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DEFINITIONS AND GENERAL EQUIREMENTS1.1 INTRODUCTION

1.1.1 SCOPE

The definitions providing meanings of different terms and general requirements for the structural design of

buildings,structures,andcomponents thereofarespecified in thischapter.Theserequirementsshallapplytoall

buildingsandstructuresor theircomponentsregulatedbythiscode.Allanticipated loadsrequired forstructural

design shallbedetermined inaccordancewith theprovisionsofChapter2.Designparameters required for the

structuraldesignoffoundationelementsshallconformtotheprovisionsofChapter3.Designofstructuralmembers

usingvariousconstructionmaterialsshallcomplywiththe relevantprovisionsofChapters4through13.TheFPS

equivalentsoftheempiricalexpressionsusedthroughoutPart6arelistedinAppendixA.

ThisCodeshallgoverninallmatterspertainingtodesign,construction,andmaterialpropertieswhereverthisCode

is in conflictwith requirements contained inother standards referenced in thisCode.However, in special cases

wherethedesignofastructureoritscomponentscannotbecoveredbytheprovisionsofthiscode,otherrelevant

internationallyacceptedcodesreferredinthiscodemaybeused.

1.1.2

DEFINITIONS

Thefollowingdefinitionsshallprovidethemeaningofcertaintermsusedinthischapter.

BASESHEAR:Totaldesignlateralforceorshearatthebaseofastructure.

BASICWINDSPEED :Threesecondgust speedat10metresabove themean ground level in terrainExposureB

definedinSec2.4.8andassociatedwithanannualprobabilityofoccurrenceof0.02.

BEARINGWALLSYSTEM:Astructuralsystemwithoutacompleteverticalloadcarryingspaceframe.

BRACEDFRAME:Anessentiallyverticaltrusssystemoftheconcentricoreccentrictypewhichisprovidedtoresist

lateralforces.

BUILDINGFRAMESYSTEM:Anessentiallycompletespaceframewhichprovidessupportforloads.

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

COLLECTOR :Amemberor elementused to transfer lateral forces fromaportionofa structure to the vertical

elementsofthelateralforceresistingelements.

BUILDINGS:Structuresthatencloseaspaceandareusedforvariousoccupancies.

DEADLOAD:Theloadduetotheweightofallpermanentstructuralandnonstructuralcomponentsofabuildingor

astructure,suchaswalls,floors,roofsandfixedserviceequipment.

DIAPHRAGM :Ahorizontalornearly horizontal systemacting to transmit lateral forces to thevertical 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.

INTERMEDIATEMOMENTRESISTINGFRAME (IMRF) :Aconcretemomentresisting framedesigned inaccordance

withSec8.3.10.

LIVELOAD:Theloadsuperimposedbytheuseandoccupancyofabuilding.

MOMENTRESISTING FRAME :A frame inwhichmembersandjointsare capableof resisting forcesprimarilyby

flexure.

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

requirementsforductilebehaviour.

PRIMARYFRAMINGSYSTEM:Thatpartofthestructuralsystemassignedtoresistlateralforces.

SHEARWALL:Awalldesignedtoresist lateralforcesparalleltotheplaneofthewall(sometimesreferredtoasa

verticaldiaphragmorastructuralwall).

SLENDERBUILDINGSAND STRUCTURES :Buildingsand structureshavingaheightexceeding 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 ductilebehaviourcomplyingwiththerequirementsofChapter8or10forconcreteorsteelframesrespectively.

SPECIALSTRUCTURALSYSTEM :A structural systemnot listed inTable1.3.1and speciallydesigned 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 SYMBOLSANDNOTATION

The 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 CONSIDERATIONS

1.2.1 GENERAL

Allbuildingsandstructuresshallbedesignedandconstructed inconformancewiththeprovisionsofthissection.

Thebuildingsandportionsthereofshallsupportallloadsincludingdeadloadspecifiedinthischapterandelsewhere

inthisCode.Impact,fatigueandselfstrainingforcesshallbeconsideredwheretheseforcesoccur.

1.2.2

BUILDINGSANDSTRUCTURES

A 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 BUILDINGANDSTRUCTUREOCCUPANCYCATEGORIES

Buildingsandotherstructuresshallbeclassified,basedonthenatureofoccupancy,accordingtoTable1.2.1forthe

purposesofapplying flood,surge,windandearthquakeprovisions.Theoccupancycategories 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 SAFETY

Buildings, structuresand components thereof, shallbedesignedand constructed to support all loads, including

deadloads,withoutexceedingtheallowablestressesorspecifiedstrengths(underapplicablefactoredloads)forthe

materialsofconstructioninthestructuralmembersandconnections.

1.2.5 SERVICEABILITY

Structuralframingsystemsandcomponentsshallbedesignedwithadequatestiffnesstohavedeflections,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 thatpermittedbyTable1.2.2orthenotesthatfollow.Forwindandearthquake loading,storydriftandswayshallbe

limitedinaccordancewiththeprovisionsofSec1.5.6.

1.2.6 RATIONALITY

Structuralsystemsandcomponentsthereofshallbeanalyzed,designedandconstructedbasedonrationalmethods

whichshallinclude,butnotbelimitedto,theprovisionsofSec1.2.7

1.2.7 ANALYSIS

Analysisof the structural systems shallbemade fordetermining the loadeffectson the resistingelementsand

connections, basedonwellestablishedprinciplesofmechanicstakingequilibrium,geometriccompatibilityandboth

shortandlongtermpropertiesoftheconstruction materialsintoaccountandincorporatingthefollowing:

1.2.7.1 MATHEMATICALMODEL

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

propertiesofthestructurewhichisadequatetoprovideacompleteloadpathcapableoftransferringallloadsand

forces from theirpoints of origin to the loadresisting elements forobtaining various load effects. Fordynamic

analysis,mathematical modelshallalso incorporatetheappropriatelydistributedmassanddampingpropertiesof

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thestructureadequateforthedeterminationofthesignificantfeaturesof itsdynamicresponse.Allbuildingsand

structuresshallbe thusananlyzedpreferablyusinga threedimensionalcomputerizedmodel 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,WindandEarthquakeLoads

NatureofOccupancyOccupancy

Category

Buildingsandotherstructuresthatrepresentalowhazardtohumanlifeintheeventoffailure,including,butnotlimited

to:

Agriculturalfacilities Certaintemporaryfacilities Minorstoragefacilities

I

AllbuildingsandotherstructuresexceptthoselistedinOccupancyCategoriesI,III,andIV II

Buildingsandotherstructuresthatrepresentasubstantialhazardtohumanlifeintheeventoffailure,including,butnot

limitedto:

Buildingsandotherstructureswheremorethan300peoplecongregateinonearea Buildingsandotherstructureswithdaycarefacilitieswithacapacitygreaterthan150 Buildingsandotherstructureswithelementaryschoolorsecondaryschoolfacilitieswithacapacitygreaterthan250 Buildingsandotherstructureswithacapacitygreaterthan500forcollegesoradulteducationfacilities Healthcarefacilitieswithacapacityof50ormoreresidentpatients,butnothavingsurgeryoremergency

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 Designatedemergencypreparedness,communication,andoperationcentersandotherfacilitiesrequiredfor

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,ordisposeof such substancesashazardous fuels,hazardous chemicals,or hazardouswaste) containinghighly toxicsubstanceswhere the quantityof thematerialexceeds a thresholdquantityestablishedby the authorityhavingjurisdiction.

IV

aCogenerationpowerplantsthatdonotsupplypoweronthenationalgridshallbedesignatedOccupancyCategoryII.

1.2.7.2

LOADSAND

FORCES

Allprescribed 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-STRUCTUREINTERACTION

Soilstructure interactioneffects,where required, shallbe included in theanalysisbyappropriately including the

properlysubstantiatedpropertiesofsoilintothemathematicalmodelspecifiedinSec.1.2.7.1above.

1.2.8 DISTRIBUTIONOFHORIZONTALSHEAR

Thetotallateralforceshallbedistributedtothevariouselementsofthelateralforceresistingsysteminproportion

totheirrigiditiesconsideringtherigidityofthehorizontalbracingsystemsordiaphragms.

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1.2.9 HORIZONTALTORSIONALMOMENTS

Structural systemsand components shallbedesigned to sustainadditional forces resulting from torsiondue to

eccentricitybetween thecentreofapplicationof the lateral forcesand thecentreof rigidityof the lateral force

resistingsystem.Forcesshallnotbedecreaseddue to torsionaleffects.Foraccidental torsioneffectson seismic

forces,requirementsshallconformtoSec2.5.9.6

1.2.10 STABILITYAGAINSTOVERTURNINGANDSLIDING

Everybuildingorstructureshallbedesignedtoresisttheoverturningandslidingeffectscausedbythelateralforces

specifiedinthischapter.

1.2.11

ANCHORAGE

Anchorageoftherooftowallandcolumns,andofwallsandcolumnstofoundations,shallbeprovidedtoresistthe

upliftandslidingforcesresultingfromtheapplicationoftheprescribedloads.Additionalrequirementsformasonry

orconcretewallsshallbethosegiveninSec1.7.3.6.

1.2.12 GENERALSTRUCTURALINTEGRITY

Buildingsandstructuralsystemsshallpossessgeneralstructuralintegrity,that istheabilitytosustainlocaldamage

causeddue tomisuseor accidentaloverloading,with the structure as awhole remaining stable andnotbeing

damagedtoanextentdisproportionatetotheoriginallocaldamage.

1.2.13 PROPORTIONINGOFSTRUCTURALELEMENTS

Structuralelements,componentsandconnectionsshallbeproportionedanddetailedbasedonthedesignmethods

provided inthesubsequentchapters forvariousmaterialsofconstruction,suchasreinforcedconcrete,masonry,

steeletc.toresistvariousloadeffectsobtainedfromarationalanalysisofthestructuralsystem.

1.2.14 WALLSANDFRAMING

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

permanentpartitionsand temporarypartitionsexceeding1.8mofheightshallbedesigned to resistall loads to

whichtheyaresubjected.IfnototherwisespecifiedelsewhereinthisCode,wallsshallbedesignedforaminimum

loadof0.25kN/m2appliedperpendiculartothewallsurfaces.Thedeflectionofsuchwallsundera loadof0.25

kN/m2shall not exceed

1/240ofthespanforwallswithbrittlefinishesand

1/120ofthespanforwallswithflexible

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

deflectioncriteria,butshallbeanchoredtothesupportingstructure.

1.2.15 ADDITIONSTOEXISTINGSTRUCTURES

Whenanexistingbuildingorstructureisextendedorotherwisealtered,allportionsthereofaffectedby suchcause

shall

be

strengthened,

if

necessary,

to

comply

with

the

safety

and

serviceability

requirements

provided

in

Sec

1.2.4

and1.2.5respectively.

1.2.16 PHASEDCONSTRUCTION

Whenabuildingorstructureisplannedoranticipatedtoundergophasedconstruction,structuralmemberstherein

shallbeinvestigatedanddesignedforanyadditionalstressesarisingduetosuchconstruction.

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1.2.17 LOADCOMBINATIONSANDSTRESSINCREASE

Every 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,loadcombinationsandstressincreasespecifiedinSec2.7.4forallowablestressdesignmethodshallbeused.

1.3 STRUCTURALSYSTEMS

1.3.1 GENERAL

Everystructureshallhaveoneofthebasicstructuralsystemsspecified inSec1.3.2oracombinationthereof.The

structuralconfigurationshallbeasspecifiedinSec1.3.4withthelimitationsimposedinSec2.5.7.4.

1.3.2 BASICSTRUCTURALSYSTEMS

StructuralsystemsforbuildingsandotherstructuresshallbedesignatedasoneofthetypesAtoGlisted inTable

1.3.1.Each type isagain classifiedas shown in the tableby the typesof verticalelementsused to resist lateral

forces.Abriefdescriptionofdifferentstructuralsystemsarepresentedinfollowingsubsections.

Table1.3.1:BasicStructuralSystems

A.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 wallsE.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

BEARINGWALLSYSTEM

A structural systemhavingbearingwallsorbracing systemswithout a complete vertical load carrying frame to

supportgravityloads.Resistancetolateralloadsisprovidedbyshearwallsorbracedframes.

1.3.2.2 BUILDINGFRAMESYSTEM

A structural systemwithanessentially complete space frameproviding support for gravity loads.Resistance tolateralloadsisprovidedbyshearwallsorbracedframesseparately.

1.3.2.3 MOMENTRESISTINGFRAMESYSTEM

Astructuralsystemwithanessentiallycompletespaceframeprovidingsupportforgravityloads.Momentresisting

framesalso provideresistancetolateralloadprimarilybyflexuralactionofmembers,andmaybeclassifiedasone

ofthefollowingtypes:

a) SpecialMomentResistingFrames(SMRF)

b) IntermediateMomentResistingFrames(IMRF)

c) OrdinaryMomentResistingFrames(OMRF).

The framing system, IMRFandSMRF shallhave specialdetailing toprovideductilebehaviour conforming to the

provisionsofSec8.3and10.20 forconcreteandsteelstructures respectively.OMRFneednotconform to these

specialductilityrequirementsofChapter8or10.

1.3.2.4 DUALSYSTEM

Astructuralsystemhavingacombinationofthefollowingframing systems:

a) Momentresistingframes(SMRF,IMRForsteelOMRF),and

b) Shearwallsorbracedframes.

Thetwosystemsspecifiedin(a)and(b)aboveshallbedesignedtoresistthetotallateralforceinproportiontotheir

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-BUILDINGSTRUCTURALSYSTEM

AstructuralsystemusedforpurposesotherthaninbuildingsandconformingtoSec1.5.4.8,1.5.4.9,2.4and2.5.

1.3.3 COMBINATIONOFSTRUCTURALSYSTEMS

WhendifferentstructuralsystemsofSec1.3.2arecombinedfor incorporation intothesamestructure,designof

thecombinedseismicforceresistingsystemshallconformtotheprovisionsofSec2.5.7.5.

1.3.4 STRUCTURALCONFIGURATIONS

Based 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

REGULARSTRUCTURES

Regularstructureshavenosignificantphysicaldiscontinuitiesorirregularitiesinplanorverticalconfigurationorin

theirlateralforceresistingsystems.TypicalfeaturescausingirregularityaredescribedinSec1.3.4.2.

1.3.4.2

IRREGULARSTRUCTURES

Irregularstructureshaveeithervertical irregularityorplan irregularityorboth intheirstructuralconfigurationsor

lateralforceresistingsystems.

1.3.4.2.1 VerticalIrregularity

StructureshavingoneormoreoftheirregularfeatureslistedinTable1.3.2shallbedesignatedashavingavertical

irregularity.

Table1.3.2:VerticalIrregularitiesofStructures

VerticalIrregularity Reference*

Type Definition Section

I StiffnessIrregularity (SoftStorey):A soft storey is one in which the lateral stiffness is less than 70 per cent of thatin 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

Va DiscontinuityinCapacity (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 PlanIrregularity

Structureshavingoneormoreof the irregular features listed inTable1.3.3shallbedesignatedashavingaplan

irregularity.

Table1.3.3:Plan Irregularities ofStructures

PlanIrregularity 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 DESIGNFORGRAVITYLOADS

1.4.1

GENERAL

Designofbuildingsand components thereof forgravity loads shall conform to the requirementsof this section.

Gravity loads, suchasdead loadand live loadsappliedat the floorsor roofofabuildingshallbedetermined in

accordancewiththeprovisionsofChapter2.

1.4.2 FLOORDESIGN

Floorslabsanddecksshallbedesignedforthefulldeadandliveloadsasspecified inSec2.2and2.3respectively.

Floor supporting elements such asbeams,joists, columns etc. shallbedesigned 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,considerationmaybe

limitedtofulldeadloadonallspansincombinationwithfullliveloadonadjacentspans and

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

concerned.

b) ConcentratedLoads : Provisionshallbemade indesigningfloorsforaconcentrated loadas

set 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 :Loadsdue topermanentpartitionsshallbetreatedasadead loadapplied

overthefloorasauniformlineloadhavinganintensityequaltotheweightpermetrerunof

thepartitionsasspecifiedinSec2.2.5.Loadsforlightmovablepartitionsshallbedetermined

inaccordancewiththeprovisionsofSec2.3.6.

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

designedtosustaintheworsteffectofthedeadplusliveloadsoranyotherloadcombinations

asspecifiedinSec2.7.Wherefloorsareusedasdiaphragmstotransmitlateralloadsbetween

various resisting elements, those loads shallbedetermined following theprovisionsof 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 ROOFDESIGN

Roofs 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 of

continuousstructuralmembers,loadincludingfulldeadloadsonallspansincombinationwith

fullliveloadsonadjacentspansandonalternate span,shallbeinvestigatedtodeterminethe

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

applicable,shallalsobeconsideredindesign.

b) UnbalancedLoading:Effectsduetounbalancedloadsshallbeconsideredinthedesignofroof

membersandconnectionswheresuchloadingwillresultinmorecriticalstresses.Trussesand

archesshallbedesignedtoresistthestressescausedbyuniformliveloadsononehalfofthe

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

stressesproducedbythisunitliveloadwhenappliedupontheentirespan.

c) RainLoads: Roofs,wherepondingofrainwaterisanticipatedduetoblockageofroofdrains,

excessivedeflectionor insufficientslopes,shallbedesignedtosupportsuch 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 REDUCTIONOFLIVELOADS

Thedesign live loadsspecified inSec2.3,maybereducedtoappropriatevaluesaspermittedbytheprovisionsof

Sec2.3.13.andSec.2.3.14.

1.4.5

POSTINGOFLIVELOADS

Ineverybuilding,ofwhichthefloorsorpartsthereofhaveadesignliveloadof3.5kN/m2ormore,andwhichare

usedas library stack room, file room, parking garage,machineorplant room,orused for industrialor storage

purposes,theownerofthebuildingshallensurethatthe live loadsforwhichsuchspacehasbeendesigned,are

postedondurablemetalplatesasshowninFig1.1,securelyaffixedinaconspicuousplaceineachspacetowhich

theyrelate.Ifsuchplatesarelost,removed,ordefaced,theownershallberesponsibletohavethemreplaced.

1.4.6

RESTRICTIONSONLOADING

Thebuildingowner shallensure that the live load forwhicha flooror roof isorhasbeendesigned,willnotbe

exceededduringitsuse.

1.4.7 SPECIALCONSIDERATIONS

Intheabsenceofactualdeadandliveloaddata,theminimumvaluesoftheseloadsshallbethosespecifiedinSec

2.2and2.3.Inaddition,specialconsiderationshallbegiventothefollowingaspectsofloadinganddueallowances

shallbemadeindesignifoccurrenceofsuchloadingisanticipatedafterconstructionofabuilding:

a) IncreaseinDeadLoad:Actualthicknessoftheconcreteslabsorothermembersmaybecome

largerthanthedesignedthicknessduetomovementsordeflectionsoftheformworkduring

construction.

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1.4.8

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1.5.3.1

DIRECTIONOFWIND

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

direction.

1.5.3.2 DESIGNCONSIDERATIONS

DesignwindloadontheprimaryframingsystemsandcomponentsofabuildingorstructureshallbedeterminedonthebasisoftheproceduresprovidedinSec2.4consideringthebasicwindspeed,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

SHIELDINGEFFECT

Reductions inwindpressureonbuildingsandstructuresdue toapparentdirect shieldingeffectsof theupwind

obstructions,suchasmanmadeconstructionsornaturalterrainfeatures,shallnotbepermitted.

1.5.3.4

DYNAMICEFFECTS

Dynamicwind forces suchas that fromalongwind vibrations causedby thedynamicwindstructure interaction

effects,as set forthby theprovisionsofSec2.4.10, shallbe considered in thedesignof regular shaped slender

buildings.Forotherdynamiceffectssuchascrosswindortorsionalresponsesasmaybeexperiencedbybuildings

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

responsecharacteristics,orsitelocations,structuraldesignshallbemadebasedontheinformationobtainedeither

fromother reliable referencesor fromwindtunnel testspecified inSec1.5.3.5below,complyingwiththeother

requirementsofthissection.

1.5.3.5 WINDTUNNELTEST

Properlyconductedwindtunneltestsshallberequiredforthosebuildingsorstructureshavingunusualgeometricshapes,responsecharacteristics,orsitelocationsforwhichcrosswindresponsesuchasvortexshedding,galloping

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

available.This test isalso recommended for thosebuildingsor structures forwhichmoreaccuratewindloading

informationisdesiredthanthosegiveninthissectionandinSec2.4.

Testsforthedeterminationofmeanandfluctuatingcomponentsofforcesandpressuresshallbeconsideredtobe

properlyconductedonlyifthefollowing requirementsaresatisfied:

a)

Thenaturalwindhasbeenmodelledtoaccountforthevariationofwindspeedwithheight,

b)

The intensityofthe longitudinalcomponentsof turbulencehasbeen taken intoconsideration in the

model,

c) Thegeometricscaleofthestructuralmodel isnotmorethanthreetimesthegeometricscaleofthe

longitudinal component ofturbulence,

d)

Theresponsecharacteristicsofthewindtunnelinstrumentationareconsistentwiththemeasurements

tobemade, and

e)

The Reynolds number is taken into consideration when determining forces and pressures on the

structuralelements.

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

conductedonly ifrequirements (a)through (e)aboveare fulfilledand, inaddition,thestructuralmodel isscaled

withdueconsiderationtolength,distributionofmass,stiffnessanddamping ofthestructure.

1.5.3.6 WINDLOADSDURINGCONSTRUCTION

Buildings, structures and portions thereof under construction, and construction structures such as formwork,

stagingetc.shallbeprovidedwithadequatetemporarybracingsorotherlateralsupportstoresistthewindloadon

themduringtheerectionandconstructionphase.

1.5.3.7 MASONRYCONSTRUCTIONINHIGH-WINDREGIONS

Designandconstructionofmasonrystructuresinhighwindregionsshallconformtotherequirementsofrelevant

sectionsofChapter7.

1.5.3.8 HEIGHTLIMITS

UnlessotherwisespecifiedelsewhereinthisCode,noheightlimitsshallbeimposed,ingeneral,onthedesignand

constructionofbuildingsorstructurestoresistwindinducedforces.

1.5.4 DESIGNFOREARTHQUAKEFORCES

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

requirementsofthissection.

1.5.4.1

BASICDESIGNCONSIDERATION

Forthepurposeofearthquakeresistantdesign,eachstructureshallbeplacedinoneoftheseismiczonesasgivenin

Sec2.5.6.2andassignedwitha structure importance categoryas set forth inSec2.5.7.1.The seismic forceson

structuresshallbedeterminedconsideringseismiczoning,sitesoilcharacteristics,structureimportance,structural

systemsandconfigurations,heightanddynamicpropertiesofthestructureasprovided inSec2.5.Thestructural

systemand

configuration

types

for

abuilding

or

astructure

shall

be

determined

in

accordance

with

the

provisions

ofSec2.5.7.4.Otherseismicdesignrequirementsshallbethosespecifiedinthissection.

1.5.4.2 REQUIREMENTSFORDIRECTIONALEFFECTS

Thedirectionsofapplicationofseismicforcesusedinthedesignshallbethosewhichwillproducethemostcritical

loadeffects.Earthquakeforcesactinbothprincipaldirectionsofthebuildingsimultaneously.Designprovisionsfor

consideringearthquakecomponentinorthogonaldirectionshavebeenprovidedinSec2.5.15.1.

1.5.4.3 STRUCTURALSYSTEMANDCONFIGURATIONREQUIREMENTS

Seismicdesignprovisionsimposethefollowinglimitationsontheuseofstructuralsystemsandconfigurations:

a)

The

structural

system

used

shall

satisfy

requirements

of

the

Seismic

Design

Category

(defined

in

Sec.2.5.7.2)andheightlimitationsgiveninSec2.5.7.4.

b)

StructuresassignedtoSeismicDesignCategoryDhavingverticalirregularityTypeVbofTable1.3.2

shall 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 in

compliancewiththeadditionalrequirementsofthesectionsreferencedintheseTables.

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d) SpecialStructuralSystemsdefined inSec1.3.2.5maybepermitted if it canbedemonstratedby

analytical 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 METHODSOFANALYSIS

Earthquake forces and their effects on various structural elements shallbedetermined by using either a static

analysismethodoradynamicanalysismethodwhicheverisapplicablebasedonthelimitationssetforthinSec2.5.7

through2.5.14andconformingtoSec1.2.7.

1.5.4.5 MINIMUMDESIGNSEISMICFORCE

Theminimumdesign seismic forces shallbe thosedetermined inaccordancewith the Sec2.5.7 through 2.5.14

whicheverisapplicable.

1.5.4.6 DISTRIBUTIONOFSEISMICFORCES

Thetotallateralseismicforcesandmomentsshallbedistributedamongvariousresistingelementsatanyleveland

alongtheverticaldirectionofabuildingorstructureinaccordancewiththeprovisionsofSec2.5.7through2.5.14

asappropriate.

1.5.4.7

VERTICALCOMPONENTSOFSEISMICFORCES

DesignprovisionsforconsideringverticalcomponentofearthquakegroundmotionisgiveninSec2.5.15.2

1.5.4.8 HEIGHTLIMITS

Height limitationsfordifferentstructuralsystemsaregiven inTable2.5.7ofSec2.5.7.4ofPart6ofthiscodeasa

functionofseismicdesigncategory.

1.5.4.9 NON-BUILDINGSTRUCTURES

SeismiclateralforceonnonbuildingstructuresshallbedeterminedinaccordancewiththeprovisionsofChapter15

ofASCE7 05.However,provisionsofChapter15ofASCE705maybesimplified,consistentwiththeprovisionsof

Section2.5ofPart6ofthiscode.Otherdesignrequirementsshallbethoseprovidedinthischapter.

1.5.5

OVERTURNINGREQUIREMENTS

Everystructureshallbedesignedtoresisttheoverturningeffectscausedbywindorearthquakeforcesspecifiedin

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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1.6 DESIGNFORMISCELLANEOUSLOADS

1.6.1 GENERAL

Buildings,structuresandcomponentsthereof,whensubjectto loadsotherthandead, live,windandearthquake

loads,shallbedesignedinaccordancewiththeprovisionsofthissection.Miscellaneousloads,suchasthosedueto

temperature,rain,

flood

and

surge

etc.

on

buildings

or

structures,

shall

be

determined

in

accordance

with

Sec

2.6.

Structural memberssubjecttomiscellaneousloads,notspecifiedinSec2.6shallbedesignedusingwellestablished

methods giveninanyreliablereferences,andcomplyingwiththeotherrequirementsofthisCode.

1.6.2 SELF-STRAININGFORCES

Selfstraining 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

STRESSREVERSALANDFATIGUE

Structuralmembersandjointsshallbe investigatedanddesignedagainstpossiblestressreversalscauseddueto

variousconstruction loads.Where required,allowanceshallbemade in thedesign toaccount for theeffectsof

fatigue.Theallowablestressmaybeappropriatelyreducedtoaccountforsucheffectsinthestructuralmembers.

1.6.4 FLOOD,TIDAL/STORMSURGEANDTSUNAMI

Buildings, structures and components thereof shall be designed, constructed and anchored to resist flotation,

collapseoranypermanentmovementduetoloadsincludingflood,tidal/Stormsurgeandtsunami,whenapplicable.

Structuralmembersshallbedesignedtoresistbothhydrostaticandsignificanthydrodynamic loadsandeffectsof

buoyancyresultingfromfloodorsurge.Floodandsurge loadsonbuildingsandstructuresshallbedetermined in

accordancewithSec2.6.4.Loadcombination including floodandsurge loadsshallconform 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 RAINLOADS

Roofsofthebuildingsandstructuresaswellastheirothercomponentswhichmayhavethecapabilityofretaining

rainwatershallbedesignedforadequategravityloadinducedbyponding.Roofsandsuchothercomponentsshall

beanalysedanddesignedforloadduetopondingcausedbyaccidentalblockageofdrainagesystemcomplyingwith

Sec.2.6.3.

1.6.6

OTHERLOADS

Buildingsand

structures

and

their

components

shall

be

analyzed

and

designed

for

stresses

caused

by

the

following

effects

a. TemparatureEffects(Sec2.6.5).

b. SoilandHydrostaticPressure(Sec2.6.6).

c. ImpactsandCollisions

d.

Explosions(Sec2.6.7).

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e. Fire

f. VerticalForcesonAirRaidShelters(Sec2.6.8).

g. LoadsonHelicopterLandingAreas(Sec2.6.9).

h.

ErectionandConstructionLoads(Sec2.6.10).

i.

MovingLoadsforCraneMovements

j. CreepandShrinkage

k.

DynamicLoadsduetoVibrations

l. ConstructionLoads

Designofbuildingsandstructuresshallincludeloadingandstressescausedbytheaboveeffectsinaccordancewith

theprovisionssetforthinChapter2.

1.7 DETAILEDDESIGNREQUIREMENTS

1.7.1

GENERAL

All structural framing systems shall comply with the requirements of this section. Only the elements of the

designated lateral force resisting systems canbeused to resistdesign lateral forces specified inChapter2.The

individual componentsshallbedesignedtoresisttheprescribedforcesactingonthem.Designofcomponentsshall

alsocomplywiththespecificrequirementsforthematerialscontainedinChapters4through13.Inaddition,such

framingsystemsandcomponentsshallcomplywiththedesignrequirementsprovidedinthissection.

1.7.2 STRUCTURALFRAMINGSYSTEMS

Thebasicstructuralsystemsaredefined inSec1.3.2andshowninTable1.3.1,andeachtypeissubdividedbythe

typesofframingelementsusedtoresistthelateralforces.Thestructuralsystemusedshallsatisfyrequirementsof

seismicdesigncategoryandheight limitations indicated inTable 2.5.7.Specialframingrequirementsaregiven in

thefollowingsectionsinadditiontothoseprovidedinChapters4through13.

1.7.3 DETAILINGREQUIREMENTSFORCOMBINATIONSOF STRUCTURAL

SYSTEMS:

Forcomponentscommontodifferentstructuralsystems,amorerestrictivedetailingshallbeprovided.

1.7.3.1 CONNECTIONSTORESISTSEISMICFORCES

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

requirements provided inChapters 4 through 13.Detailed sketches for these connections shallbe given in the

structuraldrawings.

1.7.3.2 DEFORMATIONCOMPATIBILITY

Allframingelementsnotrequiredbydesigntobepartofthelateralforceresistingsystem,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 : Momentresistingframesmaybeenclosedoradjoinedbymorerigid

elementswhichwouldtendtoprevent aspaceframefromresistinglateralforceswhereitcanbe

shownthattheactionorfailureofthemorerigidelementswillnotimpairtheverticalandlateral

loadresistingabilityofthespaceframe.

b. ExteriorElements:Exteriornonbearing,nonshearwallpanelsorelementswhichareattachedto

orenclosetheexterior ofastructure,shallbedesignedtoresisttheforcesaccordingtoSec.2.5.17ofChapter2, if seismic forcesarepresent,and shallaccommodatemovementsof 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.

Connectionsandpaneljointsshallallowforarelativemovementbetweenstoreysofnotless

than two times thestoreydriftcausedbywind forcesordesign seismic forces,or12mm,

whicheverisgreater.

ii. Connections topermitmovement in theplaneof thepanel for storeydrift shallbe either

slidingconnectionsusingslottedoroversizedholes,connectionswhichpermitmovementby

bendingofsteel,orotherconnectionsprovidingequivalentslidingandductilitycapacity.

iii. Bodiesof connectionsshallhavesufficientductilityand rotation capability toprecludeany

fractureoftheanchoringelementsorbrittlefailuresatornearweldings.

iv. Bodiesof the connectionshallbedesigned for1.33 times theseismic forcedeterminedby

Sec.2.5.17ofChapter2,orequivalent.

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

designedfor4timestheforcesdeterminedbySec.2.5.17ofChapter2orequivalent.

vi.

Fastenersembeddedinconcreteshallbeattachedto,orhookedaroundreinforcingsteel,or

otherwiseterminatedsoastotransferforcestothereinforcingsteeleffectively.

1.7.3.3 TIESANDCONTINUITY

Allpartsofastructureshallbe interconnected.Theseconnectionsshallbecapableoftransmittingtheprescribed

lateralforcetothelateralforceresistingsystem.Individualmembers,includingthosenotpartoftheseismicforce

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

determined inaccordancewith thisstandard.Connectionsshalldevelopthestrengthoftheconnectedmembers

andshallbecapableoftransmittingtheseismicforce(Fp)inducedbythepartsbeingconnected.

1.7.3.4 COLLECTORELEMENTS

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

portionsofthestructuretotheelementprovidingtheresistancetothoseforces.

1.7.3.5 CONCRETEFRAMES

Whenconcreteframesareprovidedbydesigntobepartofthelateralforceresistingsystem,theyshallconformto

thefollowingprovisions:

a) InSeismicZones3and4theseframesshallbedesignedasspecialmomentresistingframes(SMRF).

b) InSeismicZone2theyshall,asaminimum,beintermediatemomentresistingframes(IMRF).

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1.7.3.6

ANCHORAGEOFCONCRETEANDMASONRYSTRUCTURALWALLS

The 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 Secs2.4.13 and 2.5.17,oraminimum forceof4.09 kN/mofwall.Walls shallbe

designedtoresistbendingbetweenanchorswheretheanchorspacingexceeds1.2m.Inmasonrywallsofhollow

units or cavity walls, anchors shall be embedded in a reinforced grouted structural element of the wall.Deformationsofthe floorandroofdiaphragmsshallbeconsidered in thedesignof thesupportedwallsand the

anchorageforcesinthediaphragmsshallbedeterminedinaccordancewithSec1.7.3.9below.

1.7.3.7

BOUNDARYMEMBERS

Speciallydetailedboundarymembers shallbe considered for shearwallsand shearwallelementswhenever their

designisgovernedbyflexure.

1.7.3.8 FLOORANDROOFDIAPHRAGMS

Deflection in theplaneof thediaphragm shallnotexceed thepermissibledeflectionof the attachedelements.

Permissibledeflection shallbe thatdeflectionwhichwillpermit theattachedelement tomaintain its structural

integrityundertheindividual loadingandcontinuetosupporttheprescribedloads.Designofdiaphragmsshallalso

complywiththefollowingrequirements.

a) DiaphragmForces: Diaphragmsshallbe designedtoresist theseismicforcesgiveninSec2.5or

forsimilarnonseismiclateralforces,whicheverisgreater.

b) DiaphragmTies:Diaphragmssupportingconcreteormasonrywallsshallhavecontinuousties,or

strutsbetween thediaphragm chords todistribute theanchorage forces specified inSec1.7.3.6

above.Addedchordsmaybeprovidedtoformsubdiaphragmstotransmittheanchorageforcesto

themaincrossties.

c) WoodDiaphragms :Wherewooddiaphragmsareused to laterallysupportconcreteormasonry

walls,theanchorageshallconformtoSec1.7.3.6 above.InseismicZones2,3and4thefollowingrequirementsshallalsoapply:

i.

Anchorageshallnotbeaccomplishedbyuseoftoenailsornailssubjecttowithdrawal,

norshallwoodledgersorframingbeusedincrossgrainbendingorcrossgraintension.

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

diaphragmsheathing.

d) Structureshavingirregularities

i) ForstructuresassignedtoSeismicDesignCategoryDandhavingaplanirregularityofType

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

designforcesdeterminedfromSection2.5.9shallbeincreased25percentforconnectionsofdiaphragms toverticalelementsandtocollectorsand 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 structureshavingaplan irregularityofType II inTable1.3.3,diaphragm chords and

collectorsshallbedesignedconsideringindependentmovementofanyprojectingwingsof

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thestructure.Eachofthesediaphragmelementsshallbedesignedforthemoresevereof

thefollowingcases:

1. Motionoftheprojectingwingsinthesamedirection.

2. Motionoftheprojectingwingsinopposingdirections.

Exception:

ThisrequirementmaybedeemedtobesatisfiediftheproceduresofSec2.5.10whenseismicforcesarepresent,in

conjunctionwithathreedimensionalmodel,havebeenusedtodeterminethelateralseismicforcesfordesign.

1.7.3.9 FRAMINGBELOWTHEBASE

Whenstructuralframingscontinuebelowthebase,thefollowingrequirementsshallbesatisfied.

a.

FramingbetweentheBaseandtheFoundation: Thestrengthandstiffnessoftheframingbetween

thebaseandthefoundationshallnotbelessthanthatofthesuperstructure.Thespecialdetailing

requirementsof Sec8.3or10.20,asappropriate for reinforced concreteor steel, shallapply 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 the

overturning forces from the superstructure into the supporting soil,but the short termdynamic

natureof the loadsmaybe taken intoaccount inestablishing thesoilproperties.Sec1.8below

prescribestheadditionalrequirementsforspecifictypesoffoundationconstruction.

1.8 FOUNDATIONDESIGNREQUIREMENTS

1.8.1 GENERAL

Thedesignandconstructionof foundation, foundationcomponentsandconnectionbetweenthe foundationand

superstructureshallconformtotherequirementsofthissectionandapplicableprovisionsofChapter3andother

portionsofthisCode.

1.8.2 SOILCAPACITIES

The 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 shallbe sufficient to resist loadsatacceptable strains consideringboth the short time loadingand the

dynamicpropertiesofthesoil.Thestressandsettlementofsoilunderappliedloadsshallbedeterminedbasedon

establishedmethodsofSoilMechanics.

1.8.3 SUPERSTRUCTURE-TO-FOUNDATIONCONNECTION

Theconnectionofsuperstructureelementstothefoundationshallbeadequatetotransmittothefoundationthe

forcesforwhichtheelementsarerequiredtobedesigned.

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1.8.4 FOUNDATION-SOILINTERFACE

For regularbuildings thebaseoverturningmoments for the entire structureor for anyoneof 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

PILESANDCAISSONS

Pilesand caissonsshallbedesigned for flexurewhenever the topof suchmembers isanticipated tobe laterally

displacedbyearthquakemotions.ThecriteriaanddetailingrequirementsofSec8.3forconcreteandSec10.20for

steelshallapplyforalengthofsuchmembersequalto120percentoftheflexurallength.

1.8.5.2 FOOTINGINTERCONNECTION

a. Footingsandpilecapsshallbecompletely interconnectedbystruttiesorotherequivalentmeans

torestraintheirlateralmovementsinanyorthogonaldirection.

b. Thestruttiesorotherequivalentmeansasspecified in(a)above,shallbecapableofresisting in

tensionorcompressionaforcenotlessthan10%ofthelargerfootingorcolumnloadunlessitcan

bedemonstratedthatequivalentrestraintcanbeprovidedbyfrictionalandpassivesoilresistance

orbyotherestablishedmeans.

1.8.6 RETAININGWALLDESIGN

Retainingwallsshallbedesignedtoresistthelateralpressureoftheretainedmaterial,underdrainedorundrained

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

minimumfactorofsafetyagainstbaseoverturningandslidingduetoappliedearthpressureshallbe1.5.

1.9

DESIGNAND

CONSTRUCTION

REVIEW

Everybuildingorstructuredesignedshallhaveitsdesigndocumentspreparedinaccordancewiththeprovisionsof

Sec1.9.1.Theminimumrequirementsfordesignreviewandconstructionobservationshallbethosesetforthunder

Sec1.9.2and1.9.3respectively.

1.9.1 DESIGNDOCUMENT

Thedesigndocumentsshallbepreparedandsignedby theengineer responsible for thestructuraldesignofany

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 DESIGNREPORT

Thedesignreportshallcontainthedescriptionofthestructuraldesignwithbasicdesign informationasprovided

below,sothatanyotherstructuraldesignengineerwillbeabletoindependently verifythedesignparametersand

themembersizesusingthesebasicinformation.Thedesignreportshallinclude,butnotbelimitedto,thefollowing

:

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a) Nameand governing editionof thisCodeandother referenced standards, and the specific

portions, stating chapter, section, clause etc. of these Code and standards including any

specialistreportusedforthestructuraldesign.

b) Methodsusedforthecalculationofallapplied loadsalongwith basic loadcoefficientsand

other basic information including any assumption or judgment made under special

circumstances.

c) Adrawingof the completemathematicalmodelprepared inaccordancewithSec1.2.7.1 to

represent the structureand showingon it thevalues, locationsanddirectionsofallapplied

loads,andlocationofthelateralloadresistingsystemssuchasshearwalls,bracedframesetc.

d) Methodsofstructuralanalysis,andresultsoftheanalysissuchasshear,moment,axialforce

etc., used for proportioning various structural members and joints including foundation

members.

e) Methods of structural design including types and strengthof thematerialsof construction

usedforproportioningthestructuralmembers.

f)

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

g) Statementsupportingthevalidityoftheabovedesigndocumentswithdateandsignatureof

theengineerresponsibleforthestructuraldesign.

h)

When computer programs are used, to any extent, to aid in the analysis or design of the

structure,thefollowing items,inadditiontoitems(a)through(g)above,shallberequiredto

beincludedinthedesignreport:

i.

Asketchofthemathematicalmodelusedtorepresentthestructure inthecomputer

generatedanalysis.

ii.

Thecomputer

output

containing

the

date

of

processing,

program

identification,

identificationofstructuresbeinganalysed,all inputdata,unitsand final results.The

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

program.

iii.

Aprogramdescription containing the informationnecessary toverify the inputdata

and interpret the results todetermine thenatureandextentof theanalysisand to

checkwhetherthecomputationscomplywiththeprovisionsofthisCode.

iv.

Thefirstsheetofeachcomputerrunshallbesignedbytheengineerresponsibleforthe

structuraldesign.

1.9.3

STRUCTURAL

DRAWINGS

AND

MATERIAL

SPECIFICATIONS

Thestructuraldrawingsshallinclude,butnotbelimitedto,thefollowing:

a)

Thefirstsheetshallcontain:(1)identificationoftheprojecttowhichthebuildingorthestructure,

orportionthereofbelongs,(2)referencetothedesignreportspecifiedinSec1.9.2above,(3)date

ofcompletionofdesign,and(4)identificationandsignaturewithdateoftheengineerresponsible

forthestructuraldesign.

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b) The secondsheetshall containdetailmaterial specificationsshowing : (1)Specified compressive

strengthofconcreteat statedagesor stagesof construction forwhicheachpartofstructure is

designed (2)Specified strengthor gradeof reinforcement (3)Specified strengthofprestressing

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

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

compressivestrengthattimeofposttensioning(8)Stressingsequenceforposttensioningtendons

(9)Generalnotes indicating clear cover, development lengthsof reinforcements,oranyother

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 detailsof theelementsof the

structure clearly showing all sizes, crosssections and relative locations, connections,

reinforcements, laps, stiffeners,welding types, lengthsand locationsetc.whichever isapplicable

foraparticularconstruction. Floor levels, columncentresandoffsetetc.,shallbedimensioned.

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

members,connectiontypessuchasslip,critical,tensionorbearingtype,shallbeindicatedonthe

drawing.

d) Drawingsshallbepreparedtoascalelargeenoughtoshowtheinformationclearlyandthescales

shallbemarkedonthedrawingsheets.Ifanyvariationfromthedesignspecificationsprovided in

sheettwooccurs, thedrawingsheet shallbeprovidedadditionallywiththedesignspecifications

includingmaterialtypesandstrength,clearcoveranddevelopment lengthsofreinforcements,or

anyotherdesignparameterrelevanttothememberorconnectiondetailsprovidedinthatdrawing

sheet.Eachdrawingsheetshallalsocontainthesignaturewithdateoftheengineerresponsiblefor

thestructuraldesign.

1.9.4 DESIGNREVIEW

ThedesigndocumentsspecifiedinSec1.9.1shallbeavailableforreviewwhenrequiredbytheconcernedauthority.

Reviewshallbeaccomplishedbyan independentstructuralengineerqualified forthistaskandappointedbythe

concernedauthority.Designreviewshallbeperformedthroughindependentcalculations,basedontheinformation

provided in thedesigndocumentsprepared and signedby theoriginal structuraldesign engineer, to verify the

designparameters includingapplied loads,methodsofanalysisanddesign,andfinaldesigndimensionsandother

detailsofthestructuralelements.Thereviewingengineershallalsocheckthesufficiencyandappropriatenessof

thesuppliedstructuraldrawingsforconstruction.

1.9.5 CONSTRUCTIONOBSERVATION

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

appointedbytheownerofthebuildingorthestructure.Constructionobservationshallinclude,butnotbelimited

to,thefollowing:

a.

Specificationofanappropriatetestingand inspectionschedulepreparedandsignedwithdateby

theresponsibleperson;

b.

Reviewoftestingandinspectionreports;and

c. Regular site visit to verify the general compliance of the constructionworkwith the structural

drawingsandspecificationsprovidedinSec1.9.3above.