effect of sloping ground on structural … · · 2014-09-01the structural analysis software staad...

EFFECTOFSLOPINGGROUNDONSTRUCTURALPERFORMANCEOFRCCBUILDING

UNDERSEISMICLOAD

1SUJITKUMAR,2Dr.VIVEKGARG,3Dr.ABHAYSHARMA

1PostGraduateStudent,StructuralEngineeringDepartmentofCivilEngineering,MANIT,Bhopal,MadhyaPradesh,India,Email:[email protected]

2AssistantProfessor,CivilEngineeringDepartment,MANIT,Bhopal,MadhyaPradesh,India,

Email:[email protected]

3AssociateProfessor,CivilEngineeringDepartment,MANIT,Bhopal,MadhyaPradesh,India,Email:[email protected]

ABSTRACT

Previous studies emphasize for proper planning and construction practices of multistoried buildings on sloping ground.However,innormaldesignpracticethedesignersgenerallyignoretheeffectofslopinggroundonthestructuralbehaviorofthe building. The seismic analysis of a G+4 storey RCC building on varying slope angles i.e., 7.50 and 150 is studied andcomparedwiththesameontheflatground.TheseismicforcesareconsideredasperIS:1893‐2002.Thestructuralanalysissoftware STAADPro v8i isused to study theeffect of sloping groundonbuildingperformanceduring earthquake. Seismicanalysis has been done using Linear Staticmethod. The analysis is carried out to evaluate the effect of sloping ground onstructural forces. The horizontal reaction, bending moment in footings and axial force, bending moment in columns arecriticallyanalyzedtoquantifytheeffectsofvariousslopingground.Ithasbeenobservedthatthefootingcolumnsofshorterheightattractmoreforces,becauseofaconsiderable increase intheirstiffness,whichinturnincreasesthehorizontalforce(i.e.shear)andbendingmomentsignificantly.Thus,thesectionofthesecolumnsshouldbedesignedformodifiedforcesduetothe effect of sloping ground. The present study emphasizes the need for proper designing of structure resting on slopingground.IndexTerms:Slopingground,Seismicforces,RCCBuilding,Structuralanalysis,STAADetc.1.INTRODUCTION

Earthquake is the most disastrous due to itsunpredictability and huge power of devastation.Earthquakes themselves do not kill people, rather thecolossal loss of human lives and properties occur due tothedestructionofstructures.Buildingstructurescollapseduringsevereearthquakes,andcausedirectlossofhumanlives. Numerous research works have been directedworldwide in last fewdecades to investigate thecauseoffailureofdifferenttypesofbuildingsundersevereseismicexcitations.Massivedestructionofhigh‐riseaswellaslow‐risebuildingsinrecentdevastatingearthquakeprovesthatindevelopingcountieslikeIndia,suchinvestigationistheneed of the hour. Hence, seismic behavior of asymmetricbuildingstructureshasbecomeatopicofworldwideactiveresearch. Many Investigations have been conducted onelastic and inelastic seismic behavior of asymmetricsystems to find out the cause of seismic vulnerability ofsuch structures. The purpose of the paper is to performlinear static analysis ofmedium height RC buildings andinvestigate the changes in structural behavior due toconsiderationofslopingground.

1.1SEISMICBEHAVIOUROFBUILDINGSONSLOPESININDIA

NorthandnortheasternpartsofIndiahavelargescalesofhilly region,whichare categorizedunderseismiczone IVand V. In this region the construction of multistory RCframedbuildingsonhillslopeshasapopularandpressingdemand, due to its economic growth and rapidurbanization. This growth in construction activity isaddingincreaseinpopulationdensity.Whileconstruction,itmustbenotedthatHillbuildingsaredifferentfromthoseinplainsi.e.,theyareveryirregularandunsymmetricalinhorizontal and vertical planes, and torsionally coupled.Since there is scarcity of plain ground in hilly areas, itobligatestheconstructionofbuildingsonslopes.

During past earthquakes, reinforced concrete (RC) framebuildingsthathavecolumnsofdifferentheightswithinonestorey, suffered more damage in the shorter columns ascompared to taller columns in the same storey. Oneexampleofbuildingswithshortcolumnsinbuildingsonaslopinggroundcanbeseeninthefigure(1)given

SUJIT KUMAR et al. DATE OF PUBLICATION: SEPTEMBER 01, 2014

ISSN: 2348-4098 VOLUME 2 ISSUE 6 AUGUST 2014 (VER II)

INTERNATIONAL JOURNAL OF SCIENCE, ENGINEERING AND TECHNOLOGY- www.ijset.in 1310

Poorearthsectiseen

Figu

HowtallStiffnlargeit.

Sevestruslopforcestudvario

ChensystegrouutilizsupegrouUtiliof aresusupegrou

Chanthe

Figure1:

rbehaviorofhquake,atallionmove honfromthegiv

ure2:Structu

wever, the shcolumn, annessofacolueristhestiffn

eral studiesctural perfoing ground.e, moment sdiedformoreousslopeofg

n and Constaem deliberatund storey ozes Teflonerstructure.und story duzing thiscona multistoryults show thaerstructure wundstorey.

ndrasekarandesign ofmu

Buildingfram

fshortcolumlcolumnandorizontally byvenfigure(2)

uralbehaviorloa

hort columnnd it attractumnmeansrness,largeris

have beenormance ofThe effect insupport reacrealisticanaground.

antinou (199tely introducof structuressliders toEnergy dissuctile columnncept theseisframe are aat it is possiwhile maint

andRao(20ulti‐ storied

mewithshort

nsisduetotdashortcolumy same amou)below.

ofshortcoluad

is stiffer asts larger earesistancetostheforcere

n made tobuilding fran terms of action, and dalysistoquan

98) studied tces flexibilitywas describcarry a

sipation is pns and by thsmicresponsanalyzed andible to provitaining the

02)investigaRCC building

tcolumns

thefactthatimnofsamecuntwhich can

umnunderlat

compared toarthquake fodeformationquiredtodef

investigateame restingaxial force, sdisplacementntifytheeffec

that the pracy to the slobed. The sysportion ofprovided byhe Teflon slidsecharacterid discussed.ide safely tostability of

atedanalysisgs for seismi

inancrossn be

teral

o theorce.‐theform

theg onhearare

ctsof

cticalpingstemthethe

ders.sticsThe

o thethe

andicity.

Reinforcedcomplex toUsually, theydimensionaldifferent anbuildingsinthe axial forstress inbeaversionofth1984.

Birajdar B.Ganalyses pedifferentconSetbackbuilanalysisinclusing responpropertiesdisplacemencolumns hasuitabilityofisobservedbemoresuit

Kadid A. anpushover anperformanceearthquakesbuildings wanalyzed.Thcompare thdisplacemendesigned fraSome of thepushoveranlinearandno

AbuL.(2010buildingusinthe Indian s1893), the sandtheaverthe soil typmodificationplaneandslhas been mspecific soilandIV,studyrespect to dandMeghalato analyzeSTAADProV

Saptadip S.resistant muwhich involvarying floopopular sofresultsvarioaxial force,moment, mcompressiveplaneground

concrete mmodel asy are model frame systegles 5o, 10o,thecountryrce, shear foramandsuppheIS:1893–

G. (2004) preerformed onnfigurationslldingandSetludingtorsionnse spectrumi.e. fundamnt and, theave been sfabuildingcthatStepbactableonslopi

nd Boumrkiknalysis wase of frameds.Slopinggrowith 5, 8 anheresultsobthe axial font, base shames will pee conclusionnalysisisareonlinearbeh

0)studiedthngSiteRespostandard forseismic forcerageresponsepes at twenn dependinglopinggrounmade to geneparametersythevariatiodifferent slopayaarethegesome structuV8i.

(2010) stuulti stories Rlves the anarheightsandftware toolousgraphswmaximum

maximum te stress beindandsloping

multi‐storiedstructural sled as two‐dems are in p, and 15o. Aforseismicfrce,moment,portreaction2002tothe

esented then 24 RC blike,Stepbactbackbuildinnaleffecthasmmethod. Thental timebase shear

studied withconfigurationckSetbackbingground.

k A. (2005) scarried oubuildings unundareconsnd 12 storietainedinthesorce, bendiear and sherform well uns made bylativelysimphaviorofBuild

eAnalysisofonsespectraEarthquake

e depends oneaccelerationnty meterupon the ded. In thetheerate responsforsomesiteonoftopstorping angle i.eeneratedrespures using c

udied the DeRCC buildingalysis of simdvaryingnoSTAAD Pro.

weredrawnbeshear force,tensile forcng developedgground.

buildings aystems fordimensional oplane and sloAnalyze mulforcesandco, nodal displcompared tolastversion

results fromuildings witckbuilding;Sngarepresensbeencarriehe dynamic rperiod, top

r action indh referenceonslopingg

buildingsare

studied expet with a stnder futuresiderthethrees respectivesethreebuildng momenthows thatunder seismthe authorsplewaytoexpdings.

fearthquakemethod.Accoresistant den the zone fancoefficientdepth withepth of foundirstudiedanse spectra ues in seismicreydisplaceme. Arunachalponsespectrcommercial

esign of Earon a slopingmple 2‐D frofbaysusin. Using theetweenthem, maximumce and md for the fr

are veryanalysis.or three‐ope withltistoriedomparingacement,ocurrentIS:1893‐

m seismicth threeStepbacknted.3–Dedoutbyresponsep storeyduced into the

ground.Itfoundto

erimentaltudy theexpectedeeframedely weredingsandt, nodalproperlyic codes. are theplorethe

resistantordingtoesign (IS:actor (Z)(Sa/g)ofsuitabledation innattemptusing sitec zone IIImentwithPradesh

raisusedsoftware

rthquakeg groundrames ofngaveryanalysis

maximumbending

maximumames on




Balaji K.V.G.D (2011) studied the non‐linear analysis ofvarioussymmetricandasymmetricstructuresconstructedon plain as well as sloping grounds subjected to variouskinds of loads. Different structures constructed on planegroundand inclined groundof30o slope is considered inthe study. Various structures are considered in plansymmetryandalsoasymmetrywithdifferenceinbaysizesin mutual directions. The analysis has been carried outusingSAP‐2000andETABSsoftware.

Mohammed U. and Farooque P. (2012) studied thebuildings on hill differ from other buildings. The variousfloors of such building steps back towards the hill slopeand at the same time buildings may have setbacks also.Buildingssituatedinhillyareasaremuchmorevulnerabletoseismicenvironment.Inthisstudytheeffectofvaryingheightofcolumnsingroundstoreyduetoslopinggroundand the effect of shear wall at different positions duringearthquake. Seismic analysis has been done using LinearStatic, Linear Dynamic method and evaluated usingpushoveranalysisEightStoriedbuilding.

KeyvanRamin(2013) studiedtheexperimentalmodelingand numerical modeling for a four‐story reinforcedconcretebuildingthattheanalysisofsimple3‐Dframesofvarying floor heights and varying number of bays withdifferent slope angles using a very popular software toolSTAADPro.onbothaslopingandaflat lot.AlsoSap2000softwarehadbeenusedtoshowthat thedisplacementoffloors is greater for a flat lot building than a sloping lotbuilding.

PradeepKumarRamancharla(2013)studiedthebehaviorofabuildingonvaryingslopeanglesi.e.,15°,30°and45°isstudied using shear wall in different location andcompared with the same on the flat ground. Building isdesignedasper IS456and latersubjected toearthquakeloads.

The salient objectives of the present study have been tostudy the effect of sloping groundon structural forces incriticalhorizontalreaction,bendingmomentinfootingandcriticalaxialforce,bendingmomentincolumns.2.METHODOLOGY

Thispresentworkdealswithstudyofbehaviorofslopingground building frames considering different inclination(7.5o, 15o) under earthquake forces. The comparison ofsloping ground and plane ground building under seismicforcesisdone.HereG+4storeyistakenandsameliveloadis applied in three the buildings for its behavior andcomparison.

The framedbuildingsaresubjected tovibrationsbecauseof earthquake and therefore seismic analysis is essentialfor these building frames. The fixed base system isanalyzedbyemployinginthreebuildingframesinseismiczoneIVbymeansofSTAADPro.Software.Theresponseofthree the building frames is studied for usefulinterpretationofresults.

2.1STEPSFORCOMPARISON

Comparisons of results in terms of horizontal reaction,

bendingmoments,axialforce.Followingstepsareadoptedinthisstudy

Step‐1 Selection of building geometry and Seismic zone:The behavior of three the models is studied for seismiczone IV of India as per IS code 1893 (Part 1):2002 forwhichzonefactor(Z)is0.24.

Step‐2Formationofloadcombination

Types of Primary Loads and Load Combinations: ThestructuralsystemsaresubjectedtoPrimaryLoadCasesasper IS 875:1987 and IS 1893:2002.Six primary load caseandthirteenloadcombinationsusedforanalysis.

Step‐3 Modelling of building frames using STADD Pro.Software

Step‐4 Analysis of three the building frames are doneunderseismiczoneIVforeachloadcombination.

Step‐5 Comparative study of results in terms of bendingmomentsandhorizontal force in footings, axial forceandbendingmomentincolumns.

3.MODELLING

STAAD Pro. Software is used in modeling of buildingframes. STAAD stands for Structural analysis and designProgramanditisgeneralpurposesoftwareforperformingtheanalysisanddesignofawidevarietyofstructures.Thebasicactivitieswhicharetobecarriedouttoachievethisgoal:

a.Geometryofthestructure

b.Providingmaterialandmemberproperties

c.Applyingloadsandsupportconditions

3.1NOMENCLATUREOFSTRUCTURALMODELS

Apropernomenclatureforjointandmembersnumberingis very important as it gives the exact idea where thejoint/memberislocatedintheentirestructure.Thenodes,beams and columns numbering is according to the floornumbergivenintables.

Table‐1Numberingofnodesinstructure

NodeNo. Location

1‐25 Belowplinthlevel

51‐90 plinthlevel

101‐125 1ststorey

201‐225 2ndstorey

301‐325 3rdstorey

401‐425 4thstorey

Table‐2Numberingofcolumnsinstructure

ColumnsNo Location

1‐25Below plinthlevel

101‐125 1ststorey




4.ST

Struin pslop

201

301

401

Table‐3

Beam

51‐9

151

251

351

451

Figure

TRUCTURA

cturalmodellan, elevatioinggroundst

‐225

‐325

‐425

Numberingo

msNo

90

‐190

‐290

‐390

‐490

3:Nodenum

ALMODELS

ls fordifferen and 3D sttructuresinF

2ndstorey

3rdstorey

4thstorey

ofbeamsins

Location

plinthlevel

1ststorey

2ndstorey

3rdstorey

4thstorey

mberinginstr

ntslopinggrtructural modFig.4to7.

structure

ructure

roundareshdel of plane

hownand

Figure5

Figure.6:3

Figure4:Pl

5:Elevationo

3Dstructural

lanofbuildin

fplanegroun

modelofplaframe

ngframe

ndbuildingfr

anegroundbu

rame

uilding




Figu

F

Tab

MateDensDensYounPoisComStee

Tab

ure7:Elevati

igure8:3Dst

le‐4Material

erialpropertisityofRCCsityofMasonng’smodulussonratio,μ

mpressivestrel

le‐5Data/pa

ionofsloping

tructuralmobuilding

lpropertiesc

ies

nrysofconcrete,

ength,Fck

arametersfor

gground(15o

delofslopinggframe

consideredin

Val 25 20

EC 2.1 0.1

25 Fe4

rtheanalysis

o)buildingfra

gground(15o

nthemodellin

lueskN/m3kN/m317x104N/mm17N/mm2415

ofproblem

ame

o)

ng

m2

Description

Numberofs

NumberofbdirectionNumberofbdirection

Storeyheigh

Columnheigplinthbeam

Baywidthin

Baywidthin

Plansize

Buildinghei

Wallsthickninterior

Sizeofbeam

Sizeofcolum

Thicknessof

Buildingfram

4.1LOADINFollowinglo(a)DeadLoConsideringSelf wt. of s25=3.125kFloorFinishTotalfloorloMasonry wa12.4kN/mMasonrywaParapetwall(b)LiveLoaLiveLoadon(c)EarthQuAll thebuild(IV)

The earth qparametersa

Table‐6Seis

Seismicp

EarthQu

Response

Importan

Damping

SoilType

5.RESULTS

storey’s

baysinX‐

baysinZ‐

ht

ghtbelow

nX‐direction

nZ‐direction

ght

nessexterior,

m

mn

fallslabs

mesystem

NGCONDITIOadingareconoads:slabthicknesslab considerkN/m2load=1kN/oad=4.124kNall load oute

llloadinnerflload=1.25xad:ntypicalflooruakeLoads:ding framesa

quake loads aasperIS:189

smicparamet

parameters

akeZone

eReductionF

nceFactor

g

e

SANDDISC

n

n

0

0

0

Ordir

ONSnsideredfora

ss=125mmring 125mm

/m2N/m2er face = (3.

face=3.1x0.1x20x0.2=5k

rs=3kN/m2areanalyzed

are derived93(2002)

terinbuildin

Factor

CUSSION

Value/type

G+4

4

4

3.5m

1.5m

3m

3m

12×12m

14m

0.20m,0.10m

0.2m×0.3m

0.4m×0.4m

0.125m

naryRCmomesistingfram

analysis–

thick Slab =

.5‐0.4) x 0.2

1x20=6.2kkN/m

foroneseism

for following

ngframe

Data/Value

IV

3

1

5%

MediumSoil

m

m

m

ment‐me

= 0.125 x

20 x 20=

kN/m

miczone

g seismic




Theresultsofvariousanalysesfordifferentgroundslopes(0o, 7.5o, 15o) are presented and a comparative studybetween results of different slopes and plane ground ismadetoanalysestheeffectofslopinggroundonstructuralforces. In the present work horizontal reaction andbendingmoment in footingofstructure,bendingmomentin columns are compared for different ground slopesunder different seismic loads. The analysis resultsobtained in Staad Pro. are shown below in the form oftablesandgraphs.

5.1FOOTINGREACTIONINTHEBUILDINGFRAME

The footing reaction in the building frame systemdue tovarious analyses in terms of horizontal reaction, andComparison of horizontal reaction Fx (kN) in footing forvariousgroundslopesunderseismicloadsinX‐direction.

Table‐7ComparisonofhorizontalreactionFx(kN)infootingforvariousanalysesinX‐direction

FootingNo. Loadcase

Groundslope(indegree) Comparisonofvariousanalyses0 7.5 15

1 2 3 2/1 3/1

1 EQX ‐29.21 ‐89.91 ‐122.99 3.08 4.21

2 EQX ‐43.66 ‐50.88 ‐36.33 1.17 0.83

3 EQX ‐43.49 ‐25.15 ‐10.03 0.58 0.23

4 EQX ‐43.66 ‐12.24 ‐1.68 0.28 0.04

5 EQX ‐29.21 1.18 4.52 ‐0.04 ‐0.15

6 EQX ‐29.93 ‐92.14 ‐126.21 3.08 4.22

7 EQX ‐44.72 ‐52.14 ‐37.31 1.17 0.83

8 EQX ‐44.54 ‐25.78 ‐10.33 0.58 0.23

9 EQX ‐44.72 ‐12.56 ‐1.76 0.28 0.04

10 EQX ‐29.93 1.18 4.60 ‐0.04 ‐0.15

11 EQX ‐30.24 ‐93.04 ‐127.45 3.08 4.21

12 EQX ‐45.17 ‐52.65 ‐37.68 1.17 0.83

13 EQX ‐44.99 ‐26.04 ‐10.44 0.58 0.23

14 EQX ‐45.17 ‐12.69 ‐1.78 0.28 0.04

15 EQX ‐30.24 1.18 4.64 ‐0.04 ‐0.15

16 EQX ‐29.93 ‐92.14 ‐126.21 3.08 4.22

17 EQX ‐44.72 ‐52.14 ‐37.31 1.17 0.83

18 EQX ‐44.54 ‐25.78 ‐10.33 0.58 0.23

19 EQX ‐44.72 ‐12.56 ‐1.76 0.28 0.04

20 EQX ‐29.93 1.18 4.60 ‐0.04 ‐0.15

21 EQX ‐29.21 ‐89.91 ‐122.99 3.08 4.21

22 EQX ‐43.66 ‐50.88 ‐36.33 1.17 0.83

23 EQX ‐43.49 ‐25.15 ‐10.03 0.58 0.23

24 EQX ‐43.66 ‐12.24 ‐1.68 0.28 0.04

25 EQX ‐29.21 1.18 4.52 ‐0.04 ‐0.15Table‐7depicts thathorizontalreaction in footingsvariessignificantlyforvariousgroundslopesunderseismicloadinXdirection.SLOPE7.50providessignificantvariationof‐0.04 to3.08 times in the footingreaction (Fx) comparedtoSLOPE0o.Themaximumincreaseinratio3.08timesisfoundinfootingslocatedatlesserdepth(i.e.footingF1,F6,F11,F16andF21)whereasthemaximumdecreaseinratio

ofnearly‐0.04timesisfoundinfootingslocatedathigherdepth (i.e. footing F5, F10, F15, F20 and F25). Themaximumhorizontalreaction(Fx)infootingforSLOPE00is ‐45.17kN is found in footingF12andF14whereasthemaximumhorizontalreactioninfootingforSLOPE7.50is‐93.04 kN is found in footing F11. The sloping groundcausesincreaseoffootingreaction(Fx)forfootingslocated




atlesserdepthwhereasitdecreasesthisvalueforfootinglocatedathigherdepth.

SLOPE15o provides significant variation of 0.04 to 4.21times in the footinghorizontal reaction (Fx)compared toSLOPE 0o. The maximum increase in ratio 4.21 times isfoundinfootingslocatedatlesserdepth(i.e.footingF1,F6,F11,F16andF21)whereasthemaximumdecreasein

ratio of nearly 0.04 times is found in footings located athigher depth (i.e. footing F4, F9, F14, F19 and F24). Themaximumfootinghorizontalreaction(Fx)forSLOPE00is‐45.17 kN is found in footing F12 and F14 whereas the

maximumfootingreaction forSLOPE150 is ‐127.45kNisfound in footingF11.The slopinggroundcauses increaseoffootingreaction(Fx)forfootingslocatedatlesserdepthwhereas it decreases this value for footing located athigher depth. The maximum horizontal reaction (Fx) infootings value increases at lesser depth and maximumdeceases valueathigherdepth.Themaximumhorizontalreaction (Fx) in footings value significant change inearthquakeinZ‐direction.

Comparison of bending moment Mz (kN‐m) reaction infootingsinslopinggroundforvariousanalysesisdepictedintable8

Table‐8ComparisonofbendingmomentMzinfootingsforvariousanalyses(EQX)

FootingNo Loadcase


1 2 3 2/1 3/1

1 EQX 83.31 145.44 176.64 1.62 2.12

2 EQX 89.76 99.49 82.40 1.11 0.92

3 EQX 89.66 68.76 43.02 0.77 0.48

4 EQX 89.76 48.90 23.92 0.59 0.27

5 EQX 83.31 28.46 8.29 0.34 0.10

6 EQX 85.30 148.95 181.12 1.62 2.12

7 EQX 91.90 101.89 84.51 1.11 0.92

8 EQX 91.80 70.42 44.14 0.77 0.48

9 EQX 91.90 50.09 24.57 0.59 0.27

10 EQX 85.30 29.17 8.55 0.34 0.10

11 EQX 86.16 150.39 182.88 1.62 2.12

12 EQX 92.82 102.87 85.33 1.11 0.92

13 EQX 92.71 71.10 44.58 0.77 0.48

14 EQX 92.82 50.58 24.81 0.59 0.27

15 EQX 86.16 29.46 8.64 0.34 0.10

16 EQX 85.30 148.95 181.12 1.62 2.12

17 EQX 91.90 101.89 84.51 1.11 0.92

18 EQX 91.80 70.42 44.14 0.77 0.48

19 EQX 91.90 50.09 24.57 0.59 0.27

20 EQX 85.30 29.17 8.55 0.34 0.10

21 EQX 83.31 145.44 176.64 1.62 2.12

22 EQX 89.76 99.49 82.40 1.11 0.92

23 EQX 89.66 68.76 43.02 0.77 0.48

24 EQX 89.76 48.90 23.92 0.59 0.27

25 EQX 83.31 28.46 8.29 0.34 0.10Table‐8depictsthatbendingmomentreactionin footingsvaries significantly for various ground slopes underseismicloadinXdirection.SLOPE7.50providessignificantvariationof0.34to1.62timesinthefootingreaction(Mz)compared to SLOPE 0o. The maximum increase in ratio1.62timesisfoundinfootingslocatedatlesserdepth(i.e.footingF1, F6, F11, F16 andF21)whereas themaximum

decrease inratioofnearly0.34times is found in footingslocatedathigherdepth(i.e. footingF5,F10,F15,F20andF25).

Themaximumfootingmomentreaction(Mz)forSLOPE00is92.82kN‐misfoundinfootingF12andF14whereasthemaximumfootingreactionforSLOPE7.50 is150.39kN‐misfoundinfootingF11.Theslopinggroundcausesincreaseoffootingreaction(Mz)forfootingslocatedatlesserdepth




whehigh

SLOPtimeThefootiF16neardeptmaxmisfootifooti

Tablandfooti1.97toplinfo

Figfo

1

1

2

2

Horizontal R

eaction (kN

)

reas it decrherdepth.

PE15o provides in the footmaximum iings locatedandF21)whrly 0.10 timeth (i.e. footiximumfootinsfoundinfooingreactioningF11.

T

Force

Compo

HorizoReactiFx(kVerticReactiFy(kBendi

Momen(kN‐m

le‐9 depictscritical bendingvariessig7timesrespelaneground.ootingremain

gure13:Comootingbetwee

0

50

100

150

200

250

Plane g

reases this v

des significantingreactionincrease in rat lesser dehereas themes is found iing F5, F10greaction(MotingF12andforSLOPE15

Table‐9Comp

es/

nent

P

FootigNo

ontalionN)

12

calionkN)

13

ingntMzm)

14

that criticalding momengnificantlywictivelyforsloHowevercrinalmostsame

mparisonofcrenplaneand

build

ground Slopin

value for fo

nt variation(Mz)comparatio 2.12 tiepth (i.e. footmaximumdecin footings l0, F15, F20Mz)forSLOPdF14where50is182.88

parisonofcri

laneGround

1

ino. Valu

68.4

863.

139.

horizontal rt Mz (kN‐m)ithchangeinopinggroundticalvalueofefordifferen

riticalhorizonslopinggroudings

g ground 7.5 Slo

oting locate

of 0.10 toaredtoSLOPEmes is founting F1, F6,crease in ratiocated at hiand F25).E00is92.82easthemaximkN‐misfoun

iticalforcesin

Slopi

ueFootinNo.

47 11

25 14

77 11

reaction Fx) reaction inratioof2.85d(15o)compfverticalreacntgroundslop

ntalreactionunds(7.5o,15

oping ground 15

d at

2.12E0o.d inF11,ioofgherThe

2kN‐mumndin

nfootingfor

ingGround(7

2

ng Va

145

868

226

(kN)n the5andaredctionpes.

ino)

The slopingreaction(MzitdecreasesSeismic inmomentoffo

5.1 CRITICFRAME

Comparisonandbendingforvariousa

differentgro

7.50) Slo

alueFoogN

5.68 1

8.05 1

6.38 1

Figure14footingbe

5.2BENDIN

Thebendingtovariousan

0

50

100

150

200

250

300

Bending Moment (kN‐m

)

ground cauz)forfootingthisvaluefoZ‐directionootinginslop

CAL FORCES

of critical hgmomentinfanalyses

undslopesfo

opingGround

3

otinNo. V

1 1

4 8

1 2

4:Comparisonetweenplane

NGMOMENT

gmomentintnalysesisdep

Plane ground

ses increasegslocatedatorfooting locsignificant

pinggrounds

S IN FOOT

orizontal forfootingfordi

orvariousan

d(150)C

2Value

95.29 2

73.72 1

75.97 1

nofcriticalbandslopingbuildings

INTHECOLU

thecolumnsopictedinTabl

Sloping ground

of bendinglesserdepthcatedathighechange instructures.

TING OF BU

rces, verticalfferentgroun

alyses

Comparisonofvariousanalysis

2/1 3/1

.13 2.85

.01 1.01

.61 1.97

bendingmomgrounds(7.5

UMNS

ofslopinggrole‐10

d 7.5 Sloping gro

momentwhereaserdepth.bending

UILDING

reactionndslopes

mentin5o,15o)

ounddue

und 15




Comparison of bending moment Mz (kN‐m) in columnsbelowplinthlevelforvariousgroundslopesunderseismic

loadsinX‐direction.

Table‐10ComparisonofbendingmomentMz(kN‐m)infootingcolumnsforvariousanalyses(EQX)

ColumnNo

Loadcase Nodes


1 2 3 2/1 3/11 EQX 51 ‐39.49 ‐10.58 7.81 0.27 ‐0.20

1 83.31 145.44 176.64 1.75 2.122 EQX 52 ‐24.27 ‐2.82 1.14 0.11 ‐0.05

2 89.76 99.49 82.40 1.11 0.923 EQX 53 ‐24.43 ‐10.92 ‐11.94 0.45 0.49

3 89.66 68.76 43.02 0.77 0.484 EQX 54 ‐24.27 ‐15.85 ‐17.38 0.65 0.72

4 89.76 48.90 23.92 0.54 0.275 EQX 55 ‐39.49 ‐32.12 ‐29.52 0.81 0.75

5 83.31 28.46 8.29 0.34 0.106 EQX 56 ‐40.41 ‐10.75 8.17 0.27 ‐0.20

6 85.30 148.95 181.12 1.75 2.127 EQX 57 ‐24.83 ‐2.83 1.28 0.11 ‐0.05

7 91.90 101.89 84.51 1.11 0.928 EQX 58 ‐24.99 ‐11.13 ‐12.14 0.45 0.49

8 91.80 70.42 44.14 0.77 0.489 EQX 59 ‐24.83 ‐16.18 ‐17.72 0.65 0.71

9 91.90 50.09 24.57 0.55 0.2710 EQX 60 ‐40.41 ‐32.83 ‐30.16 0.81 0.75

10 85.30 29.17 8.55 0.34 0.1011 EQX 61 ‐40.79 ‐10.84 8.28 0.27 ‐0.20

11 86.16 150.39 182.88 1.75 2.1212 EQX 62 ‐25.06 ‐2.85 1.31 0.11 ‐0.05

12 92.82 102.87 85.33 1.11 0.9213 EQX 63 ‐25.23 ‐11.22 ‐12.24 0.44 0.49

13 92.71 71.10 44.58 0.77 0.4814 EQX 64 ‐25.06 ‐16.33 ‐17.88 0.65 0.71

14 92.82 50.58 24.81 0.54 0.2715 EQX 65 ‐40.79 ‐33.13 ‐30.44 0.81 0.75

15 86.16 29.46 8.64 0.34 0.10

Table‐10depicts thatbendingmoment in columnsvariessignificantlyforvariousgroundslopesunderseismicloadinXdirection.SLOPE7.50providessignificantvariationof0.11to1.75timesinthebendingmomentincolumn(Mz)compared to SLOPE 0o. The maximum increase in ratio1.75timesisfoundincolumnslocatedatlesserdepth(i.e.column C11) below plinth level. Whereas the maximumdecreaseinratio0.11timesisfoundincolumnslocatedatintermediate depth (i.e. column C2, C7 and C12) belowplinth level. The maximum bending moment in column(Mz) for SLOPE 00 is 92.82kN‐m is found in column (i.e.C12) whereas themaximum bendingmoment in columnforSLOPE7.50is150.39kN‐misfoundincolumnC11.Thesloping ground causes increase in bending moment forcolumns locatedat lesserdepthwhereas itdecreasesthis

value for column located at higher depth below plinthlevel.

SLOPE 150 provides significant variation of ‐0.05 to 2.12timesinthebendingmomentincolumn(Mz)comparedtoSLOPE 0o. The maximum increase in ratio 2.12 times isfoundincolumnslocatedatlesserdepth(i.e.columnC11)belowplinthlevelWhereasthemaximumdecreaseinratio‐0.05times is found in columns located at intermediatedepth(i.e.columnC2,C7andC12)belowplinthlevel.

Themaximumbendingmomentincolumn(Mz)forSLOPE00is92.82kN‐misfoundincolumn(i.e.C12)whereasthemaximum bending moment in column for SLOPE 150 is182.88kN‐m is found in columnC11. The sloping groundcauses increase of bending moment in column (Mz) forcolumns locatedat lesserdepthwhereas itdecreasesthisvalue for column located at higher depth in belowplinth




level. BendingmomentMz (kN‐m) in columnsbelowandaboveplinthlevelforvariousgroundslopesunderseismicloadsinZ‐directionisminutelyaffected.

5.2CRITICALFORCESINCOLUMNOFBUILDINGFRAME

Comparison of critical axial forces Fx (kN) and bendingmomentMz(kN‐m)incolumnsforvariousgroundslopesarediscussedforvariousanalyses.

Table11‐Comparisonofcriticalforcesincolumnfordifferentgroundslopesforvariousanalyses

Forces/

Component

PlaneGround SlopingGround(7.5o) SlopingGround(15o)Comparisonofvariousanalysis

1 2 3

3/1Column

No. Value

Column

No. Value

Column

No. Value

2/1

AxialForceFx(kN)

13 863.25 14 868.10 14 873.72 1.01 1.01

BendingMomentMz(kN‐m)

14 139.78 11 226.40 11 276.00 1.62 1.97

Table‐11depictsthatcriticalbendingmomentMz(kN‐m)in the column increases significantlywith change in ratioof1.97times forslopingground(15o)comparedtoplaneground. However critical value of vertical reaction incolumnremainsalmostsamefordifferentgroundslopes.

Figure 15: Comparison of critical bending moment incolumn between plane and sloping grounds (7.5o, 15o)buildings

Figure 16: Comparison of critical axial force in columnbetweenplaneandslopinggrounds(7.5o,15o)buildingsFigure 17 and figure18 shows the bending moment inplane ground and sloping ground (15o) building changesaccordinglyvaryingdepth.Graphsshowsclearthathigherbendingmomentinsmallerdepthsideanddecreaseswithincreaseindepth.0

50

100

150

200

250

300

Plane ground Sloping ground 7.5 Sloping ground 15

Bending moment (kN‐m

)

500

550

600

650

700

750

800

850

900

Plane ground Sloping ground 7.5 Sloping ground 15

Axial Force (kN

)




F

Fi

6.C

The

a)

b)

Figure17:Ben

igure18:Bend

ONCLUSION

followingcon

Thecriticalhfootingincreslope. Howefooting remslopes.Thecriticalbsignificantlyplanegroundcolumn rem

ndingmomenbuilding

dingmoment(15o)build

NS

nclusionsma

horizontal foeasessignificaver critical v

main almost

bendingmomfor slopingd.However cmains almost

ntdiagramofgframe

tdiagramofsdingframe

aybedrawnf

orcesandbenantlywithinvalues of versame for d

ment in thecground (15

criticalvaluet same for d

f planegroun

slopinggroun

fromthestud

ndingmomenncreaseingrortical reactiodifferent gro

column incre5o) comparedeof axial forcdifferent gro

d

nd

dy:

nt inoundon inound

easesd toce inound

slopes.Ttoconta

REFERENC1. Montgom

seismic1981;8:

2. IS 875(Design lIndianStephenstatic awinter,Commenbuilding

3. Wilson,DynamicDeltaEff

4. Paul, Dbuildingearthqua1993,pp

5. Paul, D.KSlope wEarthqu

6. Kumar,forElastEarthqu

7. Satishconfigurstructur185.

8. SatishKfrom seengineer

9. Tagel‐DiMethodand app/Earthq

10. VamvatDynamicStructur

11. BIS.(20forEarthGeneralDelhi,Bu

12. IS 189ResistanProvisioIndianS

13. NalawaSlopingPuneDe

Thus,thesecinmoresteel

CES

mery CJ. “Idesign”,Can:pp31‐43.

1987), Indialoads for buiStandards,

n Pyle, Practiand dynamic1998 FEMAntary forgs,AmericanS

E.L., Eeri, McAnalysisoffects”,Earthq

.K. “Simplifigs on hill sloake technolop113‐124.

K. and Kumawith BuildinuakeEngineer

S.,andPaul,ticSeismicAnuakeEngineer

Kumar andration from sralEngg.Vol.

Kumar&Pauleismic consiring,Vol26,N

in Hatem, Kforsimulatioplication foruakeEng.,JSC

tsikos D., Coc Analysis.ralDynamics,

002).IS1893hquakeResisProvisionsaureauofIndia

93 (Part‐I)nt Designons and Builtandards,Ne

de S.S. “SeiGround,”M.Eec‐2003.

ctionof theseltoprovidea

nfluence ofadianJourna

an Standardildings and sNew Delhi.ical three‐dimc analysis,A‐356(2000)the seismicSocietyofCiv

M. and Habibf MultiStoryquakespectra

ied seismicopes Bulletinogy, Vol 30,

ar, S. (1997)ng Loads.ring,16,pp39

D.K.(1998).nalysisofHilring2:(2),2

d Paul. Dseismic cons26,No.3,Oc

D.K.,Hillbuiderations, JoNo3,Oct.1999

Kimiro Meguronofnonliner RC structuCE,Vol17,N

ornell C.A.Earthquake

,31(3):491–

3(Part1)IndstantDesignndbuildingsanStandards

2002: Criteof Structurldings, FifthewDelhi.

ismic AnalysE.Dissertatio

ecolumnsisagreaterresis

seismic efalofCivilEng

Code of prastructures, BAshraf Ha

mensional noStructure M, Pre standc RehabilitavilEngineers,

bullah, A. “StBuildingIncla,3,2(1987)

analysis of of Indian SNo4, paper

Stability AnSoil Dynam95‐405.

ASimplifiedlBuildings.Jo41‐266.

.K., “Hill bideration”, Joctober1999,

ildingsconfigournal of S9,pp179‐185

ro., Appliedearmaterialsures, Structuo.2,2000.

(2002). Incre Engineeri514.

dianStandardofstructures(FifthRevisis.

eria for Earres, Part‐IRevision, B

sis of Buildn,University

requiredstance.

ffects ongineering

actice forBureau ofabibullah,on‐linearMagazine,dard andation of,USA.

tatic andludingP‐.

f framedociety of335,Dec

nalysis ofmics and

dMethodournalof

buildingsournal ofpp.179‐

gurationstructural5.

Elements:Theoryural Eng.

rementaling and

dcriterias,Part1:on).New

rthquakeGeneralureau of

dings onyofPune,




14.

15.

16.

17.

18.

19.

20.

Bozorgnia YFrom EngineEngineering"

Birajdar B.Ganalysis of bConferenceo‐30August2

Birajdar B.Analysis ofThirteenthEngineeringNo.1472.

HajraBandonTallBuildKolkata,pp2

Agarwal P.resistant desPrivateLimitCouncil (199ConcreteBui

C.V.R. MurtyIndia EarthTechnologyP

Emrah erdunonlinear sttorsionaleffeground”, En2558.

Y, Bertero Veering Seism",CRCPress,

G., Nalawade.buildings reonOurWorld2002,Singapo

G., and NaBuildings ReWorld Co(13WCEE).

GodboleP.Ndings Indian285‐292.

and Shrikhsign of structed,NewDel96): Seismicildings,ATC‐4

y, Indian Insthquake TipPromotionCo

uran (2008)tatic procedectsinlow‐ringineering St

V, "Earthquamology to Per2004.

. S.S., 13WCEsting on slodinConcreteore.

alawade S. Sesting on Sloonference oVancouver,

N.(2006).“AloCodalProvis

hande M. 20ctures (Prenthi,India)Appc Evaluation40,Vol.1.

titute of Tec, Buildingouncil,NewD

), “Assessmdures on thiseframebuitructures 30

ake Engineerrformance‐Ba

EE 2004 Seisping gro&Structures

S. 2004. Seisoping Groundon Earthqu Canada, P

ongSeismicLsions.”3NCW

006, Earthqutice‐Hall of IpliedTechnoand Retrofi

hnology KanMaterials

Delhi,India.

ment of cure estimationildingsinslo0 (2008): 25

ring:ased

smicund.s:29

smicd. Inuakeaper

LoadWE06

uakendiaologyit of

npur,and

rrentn ofping548‐

BIOGRAPH

HY

Sujit KGraduateStructuralDepartmenEngineerinBhopal, MIndia

Dr. VivAssistantPEngineerinMANIT, BPradesh,In

Dr.AbhaAssociateEngineerinMANIT,BhPradesh,In

Kumar, PStude

Engineernt of Cng MANMadhya Prade

vek GaProfessor,Civng DepartmBhopal, Madhndia

aySharma,Professor,CingDepartmenhopal,Madhyndia

Postent,ringCivilNIT,esh,

arg,vilmenthya

ivilntya




effect of sloping ground on structural … · · 2014-09-01the structural analysis software staad...

Documents