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DEFINITIONS AND GENERAL EQUIREMENTS1.1 INTRODUCTION1.1.1 SCOPEThe definitions providing meanings of different terms and general requirements for the structural design of

buildings,structures,andcomponents thereofarespecified in this chapter.Theserequirementsshall applytoall

buildings and structuresor their componentsregulated bythis code. All anticipated loadsrequired for structural

design shall be determined in accordance with the provisions of Chapter 2. Design parameters required for the

structuraldesignoffoundationelementsshallconformtotheprovisionsofChapter3.Designofstructuralmembers

usingvariousconstructionmaterialsshall comply withthe relevantprovisionsof Chapters 4through13.The FPS

equivalentsoftheempiricalexpressionsusedthroughoutPart6arelistedinAppendixA.

ThisCodeshallgoverninallmatterspertainingtodesign,construction,andmaterialpropertieswhereverthisCode

is in conflict with requirements contained in other standards referenced in this Code. However, in special cases

wherethedesignofastructureoritscomponentscannotbecoveredbytheprovisionsofthiscode,otherrelevant

internationallyacceptedcodesreferredinthiscodemaybeused.

1.1.2 DEFINITIONSThefollowingdefinitionsshallprovidethemeaningofcertaintermsusedinthischapter.

BASESHEAR:Totaldesignlateralforceorshearatthebaseofastructure.

BASIC WIND SPEED : Threesecond gust speed at 10 metres above the mean ground level in terrain ExposureB

definedinSec2.4.8andassociatedwithanannualprobabilityofoccurrenceof0.02.

BEARINGWALLSYSTEM:Astructuralsystemwithoutacompleteverticalloadcarryingspaceframe.

BRACEDFRAME:Anessentiallyverticaltrusssystemoftheconcentricoreccentrictypewhichisprovidedtoresist

lateralforces.

BUILDINGFRAMESYSTEM:Anessentiallycompletespaceframewhichprovidessupportforloads.

CONCENTRICBRACEDFRAME(CBF):AsteelbracedframedesignedinconformancewithSec10.20.13.or10.20.14.

COLLECTOR : A member or element used to transfer lateral forces from a portion of a structure to the vertical

elementsofthelateralforceresistingelements.

BUILDINGS:Structuresthatencloseaspaceandareusedforvariousoccupancies.

DEADLOAD:Theloadduetotheweightofallpermanentstructuralandnonstructuralcomponentsofabuildingor

astructure,suchaswalls,floors,roofsandfixedserviceequipment.

DIAPHRAGM : A horizontal or nearly horizontal system acting to transmit lateral forces to the vertical resisting

elements.Theterm"diaphragm"includeshorizontal bracingsystems.

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DUALSYSTEM:AcombinationofMomentResistingFramesandShearWallsorBracedFramestoresistlateralloads

designedinaccordancewiththecriteriaofSec1.3.2.

ECCENTRICBRACEDFRAME(EBF):AsteelbracedframedesignedinconformancewithSec10.20.15.

HORIZONTAL BRACING SYSTEM : A horizontal truss system that serves the same function as a floor or roof

diaphragm.

INTERMEDIATE MOMENT RESISTINGFRAME (IMRF) :A concrete momentresisting frame designed in accordance

withSec8.3.10.

LIVELOAD:Theloadsuperimposedbytheuseandoccupancyofabuilding.

MOMENT RESISTING FRAME : A frame in which members andjoints are capable of resisting forces primarily by

flexure.

ORDINARY MOMENT RESISTING FRAME (OMRF) : A moment resisting frame not meeting special detailing

requirementsforductilebehaviour.

PRIMARYFRAMINGSYSTEM:Thatpartofthestructuralsystemassignedtoresistlateralforces.

SHEARWALL:Awalldesignedtoresist lateralforcesparalleltotheplaneofthewall(sometimesreferredtoasa

verticaldiaphragmorastructuralwall).

SLENDER BUILDINGS AND STRUCTURES : Buildings and structures having a height exceeding five times the least

horizontal dimension, or having a fundamental natural frequency less than 1 Hz. For those cases where the

horizontaldimensionsvarywithheight,theleasthorizontaldimensionatmidheightshallbeused.

SOFTSTOREY:Storeyinwhichthelateralstiffnessislessthan70 percentofthestiffnessofthestoreyabove.

SPACEFRAME:Athreedimensionalstructuralsystemwithoutbearingwallscomposedofmembersinterconnected

soastofunctionasacompleteselfcontainedunitwithorwithouttheaidofhorizontaldiaphragmsorfloorbracing

systems.

SPECIAL MOMENT RESISTING FRAME (SMRF) : A moment resisting frame specially detailed to provide ductile

behaviourcomplyingwiththerequirementsofChapter8or10forconcreteorsteelframesrespectively.

SPECIAL STRUCTURAL SYSTEM : A structural system not listed in Table 1.3.1 and specially designed to carry the

lateralloads.SeeSec1.3.2.5.

STOREY:Thespacebetweenanytwofloorlevelsincludingtheroofofabuilding.Storeyxisthestoreybelowlevel

x.

STOREYSHEAR,Vx :Thesummationofdesignlateralforcesabovethestoreyunderconsideration.

STRENGTH:Theusablecapacityofanelementoramembertoresisttheloadasprescribedintheseprovisions.

TERRAIN:Thegroundsurfaceroughnessconditionwhenconsideringthesizeandarrangementofobstructionsto

thewind.

THREESECONDGUSTSPEED: Thehighestaveragewindspeedovera3seconddurationataheightof10m.The

threesecondgustspeedisderivedusingDurst'smodelintermsofthemeanwindspeedandturbulenceintensity.

TOWER:Atall,slimverticalstructure.

VERTICALLOADCARRYINGFRAME: Aspaceframedesignedtocarryallverticalgravityloads.

WEAKSTOREY: Storeyinwhichthelateralstrengthislessthan80percentofthatofthestoreyabove.

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1.1.3 SYMBOLSANDNOTATIONThe following symbols and notation shall apply to the provisions of this chapter:D =dead load on a member including self weight and weight of components, materials andpermanent equipments supported by the memberE

=earthquake loadFi =lateral force applied at leveliof a buildingh =height of a building or a structure above ground level in metreshi,hn,hx =height in metres above ground level to leveli, nor xrespectivelyleveli = ith level of a structure above the base; i=1 designates the first level above

the baseleveln =upper most level of a structurelevelx =xth level of a structure above the base;x=1 designates the first level above the base.L

=live load due to intended use or occupancyl =span of a member or component.Mx =overturning moment at levelxV =the total design lateral force or shear at the baseVx =the storey shear at storey levelxR =response modification or reduction coefficient for structural system given in Table 2.5.7 for

seismic design.S =Snow loadT = Fundamental period of vibration in secondsW = Load due to wind pressure.W = Weight of an element or componentZ = Seismic zone coefficient given in Fig 2.5.1 or Tables 2.5.2 or 2.5.3 = Storey lateral drift.

1.2 BASIC CONSIDERATIONS1.2.1 GENERALAllbuildingsandstructuresshallbedesignedandconstructed inconformancewiththeprovisionsofthissection.

Thebuildingsandportionsthereofshallsupportallloadsincludingdeadloadspecifiedinthischapterandelsewhere

inthisCode.Impact,fatigueandselfstrainingforcesshallbeconsideredwheretheseforcesoccur.

1.2.2 BUILDINGSANDSTRUCTURESA structure shall ordinarily be described as an assemblage of framing members and components arranged to

support both gravity and lateral forces. Structures may be classified as building and nonbuilding structures.

Structuresthatencloseaspaceandareusedforvariousoccupanciesshallbecalledbuildingsorbuildingstructures.

Structuresotherthanbuildings,suchaswatertanks,bridges,communication towers,chimneysetc.,shallbecalled

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nonbuildingstructures.Whenusedinconjunctionwiththewordbuilding(s),thewordstructure(s)shallmeannon

buildingstructures,e.g.'buildingsandstructures'or'buildingsorstructures'.Otherwisetheword'structures'shall

includebothbuildingsandnonbuildingstructures.

1.2.3 BUILDINGANDSTRUCTUREOCCUPANCYCATEGORIESBuildingsandotherstructuresshallbeclassified,basedonthenatureofoccupancy,accordingtoTable1.2.1forthe

purposes ofapplying flood, surge,windandearthquakeprovisions.Theoccupancy categories range from Ito IV,

whereOccupancyCategoryIrepresentsbuildingsandotherstructureswithalowhazardtohumanlifeintheevent

of failure and Occupancy Category IV represents essential facilities. Each building or other structure shall be

assignedtothehighestapplicableoccupancycategoryorcategories.Assignmentofthesamestructuretomultiple

occupancycategoriesbasedonuseandthetypeofloadconditionbeingevaluated(e.g.,windorseismic)shallbe

permissible.

Whenbuildingsorotherstructureshavemultipleuses(occupancies),therelationshipbetweentheusesofvarious

partsofthebuildingorotherstructureandtheindependence ofthestructuralsystemsforthosevariouspartsshall

beexamined.Theclassificationforeachindependentstructuralsystemofamultipleusebuildingorotherstructure

shallbethatofthehighestusagegroupinanypartofthebuildingorotherstructurethatisdependentonthatbasic

structuralsystem.

1.2.4 SAFETYBuildings, structures and components thereof, shall be designed and constructed to support all loads, including

deadloads,withoutexceedingtheallowablestressesorspecifiedstrengths(underapplicablefactoredloads)forthe

materialsofconstructioninthestructuralmembersandconnections.

1.2.5 SERVICEABILITYStructuralframingsystemsandcomponentsshallbedesignedwithadequatestiffnesstohavedeflections,vibration,

or any other deformations within the serviceability limit of building or structure. The deflections of structural

members shall not exceed the more restrictive of the limitations provided in Chapters 2 through 13 or that

permittedbyTable1.2.2orthenotesthatfollow.Forwindandearthquake loading,storydriftandswayshallbe

limitedinaccordancewiththeprovisionsofSec1.5.6.

1.2.6 RATIONALITYStructuralsystemsandcomponentsthereofshallbeanalyzed,designedandconstructedbasedonrationalmethods

whichshallinclude,butnotbelimitedto,theprovisionsofSec1.2.7

1.2.7 ANALYSISAnalysis of the structural systems shall be made for determining the load effects on the resisting elements and

connections, basedonwellestablishedprinciplesofmechanicstakingequilibrium,geometriccompatibilityandboth

shortandlongtermpropertiesoftheconstruction materialsintoaccountandincorporatingthefollowing:

1.2.7.1 MATHEMATICALMODELA mathematical model of the physical structure shall represent the spatial distribution of stiffness and other

propertiesofthestructurewhichisadequatetoprovideacompleteloadpathcapableoftransferringallloadsand

forces from their points of origin to the loadresisting elements for obtaining various load effects. For dynamic

analysis,mathematical modelshallalso incorporatetheappropriatelydistributedmassanddampingpropertiesof

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thestructureadequateforthedeterminationofthesignificantfeaturesof itsdynamicresponse.Allbuildingsand

structures shall be thus ananlyzed preferably using a threedimensional computerizedmodel incorporating these

featuresofmathematicalmodel.It isessentialtousethreedimensionalcomputermodeltorepresentastructure

havingirregularplanconfigurationsuchasthoselistedinTables1.3.2and1.3.3andhavingrigidorsemirigidfloor

and roof diaphragms. Requirements for twodimensional model and three dimensional models for earthquake

analysisaredescribedinSec.2.5.11to2.5.14.

Table1.2.1 OccupancyCategoryofBuildingsandOtherStructuresforFlood,Surge,WindandEarthquakeLoadsNatureofOccupancy OccupancyCategoryBuildingsandotherstructuresthatrepresentalowhazardtohumanlifeintheeventoffailure,including,butnotlimited

to:

Agriculturalfacilities Certaintemporaryfacilities Minorstoragefacilities

I

AllbuildingsandotherstructuresexceptthoselistedinOccupancyCategoriesI,III,andIV II

Buildingsandotherstructuresthatrepresentasubstantialhazardtohumanlifeintheeventoffailure,including,butnot

limitedto:

Buildingsandotherstructureswheremorethan300peoplecongregateinonearea Buildingsandotherstructureswithdaycarefacilitieswithacapacitygreaterthan150 Buildingsandotherstructureswithelementaryschoolorsecondaryschoolfacilitieswithacapacitygreaterthan250 Buildingsandotherstructureswithacapacitygreaterthan500forcollegesoradulteducationfacilities

Healthcare

facilities

with

a

capacity

of

50

or

more

resident

patients,

but

not

having

surgery

or

emergency

treatmentfacilities Jailsanddetentionfacilities

Buildingsandotherstructures,notincludedinOccupancyCategoryIV,withpotentialtocauseasubstantialeconomicimpactand/ormassdisruptionofdaytodaycivilianlifeintheeventoffailure,including,butnotlimitedto:

Powergeneratingstationsa Watertreatmentfacilities Sewagetreatmentfacilities Telecommunicationcenters

BuildingsandotherstructuresnotincludedinOccupancyCategoryIV(including,butnotlimitedto,facilitiesthatmanufacture,process,handle,store,use,ordisposeofsuchsubstancesashazardousfuels,hazardouschemicals,hazardouswaste,orexplosives)containingsufficientquantitiesoftoxicorexplosivesubstancestobedangeroustothepublicifreleased.

III

Buildingsandotherstructuresdesignatedasessentialfacilities,including,butnotlimitedto:

Hospitalsandotherhealthcarefacilitieshavingsurgeryoremergencytreatmentfacilities Fire,rescue,ambulance,andpolicestationsandemergencyvehiclegarages Designatedearthquake,hurricane,orotheremergencyshelters

Designatedemergency

preparedness,

communication,

and

operation

centers

and

other

facilities

required

for

emergencyresponse Powergeneratingstationsandotherpublicutilityfacilitiesrequiredinanemergency Ancillarystructures(including,butnotlimitedto,communicationtowers,fuelstoragetanks,coolingtowers,

electricalsubstationstructures,firewaterstoragetanksorotherstructureshousingorsupportingwater,orotherfiresuppressionmaterialorequipment)requiredforoperationofOccupancyCategoryIVstructuresduringanemergency

Aviationcontroltowers,airtrafficcontrolcenters,andemergencyaircrafthangars Waterstoragefacilitiesandpumpstructuresrequiredtomaintainwaterpressureforfiresuppression Buildingsandotherstructureshavingcriticalnationaldefensefunctions

Buildingsandotherstructures(including,butnotlimitedto,facilitiesthatmanufacture,process,handle,store,use,ordispose of such substances as hazardous fuels, hazardous chemicals, or hazardous waste) containing highly toxicsubstances where the quantity of the material exceeds a threshold quantity established by the authority havingjurisdiction.

IV

aCogenerationpowerplantsthatdonotsupplypoweronthenationalgridshallbedesignatedOccupancyCategoryII.

1.2.7.2 LOADSANDFORCESAllprescribed loadsandforcestobesupportedbythestructuralsystemsshallbedetermined inaccordancewith

theapplicable provisionsofthischapterandChapter2.Loadsshallbeappliedonthemathematicalmodelspecified

inSec.1.2.7.1atappropriatespatiallocationsandalongdesireddirections.

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Table1.2.2DeflectionLimits(Exceptearthquakeload)

In the above table lstands for span of the member under consideration; Lstands for live load, Wstands forwind load andDstands for dead load.Notes:

a. For structural roofing and siding made of formed metal sheets, the total load deflection shall not exceed l/60. For secondary roofstructural members supporting formed metal roofing, the live load deflection shall not exceed l/150. For secondary wall memberssupporting formed metal siding, the design wind load deflection shall not exceed l/90. For roofs, this exception only applies when themetal sheets have no roof covering.b. Interior partitions not exceeding 2m in height and flexible, folding and portable partitions are not governed by the provisions of thissection.c. For cantilever members, lshall be taken as twice the length of the cantilever.d. For wood structural members having a moisture content of less than 16 percent at time of installation and used under dry conditions,the deflection resulting from L + 0.5D is permitted to be substituted for the deflection resulting from L + D.e. The above deflections do not ensure against ponding. Roofs that do not have sufficient slope or camber to assure adequate drainage shallbe investigated for ponding. See Section 1.6.5 for rain and ponding requirements.f. The wind load is permitted to be taken as 0.7 times the component and cladding loads for the purpose of determining deflection limitsherein.g. For steel structural members, the dead load shall be taken as zero.h. For aluminum structural members or aluminum panels used in skylights and sloped glazing framing, roofs or walls of sunroomadditions or patio covers, not supporting edge of glass or aluminum sandwich panels, the total load deflection shall not exceed l/60. Forcontinuous aluminum structural members supporting edge of glass, the total load deflection shall not exceed l/175 for each glass lite orl/60 for the entire length of the member, whichever is more stringent. For aluminum sandwich panels used in roofs or walls of sunroomadditions or patio covers, the total load deflection shall not exceed l/120.

1.2.7.3 SOIL-STRUCTUREINTERACTIONSoilstructure interaction effects,where required, shall be included in the analysis by appropriately including the

properlysubstantiatedpropertiesofsoilintothemathematicalmodelspecifiedinSec.1.2.7.1above.

1.2.8 DISTRIBUTIONOFHORIZONTALSHEARThetotallateralforceshallbedistributedtothevariouselementsofthelateralforceresistingsysteminproportion

totheirrigiditiesconsideringtherigidityofthehorizontalbracingsystemsordiaphragms.

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1.2.9 HORIZONTALTORSIONALMOMENTSStructural systems and components shall be designed to sustain additional forces resulting from torsion due to

eccentricity between the centre of application of the lateral forces and the centre of rigidity of the lateral force

resisting system. Forces shall notbe decreaseddue to torsional effects. For accidental torsion effects on seismic

forces,requirementsshallconformtoSec2.5.9.6

1.2.10 STABILITYAGAINSTOVERTURNINGANDSLIDINGEverybuildingorstructureshallbedesignedtoresisttheoverturningandslidingeffectscausedbythelateralforces

specifiedinthischapter.

1.2.11 ANCHORAGEAnchorageoftherooftowallandcolumns,andofwallsandcolumnstofoundations,shallbeprovidedtoresistthe

upliftandslidingforcesresultingfromtheapplicationoftheprescribedloads.Additionalrequirementsformasonry

orconcretewallsshallbethosegiveninSec1.7.3.6.

1.2.12 GENERALSTRUCTURALINTEGRITYBuildingsandstructuralsystemsshallpossessgeneralstructuralintegrity,that istheabilitytosustainlocaldamage

caused due to misuse or accidental overloading, with the structure as a whole remaining stable and not being

damagedtoanextentdisproportionatetotheoriginallocaldamage.

1.2.13 PROPORTIONINGOFSTRUCTURALELEMENTSStructuralelements,componentsandconnectionsshallbeproportionedanddetailedbasedonthedesignmethods

provided inthesubsequent chapters forvariousmaterialsofconstruction,suchasreinforcedconcrete,masonry,

steeletc.toresistvariousloadeffectsobtainedfromarationalanalysisofthestructuralsystem.

1.2.14 WALLSANDFRAMINGWalls and structural framing shall be erected true and plumb in accordance with the design. Interior walls,

permanent partitions and temporary partitions exceeding 1.8 m of height shall be designed to resist all loads to

whichtheyaresubjected.IfnototherwisespecifiedelsewhereinthisCode,wallsshallbedesignedforaminimum

load of 0.25 kN/m2

applied perpendiculartothe wall surfaces. The deflection ofsuchwalls under a load of0.25

kN/m2

shall not exceed1/240ofthespanforwallswithbrittlefinishesand

1/120ofthespanforwallswithflexible

finishes. However, flexible, folding or portable partitions shall not be required to meet the above load and

deflectioncriteria,butshallbeanchoredtothesupportingstructure.

1.2.15 ADDITIONSTOEXISTINGSTRUCTURESWhenanexistingbuildingorstructureisextendedorotherwisealtered,allportionsthereofaffectedby suchcause

shallbestrengthened,ifnecessary,tocomplywiththesafetyandserviceabilityrequirementsprovidedinSec1.2.4and1.2.5respectively.

1.2.16 PHASEDCONSTRUCTIONWhenabuildingorstructureisplannedoranticipatedtoundergophasedconstruction,structuralmemberstherein

shallbeinvestigatedanddesignedforanyadditionalstressesarisingduetosuchconstruction.

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1.2.17 LOADCOMBINATIONSANDSTRESSINCREASEEvery building, structure, foundation or components thereof shall be designed to sustain, within the allowable

stress or specified strength (under factored load), the most unfavourable effects resulting from various

combinations ofloadsspecifiedinsection2.7.Exceptotherwisepermittedorrestrictedbyanyothersectionofthis

Code,maximumincreaseintheallowablestress shallbe33%whenallowableorworkingstressmethodofdesignis

followed.Forsoilstressesduetofoundationloads,loadcombinationsandstressincreasespecifiedinSec2.7.4for

allowablestressdesignmethodshallbeused.

1.3 STRUCTURALSYSTEMS1.3.1 GENERALEverystructureshallhaveoneofthebasicstructuralsystemsspecified inSec1.3.2oracombinationthereof.The

structuralconfigurationshallbeasspecifiedinSec1.3.4withthelimitationsimposedinSec2.5.7.4.

1.3.2 BASICSTRUCTURALSYSTEMSStructuralsystemsforbuildingsandotherstructuresshallbedesignatedasoneofthetypesAtoGlisted inTable

1.3.1. Each type is again classified as shown in the table by the types of vertical elements used to resist lateral

forces.Abriefdescriptionofdifferentstructuralsystemsarepresentedinfollowingsubsections.

Table1.3.1:BasicStructuralSystemsA.BEARINGWALLSYSTEMS(noframe)

1. Special reinforced concrete shear walls

2. Ordinary reinforced concrete shear walls

3. Ordinary reinforced masonry shear walls

4. Ordinary plain masonry shear walls

B.BUILDINGFRAMESYSTEMS (withbracingorshearwall)1. Steel eccentrically braced frames, moment resisting connections atcolumns away from links2. Steel eccentrically braced frames, non-moment-resisting, connections at

columns away from links3. Special steel concentrically braced frames

4. Ordinary steel concentrically braced frames5. Special reinforced concrete shear walls

6. Ordinary reinforced concrete shear walls

7. Ordinary reinforced masonry shear walls

8. Ordinary plain masonry shear walls

C.MOMENTRESISTINGFRAMESYSTEMS(noshearwall)1. Special steel moment frames

2. Intermediate steel moment frames

3. Ordinary steel moment frames4. Special reinforced concrete moment frames

5. Intermediate reinforced concrete moment frames

6. Ordinary reinforced concrete moment frames

D.DUALSYSTEMS:SPECIALMOMENTFRAMESCAPABLEOFRESISTINGATLEAST25%OF

PRESCRIBEDSEISMICFORCES(withbracingorshearwall)1. Steel eccentrically braced frames2. Special steel concentrically braced frames

3. Special reinforced concrete shear walls

4. Ordinary reinforced concrete shear walls

E.DUALSYSTEMS:INTERMEDIATEMOMENTFRAMESCAPABLEOFRESISTINGATLEAST25%

OFPRESCRIBEDSEISMICFORCES(withbracingorshearwall)1. Special steel concentrically braced frames

2. Special reinforced concrete shear walls

3. Ordinary reinforced masonry shear walls

4. Ordinary reinforced concrete shear walls

F.DUALSHEARWALLFRAMESYSTEM:ORDINARYREINFORCEDCONCRETEMOMENT

FRAMESANDORDINARYREINFORCEDCONCRETESHEARWALLS

G.STEELSYSTEMSNOTSPECIFICALLYDETAILEDFORSEISMICRESISTANCE

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1.3.2.1 BEARINGWALLSYSTEMA structural system having bearing walls or bracing systems without a complete vertical load carrying frame to

supportgravityloads.Resistancetolateralloadsisprovidedbyshearwallsorbracedframes.

1.3.2.2 BUILDINGFRAMESYSTEMA structural system with an essentially complete space frame providing support for gravity loads. Resistance to

lateralloadsisprovidedbyshearwallsorbracedframesseparately.

1.3.2.3 MOMENTRESISTINGFRAMESYSTEMAstructuralsystemwithanessentiallycompletespaceframeprovidingsupportforgravityloads.Momentresisting

framesalso provideresistancetolateralloadprimarilybyflexuralactionofmembers,andmaybeclassifiedasone

ofthefollowingtypes:

a) SpecialMomentResistingFrames(SMRF)b) IntermediateMomentResistingFrames(IMRF)c) OrdinaryMomentResistingFrames(OMRF).

The framing system, IMRF and SMRF shall have special detailing to provide ductile behaviour conforming to the

provisions of Sec8.3 and 10.20 forconcrete and steel structures respectively. OMRF need not conform to these

specialductilityrequirementsofChapter8or10.

1.3.2.4 DUALSYSTEMAstructuralsystemhavingacombinationofthefollowingframing systems:

a) Momentresistingframes(SMRF,IMRForsteelOMRF),andb) Shearwallsorbracedframes.

The

two

systems

specified

in

(a)

and

(b)

above

shall

be

designed

to

resist

the

total

lateral

force

in

proportion

to

their

relativerigiditiesconsideringtheinteractionofthedualsystematalllevels. However,themoment resistingframes

shallbecapableofresistingatleast25%oftheapplicabletotalseismiclateralforce,evenwhenwindoranyother

lateralforcegovernsthedesign.

1.3.2.5 SPECIALSTRUCTURALSYSTEM:AstructuralsystemnotdefinedabovenorlistedinTable1.3.1andspeciallydesignedtocarrythelateralloads,such

astubeintube,bundledtube,etc.

1.3.2.6 NON-BUILDINGSTRUCTURALSYSTEMAstructuralsystemusedforpurposesotherthaninbuildingsandconformingtoSec1.5.4.8,1.5.4.9,2.4and2.5.

1.3.3 COMBINATIONOFSTRUCTURALSYSTEMSWhendifferentstructuralsystemsofSec1.3.2arecombinedfor incorporation intothesamestructure,designof

thecombinedseismicforceresistingsystemshallconformtotheprovisionsofSec2.5.7.5.

1.3.4 STRUCTURALCONFIGURATIONSBased on the structural configuration, each structure shall be designated as a regular or irregular structure as

definedbelow:

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1.3.4.1 REGULARSTRUCTURESRegularstructureshavenosignificantphysicaldiscontinuitiesorirregularitiesinplanorverticalconfigurationorin

theirlateralforceresistingsystems.TypicalfeaturescausingirregularityaredescribedinSec1.3.4.2.

1.3.4.2 IRREGULARSTRUCTURESIrregularstructureshaveeithervertical irregularityorplan irregularityorboth intheirstructuralconfigurationsor

lateralforceresistingsystems.

1.3.4.2.1 VerticalIrregularityStructureshavingoneormoreoftheirregularfeatureslistedinTable1.3.2shallbedesignatedashavingavertical

irregularity.

Table1.3.2:VerticalIrregularitiesofStructuresVerticalIrregularity Reference*

Type Definition SectionI StiffnessIrregularity (SoftStorey):A soft storey is one in which the lateral stiffness is less than 70 per cent of that

in the storey above or less than 80 per cent of the average stiffness of thethree storeys above.

2.5.7 to 2.5.14and 2.5.19

II MassIrregularity :Mass irregularity shall be considered to exist where the effective mass of anystorey is more than 150 per cent of the effective mass of an adjacent storey. Aroof which is lighter than the floor below need not be considered.

2.5.7 to 2.5.14

III VerticalGeometricIrregularity :Vertical geometric irregularity shall be considered to exist where horizontaldimension of the lateral forceresisting system in any storey is more than 130per cent of that in an adjacent storey, onestorey penthouses need not beconsidered.

2.5.7 to 2.5.14

IV In-PlaneDiscontinuityinVerticalLateralForce-ResistingElement:An inplane offset of the lateral loadresisting elements greater than thelength of those elements.

2.5.7 to 2.5.14

VaDiscontinuityinCapacity (WeakStorey) :

A weak storey is one in which the storey strength is less than 80 per cent ofthat in the storey above. The storey strength is the total strength of allseismicresisting elements sharing the storey shear for the direction underconsideration.

2.5.7 to 2.5.14and 2.5.19

Vb ExtremeDiscontinuityinCapacity (VeryWeakStorey) :A very weak storey is one in which the storey strength is less than 65 per centof that in the storey above.

2.5.7 to 2.5.14and 2.5.19

1.3.4.2.2 PlanIrregularityStructureshavingoneormoreof the irregular features listed in Table 1.3.3shallbedesignatedas havinga plan

irregularity.

Table1.3.3:Plan Irregularities ofStructuresPlanIrregularity Reference*

Type Definition SectionI Torsional Irregularity (to be considered when diaphragms are not

flexible):

Torsional irregularity shall be considered to exist when the maximum storeydrift, computed including accidental torsion, at one end of the structure is morethan 1.2 times the average of the storey drifts at the two ends of the structure.

2.5.7 to 2.5.14

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II ReentrantCorners:Plan configurations of a structure and its lateral forceresisting system containreentrant corners, where both projections of the structure beyond a reentrantcorner are greater than 15 per cent of the plan dimension of the structure inthe given direction.

2.5.7 to 2.5.14

III DiaphragmDiscontinuity :Diaphragms with abrupt discontinuities or variations in stiffness, includingthose having cutout or open areas greater than 50 per cent of the grossenclosed area of the diaphragm, or changes in effective diaphragm stiffness ofmore than 50 per cent from one storey to the next.

2.5.7 to 2.5.14

IV Out-of-planeOffsets :Discontinuities in a lateral force path, such as outofplane offsets of thevertical elements.

2.5.7 to 2.5.14

V NonparallelSystems :The vertical lateral loadresisting elements are not parallel to or symmetricabout the major orthogonal axes of the lateral forceresisting system.

2.5.7 to 2.5.14

1.4 DESIGNFORGRAVITYLOADS1.4.1 GENERALDesign of buildings and components thereof for gravity loads shall conform to the requirements of this section.

Gravity loads, such as dead load and live loads appliedat the floors or roof of a building shall be determined in

accordancewiththeprovisionsofChapter2.

1.4.2 FLOORDESIGNFloorslabsanddecksshallbedesignedforthefulldeadandliveloadsasspecified inSec2.2and2.3respectively.

Floor supporting elements such as beams,joists, columns etc. shall be designed for the full dead load and the

appropriately reduced live loads set forth by the provisions of Sec 2.3.13. Design of floor elements shall also

conformtothefollowingprovisions:

a) UniformlyDistributedLoads: Whereuniformfloorloadsareinvolved,considerationmaybelimitedtofulldeadloadonallspansincombinationwithfullliveloadonadjacentspans and

on alternate spans to determine the most unfavourable effect of stresses in the member

concerned.

b) ConcentratedLoads : Provisionshallbemade indesigningfloorsforaconcentrated loadasset forth in Sec 2.3.5 applied at a location wherever this load acting upon an otherwise

unloaded floor would produce stresses greater than those caused by the uniform load

requiredtherefore.

c) PartitionLoads :Loads due to permanent partitions shall betreatedasa dead loadappliedoverthefloorasauniformlineloadhavinganintensityequaltotheweightpermetrerunof

thepartitionsasspecifiedinSec2.2.5.Loadsforlightmovablepartitionsshallbedetermined

inaccordancewiththeprovisionsofSec2.3.6.

d) Design of Members : Floor members, such as slabs or decks, beams,joists etc. shall bedesignedtosustaintheworsteffectofthedeadplusliveloadsoranyotherloadcombinations

asspecifiedinSec2.7.Wherefloorsareusedasdiaphragmstotransmitlateralloadsbetween

various resisting elements, those loads shall be determined following the provisions of Sec

1.7.3.8. Detailed design of the floor elements shall be performed using the procedures

providedinChapters4through13for variousconstructionmaterials.

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1.4.3 ROOFDESIGNRoofs and their supporting elements shall be designed to sustain, within their allowable stresses or specified

strengthlimits,alldead loadsand live loadsassetoutbytheprovisionsofSec2.2and2.3respectively.Designof

roofmembersshallalsoconformtothefollowingrequirements:

a) Application of Loads : When uniformly distributed loads are considered for the design ofcontinuousstructuralmembers,loadincludingfulldeadloadsonallspansincombinationwith

fullliveloadsonadjacentspansandonalternate span,shallbeinvestigatedtodeterminethe

worst effects of loading. Concentrated roof live loads and special roof live loads, where

applicable,shallalsobeconsideredindesign.

b) UnbalancedLoading:Effectsduetounbalancedloadsshallbeconsideredinthedesignofroofmembersandconnectionswheresuchloadingwillresultinmorecriticalstresses.Trussesand

archesshallbedesignedtoresistthestressescausedbyuniformliveloadsononehalfofthe

span if such loading results in reverse stresses, or stresses greater in any portion than the

stressesproducedbythisunitliveloadwhenappliedupontheentirespan.

c) RainLoads: Roofs,wherepondingofrainwaterisanticipatedduetoblockageofroofdrains,excessivedeflectionor insufficientslopes, shall bedesignedtosupportsuch loads.Loadson

roofs due to rain shall be determined in accordance with the provisions of Sec 2.6.3. In

additiontothedeadloadoftheroof,eithertheroofliveloadortherainload,whicheverisof

higherintensity,shallbeconsideredindesign.

1.4.4 REDUCTIONOFLIVELOADSThedesign live loadsspecified inSec2.3,maybereducedtoappropriatevaluesaspermittedbytheprovisionsof

Sec2.3.13.andSec.2.3.14.

1.4.5 POSTINGOFLIVELOADSIneverybuilding,ofwhichthefloorsorpartsthereofhaveadesignliveloadof3.5kN/m2ormore,andwhichare

used as library stack room, file room, parking garage, machine or plant room, or used for industrial or storage

purposes,theownerofthebuildingshallensurethatthe live loadsforwhichsuchspacehasbeendesigned,are

postedondurablemetalplatesasshowninFig1.1,securelyaffixedinaconspicuousplaceineachspacetowhich

theyrelate.Ifsuchplatesarelost,removed,ordefaced,theownershallberesponsibletohavethemreplaced.

1.4.6 RESTRICTIONSONLOADINGThe building owner shall ensure that the live load for which a floor or roof is or has been designed, will not be

exceededduringitsuse.

1.4.7 SPECIALCONSIDERATIONSIntheabsenceofactualdeadandliveloaddata,theminimumvaluesoftheseloadsshallbethosespecifiedinSec

2.2and2.3.Inaddition,specialconsiderationshallbegiventothefollowingaspectsofloadinganddueallowances

shallbemadeindesignifoccurrenceofsuchloadingisanticipatedafterconstructionofabuilding:

a) IncreaseinDeadLoad:Actualthicknessoftheconcreteslabsorothermembersmaybecomelargerthanthedesignedthicknessduetomovementsordeflectionsoftheformworkduring

construction.

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1.5.3.1 DIRECTIONOFWINDStructural design for wind forces shall be based on the assumption that wind may blow from any horizontal

direction.

1.5.3.2 DESIGNCONSIDERATIONSDesignwindloadontheprimaryframingsystemsandcomponentsofabuildingorstructureshallbedeterminedon

thebasisoftheproceduresprovidedinSec2.4consideringthebasicwindspeed,shapeandsizeofthebuilding,and

theterrainexposureconditionofthesite.Forslenderbuildingsandstructures,dynamicresponsecharacteristics,

such as fundamental natural frequency, shall be determined for calculating the gust response coefficient. Load

effects, such as forces, moments, deflections etc. on various components of the building due to wind shall be

determinedfromastaticanalysisofthestructureasspecifiedinSec1.2.7.1.

1.5.3.3 SHIELDINGEFFECTReductions in wind pressure on buildings and structures due to apparent direct shielding effects of the up wind

obstructions,suchasmanmadeconstructionsornaturalterrainfeatures,shallnotbepermitted.

1.5.3.4 DYNAMICEFFECTSDynamic wind forces such as that from alongwind vibrations caused by the dynamic windstructure interaction

effects, as set forth by the provisions of Sec 2.4.10, shall be considered in the design of regular shaped slender

buildings.Forotherdynamiceffectssuchascrosswindortorsionalresponsesasmaybeexperiencedbybuildings

orstructureshavingunusualgeometricalshapes(i.e.verticalorplan irregularitieslistedinTables1.3.2and1.3.3),

responsecharacteristics,orsitelocations,structuraldesignshallbemadebasedontheinformationobtainedeither

fromother reliable referencesor from windtunnel testspecified inSec 1.5.3.5below, complying withthe other

requirementsofthissection.

1.5.3.5 WINDTUNNELTESTProperlyconductedwindtunneltestsshallberequiredforthosebuildingsorstructureshavingunusualgeometric

shapes,responsecharacteristics,orsitelocationsforwhichcrosswindresponsesuchasvortexshedding,galloping

etc. warrant special consideration, and for which no reliable literature for the determination of such effects is

available. This test is also recommended for those buildings or structures for which more accurate windloading

informationisdesiredthanthosegiveninthissectionandinSec2.4.

Testsforthedeterminationofmeanandfluctuatingcomponentsofforcesandpressuresshallbeconsideredtobe

properlyconductedonlyifthefollowing requirementsaresatisfied:

a) Thenaturalwindhasbeenmodelledtoaccountforthevariationofwindspeedwithheight,b) The intensity ofthe longitudinal components of turbulence has been taken into consideration in the

model,

c) The geometricscaleofthestructuralmodel isnotmorethanthreetimesthegeometric scaleofthelongitudinal component ofturbulence,

d) Theresponsecharacteristicsofthewindtunnelinstrumentationareconsistentwiththemeasurements tobemade, and

e) The Reynolds number is taken into consideration when determining forces and pressures on thestructuralelements.

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Tests for the purpose of determining the dynamic response of a structure shall be considered to be properly

conductedonly ifrequirements (a)through (e) aboveare fulfilledand, inaddition,the structural model is scaled

withdueconsiderationtolength,distributionofmass,stiffnessanddamping ofthestructure.

1.5.3.6 WINDLOADSDURINGCONSTRUCTIONBuildings, structures and portions thereof under construction, and construction structures such as formwork,

stagingetc.shallbeprovidedwithadequatetemporarybracingsorotherlateralsupportstoresistthewindloadon

themduringtheerectionandconstructionphase.

1.5.3.7 MASONRYCONSTRUCTIONINHIGH-WINDREGIONSDesignandconstructionofmasonrystructuresinhighwindregionsshallconformtotherequirementsofrelevant

sectionsofChapter7.

1.5.3.8 HEIGHTLIMITSUnlessotherwisespecifiedelsewhereinthisCode,noheightlimitsshallbeimposed,ingeneral,onthedesignand

constructionofbuildingsorstructurestoresistwindinducedforces.

1.5.4 DESIGNFOREARTHQUAKEFORCESDesign of structures and components thereof to resist the effects of earthquake forces shall comply with the

requirementsofthissection.

1.5.4.1 BASICDESIGNCONSIDERATIONForthepurposeofearthquakeresistantdesign,eachstructureshallbeplacedinoneoftheseismiczonesasgivenin

Sec 2.5.6.2 and assigned with a structure importance category as set forth in Sec 2.5.7.1. The seismic forces on

structuresshallbedeterminedconsideringseismiczoning,sitesoilcharacteristics,structureimportance,structural

systemsandconfigurations,heightanddynamicpropertiesofthestructureasprovided inSec2.5.Thestructural

systemandconfigurationtypesforabuildingorastructureshallbedeterminedinaccordancewiththeprovisionsofSec2.5.7.4.Otherseismicdesignrequirementsshallbethosespecifiedinthissection.

1.5.4.2 REQUIREMENTSFORDIRECTIONALEFFECTSThedirectionsofapplicationofseismicforcesusedinthedesignshallbethosewhichwillproducethemostcritical

loadeffects.Earthquakeforcesactinbothprincipaldirectionsofthebuildingsimultaneously.Designprovisionsfor

consideringearthquakecomponentinorthogonaldirectionshavebeenprovidedinSec2.5.15.1.

1.5.4.3 STRUCTURALSYSTEMANDCONFIGURATIONREQUIREMENTSSeismicdesignprovisionsimposethefollowinglimitationsontheuseofstructuralsystemsandconfigurations:

a) The structural system used shall satisfy requirements of the Seismic Design Category (defined inSec.2.5.7.2)andheightlimitationsgiveninSec2.5.7.4.

b) StructuresassignedtoSeismicDesignCategoryDhavingverticalirregularityTypeVbofTable1.3.2shall not be permitted. Structures with such vertical irregularity may be permitted for Seismic

DesignCategoryBorCbutshallnotbeovertwostoriesor9minheight.

c) Structures having irregular features described in Table 1.3.2 or 1.3.3 shall be designed incompliancewiththeadditionalrequirementsofthesectionsreferencedintheseTables.

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d) Special Structural Systems defined in Sec 1.3.2.5 may be permitted if it can be demonstrated byanalytical and test data to be equivalent, with regard to dynamic characteristics, lateral force

resistance and energy absorption, to one of the structural systems listed in Table 2.5.7, for

obtaininganequivalentRandCdvalueforseismicdesign.

1.5.4.4 METHODSOFANALYSISEarthquake forces and their effects on various structural elements shall be determined by using either a static

analysismethodoradynamicanalysismethodwhicheverisapplicablebasedonthelimitationssetforthinSec2.5.7

through2.5.14andconformingtoSec1.2.7.

1.5.4.5 MINIMUMDESIGNSEISMICFORCEThe minimum design seismic forces shall be those determined in accordance with the Sec 2.5.7 through 2.5.14

whicheverisapplicable.

1.5.4.6 DISTRIBUTIONOFSEISMICFORCESThetotallateralseismicforcesandmomentsshallbedistributedamongvariousresistingelementsatanyleveland

alongtheverticaldirectionofabuildingorstructureinaccordancewiththeprovisionsofSec2.5.7through2.5.14

asappropriate.

1.5.4.7 VERTICALCOMPONENTSOFSEISMICFORCESDesignprovisionsforconsideringverticalcomponentofearthquakegroundmotionisgiveninSec2.5.15.2

1.5.4.8 HEIGHTLIMITSHeight limitationsfordifferentstructuralsystemsaregiven inTable2.5.7ofSec2.5.7.4ofPart6ofthiscodeasa

functionofseismicdesigncategory.

1.5.4.9 NON-BUILDINGSTRUCTURESSeismiclateralforceonnonbuildingstructuresshallbedeterminedinaccordancewiththeprovisionsofChapter15

ofASCE7 05.However,provisionsofChapter15ofASCE705maybesimplified,consistentwiththeprovisionsof

Section2.5ofPart6ofthiscode.Otherdesignrequirementsshallbethoseprovidedinthischapter.

1.5.5 OVERTURNINGREQUIREMENTSEverystructureshallbedesignedtoresisttheoverturningeffectscausedbywindorearthquakeforcesspecifiedin

Sec2.4and2.5respectivelyaswellotherlateralforceslikeearthpressure,tidalsurgeetc.Theoverturningmoment

Mx atanystoreylevelxofabuildingshallbedeterminedas:

1.5.1

where,

hi,hx,hn = Heightinmetresatlevel i, xor nrespectively.Fi = Lateralforceappliedatleveli,i=1ton.

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Atanylevel,theincrementofoverturningmomentshallbedistributedtothevariousresistingelementsinthesame

mannerasthedistributionofhorizontalshearprescribedinSec2.5.9.5.Overturningeffectsoneveryelementshall

becarrieddowntothefoundationlevel.

1.5.6 DRIFTANDBUILDINGSEPARATION1.5.6.1 STOREYDRIFTLIMITATIONStoreydriftisthehorizontaldisplacementofonelevelofabuildingorstructurerelativetothelevelaboveorbelow

duetothedesigngravity(deadandliveloads)orlateralforces(e.g.windandearthquakeloads).Exceptotherwise

permitted in Sec 1.3.4.2.1 calculated storey drift shall include both translational and torsional deflections and

conformtothefollowingrequirements:

1. Storeydrift, ,forloadsotherthanearthquakeloads, shallbelimitedasfollows: 0.005h for T

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1.6 DESIGNFORMISCELLANEOUSLOADS1.6.1 GENERALBuildings,structuresandcomponentsthereof,whensubjectto loadsotherthandead, live,windandearthquake

loads,shallbedesignedinaccordancewiththeprovisionsofthissection.Miscellaneousloads,suchasthosedueto

temperature,rain,floodandsurgeetc.onbuildingsorstructures,shallbedeterminedinaccordancewithSec2.6.Structural memberssubjecttomiscellaneousloads,notspecifiedinSec2.6shallbedesignedusingwellestablished

methods giveninanyreliablereferences,andcomplyingwiththeotherrequirementsofthisCode.

1.6.2 SELF-STRAININGFORCESSelfstraining forces such as those arising due to assumed differential settlements of foundations and from

restraineddimensionalchangesduetotemperature,moisture,shrinkage,creep,andsimilareffects,shallbetaken

intoconsiderationinthedesignofstructural members.

1.6.3 STRESSREVERSALANDFATIGUEStructural members andjoints shall be investigated and designedagainstpossible stressreversals caused dueto

various construction loads. Where required, allowance shall be made in the design to account for the effects of

fatigue.Theallowablestressmaybeappropriatelyreducedtoaccountforsucheffectsinthestructuralmembers.

1.6.4 FLOOD,TIDAL/STORMSURGEANDTSUNAMIBuildings, structures and components thereof shall be designed, constructed and anchored to resist flotation,

collapseoranypermanentmovementduetoloadsincludingflood,tidal/Stormsurgeandtsunami,whenapplicable.

Structuralmembersshallbedesignedtoresistbothhydrostaticandsignificanthydrodynamic loadsandeffectsof

buoyancyresultingfromfloodorsurge.Floodandsurge loadsonbuildingsandstructuresshallbedetermined in

accordance with Sec2.6.4. Loadcombination including flood and surge loads shall conform toSec2.7.Designof

foundationstosustaintheseloadeffectsshallconformtotheprovisionsofSec1.8.

Stability against overturning and sliding caused due to wind and flood or surge loads simultaneously shall be

investigated,andsucheffectsshallberesistedwithaminimumfactorofsafetyof1.5,consideringdeadloadonly.

1.6.5 RAINLOADSRoofsofthebuildingsandstructuresaswellastheirothercomponentswhichmayhavethecapabilityofretaining

rainwatershallbedesignedforadequategravityloadinducedbyponding.Roofsandsuchothercomponentsshall

beanalysedanddesignedforloadduetopondingcausedbyaccidentalblockageofdrainagesystemcomplyingwith

Sec.2.6.3.

1.6.6 OTHERLOADSBuildingsandstructuresandtheircomponentsshallbeanalyzedanddesignedforstressescausedbythefollowingeffects

a. TemparatureEffects(Sec2.6.5).b. SoilandHydrostaticPressure(Sec2.6.6).c. ImpactsandCollisionsd. Explosions(Sec2.6.7).

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e. Firef. VerticalForcesonAirRaidShelters(Sec2.6.8).g. LoadsonHelicopterLandingAreas(Sec2.6.9).h. ErectionandConstructionLoads(Sec2.6.10).i. MovingLoadsforCraneMovementsj. CreepandShrinkagek. DynamicLoadsduetoVibrationsl. ConstructionLoads

Designofbuildingsandstructuresshallincludeloadingandstressescausedbytheaboveeffectsinaccordancewith

theprovisionssetforthinChapter2.

1.7 DETAILEDDESIGNREQUIREMENTS1.7.1 GENERALAll structural framing systems shall comply with the requirements of this section. Only the elements of the

designated lateral force resisting systems can be used to resist design lateral forces specified in Chapter 2. The

individual componentsshallbedesignedtoresisttheprescribedforcesactingonthem.Designofcomponentsshall

alsocomplywiththespecificrequirementsforthematerialscontainedinChapters4through13.Inaddition,such

framingsystemsandcomponentsshallcomplywiththedesignrequirementsprovidedinthissection.

1.7.2 STRUCTURALFRAMINGSYSTEMSThebasicstructuralsystemsaredefined inSec1.3.2andshowninTable1.3.1,andeachtypeissubdividedbythe

typesofframingelementsusedtoresistthelateralforces.Thestructuralsystemusedshallsatisfyrequirementsof

seismicdesigncategoryandheight limitations indicated inTable 2.5.7.Specialframingrequirementsaregiven in

thefollowingsectionsinadditiontothoseprovidedinChapters4through13.

1.7.3 DETAILINGREQUIREMENTSFORCOMBINATIONSOF STRUCTURALSYSTEMS:

Forcomponentscommontodifferentstructuralsystems,amorerestrictivedetailingshallbeprovided.

1.7.3.1 CONNECTIONSTORESISTSEISMICFORCESConnections which resist prescribed seismic forces shall be designed in accordance with the seismic design

requirements provided in Chapters 4 through 13. Detailed sketches for these connections shall be given in the

structuraldrawings.

1.7.3.2 DEFORMATIONCOMPATIBILITYAllframingelementsnotrequiredbydesigntobepartofthelateralforceresistingsystem,shallbeinvestigatedand

showntobeadequateforverticalloadcarryingcapacitywhensubjectedtolateraldisplacementsresultingfromthe

seismic lateral forces. For designs using working stress methods, this capacity may be determined using an

allowablestressincreaseof30percent.PDeltaeffectsonsuchelementsshallbeaccountedfor.

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a. AdjoiningRigidElements : Momentresistingframesmaybeenclosedoradjoinedbymorerigidelementswhichwouldtendtoprevent aspaceframefromresistinglateralforceswhereitcanbe

shownthattheactionorfailureofthemorerigidelementswillnotimpairtheverticalandlateral

loadresistingabilityofthespaceframe.

b. ExteriorElements:Exteriornonbearing,nonshearwallpanelsorelementswhichareattachedtoorenclosetheexterior ofastructure,shallbedesignedtoresisttheforcesaccordingtoSec.2.5.17of Chapter 2, if seismic forces are present, and shall accommodate movements of the structure

resulting from lateral forces or temperature changes. Such elements shall be supported by

structural members or by mechanical connections and fasteners joining them to structural

membersinaccordancewiththefollowingprovisions:

i. Connectionsandpaneljointsshallallowforarelativemovementbetweenstoreysofnotlessthan two times the storey drift caused by wind forces or design seismic forces, or 12 mm,

whicheverisgreater.

ii. Connections to permit movement in the plane of the panel for storey drift shall be eitherslidingconnectionsusingslottedoroversizedholes,connectionswhichpermitmovementby

bendingofsteel,orotherconnectionsprovidingequivalentslidingandductilitycapacity.

iii. Bodies of connections shall have sufficient ductility and rotation capability to preclude anyfractureoftheanchoringelementsorbrittlefailuresatornearweldings.

iv. Bodies of the connection shall be designed for 1.33 times the seismic force determined bySec.2.5.17ofChapter2,orequivalent.

v. All fasteners in the connection system, such as bolts, inserts, welds, dowels etc. shall bedesignedfor4timestheforcesdeterminedbySec.2.5.17ofChapter2orequivalent.

vi. Fastenersembeddedinconcreteshallbeattachedto,orhookedaroundreinforcingsteel,orotherwiseterminatedsoastotransferforcestothereinforcingsteeleffectively.

1.7.3.3 TIESANDCONTINUITYAllpartsofastructureshallbe interconnected.Theseconnectionsshallbecapableoftransmittingtheprescribed

lateralforcetothelateralforceresistingsystem.Individualmembers,includingthosenotpartoftheseismicforce

resisting system, shall be provided with adequate strength to resist the shears, axial forces, and moments

determined in accordancewith this standard.Connectionsshall developthe strengthoftheconnectedmembers

andshallbecapableoftransmittingtheseismicforce(Fp)inducedbythepartsbeingconnected.

1.7.3.4 COLLECTORELEMENTSCollector elements shall be provided which are capable of transferring the lateral forces originating in other

portionsofthestructuretotheelementprovidingtheresistancetothoseforces.

1.7.3.5 CONCRETEFRAMESWhenconcreteframesareprovidedbydesigntobepartofthelateralforceresistingsystem,theyshallconformto

thefollowingprovisions:

a) InSeismicZones3and4theseframesshallbedesignedasspecialmomentresistingframes(SMRF).b) InSeismicZone2theyshall,asaminimum,beintermediatemomentresistingframes(IMRF).

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1.7.3.6 ANCHORAGEOFCONCRETEANDMASONRYSTRUCTURALWALLSThe concrete and masonry structural walls shall be anchored to supporting construction. The anchorage shall

provide a positive direct connection between the wall and floor or roof and shall be capable of resisting the

horizontal forces specified in Secs 2.4.13 and 2.5.17, or a minimum force of 4.09 kN/m of wall. Walls shall be

designedtoresistbendingbetweenanchorswheretheanchorspacingexceeds1.2m.Inmasonrywallsofhollow

units or cavity walls, anchors shall be embedded in a reinforced grouted structural element of the wall.Deformations ofthe floor androofdiaphragmsshallbe considered in thedesign of the supported walls and the

anchorageforcesinthediaphragmsshallbedeterminedinaccordancewithSec1.7.3.9below.

1.7.3.7 BOUNDARYMEMBERSSpecially detailed boundary members shall be considered for shearwalls and shearwall elements whenever their

designisgovernedbyflexure.

1.7.3.8 FLOORANDROOFDIAPHRAGMSDeflection in the plane of the diaphragm shall not exceed the permissible deflection of the attached elements.

Permissible deflection shall be that deflection which will permit the attached element to maintain its structural

integrityundertheindividual loadingandcontinuetosupporttheprescribedloads.Designofdiaphragmsshallalso

complywiththefollowingrequirements.

a) DiaphragmForces: Diaphragmsshallbe designedtoresist theseismicforcesgiveninSec2.5orforsimilarnonseismiclateralforces,whicheverisgreater.

b) DiaphragmTies:Diaphragmssupportingconcreteormasonrywallsshallhavecontinuousties,orstruts between the diaphragm chords to distribute the anchorage forces specified in Sec 1.7.3.6

above.Addedchordsmaybeprovidedtoformsubdiaphragmstotransmittheanchorageforcesto

themaincrossties.

c) WoodDiaphragms :Wherewooddiaphragmsareused to laterallysupport concreteormasonrywalls,theanchorageshallconformtoSec1.7.3.6 above.InseismicZones2,3and4thefollowing

requirementsshallalsoapply:

i. Anchorageshallnotbeaccomplishedbyuseoftoenailsornailssubjecttowithdrawal,norshallwoodledgersorframingbeusedincrossgrainbendingorcrossgraintension.

ii. The continuous ties required by paragraph (b) above, shall be in addition to thediaphragmsheathing.

d) Structureshavingirregularitiesi) ForstructuresassignedtoSeismicDesignCategoryDandhavingaplanirregularityofType

I,II,III,orIVinTable1.3.3oraverticalstructuralirregularityofTypeIVinTable1.3.2,the

designforcesdeterminedfromSection2.5.9shallbeincreased25percentforconnections

ofdiaphragms tovertical elementsandtocollectors and forconnectionsofcollectorsto

the vertical elements. Collectors and their connections also shall be designed for these

increased forces unless they are designed for the load combinations with overstrength

factor.

ii) For structures having a plan irregularity of Type II in Table 1.3.3, diaphragm chords andcollectorsshallbedesignedconsideringindependentmovementofanyprojectingwingsof

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thestructure.Eachofthesediaphragmelementsshallbedesignedforthemoresevereof

thefollowingcases:

1. Motionoftheprojectingwingsinthesamedirection.2. Motionoftheprojectingwingsinopposingdirections.

Exception:ThisrequirementmaybedeemedtobesatisfiediftheproceduresofSec2.5.10whenseismicforcesarepresent,in

conjunctionwithathreedimensionalmodel,havebeenusedtodeterminethelateralseismicforcesfordesign.

1.7.3.9 FRAMINGBELOWTHEBASEWhenstructuralframingscontinuebelowthebase,thefollowingrequirementsshallbesatisfied.

a. FramingbetweentheBaseandtheFoundation: Thestrengthandstiffnessoftheframingbetweenthebaseandthefoundationshallnotbelessthanthatofthesuperstructure.Thespecialdetailing

requirements of Sec 8.3 or 10.20, as appropriate for reinforced concrete or steel, shall apply to

columns supporting discontinuous lateral force resisting elements and to SMRF, IMRF, and EBF

systemelementsbelowthebasewhicharerequiredtotransmitthe forcesresulting from lateralloadstothefoundation.

b. Foundations: The foundation shall be capable of transmitting the design base shear and theoverturning forces from the superstructure into the supporting soil, but the short term dynamic

nature of the loads may be taken into account in establishing the soil properties. Sec 1.8 below

prescribestheadditionalrequirementsforspecifictypesoffoundationconstruction.

1.8 FOUNDATIONDESIGNREQUIREMENTS1.8.1 GENERALThe

design

and

construction

of

foundation,

foundation

components

and

connection

between

the

foundation

and

superstructureshallconformtotherequirementsofthissectionandapplicableprovisionsofChapter3andother

portionsofthisCode.

1.8.2 SOILCAPACITIESThe bearingcapacityofthesoil,orthecapacityofthesoilfoundationsystemincludingfooting,pile,pierorcaisson

andthesoil,shallbesufficienttosupportthestructurewithallprescribedloads,consideringthesettlementofthe

structure. For piles, this refers to pile capacity as determined by pilesoil friction and bearing which may be

determinedinaccordancewiththeprovisionsofChapter3.Fortheloadcombinationincludingearthquake,thesoil

capacity shall be sufficient to resist loads at acceptable strains considering both the short time loading and the

dynamicpropertiesofthesoil.Thestressandsettlementofsoilunderappliedloadsshallbedeterminedbasedon

establishedmethodsofSoilMechanics.

1.8.3 SUPERSTRUCTURE-TO-FOUNDATIONCONNECTIONTheconnectionofsuperstructureelementstothefoundationshallbeadequatetotransmittothefoundationthe

forcesforwhichtheelementsarerequiredtobedesigned.

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1.8.4 FOUNDATION-SOILINTERFACEFor regular buildings the base overturning moments for the entire structure or for any one of its lateral force

resisting elements, shall not exceed twothirds of the dead load resisting moment. The weight of the earth

superimposedoverfootingsmaybeusedtocalculatethedeadloadresistingmoment.

1.8.5

SPECIAL

REQUIREMENTS

FOR

FOOTINGS,

PILES

AND

CAISSONS

IN

SEISMIC

ZONES2,3AND4

1.8.5.1 PILESANDCAISSONSPiles and caissons shall be designed for flexure whenever the top of such members is anticipated to be laterally

displacedbyearthquakemotions.ThecriteriaanddetailingrequirementsofSec8.3forconcreteandSec10.20for

steelshallapplyforalengthofsuchmembersequalto120percentoftheflexurallength.

1.8.5.2 FOOTINGINTERCONNECTIONa. Footingsandpilecapsshallbecompletely interconnectedbystruttiesorotherequivalentmeans

torestraintheirlateralmovementsinanyorthogonaldirection.

b. Thestruttiesorotherequivalentmeansasspecified in(a)above,shallbecapableofresisting intensionorcompressionaforcenotlessthan10%ofthelargerfootingorcolumnloadunlessitcan

bedemonstratedthatequivalentrestraintcanbeprovidedbyfrictionalandpassivesoilresistance

orbyotherestablishedmeans.

1.8.6 RETAININGWALLDESIGNRetainingwallsshallbedesignedtoresistthelateralpressureoftheretainedmaterial,underdrainedorundrained

conditions and including surcharge, in accordance with established engineering practice. For such walls, the

minimumfactorofsafetyagainstbaseoverturningandslidingduetoappliedearthpressureshallbe1.5.

1.9 DESIGNANDCONSTRUCTIONREVIEWEverybuildingorstructuredesignedshallhaveitsdesigndocumentspreparedinaccordancewiththeprovisionsof

Sec1.9.1.Theminimumrequirementsfordesignreviewandconstructionobservationshallbethosesetforthunder

Sec1.9.2and1.9.3respectively.

1.9.1 DESIGNDOCUMENTThe designdocumentsshall be prepared andsigned by theengineer responsible for thestructural design of any

building or structure intended for construction. The design documents shall include a design report, material

specificationsandasetofstructuraldrawings,whichshallbepreparedincompliancewithSec1.9.2and1.9.3below

forsubmittaltotheconcernedauthority.Forthepurposeofthisprovision,theconcernedauthorityshallbeeither

personsfromthegovernmentapprovalagencyfortheconstruction,ortheownerofthebuildingorthestructure,or

oneofhisrepresentatives.

1.9.2 DESIGNREPORTThedesignreportshallcontainthedescriptionofthestructuraldesignwithbasicdesign informationasprovided

below,sothatanyotherstructuraldesignengineerwillbeabletoindependently verifythedesignparametersand

themembersizesusingthesebasicinformation.Thedesignreportshallinclude,butnotbelimitedto,thefollowing

:

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a) Name and governing edition of this Code and other referenced standards, and the specificportions, stating chapter, section, clause etc. of these Code and standards including any

specialistreportusedforthestructuraldesign.

b) Methodsusedforthecalculationofallapplied loadsalongwith basic loadcoefficientsandother basic information including any assumption or judgment made under special

circumstances.

c) A drawing of the complete mathematical model prepared in accordance with Sec 1.2.7.1 torepresent the structure and showing on it thevalues, locations and directions of all applied

loads,andlocationofthelateralloadresistingsystemssuchasshearwalls,bracedframesetc.

d) Methodsofstructuralanalysis,andresultsoftheanalysissuchasshear,moment,axialforceetc., used for proportioning various structural members and joints including foundation

members.

e) Methods of structural design including types and strength of the materials of constructionusedforproportioningthestructuralmembers.

f) Reference of the soil report or any other documents used in the design of the structure,foundationorcomponentsthereof.

g) Statementsupportingthevalidityoftheabovedesigndocumentswithdateandsignatureoftheengineerresponsibleforthestructuraldesign.

h) When computer programs are used, to any extent, to aid in the analysis or design of thestructure,thefollowing items,inadditiontoitems(a)through(g)above,shallberequiredto

beincludedinthedesignreport:

i. Asketchofthemathematicalmodelusedtorepresentthestructure inthecomputergeneratedanalysis.

ii. The computer output containing the date of processing, program identification,identification of structures being analysed, all input data, units and final results. The

computer input data shall be clearly distinguished from those computed in the

program.

iii. A program description containing the information necessary to verify the input dataand interpret the results to determine the nature and extent of the analysis and to

checkwhetherthecomputationscomplywiththeprovisionsofthisCode.

iv. Thefirstsheetofeachcomputerrunshallbesignedbytheengineerresponsibleforthestructuraldesign.

1.9.3 STRUCTURALDRAWINGSANDMATERIALSPECIFICATIONSThestructuraldrawingsshallinclude,butnotbelimitedto,thefollowing:

a) Thefirstsheetshallcontain:(1)identificationoftheprojecttowhichthebuildingorthestructure,orportionthereofbelongs,(2)referencetothedesignreportspecifiedinSec1.9.2above,(3)date

ofcompletionofdesign,and(4)identificationandsignaturewithdateoftheengineerresponsible

forthestructuraldesign.

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b) The second sheet shall contain detail material specifications showing : (1) Specified compressivestrength of concrete at stated ages or stages of construction for which each part of structure is

designed (2) Specified strength or grade of reinforcement (3) Specified strength of prestressing

tendonsorwires(4)Specifiedstrengthorgradeofsteel(5)Specifiedstrengthsforbolts,weldsetc.

(6) Specified strength of masonry, timber, bamboo, ferrocement (7) Minimum concrete

compressivestrengthattimeofposttensioning(8)Stressingsequenceforposttensioningtendons

(9) General notes indicating clear cover, development lengths of reinforcements, or any other

design parameter relevant to the member or connection details provided in drawings to be

followed,asapplicable,and(10)identificationandsignaturewithdateoftheengineerresponsible

forthestructuraldesign.

c) Drawing sheets, other than the first two, shall include structural details of the elements of thestructure clearly showing all sizes, crosssections and relative locations, connections,

reinforcements, laps, stiffeners, welding types, lengths and locations etc. whichever is applicable

for a particularconstruction. Floor levels, column centresand offset etc., shall be dimensioned.

Camber of trusses and beams, if required, shall be shown on drawings. For bolt connected

members,connectiontypessuchasslip,critical,tensionorbearingtype,shallbeindicatedonthe

drawing.

d) Drawingsshallbepreparedtoascalelargeenoughtoshowtheinformationclearlyandthescalesshallbemarkedonthedrawingsheets.Ifanyvariationfromthedesignspecificationsprovided in

sheettwooccurs, thedrawingsheet shallbeprovidedadditionallywiththedesignspecifications

includingmaterialtypesandstrength,clearcoveranddevelopment lengthsofreinforcements,or

anyotherdesignparameterrelevanttothememberorconnectiondetailsprovidedinthatdrawing

sheet.Eachdrawingsheetshallalsocontainthesignaturewithdateoftheengineerresponsiblefor

thestructuraldesign.

1.9.4 DESIGNREVIEWThedesigndocumentsspecifiedinSec1.9.1shallbeavailableforreviewwhenrequiredbytheconcernedauthority.

Reviewshallbeaccomplishedbyan independentstructuralengineerqualified forthistaskandappointedbythe

concernedauthority.Designreviewshallbeperformedthroughindependentcalculations,basedontheinformation

provided in the design documents prepared and signed by the original structural design engineer, to verify the

designparameters includingapplied loads,methodsofanalysisanddesign,andfinaldesigndimensionsandother

detailsofthestructuralelements.Thereviewingengineershallalsocheckthesufficiencyandappropriatenessof

thesuppliedstructuraldrawingsforconstruction.

1.9.5 CONSTRUCTIONOBSERVATIONConstruction observation shall be performed by a responsible person who will be a competent professional

appointed

by

the

owner

of

the

building

or

the

structure.

Construction

observation

shall

include,

but

not

be

limited

to,thefollowing:

a. Specificationofanappropriatetestingand inspectionschedulepreparedandsignedwithdatebytheresponsibleperson;

b. Reviewoftestingandinspectionreports;andc. Regular site visit to verify the general compliance of the construction work with the structural

drawingsandspecificationsprovidedinSec1.9.3above.