1Example42Title25-storylinkedtripletowerbuildingDescriptionCalculatethenaturalperiodsofa25-storytripletowerbuildingwithrigiddiaphragmfloors.Performadynamicresponsespectrumanalysisandcomputethemaximumlateraldisplacement.VerificationExample2StructuralgeometryExample423Z-directionelevationandsectionpropertiesVerificationExample4ModelAnalysisType3-DresponsespectrumanalysisUnitSystemin,kipDimensionRadiusR=600inLevelheight1st=240in2nd~25th=150inFloormassMx=My=2.813147kips⋅sec2/inRotationalmassmomentofinertiaoffloorMzz=6.254×106kips⋅sec2/inDampingratioξ=0.05(5%)Gravitationalaccelerationg=386.4in/sec2ResponsespectrumdataElCentroN-Scomponents(Accelerationswithrespecttoperiods)ElementBeamelementMaterialModulusofelasticityE=29500ksiPoisson’sratioν=0.25Example425SectionPropertyColumnBeamFloorC1,C21,C23C43,C45,C65C2~C20,C24~C42,C46~C64B1~B20,B22~B41,B43~B6219th~roofB24×24×0.75/0.75W14×176W30×9912th~18thB24×24×1/1W14×257W33×2216th~11thB24×24×2/2W14×398W36×2102nd~5thB24×24×3/3W14×426W36×280BoundaryConditionNodes1~66;ConstrainallDOFs.Nodes132~1716;Constrain.Dx,DyandRzofallnodesateachfloorto(atanincrementof66)thesenodes.(Masternodes)AnalysisCaseFloormassesareassignedtothemasternodesateachfloorinthedirectionsofXandY.RotationalmassmomentofinertiaaboutZ-axisisassignedtoeachmasternode.LoadCase1;ResponsespectrumdataareappliedintheXdirection.LoadCase2;ResponsespectrumdataareappliedintheYdirection.Numberofnaturalfrequenciestobecomputed=10VerificationExample6ResultsEigenvalueresultsDisplacementresultsExample4271stvibrationmodeofthestructureDeformedshapeofthestructure(Node1716)VerificationExample8ComparisonofResultsNaturalPeriodsUnit:secNaturalperiodResult1st2nd3rd4th5th6th7th8th9th10thETABS1.99511.85641.85640.77740.69750.69740.45670.39990.39990.3188MIDAS/Gen1.99511.85641.85640.77740.69750.69740.45670.39990.39990.3188MaximumLateralDisplacements:occurredatthenode1716Unit:inLoadCaseMaximumlateraldisplacementETABSMIDAS/Gen1δx11.885511.89482δy11.885511.8952Reference“ETABS,ExamplesManual”,Version6.0,ComputersandStructures,Inc.,Berkeley,California,1994,Example19.Example429ResponseSpectrumData
