International Research Journal of Engineering and Technology (IRJET)e-ISSN: 2395 -0056 Volume: 02 Issue: 4 | July-2015www.irjet.net p-ISSN: 2395-0072 2015, IRJET.NET- All Rights Reserved Page 1407 Numerical Investigation on Concrete Shear Wall with Different Percentages of Openings Tejus S1, Prashant Sunagar2,Research Scholar, Department of Civil Engineering, M.S.Ramaiah Institute of Technology, Bangalore, Karnataka, India1 Assistant Professor, Department of Civil Engineering, M.S.Ramaiah Institute of Technology, Bangalore, Karnataka, India2 ---------------------------------------------------------------------***--------------------------------------------------------------- Abstract:This investigation was carried out inorder todeterminetheefficiencyofaRCCshearwall systemforatenstoreybuildingoftwodifferent thicknesseswithdifferentpercentageofopeningsin it.TheshearwallwasdesignedbasedonIndian standards using Etabs Software. A total of ten models wereconsideredforthisstudy,outofwhichfiveare of125mmthicknessshearwallandtherestareof 150mmthicknessshearwall.Theseweremodelled usingETABSsoftware.Thefivemodelsarebare frame,completeshearwall,Shearwallwith5% opening, shear wall with 20% opening and with 50% opening.Comparisonsweremadebetweenbare frame,125mmthickcompleteshearwalland150 mmthickcompleteshearwall.Alsoin125and150 mmwalls comparisons were madebetween thebare frameandcompleteshearwallmodels.The parametersconsideredforthecomparisonswere Lateraldisplacement,BaseshearandLateralstorey forces. It was found that the displacements were well withinthepermissiblelimitandtheshearwallwith 150 mm thickness and 20% opening was found to be the most efficient. Keywords:Shearwall,Openings,Finitemodelling, Lateral storey displacements, Storey forces I.INTRODUCTION Shearwallsareoneoftheexcellentmeansof providingearthquakeresistancetomulti-storeyed reinforcedconcretebuilding.Behaviorofstructure during earthquake motion depends on distribution of weight,stiffnessandstrengthinbothhorizontaland planesofbuilding.Theprovisionofshearwallin buildingtoachieverigidityhasbeenfoundeffective andeconomical.Shearwallsmaybedefinedasthe walls that are entirely responsible for the lateral load resistanceofthebuilding.Theintroductionofshear wallrepresentsastructurallyefficientsolutionto stiffen a building structural system because the main functionof ashearwallistoincreasetherigidityfor lateralloadresistance.Thewallsarestructurally integratedwithdiaphragmsandotherlateralwalls runningacrossatrightanglesthereby,givingthe threedimensionalstabilityforthestructures.Shear wallstructuralsystemsaremorestable,because their supporting area (total cross-sectional area of all shearwalls)withreferencetototalplanareaofthe building,iscomparativelymore,unlikeinthecaseof RCCframedstructures.Shearwallsinapartment buildingswillbeperforatedwithrowsofopenings thatarerequiredforwindowsinexternalwallsor doorwaysandcorridorsininternalwalls.However the opening sizes in the shear wall building may have anadverseeffectonseismicresponsesofframe-shear wall structures. Relative stiffness of shear walls is important since lateral forces are distributed to the individualshearwallaccordingtotheirrelative stiffness.Simplifiedmethodsforstiffnessofshear wallswithopeningsarerecommendedinseveral designguidelines.Itisnecessarytoknowtheeffects of openings sizes and configurations in shear wall on stiffnessaswellasonseismicresponsesand behaviorofstructuralsystemsothatasuitable configuration of openings in shear walls can be made. In this study linear static analysis is performed on 10 storeybuildingprovidingopeningintheshearwall, withfiniteelementsoftware(ETABS)under earthquakeloads.Here,anattemptismadetostudy the behaviour of shear wall with different percentage ofopeningssoastoarriveattheoptimum percentageofopeningthatcanbeprovidedina structure.Thetopdisplacementandthebaseshear parameters are considered for the study.Themainobjectiveoftheresearchisto investigate the following. 1)Tostudytheeffectofshearwallsina structure under the action of lateral loads.2)Todeterminetheeffectofpercentageof openings in shear wall under the action of lateral loads in buildings with help of comparison. International Research Journal of Engineering and Technology (IRJET)e-ISSN: 2395 -0056 Volume: 02 Issue: 4 | July-2015www.irjet.net p-ISSN: 2395-0072 2015, IRJET.NET- All Rights Reserved Page 1408 Figure 1 Pictorialrepresentation of Shear Wall II. METHODOLOGY Modellingof 10storey,15m15mbayframeshear wall building, with floor height of 3.2m,bottom storey height4m,havingwindowopenings,locatedatthe centerofthewallwithvaryingpercentageof openingsi.e.5%,20%&50%iscarriedoutwiththe help of Etabs -9.7.4 software package. Analysisiscarriedoutwithrespecttoshearwall placed in plane of loading. Earthquake load is applied consideringthezoneco-efficientofzonev,response reductionfactorof3forsoftsoilandimportance factor of 1. The results obtained are compared for the displacementandbaseshearatdifferentstorey levels for different percentage of openings. Modelling ofshearwallpanel5m3.2m0.15mwith50% openingiscarriedoutusingAnsysSoftwarepackage andthecrackpatternfortheappliedlateralloadis studied. Geometrical details of the model A10-storybuildingwitha3.2metersstoreyheight and4mbottomstoreyheight,regularinplanand withashearwalls,isadoptedforthestudy.This buildingconsistsoft h r e e spansof5-meterinX directionandthree5-meterspansinYdirection. Shear walls areplacedinthemiddlespanalongthe Xdirection.Themodelledbuildingisshownin Figurebelow. The live load is taken as 3.0 KN/m2 for all typical floors and 1.5 KN/m2 for roof and 2 KN/m2 as SDL for wall and finishing load. Figure 2 Shear wall building system Cross Sectional and Material Properties for structural elements Allbeamsandcolumnsareofsizes230x450and 500x500respectively.Allslabsandshearwallsare 150mmthick.M25concretegradeisusedforall beams,columns,slabsandshearwalls.Material propertieslikeModulusofelasticity,Poissonsratio, densityofconcretearetaken25000N/mm2,0.2and 25kN/m2 respectively.Inthispaper,thebehaviorof 10storeybuildingwithshearwallisevaluatedby numericalmethodsundertheactionofearthquake forces and compared the different models of different percentagesofopeningsbytheparameterslike displacement, base shear and storey drift. UsingthesoftwarepackageEtabsversion9.7.4,five modelsaredeveloped,forbareframewithoutshear wall, frame with complete shear wall, shear wall with 5%,20%and50%openingswithshearwall thickness125mmandsimilar5moremodelswith shear wall thickness 150mm.Displacements and base shearfordifferentmodelssubjectedtoearthquake forceofSeismicZoneVaredeterminedbycarrying outequivalentlinearstaticanalysisinEtabs.Bare frameandframewithcompleteshearwallare comparedfordisplacementandbasesheartostudy the significance of shear wall in resisting lateral force suchasearthquake.Shearwallwithdifferent percentageofopeningsareanalysedforthesame earthquakeforceandcomparedwithframewith completeshearwalltostudytheeffectofdifferent percentages of openings in the shear wall. International Research Journal of Engineering and Technology (IRJET)e-ISSN: 2395 -0056 Volume: 02 Issue: 4 | July-2015www.irjet.net p-ISSN: 2395-0072 2015, IRJET.NET- All Rights Reserved Page 1409 III. RESULTS AND DISCUSSIONS Lateral displacement: The maximum lateral displacement values obtained for earthquakes in X and Y direction from theanalysisof10storeyframedbuildingforBareframe,forcompleteshearwallandfortheshearwallswith different percentage of openings i.e., (5%, 20% and 50%) at each storey level for two shear wall thickness of 125mm and 150mm separately and are tabulated as shown below. Case 1: 125mm thick Shear wall Table 1 Displacement in mm along X & Y directions at different storey levels Storey No. Bare frame CSW 125 5%SWO 20% SWO 50% SWO 121.452.893.1234.2911.11 245.647.397.7959.8824.55 370.4813.33 13.8716.7639.40 494.9020.29 20.9524.5354.47 5118.21 27.92 28.6632.8369.122 6139.68 35.87 36.693 41.319 82.81 7158.51 43.88 44.7549.7095.02 8173.76 51.73 52.6257.51105.22 9184.57 59.27 60.1665.19112.96 10190.79 66.37 67.0771.79118.23 0501001502002500 5 10 15Displacement (mm)Storey numberStorey NumberVs. DisplacementBare frameCSW5% SWO20%SWO50%SWO Figure 3 Figure 3: Variation of displacement in mm along X and Y direction for Bare frame, CSW125, 5%SWO, 20%SWO and 50%SWO. Case 2: 150mm thick Shear wallTable 2: Displacement in mm along X and Y direction at different storey levels Storey no. Bare frame CSW 150 5% SWO 20% SWO 50% SWO 121.452.742.913.9510.504 245.647.0297.379.2323.44 370.4812.7613.2315.8237.90 494.9019.5220.0923.3052.63 5118.2126.9427.5931.3366.98 6139.6834.7335.4339.5880.41 7158.5142.5843.3247.7792.40 8173.7650.3051.0655.63102.44 9184.5757.7558.5263.04110.11 10190.7964.8265.4069.64115.41 International Research Journal of Engineering and Technology (IRJET)e-ISSN: 2395 -0056 Volume: 02 Issue: 4 | July-2015www.irjet.net p-ISSN: 2395-0072 2015, IRJET.NET- All Rights Reserved Page 1410 0501001502002500 5 10 15Displacement (mm)Storey numberStorey NumberVs. DisplacementBare frameCSW5% SWO20%SWO50%SWOFigure 4 Figure 4: Variation of displacement in mm along X and Y direction for Bare frame, CSW150, 5%SWO, 20%SWO and 50%SWO. 0501001502002500 5 10 15Displacement (mm)Storey NumberBare frameCSW 125CSW 150Figure 5: Variation of displacement in mm along X and Y direction for Bare frame, CSW125 and CSW150 Figure3,showsthecomparisonofdisplacementsat different storey levels of the 10 storiedbuildingwith shearwall of thickness 125mmbetween,when there willbenoopeninginshearwallandwhentherewill differentpercentageofopenings.Itcanbeobserved thatthevariationofdisplacementcurvesforthe models05SWO,20SWOand50SWOareclosely spacedwhencomparedwiththemodelCSW. Whereas,thevariationofdisplacementcurveforthe models20SWOand50SWOaresignificant.Thisis duetodecreaseinthestiffnessofthestructurewith increasing percentage of opening. Figure4,showsthecomparisonofdisplacementsat different storey levels of the 10 storiedbuildingwith shearwall of thickness 150mmbetween,when there willbenoopeninginshearwallandwhentherewill bedifferentpercentageofopenings.Itcanbe observedthatthevariationofdisplacementcurves for the models 5SWO, 20SWO and 50SWO are closely spacedwhencomparedwiththemodelCSW. Whereas,thevariationofdisplacementcurveforthe models20SWOand50SWOaresignificant.Thisis duetodecreaseinthestiffnessofthestructurewith increasing percentage of opening. In Figure 5, it can be observed that at the first storey thedisplacementisalmostsame.But,asthestorey heightincreasesthedisplacementalsoincreasesand thedisplacementismaximumatthetopmoststorey. Itisalsoobservedthatthedisplacementatdifferent storeyheightsforcompleteshearwallis comparativelylessthanthatofBareframe.Thisis duetotheincreaseinthestiffnessofthestructure duetopresenceofshearwall.Theresultsarebased on linear static method of analysis. Toplateraldisplacement:Themaximum displacementatthetopstoreyforeachmodelhas beenconsideredforthestudywhichistabulated below. Table 3: Top lateral displacements along X direction for all the models of 125mm thick Shear wall ModelsDisplacementsalongX direction in mm Bare Frame190.79 CSW66.37 5%SWO67.07 20%SWO71.79 50%SWO118.23 International Research Journal of Engineering and Technology (IRJET)e-ISSN: 2395 -0056 Volume: 02 Issue: 4 | July-2015www.irjet.net p-ISSN: 2395-0072 2015, IRJET.NET- All Rights Reserved Page 1411 190.7966.37 67.0771.79118.23050100150200250Top storey Displacements in mm(SW125)Displacementin mm Figure 6: Variation of top displacement in mm along X direction for bare frame, CSW, 5%SWO, 20% SWO, 50%SWO in model with shear wall of 125mm Table 4: Top lateral displacements along X direction for all the models of 150mm thick Shear wall. ModelsDisplacements along X direction in mm Bare Frame190.79 CSW64.82 5% SWO65.40 20% SWO69.64 50%SWO115.41 190.7964.82 65.4 69.64115.41050100150200250Top Storey Displacements in mmDisplacements along X direction in mmFigure 7: Variation of top displacement in mm along X direction for Bare frame, CSW, 5%SWO, 20%SWO, 50%SWO in model with Shear Wall of 150mm Baseshear:Theabovemodelsarealsoanalysedfor the base shear values and are tabulated as below Table 5: Maximum base shear values along X direction for 125mm thick shear wall ModelsBase shear in KN Bare frame3760.81 CSW4013.94 5% SWO3999.90 20% SWO3967.43 50% SWO3886.99 Table 6: Maximum base shear values along X direction for 150mm thick shear wall ModelsBase shear in KN Bare frame3760.81 CSW4064.57 5% SWO4047.72 20% SWO4008.76 50% SWO3912.23 International Research Journal of Engineering and Technology (IRJET)e-ISSN: 2395 -0056 Volume: 02 Issue: 4 | July-2015www.irjet.net p-ISSN: 2395-0072 2015, IRJET.NET- All Rights Reserved Page 1412 3760.814013.943999.93967.433886.994064.574047.724008.763912.2336003650370037503800385039003950400040504100Bare frameCSW 5% SWO20% SWO50% SWOMaximum Base shear in kNSW125SW150Figure 8 Comparison of base shear in KN along X direction for 125mm and 150mm thick shear wall for the different cases- Bare frame, CSW, 5% SWO, 20% SWO and 50% SWO Table 7: LATERAL STOREY FORCES (KN) For Shear Wall of thickness 125mm Storey number Bare frame CSW125 5%SWO 20%SWO 50%SWO 116.4417.6717.5517.3417.02 252.5656.1155.9155.4154.27 3 109.66 117.06116.66115.62113.23 4 187.52 200.19199.49197.71193.63 5 286.14 305.48304.42301.80297.47 6 405.53 432.93431.42427.57418.76 7 545.69 582.56580.53575.34563.48 8 706.60 754.351 751.72745.01729.64 9 888.28 948.307 945.01936.56917.24 10 562.40 599.264 597.15595.15584.24 010020030040050060070080090010001 2 3 4 5 6 7 8 9 10Bare frameCSW125Figure 9:Comparison of Later Storey Forces for Shear wall of 125 mm thick Table 8: LATERAL STOREY FORCES (KN) For Shear Wall of thickness 150mm Storey number Bare frame CSW150 5%SWO 20%SWO 50%SWO 116.4417.9217.7817.5317.13 252.5656.8256.5855.9854.61 3109.66 118.55118.06116.8113.95 4187.52 202.73201.89119.15194.86 5286.14 309.35309.07304.80297.34 6405.53 438.42436.61431.78421.4 7545.69 589.94587.5581.28567.04 International Research Journal of Engineering and Technology (IRJET)e-ISSN: 2395 -0056 Volume: 02 Issue: 4 | July-2015www.irjet.net p-ISSN: 2395-0072 2015, IRJET.NET- All Rights Reserved Page 1413 8706.60 763.90760.75752.69734.25 9888.28 960.31956.35946.22923.04 10562.40 606.64604.13601.72588.61 0200400600800100012001 2 3 4 5 6 7 8 9 10Bare frameCSW1505%SWO20%SWO50%SWOFigure 10:Comparison of Later Storey Forces for Shear wall of 150 mm thick Discussions: Bare Frame results compared with CSW (solid shear wall without opening) for Shear Wall 125mm thick and 150 mm thick respectively are: PercentagedecreaseinbaseshearinbothX and Y direction is 6.30% & 7.47% Percentageincreaseintopstoreylateral displacement in X and Y direction is65.21% & 66.03 % Percentagedecreaseinlateralstoreyforces instoreynumber9[Maximumvalue]is6.33% &0.075%5%SWO(Shearwallwith5%opening)results comparedwithCSW(solidshearwallwithout opening) PercentagedecreaseinbaseshearinbothX and Y direction is 0.34% & 0.41% Percentageincreaseintopstoreylateral displacementinXandYdirectionis1.04% & 0.88% Percentagedecreaseinlateralstoreyforces instoreynumber9[Maximumvalue]is0.34% & 3.88% 20%SWO(Shearwallwith20%opening)results comparedwithCSW(solidshearwallwithout opening) PercentageincreaseinbaseshearinbothX and Y direction is 1.15% & 1.37% Percentagedecreaseintopstoreylateral displacement in X and Y direction is 7.54% & 6.92% Percentagedecreaseinlateralstoreyforces instoreynumber9[Maximumvalue]is0.012% & 0.015% 50%SWO(Shearwallwith50%opening)results comparedwithCSW(solidshearwallwithout opening) PercentageincreaseinbaseshearinbothX and Y direction is 3.16 % & 3.74% Percentagedecreaseintopstoreylateral displacement in X and Y direction is 43.86% & 43.82 % Percentagedecreaseinlateralstoreyforces instoreynumber9[Maximumvalue]is2.66% & 7.5% III. CONCLUSIONS Generally,withincreaseinweightofthebuilding, baseshearalsoincreases.Thebaseshearismorein CSWanditislessforthebareframe.Ifweconsider variouspercentagesofopeningsthenthebaseshear valuecanbeobservedmoreincaseofCSWand graduallydecreaseswiththeincreaseinthe percentage of opening. The value of base shear when comparedwiththemodelsof differentpercentageof openingswasfoundleastforthemodel50%SWO when compared with the model CSW. The model with leastbaseshearhasthehighestlateraldisplacement and in the top storey .It canbe observedthat the top lateraldisplacementtendstoincreasewiththe increasingpercentageofopeninginthebareframe, 5%SWO,20%SWOand50%SWOmodelswhen comparedwithCSWmodel.Thereisasignificant changeintheslopeofthecurveofthebareframe modelwhencomparedwithCSW.Theslopeofthe displacementcurvesforthemodels5%SWO, 20%SWOand30%SWOdonotvarysignificantly. Whereas,thedrasticchangeintheslopeofthe displacementcurveforthemodels20%SWOand 50%SWOareobservedwhencomparedwiththe CSWmodel.Thesameobservationcanbedrawnby goingthroughthepercentageincreaseinthelateral displacementfortopstoreysforalltheconsidered models.Thesignificantincreasesinthetoplateral International Research Journal of Engineering and Technology (IRJET)e-ISSN: 2395 -0056 Volume: 02 Issue: 4 | July-2015www.irjet.net p-ISSN: 2395-0072 2015, IRJET.NET- All Rights Reserved Page 1414 displacementinbothXandYdirectionofthe structureintermsof percentagecanbeobservedfor the model bare frame, CSW and 50%SWO. It has been observedthatLateralStoreyForcesaremaximumin the9thStorey(storeybelowtopstorey)and decreaseswithincreaseindisplacementand increases with decrease in base shear. ACKNOWLEDGEMENT We sincerely thank management, CE, Principal and HeadofDepartmentofM.S.RamaiahInstituteof Technology,Bangalore-560054,affiliatedtoVTU, Belgaum for all the technical guidance.

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