Structural Dynamics In Earthquake And Blast Resistant Design

337 Pages·2020·41.822 MB·English

by  Bk Raghu Prasad

Structural Dynamics
in Earthquake and Blast
Resistant Design

Structural Dynamics
in Earthquake and Blast
Resistant Design
B.K. Raghu Prasad
Professor(Retd),Departmentof
CivilEngineering,IndianInstituteof Science
Bengaluru,India
Firsteditionpublished2020
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Contents
Preface.......................................................................................................................xi
Acknowledgments...................................................................................................xiii
Author....................................................................................................................xvii
Symbols..................................................................................................................xix
Chapter1 Introduction.....................................................................................1
1.1 TypesofAnalysis....................................................................2
1.2 ModellingofaDynamicSystem............................................3
1.2.1 DegreesofFreedom...................................................4
1.3 D’Alembert’sPrinciple...........................................................4
Chapter2 SingleDegreeofFreedomSystems.................................................7
2.1 Introduction.............................................................................7
2.2 FreeandForcedVibrations.....................................................7
2.2.1 FreeVibrations...........................................................7
2.2.2 DampedFreeVibrations..........................................11
2.2.3 LogarithmicDecrement...........................................16
2.3 ForcedVibrationofaDampedSingleDegree
ofFreedom............................................................................17
2.4 ASingleDegreeofFreedomSystemSubjectedto
SupportMotion.....................................................................21
2.5 Rayleigh’sMethodtoObtainNaturalFrequency.................23
2.6 ResponseinFrequencyDomainandLaplace
Transformation......................................................................25
2.7 SolvedProblems...................................................................30
2.8 ExerciseProblems................................................................40
Chapter3 TwoDegreeofFreedomSystems..................................................43
3.1 ForcedResponseofDampedTwo-StoreyBuildings............46
3.2 ExerciseProblems................................................................48
Chapter4 ForceTransmittedtotheSupport..................................................49
4.1 ExerciseProblems................................................................52
vii
viii Contents
Chapter5 Duhamel’sIntegral........................................................................53
Chapter6 ModalAnalysis..............................................................................61
6.1 Multi-DegreeofFreedomSystemsSubjectedto
ExternalDynamicForces:ModalAnalysis..........................61
6.2 AMulti-StoreyBuildingSubjectedto
GroundMotions:ModalAnalysis........................................65
6.3 SolvedProblems...................................................................68
6.4 ExerciseProblemsforChapters5and6...............................81
Chapter7 EarthquakeResistantDesign.........................................................83
7.1 Introduction...........................................................................83
7.2 StructuralAnalysis................................................................83
7.3 StructuralModel...................................................................84
7.4 ShearBuilding......................................................................84
7.5 ResponseSpectrum...............................................................85
7.6 CapacitySpectrum................................................................98
Chapter8 InelasticVibrationAbsorberSubjectedtoEarthquake
GroundMotion............................................................................107
8.1 Introduction.........................................................................107
8.2 TheLinearElasticVibrationAbsorber...............................108
8.3 TheHystericVibrationAbsorber........................................111
8.4 StructuralModelandtheEquationsofMotion..................112
8.5 NumericalStudies...............................................................113
8.6 AnalysisofResults.............................................................114
8.6.1 ResponseoftheAbsorberMass.............................119
8.6.2 ResponseHistoryCurves.......................................120
8.6.3 HystericEnergyDissipation..................................124
8.6.4 InfluenceofViscousDamping...............................130
8.6.5 MaximumDuctilityResponseSpectra..................130
8.7 Conclusions.........................................................................132
Chapter9 InelasticTorsionalResponseofaSingle-StoreyFramed
Structure:TwoDegreeofFreedomSystem.................................133
9.1 Introduction.........................................................................133
9.2 EarthquakeResponseofElasticStructurewithCoupled
TranslationalandTorsionalMotions..................................134
9.3 StructuralModel.................................................................136
9.4 EquationsofMotion...........................................................139
9.4.1 SolutionoftheEquationsofMotion......................142
9.4.2 ParametersConsideredintheStudy......................142
9.4.3 DetailsoftheComputerProgram..........................144
Contents ix
9.5 DiscussionofResults..........................................................144
9.5.1 InfluenceofEccentricityEnvelopesof
MaximumFrameDuctility....................................144
9.5.2 InfluenceofYieldStrength....................................146
9.5.3 InfluenceofP-∆Effect...........................................149
9.5.4 InfluenceofStrengtheningtheExteriorFrames....149
9.5.5 ResponseHistoryCurves.......................................151
9.5.6 EnergyDissipationduetoHysteresis....................156
9.5.7 MaximumDuctilityResponseSpectra..................161
9.6 SummaryandConclusions.................................................162
Chapter10 InelasticTorsionalResponseofaSingle-StoreyFramed
Structure:ThreeDegreeofFreedomSystem..............................165
10.1 Introduction.........................................................................165
10.2 StructuralModel.................................................................166
10.2.1 YieldingBehavior..................................................167
10.3 EquationsofMotion...........................................................170
10.4 SolutionsoftheEquationsofMotion.................................172
10.4.1 ParametersConsideredintheStudy......................173
10.5 DiscussionofResults..........................................................174
10.5.1 InfluenceofEccentricity........................................174
10.5.2 InfluenceofYieldStrengthq =q =q and
iuo ivo i
Period(T =T =T)............................................180
iu iv i
10.5.3 Time-ResponseCurves..........................................181
10.6 SummaryandConclusions.................................................183
Chapter11 EarthquakeResistantDesignasperIS1893:2016......................189
11.1 Introduction.........................................................................189
11.2 Project-01..........................................................................189
11.2.1 Introduction............................................................189
11.2.2 FloatingColumns...................................................191
11.2.3 SoftStorey.............................................................197
11.2.4 BuildingAsymmetricinPlan................................197
11.2.5 MassParticipationFactor.......................................206
11.2.6 Conclusions............................................................208
11.3 Project-02..........................................................................209
11.3.1 Introduction............................................................209
11.3.2 Analysis..................................................................209
11.3.3 Conclusions............................................................217
11.4 Problems.............................................................................217