Fundamentals of Seismic Loading on Structures

390 Pages·2009·74.788 MB·English

by  Tapan K. Sen

Fundamentals of Seismic
Loading on Structures
Fundamentals of Seismic Loading on Structures Ta p a n S e n
© 2009 John Wiley & Sons, Ltd. ISBN: 978-0-470-01755-5
Fundamentals of
Seismic Loading on
Structures
Tapan K. Sen
A John Wiley and Sons, Ltd, Publication
Thiseditionfirstpublished2009
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LibraryofCongressCataloging-in-PublicationData
Sen,TapanK.
Fundamentalsofseismicloadingonstructures/byTapanK.Sen.
p. cm.
Includesbibliographicalreferencesandindex.
ISBN978-0-470-01755-5(cloth)
1. Earthquakeresistantdesign. 2. Earthquakehazardanalysis.
3. Strainsandstresses. I. Title.
TA658.44.S442009
624.1(cid:3)762—dc22
2008044377
AcataloguerecordforthisbookisavailablefromtheBritishLibrary.
ISBN:978-0-470-01755-5
Setin10/12ptTimesbyIntegraSoftwareServicesPvt.Ltd,Pondicherry,India
PrintedinSingaporebyMarkono
ToMyParents
Contents
Preface xv
Acknowledgements xvii
1 IntroductiontoEarthquakes 1
1.1 AHistoricalPerspective 1
1.1.1 SeismicAreasoftheWorld 4
1.1.2 TypesofFailure 5
1.1.3 FaultMovementanditsDestructiveAction 7
1.2 TheNatureofEarthquakes 8
1.3 PlateTectonics 9
1.3.1 TypesofPlateBoundaries 10
1.3.2 ConvergentandDivergentBoundaries 11
1.3.3 SeismicityandPlateTectonics 12
1.4 FocusandEpicentre 14
1.5 SeismicWaves 14
1.5.1 BodyWaves 15
1.5.2 SurfaceWaves 17
1.6 Seismometers 17
1.6.1 EarlySeismographs 18
1.6.2 ModernDevelopments 20
1.6.3 LocatingtheEpicentre 22
1.7 MagnitudeandIntensity 22
1.7.1 MagnitudeScales 23
1.7.2 SeismicMoment 24
1.7.3 IntensityScales 25
1.8 Reid’sElasticReboundTheory 27
1.9 SignificantMilestonesinEarthquakeEngineering 27
1.10 SeismicTomography 28
1.10.1 TheChallengesAhead 32
1.11 References 32
2 SingleDegreeofFreedomSystems 35
2.1 Introduction 35
2.2 FreeVibration 38
viii Contents
2.2.1 EquationsofMotionwithDamping 40
2.2.2 DampingRatio 41
2.2.3 TreatmentofInitialConditions 42
2.3 PeriodicForcingFunction 42
2.3.1 MagnificationFactors 46
2.3.2 Damping 46
2.3.3 SupportMotion 48
2.4 ArbitraryForcingFunction 49
2.4.1 DuhamelIntegral 49
2.4.2 NumericalEvaluation 50
2.4.3 WorkedExample–DuhamelIntegral 52
2.5 References 53
3 SystemswithManyDegreesofFreedom 55
3.1 Introduction 55
3.2 LumpedParameterSystemswithTwoDegreesofFreedom 55
3.3 LumpedParameterSystemswithmorethanTwoDegreesofFreedom 56
3.3.1 FreeVibration 58
3.3.2 AWorkedExample(TwodegreesofFreedomSystem) 60
3.3.3 NormalizationofModeShapes 62
3.3.4 OrthogonalityofModeShapes 63
3.3.5 WorkedExample–OrthogonalityCheck 64
3.4 ModeSuperposition 65
3.4.1 UseofNormalorGeneralizedCoordinates 65
3.5 DampingOrthogonality 67
3.6 Non-linearDynamicAnalysis 68
3.6.1 Introduction 68
3.6.2 IncrementalIntegrationProcess 68
3.6.3 NumericalProceduresforIntegration 69
3.6.4 EstimateofErrors 71
3.6.5 Houbolt’sMethod 72
3.6.6 ExplicitandImplicitScheme 73
3.6.7 MinimumTimeStep(cid:2)t(ExplicitIntegrationScheme) 73
3.7 References 73
4 BasicsofRandomVibrations 75
4.1 Introduction 75
4.2 ConceptsofProbability 76
4.2.1 RandomVariableSpace 76
4.2.2 GaussianorNormalDistribution 81
4.2.3 WorkedExamplewithStandardNormalVariable 84
4.3 HarmonicAnalysis 85
4.3.1 Introduction 85
4.3.2 FourierSeries(Robson,1963) 85
4.3.3 FourierIntegrals(Robson,1963,withpermission) 87
4.3.4 SpectralDensity(Robson,1963) 89
Contents ix
4.4 NumericalIntegrationSchemeforFrequencyContent 91
4.4.1 IntroducingDiscreteFourierTransform(DFT) 91
4.5 AWorkedExample(Erzincan,1992) 92
4.6 References 95
5 GroundMotionCharacteristics 97
5.1 CharacteristicsofGroundMotion 97
5.1.1 GroundMotionParticulars 97
5.1.2 AfterShocksandBeforeShocks 99
5.1.3 EarthquakeSourceModel 103
5.1.4 EmpiricalRelationsofSourceParameters 107
5.2 GroundMotionParameters 110
5.2.1 TheNatureandAttenuationofGroundMotion 114
5.2.2 PGAandModifiedMercalliIntensity(MMI) 114
5.2.3 EngineeringModelsofAttenuationRelationships 116
5.2.4 NextGenerationAttenuation(NGA)ModelsforShallow
CrustalEarthquakesinWesternUnitedStates(2008) 134
5.3 References 136
6 IntroductiontoResponseSpectra 141
6.1 GeneralConcepts 141
6.1.1 ADesigner’sPerspective 141
6.1.2 APracticalWayForward 141
6.1.3 ConstructingTripartitePlots 145
6.2 DesignResponseSpectra 149
6.2.1 AWorkedExample:AnMDOFSystemSubjectedtoEarthquake
Loading 152
6.3 SiteDependentResponseSpectra 163
6.3.1 TheDesignProcess 164
6.3.2 PracticalExample:ConstructionofaSiteDependent
ResponseSpectrum 166
6.4 InelasticResponseSpectra 174
6.4.1 ResponseSpectra:ACautionaryNote 176
6.5 References 178
7 ProbabilisticSeismicHazardAnalysis 181
7.1 Introduction 181
7.1.1 SeismicHazardAnalysis(SHA) 183
7.1.2 FeaturesofPSHA 183
7.2 BasicStepsinProbabilisticSeismicHazardAnalysis(PSHA) 183
7.2.1 HistoricalSeismicity 185
7.2.2 Geology,Tectonics,IdentificationofEarthquakeSourceandthe
Geometry 186
7.2.3 ModellingRecurrenceLaws 186
7.2.4 Gutenberg-RichterRecurrenceLaw 186
7.2.5 AlternativeModels 189
x Contents
7.2.6 WhytheGutenberg-RichterModel? 189
7.2.7 GroundMotionParameter(peakacceleration,velocityetc.) 190
7.2.8 LocalSoilConditions 190
7.2.9 TemporalModel(orthearrivalprocess) 190
7.2.10 PoissonModel 191
7.3 GuidetoAnalyticalSteps 192
7.3.1 MultiplePointSources 192
7.3.2 AreaSource 193
7.3.3 LineSource 194
7.4 PSHAasIntroducedbyCornell 195
7.4.1 LineSourceIllustrationProblem(Cornell,1968) 199
7.5 MonteCarloSimulationTechniques 200
7.5.1 MonteCarloSimulationProcess–AnInsight 203
7.5.2 Example:PointSource(extractedfromCornell,1968) 204
7.6 ConstructionofUniformHazardSpectrum 207
7.6.1 MonteCarloSimulationPlotsforPeakGroundAcceleration 208
7.6.2 ProcedureforConstructionofUniformHazardResponse
Spectrum 209
7.6.3 FurtherAttenuationEquations 212
7.7 FurtherComputationalConsiderations 212
7.7.1 De-aggregation–AnIntroduction 212
7.7.2 ComputationalSchemeforDe-aggregation 213
7.7.3 Logic-TreeSimulation–AnIntroduction 215
7.7.4 LestWeForget... 216
7.8 References 216
8 CodeProvisions 219
8.1 Introduction 219
8.1.1 HistoricalDevelopment 221
8.2 StaticForceProcedure 234
8.2.1 BaseShearMethod 234
8.3 IBC2006 239
8.3.1 IntroducingMappedSpectralAccelerations 239
8.3.2 DynamicAnalysisProcedures 239
8.4 Eurocode8 244
8.4.1 AWorkedExample 246
8.5 AWorkedExample(IBC2000) 249
8.5.1 General 249
8.5.2 DesignCriteria 250
8.5.3 DesignBasis 253
8.5.4 GravityLoadsandLoadCombinations 253
8.5.5 GravityLoadAnalysis 256
8.5.6 LoadCombinationsForDesign 257
8.5.7 EquivalentLateralForceProcedure(1617.4) 257
8.5.8 VerticalDistributionofBaseShear(1617.4.3) 258
8.5.9 LateralAnalysis 258
Contents xi
8.5.10 ModificationofApproximatePeriod 259
8.5.11 RevisedDesignBaseShear 260
8.5.12 ResultsofAnalysis 261
8.5.13 StoreyDriftLimitation 261
8.5.14 P−(cid:2)Effects 263
8.5.15 RedundancyFactor,ρ,(1617.2) 263
8.5.16 DynamicAnalysisProcedure(responsespectrumanalysis) 265
8.5.17 ModeShapes 265
8.5.18 VerificationofResultsfromSAP2000 267
8.5.19 L andM foreachmodeshape 267
m m
8.5.20 ModalSeismicDesignCoefficients,C 267
sm
8.5.21 BaseShearusingModalAnalysis 268
8.5.22 DesignBaseShearusingStaticProcedure 269
8.5.23 ScalingofElasticResponseParametersforDesign 269
8.5.24 DistributionofBaseShear 270
8.5.25 LateralAnalysis 270
8.5.26 StoreyDriftLimitation 275
8.5.27 P−(cid:2)Effects 276
8.5.28 RedundancyFactor,ρ 276
8.6 References 276
9 InelasticAnalysisandDesignConcepts(withParticularReferenceto
H-Sections) 279
9.1 Introduction 279
9.2 BehaviourofBeamColumns 280
9.2.1 ShortorStockyBeamColumn 282
9.2.2 LongorIntermediateLengthBeamColumn 282
9.3 FullScaleLaboratoryTests 283
9.3.1 TestResults 285
9.3.2 ModeofFailure 285
9.3.3 ExperimentalPlots 286
9.4 ConceptsandIssues:FramesSubjectedtoSeismicLoading 289
9.5 ProceedingwithDynamicAnalysis(MDOFsystems) 290
9.5.1 LateralTorsionalBuckling 291
9.5.2 ColumnStrengthCurves 291
9.5.3 DynamicAnalysis 292
9.6 BehaviourofSteelMembersunderCyclicLoading 293
9.6.1 FEAnalysis 294
9.6.2 ANoteonConnections 295
9.6.3 ANoteontheFactorsAffectingtheStrengthofColumns 295
9.7 EnergyDissipatingDevices 296
9.7.1 Introduction 296
9.7.2 CurrentPractice 296
9.7.3 DampingDevicesinUse 298
9.7.4 AnalyticalGuidelinesCurrentlyAvailable 303
9.8 References 303
xii Contents
10 Soil-StructureInteractionIssues 305
10.1 Introduction 305
10.2 DefinitionoftheProblem 305
10.2.1 ImportantFeaturesofSoil-StructureInteraction 306
10.2.2 GroundResponsesObservedDuringEarthquakes 308
10.3 DamagingEffectsduetoAmplification 308
10.3.1 MexicoCity(1985)Earthquake 308
10.3.2 LomaPrieta(1989)Earthquake 310
10.4 DamagingEffectsDuetoLiquefaction 316
10.4.1 DesignImplicationsforPilesduetoLiquefaction 320
10.5 References 321
11 Liquefaction 323
11.1 DefinitionandDescription 323
11.1.1 GeotechnicalAspectsofLiquefaction 323
11.2 EvaluationofLiquefactionResistance 325
11.2.1 AnalyticalProcedure–EmpiricalFormulation
(SeedandIdriss,1971) 325
11.2.2 ASimplifiedMethod(SeedandIdriss,1971) 327
11.3 LiquefactionAnalysis–WorkedExample 332
11.3.1 ProblemDefinition 332
11.3.2 CaseStudy–UsingFieldData 335
11.4 SPTCorrelationforAssessingLiquefaction 338
11.4.1 CurrentStateoftheArt 338
11.4.2 MostRecentWork 344
11.4.3 WorkedExamplewithSPTProcedure(Idriss
andBoulanger,2004) 346
11.5 InfluenceofFinesContent 348
11.6 EvaluationofLiquefactionPotentialofClay(cohesive)Soil 349
11.6.1 FreshEvidenceofLiquefactionofCohesiveSoils 349
11.7 Construction of Foundations of Structures in the Earthquake Zones
SusceptibletoLiquefaction 350
11.8 References 353
12 PerformanceBasedSeismicEngineering–AnIntroduction 357
12.1 Preamble 357
12.2 BackgroundtoCurrentDevelopments 358
12.2.1 EffortsintheUSA 359
12.2.2 EffortsinJapan 359
12.2.3 EffortsinEurope 360
12.3 Performance-BasedMethodology 360
12.3.1 PerformanceObjectives 361
12.3.2 PerformanceLevels 362
12.3.3 PerformanceObjectives 363
12.3.4 HazardLevels(designgroundmotions) 364