C.M. Ravi Kumar, M. B. Sreenivasa, Anil Kumar, M. Vijay Sekhar Reddy / InternationalJournal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.comVol. 3, Issue 3, May-Jun 2013, pp.646-652646 | P a g eSeismic Vulnerability Assessment Of Rc Buildings With ShearWallC.M. Ravi Kumar1, M. B. Sreenivasa2, Anil Kumar3, M. Vijay SekharReddy41Assistant Professor, Department of Civil Engineering, Visvesvaraya Technological University BDT College ofEngineering, Davangere, Karnataka, India2Department of Civil Engineering, Alvas Institute of Technology, Moodbidri, Karnataka, India.3Research Scholar, Department of Civil Engineering, National Institute of Technology Karnataka, Surathkal,Karnataka, India..4HOD, Department of Civil Engineering, Srikalahasti Institute of Technology, Srikalahasti, Andra Pradesha,India.AbstractReinforced concrete multi-storiedbuildings are very complex to model asstructural systems for analysis. The currentversion of the IS: 1893-2002 requires thatpractically all multi-storeyed buildings beanalyzed as three-dimensional systems. This isdue to the fact that the buildings have generallyirregularities in plan or elevation or in both.Seismic codes distinguish between regular andirregular configurations, and it is the latter thatthe irregularity may have a detrimentalinfluence on the effectiveness and on thebuilding seismic performance itself. The presentanalytical investigation proposes, discusses, andhighlights the seismic performance of RC(Reinforced Concrete) buildings having dualsystem with emphasis on various case studies.The study includes seismic vulnerabilityassessment of RC buildings without shear wall,with shear wall at centre, shear wall at diagonalcorners, shear wall at mid along X-direction,and shear wall at mid along Y-direction, lastlyshear wall at mid along X&Y-directions.Keywords: Seismic performance, evaluation,irregular RC building and shear wall,dual system1. IntroductionIt is a known fact that the Globe is facinga threat of natural disasters from time to time. Withparticular records based on earthquake occurrence,the consequences are loss of human lives anddestruction of properties, which ultimately affectsthe natural economy. The occurrence of anearthquake cannot be predicted and prevented butthe preparedness of the structures to resistearthquake forces become more important.However, more recently, several destructiveearthquakes, including the 1999 Athens (Greece)earthquake, the 1999 İzmit and Düzce earthquakes(Turkey), 1999 Chi Chi (Taiwan) earthquake, 2001Bhuj (India) earthquake, and the 2003 Boumerdes(Algeria) earthquake, have given more insights toperformance of RC frame constructions. Theseearthquakes are like a wake-up call to enforcebuilding and seismic codes, making buildinginsurance compulsory along with the use of qualitymaterial and skilled workmanship.India has experienced destructiveearthquakes throughout its history. Most notableevents of major earthquakes in India since 1819 to2001, in 1819 the epicenter was Kutch, Gujarat andlater in 2001 it was at Bhuj, Gujarat. In manyrespects, including seismological and geotechnical,the January 26, 2001 earthquake was a case ofhistory repeating itself 182 years later and hasmade the engineering community in India aware ofthe need of seismic evaluation and retrofitting ofexisting structures. Bhuj earthquake of 26 January2001 caused 14,000 casualties. Main reason forsuch huge casualties is low earthquake awarenessand poor construction practices, highlightinginherent earthquake safe character. Based on thetechnology advancement and knowledge gainedafter earthquake occurrences, the seismic code isusually revised. Last revision of IS 1893 (Criteriafor earthquake resistant design of structures) wasdone in 2002 after a long gap of about 18years.Some new clauses were included and some oldprovisions were updated. Assuming that concernedauthorities will take enough steps for codecompliance and the structures that are beingconstructed are earthquake resistant.Keeping the view of constant revision ofthe seismic zones in India, lack of proper designand detailing of structures against earthquake.Earthquake performance of RC bare frame hasbeen well documented in the past. Also, damagepatterns in reinforced concrete frames during thepast earthquakes have been extensively studied.But now a day‟s need and demand of the latestgeneration and growing population has made thearchitects or engineers inevitable towards planningof irregular configurations. Some of the poorplanning and construction practices of multi-storiedbuildings in Peninsular India in particular, whichlead to irregularities in plan and elevation of thebuildings. If the configuration is good the seismic
C.M. Ravi Kumar, M. B. Sreenivasa, Anil Kumar, M. Vijay Sekhar Reddy / InternationalJournal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.comVol. 3, Issue 3, May-Jun 2013, pp.646-652647 | P a g edesign will be simple and economical and goodperformance is more likely to be assured. If theconfiguration is bad the seismic design will beexpensive and good performance will be less thancertain. Hence earthquake engineering hasdeveloped the key issues in understanding the roleof building configurations.2. Reinforced Concrete Shear WallReinforced concrete walls, which includelift walls or shear walls, are usual requirement ofreinforced concrete multistory buildings.Constructing the shear wall in tall, medium andeven short buildings will effect and intern reinforcethe significantly and either more economical thanthe bending frames. By the shear, we can controlthe side bending of structure, much better thanother elements like closed frames and certainly theshear walls are more flexible than them. However,in many occasions the design has to be based onthe position of the lift and stair case walls withrespect to the center of mass. M. Ashraf, et al,(2008), studied that columns and beams forces arefound to increase on grids opposite to the changingposition of shear wall away from the centroid of thebuilding. Twisting moments in the members areobserved to be having increasing trend withenhancement in the eccentrically betweengeometrical centroid of the building and shear wallposition. They concluded that shear wall should beplaced at a point by coinciding center of gravity ofthe building. But the nature of stresses generated inthe shear wall according to its position is alsodifferent. The shear wall kept at very near to thecenter of stiffness act as a vertical bending elementand the shear wall kept at corner of the building aremay be compression or in axial tension accordingto the direction of the lateral force. In the bendingnature of the wall the drift generated is morecompare to shear wall kept at corner of thebuilding. So it is necessary and important to knowand investigate analytically/experimentally, whatshould be the location of the shear wall that caninduce minimum stresses in all the structuralmembers of the multistoried buildings.2.1. Structural systemThe structural system consists of shear wall (orbraced frame) and moment resisting frame suchthat: The two systems are designed to resist thetotal design force in proportion to theirlateral stiffness considering theinteraction of the dual system at all floorlevel. The moment resisting frames aredesigned to independently resist at least25% of design seismic base shear.In general, dual system comparably has a highervalue of “R” (response reduction factor), since asecondary lateral support system is available toassist the primary non-bearing lateral supportsystem3. Illustrative Examples3.1. Preliminary data for analysis Type of Structure : Multi Storeyed RCRigid Jointed Plane Frame (SpecialMoment Resisting Frame) Number of Stories: Ten ( G+9) ; 35m X25m Seismic Zone : V (Table 2, IS 1893 (Part-1):2002) Floor Height: 5m for Ground Floor, 4mfor other Floors & 3m below plinth. Infill wall: 230mm thick including plasterin longitudinal and transverse direction. Grade of Concrete: M40 for Ground, First& Second Floors Columns.M35 for Other FloorsColumns,M25 for Beams, Slabs& Shear wall Size of Columns : 600mmX600mm Size of Beams : 600mmX300mm Depth of Slab : 150mm thick Thickness of Shear Wall : 200mm Imposed Load : 3.0KN/m2 Floor Finish & Partitions : 2.0 KN/m2 Specific Weight of RCC : 25 KN/m3 Specific Weight of Infill : 18 KN/m3 Type of Soil : III Response Spectra : As per IS 1893 (Part-1) 2002 Damping : 5% Importance Factor : 1.5 Response reduction Factor : 5.0 Structural Software : ETABS Version 9.6Plan and 3D view of the illustrative exampleconsidered as depicted in Fig.1. The design ofshear wall (lift wall) at all floors (from bottom totop) was by ETABS software. The following arethe location of shear wall at different positions forvarious cases considered, which are as depicted inFig.2 (a) to 2 (e).
C.M. Ravi Kumar, M. B. Sreenivasa, Anil Kumar, M. Vijay Sekhar Reddy / InternationalJournal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.comVol. 3, Issue 3, May-Jun 2013, pp.646-652648 | P a g eFig.1 Plan and 3D –View of Model 1 (Case Study 1, R=5.0, I=1.5, Z=V, S=III, Without Shear wall)a) Case Study2; Model 2; R=5.0, I=1.5, Z=V, S=III,Shear wall at centreb) Case Study3: Model 3; R=5.0, I=1.5, Z=V, S=III,Shear wall at diagonal corners
C.M. Ravi Kumar, M. B. Sreenivasa, Anil Kumar, M. Vijay Sekhar Reddy / InternationalJournal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.comVol. 3, Issue 3, May-Jun 2013, pp.646-652649 | P a g ec) Case Study4; Model 4; R=5.0, I=1.5, Z=V, S=III,Shear wall at mid along X directiond) Case Study5; Model 5; R=5.0, I=1.5, Z=V, S=III,Shear wall at mid along Y directione) Case Study 6: Model 6; R=5.0, I=1.5, Z=V, S=III, Shear wall atmid along X&Y direction/ adjacent facesFig 2. Location of shear wall at different positionThe analysis and design of multistoried building with shear wall by hand calculation is very tedious and timeconsuming process. So for analysis and design of each five cases as described in the problem statement iscarried out with the help of structural analysis software “ETABS”. The analysis and design results are directlyused of comparison. After Analysis using ETABS, the following are the results obtained as shown in Table 1.Table 1 shows the tabulation of base shear; time period, scale-up factor and storey drift values for all themodels, which are noted as the various parameters to be compared with different variables.Table 1 Tabulation of base shear, time period, scale-up factor and storey drift for all the modelsModel No.StoryTypeBase Shear in KNScale Up Time Period in SecsMaximumStoryDisplacement atStory-1 inmmMaxStoryDrifts of10thfloor inmmEquivalentStaticMethodResponseSpectrumX Y X Y X YMode-1Mode-2Mode-3X Y X Y1 G+91666416664582559614.204.10 2.25 2.20 2.03 44 421.621.45
C.M. Ravi Kumar, M. B. Sreenivasa, Anil Kumar, M. Vijay Sekhar Reddy / InternationalJournal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.comVol. 3, Issue 3, May-Jun 2013, pp.646-652650 | P a g e2 G+91649216492758776953.193.14 1.71 1.69 1.65 23.9 22.92.742.53 G+91630416304834384452.862.83 1.50 1.48 1.02 18.2 17.8 2.82.694 G+91633716337914485512.612.81 1.37 1.34 1.01 14.1 10.72.192.455 G+91631116311835087092.862.75 1.5 1.42 1.24 19.3 16.12.632.276 G+91631116311609870413.923.39 1.64 1.45 1.09 19.6 17.92.542.4Note: Response Reduction Factor, R =5.0, Importance Factor, I =1.5, Soil Type, S -III, Zone, Z= VBased on results obtained, the following plots can be drawn. Fig. 3, 4, 5, 6, 7 & 8 shows the plot oftime period, base shear, and scale up factor, maximum story displacements and maximum story drifts versusdifferent modelsFig. 3. Plot of time period versus different models Fig.4. Plot of base shear versus different modelsFig.5 Plot of base shear versus different models Fig. 6 Plot of scale up factor versus different models
C.M. Ravi Kumar, M. B. Sreenivasa, Anil Kumar, M. Vijay Sekhar Reddy / InternationalJournal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.comVol. 3, Issue 3, May-Jun 2013, pp.646-652651 | P a g eFig. 7 Plot of maximum story displacements versus differentmodelsFig. 8 Plot of maximum story drifts versus differentmodels3.2 Summary and ConclusionsThe present study makes an effort toevaluate the effect of shear wall (lift wall) at allfloor for models 1-6 for Zone V, Soil type III, tostudy the various parameters like base shear, timeperiod, story displacement and story drift. Thestudy leads to the following broad conclusions: Time period will be very less when shear wallis constructed at X-direction. In other modelscomparatively less and high without shearwall. Time period will be less when shear wallis constructed in centre but with theconsideration of first mode will be creatingtorsion; hence that type construction should beavoided. Scale-up factor X & Y direction will be highwhen no shear wall is provided, further it willdecrease slightly after providing wall atdifferent location and less when wall isprovided at the X-direction. Maximum story displacement will be lesswhen shear wall is at X direction.Comparatively less when provided in otherlocations and high when wall is not provided. Maximum story drift will increase slightlywhen shear wall is provided at differentlocations. By comparing all parameters withand without shear wall at all floor it isadvisable to provide shear wall at X direction(as shown in model-4) for a better performanceof structure.The study as a whole identifies the influencingparameters, which can regulate the effect of dualsystem on time period, base shear, drifts anddisplacements of building frames. A large numberof curves exhibiting such variation for typicalexamples presented here can help the designer toget a primary idea about placing of lift wall in thedual system in high rise Reinforced ConcreteBuildings for zone V and Soil type III.References1. Anand S Arya (2000). „RecentDevelopments toward Earthquake RiskReduction in India‟, Current Science,12702-12777, pp. 9- 79.2. Bungale S. Taranath S (2005). „Wind andEarthquake Resistant Buildings- StructuralAnalysis and Design”, CRC Press, Taylor& Francis Group, Boca Raton.3. Clotaire Michel, Philippe Gueguen &Pierre-Yves Bard (2008). „DynamicParameters of Structures Extracted fromAmbient Vibration Measurements:An Aidfor the Seismic Vulnerability Assessmentof Existing Buildings in Moderate SeismicHazard Regions‟, Soil Dynamics andEarthquake Engineering, 28, pp. 593-604.4. C Rudra Srinivasa Reddy and Amlan KSenugupta (2010). „Validation of Indicesfor Assessing Seismic Vulnerability ofMulti-Storeyed Buildings with TypicalVertical Irregularities using Push–over
C.M. Ravi Kumar, M. B. Sreenivasa, Anil Kumar, M. Vijay Sekhar Reddy / InternationalJournal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.comVol. 3, Issue 3, May-Jun 2013, pp.646-652652 | P a g eAnalysis‟, Journal of StructuralEngineering, 4, 256-262.5. G.M. Calvi, R. Pinho, G. Magenes, J.J.Bommer (2006). „Development of SeismicVulnerability Assessment Methodologiesover the past 30 years‟, ISET Journal ofEarthquake Technology, Paper No. 472,Vol. 43, No. 3, pp. 75-104.6. “IS-1893(Part-1) 2002). „Criteria forEarthquake Resistant Design ofStructures‟, Part 1 General Provision andBuildings (Fifth Revision), Bureau ofIndian Standards, New Delhi.7. M. Ashraf, siddiqi Z.A and JavedM.A.,(2008),” Configuration of MultistoryBuilding Subjected to Lateral Forces”,Asian Journal of Civil Enginieering,Vol.9,pp.525-537.8. Terala Srikant, Ramancharla PradeepKumar, Ajay Pratap Singh, Bal KrishnaRastogi (2010). „Earthquake VulnerabilityAssessment of Existing Buildings inGandhidham and Adipur Cities Kachchh,Gujarat (India)‟, European Journal ofScientific Research, 41(3), 336-353.9. S.K Gosh (2004). „Update on the NEHRPProvisions: The Resource Document forSeismic Design‟, PCI Journal, pp.96-102.10. S Ganzerli, C.P.Pantelides and L. DReaveley (2000). „Performance BasedDesign using Structural Optimization‟,Earthquake Engineering of StructuralDynamics, 29, pp.1677-1690.11. V K Manicka Selvam (2011). „A Note onPreliminary Estimate of MemberDimensions of a Short Multi-storeyBuilding Frame based on ServiceabilityCriterion‟, Journal of StructuralEngineering, 37(5), pp. 358-363.