2. BUILDING DESCRIPTION
The aim is to study and compare the deformation or settlementandstressesoftheregularandirregularshape buildingswithdifferentsoillayers.Twosoilstratumswere consideredwithadepthof2.5meach.Groundfloor,(G+2), (G+5)regular and irregular structures is modelled using ANSYSmechanicalAPDLsoftware.
Mr Govind Krishna1 , Kavya P C2 , Madhusudhana B C2 , Rahul Dias2
1Assistant Professor, St Joseph Engineering College, Vamanjoor 2UG Students, St Joseph Engineering College, Vamanjoor ***
Abstract - The purpose of this work is to study the behavior of regular and irregular structures subjected to static loading considering the effect of ‘Soil Structure Interaction’. In this paper, displacements and differential settlements in buildings with Ground (G), (G+2) and (G+5) floors resting on soft and hard soil layers is presented. The study reflects that, the lateral deformations depend on soil conditions beneath and can not be ignored.
1.INTRODUCTION
The contact between the building, ground and soil layer underneaththefootingmodifythegenuineperformanceof the building significant. Flexibility of soil layer beneath footingreducestherigidityofthesupports.Intheparticular investigation,thebaseloadsonthefoundationarecomputed withoutconsideringsoilsettlement,thatis,thestructureis assumedtobecompletelyflexible.Thestress strainfeatures of soil layers area accountable for differential settlement. Theforcesofthestructuralmembersmaychangebecauseof differential settlement. It is essential to consider building frame,baseandsoilassingleimportantstructuralunit
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1.2 Methodology
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1.1 Objectives
HerethestudyiscarriedoutonthebehaviourofG,G+2and G+5 storied buildings with two layers of soil stratums supportingthestructure,eachof2.5mwithafloortofloor heightof3.0m.Heresixdifferentbuildingmodelscreatedin Ansys Mechanical APDL software and tested. Different geometrical configurations are assigned to the models to differentiate regular from irregular. Models are analysed under statics, differential settlements, load conditions in order to study the displacement, von mises stress and stressesinX,YandZdirections.
Comparison of Soil Structure Interaction effect on Regular and Irregular Buildings with Soil Stratum
1.3 Software used for Analysis
Table 1: DescriptionofRCframedstructure ionDescript 1Model lMode2 elMod3 lMode4 lMode5 lMode6 No. of stories dGrounfloor floorndGrou 2)(G+ (G+2) (G+5) (G+5) heightTotal 3m 3m 9m 9m 18m 18m structurenDimensioOverallofthe 12.7mx10.9m m10.9x m12.7 m12.7m10.9x m12.7m10.9x m12.7m10.9x m12.7m10.9x
Key Words: ANSYS Mechanical APDL, Soil structure interaction, Regular and Irregular Structures.
Duetorapidurbanizationandincreaseinpopulationonehas beencompelledtobuildstructuresonallavailabletypesof soils.Allstructuralloadsarrivingfrombuildingsarefinally transferredtothegroundthroughthecolumnfoundations. The reaction of the earth influencing the action of the structure and the action of the structure influencing the reaction of the soil is known as Soil Structure Interaction (SSI).ConventionalstructuraldesignmethodsneglecttheSSI effects. Neglecting SSI effect is reasonable in case of light structures resting in relatively stiff soil and simple rigid retaining walls. The effect of SSI, however becomes, prominentincaseofheavystructuresrestingonrelatively softsoilssuchashighrisebuildingsandelevated highways onsoftsoil.
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ANSYSisfiniteelementanalysissoftware.Itisthebesttool for analyzing and simulating the structural behavior very efficiently and more accurately as on today. It is a useful finiteelementmodellingsoftwareconsistingofawiderange of elements and meshing options. The primary unknowns computedinthestructuralanalysisaredisplacementsand differentialsettlements.Onpostprocessing,stresses,strains, etc., are obtained. ANSYS mechanical APDL is extensively usedinthermalanalysis,coupled physicscapacityrelating acoustics, piezoelectric, thermal structural as well as thermo electricexamination.
Aframedbuildingwithfourbays isconsideredforthestudy. Thematerialpropertiesanddimensionofthemembersare aslistedbelow.
Grade of concrete for all structural members(N/mm2) M 25
p
e
Modulus of elasticity of concrete (kN/m2) 25x106
Table 3: MaterialPropertiesofsoil
HardSoil 65x103 0.3 SoftSoil 15x103 0.4
Poisson’sratioforconcrete 0.15 Concretedensity 25kN/m3
DeadloadsareconsideredasperIS875(Part1) 1987and liveloadIS875(PartII) 1987
Parameter Value
Slabthickness 0.15m
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Gradeofsteel(N/mm2) Fe415
Soil Type Modulus of elasticity (kN/m2) Poisson’s ratio
Table-5: DetailsofDeadLoadandLiveLoad Load Value LiveLoad 3KN/m2 FloorFinishLoad 1KN/m2
Table
Footingsize 2.9mx2.7mx0.7m
6: DetailsofStudymodels S. No Model No Description 1 Model1 Regularwithgroundfloor 2 Model2 Irregularwithgroundfloor 3 Model3 RegularwithG+2floors 4 Model4 IrregularwithG+2floors 5 Model5 RegularwithG+5Floors 6 Model6 IrregularwithG+5Floors ModelFig.1 1:ElevationandIsometricviewofModel1 ModelFig.2 2:ElevationandIsometricviewofModel2 ModelFig.3 3:ElevationandIsometricviewofModel3
Table 4: GeometricParameters
Property Value
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No.ofbaysinXdirection 2
Table 2: MaterialPropertiesofConcreteandSteel
Heightofeachstorey 3m Depthofsoillayer 2.5m
Research Journal of Engineering and
Beamsize 0.23mx0.45m Columnsize 0.23mx0.45m
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SpacingofbayinXdirection 4m No.ofbaysinZdirection 2 SpacingofbayinZdirection 5m
International Research Journal of Engineering and Technology (IRJET) e ISSN: 2395 0056 Volume: 09 Issue: 03 | Mar 2022 www.irjet.net p ISSN: 2395 0072 © 2022, IRJET | Impact Factor value: 7.529 | ISO 9001:2008 Certified Journal | Page1025 ModelFig.4 4:ElevationandIsometricviewofModel4 ModelFig.5 5:ElevationandIsometricviewofModel5 ModelFig.6 6:ElevationandIsometricviewofModel6
3. RESULTS AND DISCUSSION of
Theresults
thestaticanalysisofvariousbuildingmodels consideredareexplainedthroughFigure7toFigure10and Table7formodels1andmodel2.Formodels3and4are explainedthroughFigure11to14andTable8.Formodels5 and6theresultsareexplainedthroughFigure15to18and Table9. Model 1 Fig 7:Meshingofmodel Fig 8:Deformationinmodel1
International Research Journal of Engineering and Technology (IRJET) e ISSN: 2395 0056 Volume: 09 Issue: 03 | Mar 2022 www.irjet.net p ISSN: 2395 0072 © 2022, IRJET | Impact Factor value: 7.529 | ISO 9001:2008 Certified Journal | Page1026 Model Fig 9:Meshingofmodel2 Fig 10:Deformationinmodel2 Table 7: LateralDisplacements Description Model 1 Regular building withground Model 2 Irregularbuilding withground DisplacementlateralMaximum 0.646mm 1.02mm Model 3
Fig- 11:Meshingofmodel3
Fig 12:Deformationofmodel3
6.
International Research Journal of Engineering and Technology (IRJET) e ISSN: 2395 0056 Volume: 09 Issue: 03 | Mar 2022 www.irjet.net p ISSN: 2395 0072 © 2022, IRJET | Impact Factor value: 7.529 | ISO 9001:2008 Certified Journal | Page1027 Model 4 Fig 13:Meshingofmodel4 Fig 14:Deformationofmodel4 Description Model 3 Regular buliding with ground + 2 floors Model 4 Irregular building with ground + 2 floors DisplacementMaximum 0.994mm 1.193mm Model 5 Fig. 15:Meshingofmodel5
Fig. 16:Deformationofmodel5 Model 6 :Meshingofmodel
Fig. 17
International Research Journal of Engineering and Technology (IRJET) e ISSN: 2395 0056 Volume: 09 Issue: 03 | Mar 2022 www.irjet.net p ISSN: 2395 0072 © 2022, IRJET | Impact Factor value: 7.529 | ISO 9001:2008 Certified Journal | Page1028 Fig. 18:Deformationofmodel6 Table 9: LateralDisplacements Description Model 5 Regular building withground +5Floors Model 6 Irregularbuilding withground +5floor Displacement 2.14mm 2.13mm Fig. 19:Lateraldeformation Fig. 20:Lateraldeformation 4. COMPARISON OF STRESS VALUE FOR DIFFERENT MODELSFig.19:StressinXdirectionofModel 1&Model2 Fig. 20 :StressinYdirectionof Model 1&Model2 Fig.-.21:StressinZ directionof Model 1&Model2 ComparisonofstressinModel 1andModel 2 Description Model Regular1building Model Irregular2building Stress in X direction 3651.04kN/m2 4316.4kN/m2 Stress in Y direction 1803.57kN/m2 2323.5kN/m2 Stress in Z direction 3465.24kN/m2 3540.9kN/m2
International Research Journal of Engineering and Technology (IRJET) e ISSN: 2395 0056 Volume: 09 Issue: 03 | Mar 2022 www.irjet.net p ISSN: 2395 0072 © 2022, IRJET | Impact Factor value: 7.529 | ISO 9001:2008 Certified Journal | Page1029 Fig. 22:StressinXdirectionofModel 3&Model4 Fig.-23:StressinYdirectionof Model 3&Model4 Fig. 24:StressinZ directionof Model 3&Model4 ComparisonofstressinModel 3andModel 4 Description Model Regular3building Model buildingIrregular4 Stress in X direction 3378.76kN/m2 3504.51kN/m2 Stress in Y direction 2457.57kN/m2 2795.1kN/m2 Stress in Z direction 3348.3kN/m2 3458.93kN/m2 Fig. 25 :StressinX directionof Model 5&Model6 Fig. 26:StressinYdirectionof Model 5&Model 6 Fig. 27: StressinYdirectionof Model 5&Model 6 Description Model Regular5building Model Irregular6building Stress in X direction 2507.1kN/m2 2889.54kN/m2 Stress in Y direction 3213.7kN/m2 3183.1kN/m2 Stress in Z direction 3570.75N/m2 3479.77kN/m2 4 CONCLUSIONS Fromthepresentstudyitisobservedthat,thesoilstructure interactioneffectdependsonsoiltype. The lateral deformations in buildings depend on soil structureinteraction.
[6] Ravi Kiran1, Sridhar.R2 (2016) reported on “Comparative study of regular and vertically irregular building under seismic loading” International Journal of ScientificandResearchPublications.
REFERENCES
[1]AkhilR1,AswathySKumar(2017)“Seismicanalysisof regular and irregular buildings with vertical irregularities usingStaad.Pro”.IRJET Volume:04Issue:06.
[5]PurushottamDewangan&TusharSaxena(2018)“Seismic Analysis of Regular & Irregular Structures and its Comparison”.IRJET Volume:05Issue:09
[3]DheekshithK,Anusha,BabithaB(2017)reportedon“Soil structure interactionsfor regular and irregular buildings withvariousfloorlevels”IRJET Volume:04Issue:04.
[4]. Mr. Kotkar R.K. Prof. Patankar J. P (2017) studied on “Effect of Soil Structure Interaction on Buildings with StiffnessIrregularityunderSeismicLoad”.IRJET Volume:04 Issue:07,
[2]AnkeshSharmaandBiswobhanuBhadra(2013)studied on “Seismic analysis and design of vertically regular RC buildingframes”
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Thoughitiscontradictorytowhatisgenerallythought,the studyinsiststoconsidersoilbeneathwhilemodellinginany Stresssoftware.valuesobtainedfromtheanalysisismoreforirregular buildingswhencomparedtoregularbuildings
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ACKNOWLEDGMENT
[7] ShreyaThusoo, Karan Modi, Rajesh Kumar, Hitesh Madahar(2015)studiedon“ResponseofBuildingswithSoil Structure Interaction with Varying Soil Types”. World Academy of Science, Engineering and Technology InternationalJournalofCivilandEnvironmentalEngineering Vol:9,No:4,2015.
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International Research Journal of Engineering and Technology (IRJET) e ISSN: 2395 0056
For single storey buildings the effect is objectionable for regularorforirregularbuildingwhile,itisreasonablysmall inmulti storeyedbuildings.
We expresses our gratitude to our institution and management for providing us with good infrastructure, qualified staff, whose guidance was of immense, help in completion of this paper successfully. Without their encouragement and guidance this project would not have materialized.