling and driving.

(2) Walls and Columns: -

(a) The thickness of every load bearing non-reinforced masonry wall shallbe sufficient at all points to ensure that the stresses due to the worst conditionsof loading for which the structure is designed are within the limits prescribed.

(b) Maximum slenderness ratio:

Walls: -

For a wall, the slenderness ratio shall be the effective height divided bythe effective thickness or the effective length divided by the effective thicknesswhichever is less


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Column: -

For a column, the slenderness ratio shall be the effective height divided bythe corresponding lateral dimension (thickness or width).

(i) In the case of load bearing walls set in cement mortar (1:6) or cementlime mortar (1:2:9) the slenderness ratio shall not exceed 18 and for those set inlime mortar it shall not exceed 12.

(ii) In the case of non-load bearing walls, the slenderness ratio shall notexceed 30 for panel walls and curtain walls and shall not exceed 24 for forcestanding walls and parapet walls.

(iii) The slenderness ratio for load bearing column shall not exceed 12.

(c) Where a solid wall or masonry is load bearing, its thickness shall notbe less than that determined by the calculated masonry method through themonograms of the National Building Code of India, 1970 unless otherwisedetermined through the structural analysis of the building on accepted principlesof mechanics to sustain the most adverse combination of loads to which thebuilding shall be subject to during or after erection.

(d) The design loads and other forces to be taken for the design ofmasonry structures shall conform to those laid down in part VI -Section I of theNational Building code of India, 1970 briefly extracted in Appendix L to theseRules.

(e) Where a wall is sub-divided in to plans by adequate horizontal orvertical supports or both the individual panels shall be designed for structuralsufficiency.

(f) Where reinforced concrete walls are intended to carry vertical loads,they should be designed generally in accordance with the design criteria forcolumns. The cross sectional area of vertical reinforcement and the lateralreinforcement parallel to the wall face may be reduced to not less 1.2 per cent.

(g) Concrete and Steel Structures- The design and structural use of plain,reinforced and pre-stressed concrete for buildings and the component parts shallconform to the recommendations or the National Building Code of India in its PartVI of the said National Building Code.

(4) Prefabricated Building.-

The modular planning, component sizes, joints, manufacture, storage,transport and erection of prefabricated elements for use in the building shallconform to the recommendations in section 7, part VI of the National BuildingCode of India, 1970


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(5) Excavations.-

(a) All excavations shall be protected and properly guarded in such amanner as to prevent danger to life or property; where necessary excavations

shall be sheet-piled to prevent the earth, soil or surface of any street or adjoiningproperty from caving in or being damaged thereby.

(b) No excavation for any purpose shall extend within 30 Cm. of the angleof repose or natural slope of the soil under any footing or foundation.

(c) Where an excavation is back filled, measures shall be taken to placethe back fills as to-

(i) maintain the lateral support of the soil exposed by the excavation;(ii) have a bearing capacity adequate to support the anticipated surcharge;

and(iii) prevent detrimental settlement.

11. Open spaces: -

(1) Open spaces around and about the Bui lding:

(a) There shall be a permanent open air space, forming an integral part ofthe site and of a minimum extent specified in this Rule, between each of theboundaries of the site and every building within site.

(a) The extent or the open spaces (specified in the above sub-rule) whichshall be co-extensive with the site boundaries shall be as follows:-

S.No Build ing Typeside Minimum open yard from theBoundaries

i Building up to a height of10 meters

Three meters

iiBuilding of height above10 meters up to 30 m

Three meters plus 1 meter for everyadditional 3 meters or fraction thereofover to meters.

iiiBuildings of height over 30meters

Ten meters plus 1 meters for everyadditional 5 meters or fraction thereof,subject to a maximum of 16 meters.


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(c) The space specified above shall be kept open to the sky and free from

any erection of any building other than a fence or compound wall, providedhowever that parking garages not exceeding 3 meters in height and subject tocompliance with the stipulations of F.A.R. and access ways may on the case pf

sites abutting more than one screen on the wider of the streets and provided alsothat open yards may be used for the provision of open access ways to thebuilding and parking facilities.

(2) Open spaces for amenity-

Where the building proposed is a residential building proposed is aresidential building for accommodating multi-family dwelling there shall be alsoprovided in the site common amenity open space. The extent of this additional ofthis additional open space shall be 10 per cent of the site area.

12. Means of Access and Circulation-

(1) (a) There shall be provided from the street to the entrance door ordoors every building in the site a clear way of not less than 5 meters in width as ameans of access to such building which shall be maintained free from andobstruction or any overhang or projection from the building.

(b) The space so set apart as means of access shall be separatelydistinguished from any house gully or open space for amenity requirement

prescribed under the Rules.

(c) Every such means of access shall be made drained and lighted to thesatisfaction of the Engineer and manhole covers or other drainage, water or anyother fittings laid in such means of access shall be flush with the finished surfacelevel so as not to obstruct safe travel over the same.

(d) Any person who undertakes, construction work on buildings shall notreduce the access to any building previously existing below the minimum widthprescribed under these Rules.

(2) Exits and means of egress -

(a) Every building meant for human occupation shall be provided withexits sufficient to permit safe escape of occupants in case of fire or otheremergency.


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13. Parking and Parking facilities-

(1) (a) For the use of the occupants and the persons visiting the premisesfor the purpose of professions, trade business recreation or any other work,parking space and parking facilities shall be provide within the site, to the

satisfaction of the Commissioner and conforming to the standards specified inAppendix-E to these Rules; and(b) Necessary provision shall be also made for the circulation of vehicles gainingaccess to and from (i) the parking spaces and facilities and (ii) the premises intothe street,

(2) The parking spaces and facilities provided under this Rule shall bemaintained as such to the satisfaction of the Engineer and conforming to anybylaw that may be made by the Corporation is the regard.

14. Fire safety.-

(1) All buildings in their design and construction shall be such as tocontribute to and ensure individually and collectively the safety of life from fire,smoke, fumes and panic arising from these or similar other causes.

(2) Fire detecting and extinguishing system.-

In buildings of such size, arrangement or occupancy that a fire may notitself provide adequate warning to occupants, automatic fire detecting and alarmfacilities shall be provided where necessary to warn occupants of the existenceof fire so that they may escape or to facilitate the orderly conduct of fire drills.

(3) Fire protecting and extinguishing system shall conform to acceptedstandards and shall be installed in accordance with good practice asrecommended by in the National Building Code of India, 1970, and to thesatisfaction of the Directorate of Fire Services.

15. Archi tectural Control .-

(1) The design and plans of the buildings shall be made andcountersigned by a qualified architect who is an Associate of the Indian Instituteof Architects;

(2) The design and plan shall be scrutinized and approved by a pane;comprising of the following members;-

(i) Engineer

(ii) A Town Planner of Govt. And


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(iii) A prominent private architect, provided that the Architect member if thepanel shall not have made the plans and designs for the buildings underconsideration.

(3) Any suggestions for alterations suggested by the panel shall beincorporated in the plans shall be conformed to.

B. Public Buildings

16. Sufficient exits:-

(1) Every person intending to construct, reconstruct, add to or alter anypublic building shall in addition to the general requirements laid down in theRules, also comply with Rules 9, 11(a), (b), (c), 12 and 13 prescribed for multistoried buildings and also with the following rules.

(2) (a) Every place of assembly, every tier or balcony and every individualroom used as a place of assembly in a public building shall have exits sufficientto provide for the total capacity thereof leading directly outside the building or tostairways and ramps or both.

(b) There shall be at least two separate exits as remote form each otheras practicable for each room, hall or place of assembly, with a capacity of 600persons at least three separate exits when the capacity is between 601 to 1000at least for separate exists when the capacity is over 1000.

Provided that when the capacity is less than 100 persons and no part of the roomor hall or place of assembly is 15 meters from the doorway in the line of travel, asingle doorway of 100 cm. may be permitted.

17. Aisles and spacing rows of seats.-

(a) Clear aisles not less than 1.2 meters in width shall be provided at rightangles to the line of seating in such number and manner that no seat shall bemore than 3.8 meters away from an aisle measured in the line of seating.

(b) Where all the aisles do not directly meet the exit doors, cross aisles ofminimum 1 meter width and at the rate of one cross asile for every 19 rows ofseats shall be provided parallel to the line of seating so as to provide directaccess to the exit.


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(c) Rows of seats between aisles shall not have more than 14 seats and inthe case of such rows opening too an aisle at one end, shall not have more than7 seats.

(d) There shall be a minimum space of 85 Cm, between the backs of anytwo rows of seats and a minimum of 35Cm. between the back of any sear andthe front of the seat immediately behind as measured between plumb lines.

18. Fire detecting and extinguishing systems-

Every public building a capacity of 1000 persons or more, shall beprovided with either a manually operated fire alarm system coded to alertemployers or attendants or with an automatic fire detection system to conform to

the standards and recommendations laid down in the National Building Code ofIndia, 1970 and to the satisfaction of the Directorate of Fire Services.

SINo

1

1.

2.

Land and Buildings Use

2

Residential (a) SingleFamily House

(b) Apartment Flats

Commercial :(a) Shops

(b) Shopping centers

(c) Office and Firms

Area of parking

3

17.5

17.5

17.5

20

20

Numbers of Units of spaces tobe provided.

4

One for every site with an areaof 350 square meters and over.

One for every two Families

One for the first 200 squiremeters of floor area and oneaddition unit for every 100square meters or part thereof

every 200 square meters,

One for every 250 squaremeters of site area or partthereof.

(i) For building with floor arealess than 100 square meters -


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(d) Restaurants

(e) Hotels and Lodges

(f) Cinemas and PublicHalls including Communityhall

(g) Kalyanamandapam etc.,

Warehousing and whole

sale stores.

Public and Semi-publicOffices.

Hospitals and NursingHomes

Industries

17.5

17.5

17.5

17.5

40

20

17.5

30

Nil.

(ii) For building with floor areaover 200 square meters or partthere of upto 1000 square

meters and one additional unitfor every 100 square meters offloor area over 100 squaremeters.

(i) Restaurants with less than50 seats-Nil.

(ii) With 50 seats and over oneunit for every 20 seats or partsof 20 seats.

One for every 6 beds.

One for every 25 seats.

One for every 20 squaremeters of site area

One for every 500 square

meters of floor area or partthereof.

(i) For building with floor arealess than 100 square meters-Nil

(ii) Floor area of 100 squaremeters and above; one forevery 200 square meters orpart thereof.

One for every 15 bets.

(i) Upto 100 square metersmeters of floor area -Nil

ii With floor area over 100


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For other uses Institutionsand Transport and

Communication Centers.

square meters one for every200 square meters.

Requirements to be assessedby Commissioner in

consultation with commissionerof Police and Director of TownPlanning.

APPENDIX L.

Design Loads and other forces for design of masonrystructures.

(See Special Rule 10(2) (d) of Multi-storied Buildings.)

1. Dead loads .- The dead load in a building shall compirse the weightwalls, partitions floors, and roofs and shall include the weights of all walls,partitions floors, and roofs and shall include the weights of all other permanentconstructions in the building. The dead load is determined adopting the dead

weight of the construction material and given in the following Table:

(a) Description of construction materials- Weight in Kg/M2

(1) Brick, in mud, lime or cement mortar 1920

(2) Coarsed ruble in lime or cement mortar 2240

(3) Laterite in lime or cement mortar 2000

(4) Concreate in limr or cement mortar (a) 19.20 (brick Jally)

(b) 2240

(hard broken stone)

(5) Random rubber in lime or cement mortar 2240

(6) Lime-stone 2400 to 2640

(7) Sand - stone 2240 to 2400

(8) Cuddapah slabs 2720

(9) Ashlar 2720


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(10) Granite Stone 2600 to 2800

(11) Reinforced concrete 2400

(12) Cast iron 7030 to 7130

(13) Wrought iron 7700

(14) Steel 7850

(15) Teak 625

(16) Pine 610

(17) Oak 865

(18) Fir 430 to 460

Description of roof materials and roofs.

(1) Corrugated iron sheet (1.25 mm) 10.56

(2) Corrugated iron sheet (1.00 mm) 8.60

(3) Brick, in mud, lime or cement mortar 120

(4) Coarsed rubble in lime or cement mortar 2240

(5) Laterite in lime mortar 2000

(6) Concrete in lime or cement mortar (a) 19.20 (brick jally)

(b) 2240

(hard broken stone)

(7) Random rubble in lime or cement mortar 2240

(8) Lime-stone 2400

(9) Sand-stone 2240 to 2400

2. Live loads- (a) Live loads on floors- (i) Live loads on floors shall comprise allloads other than dead load. The minimum live loads on different floors fordifferent uses are specified in the followed table in terms of uniformity distributedstatic loads.

(ii) In designing the walls, columns, piers, their support and foundationsthe following reductions in assumed total live loads on floors may be made:


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Number of floors carried by Percent reduction of total live load on allmember under consideration. floors above the member under

consideration.

1 0

2 10

3 20

4 30

5 or more 40

(iii) No reduction shall be made in the case of warehouses, garages and otherbuilding used for storage purposes and for factories and workshope designed for500 Kg/M2.

Table

Live Loads on floors


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Type of Floors

(1)

Minimum LiveLoads

Per Kg/m2 offloor area

(2)

Al terative Minimum Live Load

(3)

Floors in dwelling houses,tenements hospital wards,bed rooms and privatesitting rooms in hostels,and dormitories

Office floors other thanentrance halls, floors oflight work rooms.

Floors of banking halls,office entrance halls andreading rooms

Shop floors used for adisplay and sale ormerchandise; floors of workclass rooms generallyfloors of or places ofassembly with fixed

seating, restaurants,circulation space inmachinery halls powerstations, circulation spacein etc., where not occupiedby plant or equivalent.

Floors of warehouses,workshops factories andother building or parts ofbuildings of similar

category for light weightloads; office floors forstorage and filing purposes;floors of places ofassembly without fixedseating, public rooms inhotels, etc.,

200

250-400

300

400

500

.

.

.

Subject to a minimum total load of2.5 times the values in column 4for any given slab panel and 6times the values in column 4 forany given beam.

This total load shall be uniformlydistributed on the entire area of theslab panel or the entire length ofthe beam.


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Type of Floors

(1)

Floors of ware-houses,workshops, factories andother buildings or parts ofbuildings of similar categoryfor medium- weight loads.

Floors of ware houses,workshops, factories and

other buildings or parts ofbuildings or parts of buildingsof similar category for heavy-weight loads, floor of bookstores and libraries, roofsand pavement lights overbasements projecting underthe public roof path underthe public foot-path.

Floors used for garages for

vehicles not exceeding 2.5tonnes gross weight

Slabs

Beams

Floors Used for garages forvehicles not exceeding 4tonnes gross weight.

Minimum LiveLoads per

Kg/m2of floorarea

(2)

750

1000

400

250

750

Alterative Minimum LiveLoad.

(3)

The worst combinationof actual wheel loads,whichever is greater.

The worst combinationof actual, wheel loads,whichever is greater.

Subject to a minimumof one and a half timesmaximum wheel loadbut not less than 900Kg. considered to bedistributed over 5 Cm.squire.


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Stairs, landings and corridorsfor class 200 loading but notliable to over crowding.

Stairs, landings and corridorsfor class 200 loading butliable to overcrowding, andfor all other classes.

Balconies not liable to overcrowding:

For class 200 loading

For all other classes

Balconies liable toovercrowding.

300

500

300

500

500

Subject to minimum of130 Kg. concentratedload at the unsupportedend of each step for

stairs constructed out ofstructurally independentcantilever steps.

Explanation 1.- A reference to a "floor' includes a reference to any part ofthat floor, and a reference to "slabs' includes boarding and beams or ribs spacednot further apart than one meter between centers, and a reference to "beams'

means all other beams and ribs.

Explanation 2.- Under loading class No. 250, the reference to lightworkrooms envisages rooms in which some light machines (for example, sewingmachine used by millers or tailors) are operated without a central power-drivenUnit, that is, the machines are independently operated dither by hand or by smallmotors. Under loading class No.400, the reference to workrooms generallyenvisages the installation of machines operated with a central power-driven Unit,with the individual machines being belt driven.

Explanation 3.- "Fixed seating' implies that the removal of the seating andthe use of the space for other purposes is improbable. The maximum likely loadin this case is, therefore closely controlled.

Explanation 4.- The loading in work shops, warehouses and factoriesvaries considerably and so three loadings under the terms "light', "medium' and


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"heavy' are introduced in order to allow for more economical designs but theterms have no special meaning in themselves other than the live load for whichthe relevant floor is designed. It is however, important particularly in the case ofheavy weight loads, to assess the actual loads to ensure that they are not inexcess the design shall be based on the actual loading.

Explanation 5.- The load classification for stairs, corridors, balconies andlandings provide for the fact that these often serve several occupancies and areused for transporting the furniture and goods.(b) Live loads on roofs; Allowance for live load on flat roofs, sloping roofs andcurved roofs shall be as given in the following Table.

THE TABLE

LIVE LOADS ON FLOORS

Type of roof

(1)

Flat, sloping or curved roofwith slops up to andincluding 10 degrees.

(a) Access provided

(b) Access not provided,except for maintenance.

Sloping roof with slopgreater than 10 degrees

Live load measuredon plan

(2)

150 Kg/m2

75 Hg/m2

(a) For roof

Minimum live Loadmeasured on plan

(3)

375 Kg. uniformlydistributed over anyspan of one meter widthof the roofs slab and 900Kg. Uniformly distributedover the spand in thecause of all beams.

190 Kg. uniformlydistributed over anyspan of one meter widthof the roof slab and 450Kg. uniformly distributedover the span in the


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Curved roofs with slope atspringing greater than 10degrees.

membrance sheetsof purline 75 Kg/m2;less 2Kg/m2 forevery degreeincrease in slope

over 10 degrees.

(b) For memberssupporting the roofmembrance and roofpurlins, such astrusses, beamsgirders, etc. 2/3 ofload in (a) and (b) do

no include loads dueto show, rain dustcollection, etc., andthe effects of suchloads shall beappropriatelyconsidered.

(75-34r2 Kg/m2Where r = h/1

h=the height of thehighest point of thestructure measuredform its springing andi= chord width of theroof in singly curvedand shorter of thetwo sides, if doublycurved.

case of beam.

Subject to a minimum of40 Kg/m2.

Subject to a minimum of40 Kg/m2.

Note :- For special types of roofs with highly permeable and absorcentmaterial, the contingency of roof material increasing in weight due to absorptionof moisture shall be increased as follows.

(c) Impact and vibrations: For structure carrying live loads which reduceimpact or of vibrations, the live loads shall be increased as follows:-


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(i) For flame supporting lifts and hoists- 100 per cent.

(ii) For foundations, footings and piers supporting lifts and hoistingapparatus-40 per cent.

(iii) For light machinery, shaft or motor units - 20 per cent minimum.(iv) For reciprocating machinery or powers units - 50 per cent minimum.

3. Wind load.-The wind load a building shall be calculated on the basis ofthe basic wind pressure, given in the following Table, which is the equivalentstatic pressure in the direction of flew or wing:-

(a) Basic wind pressures for the city-

Height in Meters

(1) (2)upto 30 200

35 20840 21045 21750 22260 23070 23680 244100 254120 264150 276

For intermediate height, interpolated values may be adopted.

2. Wind pressures on roofs.- For flat and perched roofs, the wind pressures andsuctions normal to the surface due to wind blowing at right angles to the ridgeshall be determined by multiplying the basic wind pressure (p) with the factorsgiven in the Table Below:-


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TIME TABLEWind Pressures on Roofs(Winds normal and ridges)

Slope of roof on External Winy pressure

(1) (2) (3)Wind ward side Wind ward slope Leeward slope

0o -1.00 -0.50 Po

10 -0.70 P -0.50 Po -0.40 P -0.50 P20o30 -0.10 P -0.50 Po40 +0.10 P -0.50 Po50 +0.30 P -0.50 Po60 +0.30 P -0.50 Po70 +0.50 P -0.50 Po

80 +0.50 P -0.50 Po90 +0.50 P -0.50 P

4. Seismic loads:- The seismic coefficients, stress increased, design live loads asstipulated in the National Building Code India, 1970, shall be taken in to accountwhile designing the structures.

Documents

Multi-Storied Public Buildings Rules 1973