Seismic Design of Foundations Seismic Design of Foundations Seismic Design of Foundations Seismic Design of Foundations Concepts and applications Subhamoy Bhattacharya UniversityofSurrey,UnitedKingdom Rolando P Orense TheUniversityofAuckland,NewZealand Domenico Lombardi TheUniversityofManchester,UnitedKingdom Seismic Design of Foundations PublishedbyICEPublishing,OneGreatGeorgeStreet,Westminster,LondonSW1P 3AA. FulldetailsofICEPublishingrepresentativesanddistributorscanbefoundat: www.icebookshop.com/bookshop_contact.asp OthertitlesavailablefromICEPublishing: EarthquakeDesignPracticeforBuildings,Thirdedition. EdmundDwightBooth.ISBN978-0-7277-5794-4 Designers’GuidetoEurocode8:Designofbridgesforearthquakeresistance BasilKolias,MichaelN.FardisandAlainPecker.ISBN978-0-7277-5735-7 ShockTransmissionUnitsinConstruction DineshJ.Patel.ISBN978-0-7277-5713-5 www.icebookshop.com AcataloguerecordforthisbookisavailablefromtheBritishLibrary ISBN978-0-7277-6166-8 ©ThomasTelfordLimited2019 ICEPublishingisadivisionofThomasTelfordLtd,awholly-ownedsubsidiaryofthe InstitutionofCivilEngineers(ICE). Allrights,includingtranslation,reserved.ExceptaspermittedbytheCopyright, DesignsandPatentsAct1988,nopartofthispublicationmaybereproduced,stored inaretrievalsystemortransmittedinanyformorbyanymeans,electronic,mechanical, photocopyingorotherwise,withoutthepriorwrittenpermissionofthePublisher, ICEPublishing,OneGreatGeorgeStreet,Westminster,LondonSW1P3AA. Thisbookispublishedontheunderstandingthattheauthorissolelyresponsiblefor thestatementsmadeandopinionsexpressedinitandthatitspublicationdoesnot necessarilyimplythatsuchstatementsand/oropinionsareorreflecttheviewsor opinionsofthepublishers.Whileeveryefforthasbeenmadetoensurethatthe statementsmadeandtheopinionsexpressedinthispublicationprovideasafeand accurateguide,noliabilityorresponsibilitycanbeacceptedinthisrespectbythe authororpublishers. Whileeveryreasonableefforthasbeenundertakenbytheauthorandthepublisher toacknowledgecopyrightonmaterialreproduced,iftherehasbeenanoversight pleasecontactthepublisherandwewillendeavourtocorrectthisuponareprint. Coverphoto:Kobe,Japan;March2009.Preservedcraterfrom1995GreatHanshin Earthquake. CommissioningEditor:JamesHobbs ProductionEditor:MadhubantiBhattacharyya MarketingSpecialist:AprilAstaBrodie TypesetbyTheManilaTypesettingCompany IndexcreatedbyLaurenceErrington PrintedandboundinGreatBritainbyTJInternational,Padstow Seismic Design of Foundations Contents Preface ix Acknowledgements xi 01 ............................... Introduction to earthquakegeotechnical engineeringin relation to foundation design 1 1.1. Introduction 1 1.2. Overview of earthquake engineering 1 1.3. What does earthquake geotechnical engineering cover? 1 1.4. Examples of geotechnical damage 4 1.5. Major topics inearthquake geotechnical engineering 4 1.6. Historical perspective: how engineers learntfrom earthquakes 13 1.7. Complexity of earthquake geotechnical engineering 29 1.8. Summary 32 References 32 02 ............................... Basicconcepts of engineeringseismology andseismic hazard analysis 33 2.1. Introduction 33 2.2. Theories of platetectonics andelastic rebound 33 2.3. Types of faults 34 2.4. Evaluation of earthquake size 35 2.5. Hazards for the seismic design of foundations 38 2.6. Seismic hazardanalysis 39 2.7. Case study: damage to theoutlet tunnel of thesecond Kakkonda hydropowerstation (This case study isbased on theseminal work ofProf Konagai, see for further details Konagai(2005), Johansson and Konagai(2007)) 44 2.8. Case study: quantification of thePGAfor locations inIndia where strong-motion recordsare unavailable 46 2.9. Quantification of fault movement 56 2.10. Casestudy: hazard to pipelines due topermanent ground deformations 56 2.11. Quantification of theduration of an earthquake 60 2.12. Summary 60 References 60 03 ............................... Selection of strongmotion forfoundation design 63 3.1. Introduction 63 3.2. Background tothe problem 63 3.3. Criteria for theselection ofearthquake records 65 3.4. Methods for spectral matching 67 3.5. Case study: application of spectrum-compatible input motion 69 3.6. Summary 77 References 77 04 ............................... Ground response analysis 79 4.1. Introduction 79 4.2. Seismic wavepropagation inlayered media 81 4.3. Methods of ground response analysis 83 4.4. Linear groundresponse analysisprocedure 84 v Seismic Design of Foundations 4.5. Equivalent linear and non-linear programs for ground response analysis 94 4.6. Simplified method to obtain thenatural period of theground 101 4.7. Natural period of thegroundfor a layered soil 101 4.8. Summary 102 References 102 05 ............................... Seismicanalysis methodsrelated to foundation design 103 5.1. Introduction 103 5.2. Fundamental period of structures 103 5.3. Fundamentals modal analysis 104 5.4. The conceptof response spectrum 106 5.5. Application of response spectraanalysis infoundation design 110 5.6. Examplecalculationsforthebaseshearofathree-storeybuilding 115 5.7. Essentials of performance-based design 119 5.8. Beam ona non-linear Winkler foundation (SSI) 125 5.9. Summary 136 References 138 06 ............................... Liquefaction: theoreticalaspects 141 6.1. Introduction 141 6.2. Concept of effective stress anddilatancy 141 6.3. Mechanism of porepressure development 143 6.4. Laboratory undrainedtests 145 6.5. Role ofnumerical modelling 152 6.6. Actual earthquake recordsas manifestations of insitu soil liquefaction 161 6.7. Effects on thebuilt environment 164 6.8. Summary 168 References 170 07 ............................... Liquefaction: practical aspects 173 7.1. Introduction 173 7.2. Liquefaction susceptibility 173 7.3. Liquefaction triggering 178 7.4. Evaluation of theeffects ofliquefaction 187 7.5. Codes of practice-specifiedmethods 190 7.6. Liquefaction-induced grounddisplacements 194 7.7. Worked example 202 7.8. Planning and design ofa majorproject inseismic areas 207 7.9. Summary 210 References 210 08 ............................... Analysis anddesign of shallow foundations 215 8.1. Introduction 215 8.2. Seismic bearingcapacity of shallowfoundations 215 8.3. Case studies: observedsettlements ofbuildings during earthquakes 217 8.4. Case studies: settlements of footings inphysical model tests 223 vi Seismic Design of Foundations 8.5. Factors affecting settlements of shallowfoundations in liquefied ground 230 8.6. Estimation of total and differential settlements 233 8.7. Seismic design of mat foundations 238 8.8. Summary 238 References 238 09 ............................... Pile foundations 241 9.1. Introduction 241 9.2. Why piled foundation areused 241 9.3. Pile foundations inseismic areas 241 9.4. Failure mechanisms ofpile-supported structures 245 9.5. Criteria for thedesign of piles inseismic areas 253 9.6. Design checksand calculations required 255 9.7. Design codesof practice 261 9.8. Modelling of theproblem 263 9.9. Raked orbattered piles 282 9.10. Example:pile-supported LNGtanks 285 9.11. Example:Kandla Porttower building on piles 290 9.12. Summary 291 References 291 10 ............................... Analysis of foundations formajor bridges 297 10.1. Introduction 297 10.2. Surveyof theperformance of bridge foundations in seismic areas 297 10.3. Bridge foundations 305 10.4. Caissonfoundations 306 10.5. Stiffness of deep foundations 308 10.6. Methodology for fundamental frequency estimations 316 10.7. Dynamic behaviourof pile-supported bridges 320 10.8. Performance comparison of bridges supported onpileand caisson foundationsin liquefiable soils 328 10.9. Summary 329 References 329 11 ............................... Foundations in slopes andforretaining walls 331 11.1. Introduction 331 11.2. Conceptof seismic coefficientsfor slopesand retainingwalls 331 11.3. Foundationconsiderations for buildings onslopes 334 11.4. Casestudies: seismic performanceof buildings onslopes 336 11.5. Earth pressuretheory 341 11.6. Foundations for retainingwalls 347 11.7. Worked example 350 11.8. Casestudies: seismic performanceof retaining walls 354 11.9. Summary 362 References 362 vii Seismic Design of Foundations 12 ............................... Liquefaction countermeasures 365 12.1. Introduction 365 12.2. Liquefaction countermeasures 365 12.3. Ground improvement methods 369 12.4. Analysis anddesign of typical groundimprovement methods 377 12.5. Worked examplesfor typicalmethods 386 12.6. Casestudies: ground improvement method application 389 12.7. Casestudies: seismic performanceof improved-ground sites 395 12.8. Methods to strengthen shallow foundations 409 12.9. Methods to strengthen pilefoundations 414 12.10. Summary 417 References 417 Appendix ........................ Engineeringcorrelations forthedesign of foundations 421 Index 451 viii Seismic Design of Foundations Preface Inordertocarryoutdesignoffoundationsinseismicallyactiveareas, onerequiressomelevelofexpertiseinseismichazardassessment,soil behaviourundercyclicloading,structuraldynamicsandsoil-structure interaction,inadditiontostandardfoundationanalysisanddesignconcepts. Asaresult,thissubjectinitiallyemergedasaspecialistareaforonly afewresearchersaswellasahandfulofprofessionalengineering consultants,althoughovertheyears,ithasgraduallyappearedon specialistundergraduateandpostgraduatecoursesatmanyuniversities. Theflow(thatis,thestructure)ofthebookfollowsapatternthatwould betypicalofadesignprocess:assessmentandquantificationofseismic hazardsthatwouldaffectfoundationdesign(Chapters2to7),followed bydesignandmitigationaspects.Thedesignoffoundationsrequiresa fundamentalunderstandingofprobabilisticconceptsofseismichazards, groundresponseanalysisandstructuralanalysis,andthesesubjectscan themselvesbethesubjectsofanentirebook.Therefore,onlythenecessary analysisanddesignconcepts–including,butnotlimitedto,response spectra,modalanalysis,beamonWinklerfoundations,andgroundresponse analysis–arecoveredinbrief,andonlythefundamentalsareexplained, alongwithsomeexamples.Whereverpossible,referencesareprovidedfor furtherreading.Theauthorshavesincerelyattemptedtomakethebookas usefulandpracticableaspossiblebyprovidingcasestudies,example applications,andsolvedexamplesfromtherealworld. The11thMarch2011Tōhokuearthquake(Japan)wasarareandalandmark eventwhichcanbedescribedasanactofwarbetweennatureandearthquake engineers.Itisfairtosaythatiftheeffectsofthetsunamiarediscounted, theoverallperformanceofthestructuresundertheactionofearthquake (togetherwithliquefaction)showsthatthereisalottolearnfromJapanese earthquakegeotechnicalengineers.Thefirstauthor(ProfessorBhattacharya) wasinJapanonthatdayandhadfirst-handexperienceoftheperformanceof thesestructures.Followingthe2010–2011Canterburyearthquakesequence (NewZealand),thesecondauthor(AssociateProfessorOrense)worked overaperiodofmorethan18monthstoinvestigatetheimpactofground shakingandsoilliquefactiononthebuiltenvironmentofChristchurch andsurroundingareas.Thisbookheavilydrawsupontheexperiencesof thesetworecentearthquakes,aswellasfromlessonslearnedinotherrecent large-scaleearthquakes. Thebookisbornoutofresearchbytheauthorsaswellaspostgraduate andCPD(ContinuingProfessionalDevelopment)teachingandspecialist lecturestheydeliveredatvariousuniversitiesandorganisations.Examples include:ProfessorBhattacharya’scoursesonearthquakeengineering attheUniversityofSurrey(MSccourse)andUniversityofBristol (MEngcourse)intheUK,IndianInstitutesofTechnologies(IITKharagpur ix Seismic Design of Foundations andIITBhubaneswarasapartofISWT(InternationalSummerand WinterTerm)andGIAN(GlobalInitiativeforAcademicNetworks)courses respectively),ASRANetCPDcoursesinDelft,LondonandBrusselsaswell asatYamaguchiUniversityandTokyoInstituteofTechnology(Japan), ZhejiangUniversity(China),TongjiUniversity(China)andHarbinInstitute ofTechnology(China).AssociateProfessorOrense(secondauthor) providedlecturesonthesametopicattheUniversityofAuckland (NewZealand),UniversityofTokyoandYamaguchiUniversity(Japan), theUniversityofthePhilippinesandthroughtechnicalworkshopsand seminarssponsoredbytheEngineeringNewZealand(EngNZ)heldin variouscitiesinNewZealand. Itishopedthatthisbookwillbeidealforanystudentstudyingpostgraduate geotechnicalengineeringorstructuralengineering,aswellasresearchers andpractitionersworkinginthefieldofearthquakegeotechnical engineering.Duetothechangingrequirementsinthecurrenttechnological ageandmarketdemandsofthemoderneducationalsystem,ICEPublishing wishestomakeindividualchaptersofthebookavailabletoreadersthrough itse-bookplatformICEVirtualLibrary.Therefore,tomakeeachchapter self-sufficient,therearesomeinevitablerepetitionsofsomefiguresand textualanalysis. Thisfieldofengineeringisconstantlyevolvingaseachmajorearthquake teachesussomethingnew.Manyofthemethodologiesorcalculation procedurespresentedheremaybecomeoutdatedorbemodifiedinthe nextfewyears,atwhichpointthisbookmayrequireanewedition. Theremayalsobeerrorsandomissionsinthebookandwewouldbe gratefulifthosewerebroughttoourattention.Pleaseemailtheauthors [email protected] [email protected] thecommentswillbedulyacknowledgedinthenextedition. SubhamoyBhattacharya RolandoPOrense DomenicoLombardi x Seismic Design of Foundations