Guidelines EQ
-
Upload
eswara-prasad -
Category
Documents
-
view
221 -
download
0
Transcript of Guidelines EQ
-
7/31/2019 Guidelines EQ
1/34
GOVERNMENT OF INDIA
CENTRAL WATER COMMISSION
GUIDELINESFORPREPARATIONANDSUBMISSIONOF
SITESPECIFICSEISMICSTUDYREPORTOFRIVERVALLEYPROJECTTO
NATIONALCOMMITTEEONSEISMICDESIGNPARAMETERS
SecretariatofNationalCommitteeonSeismicDesignParametersFE&SADirectorate,712(S),SewaBhawan,R.K.Puram
NewDelhi110605
(October2011)
NCSDPGuidelines:2011
-
7/31/2019 Guidelines EQ
2/34
CentralWaterCommission
NCSDPGuidelines:2011
FOREWORDMinistry of Water Resources had constituted a high level interdisciplinary official body, the
NationalCommitteeonSeismicDesignParameters (NCSDP) forRiverValleyProjects in1991(formerly known as Standing Committee) to recommend the site specific design seismic
parametersfordesignofdamsandotherappurtenantstructuresoftherivervalleyprojects.The
site specific reports for determination of seismic parameters involve estimation of seismic
parameters either using the deterministic seismic hazard analysis (DSHA) method or the
probabilistic seismichazardanalysis (PSHA)method.Sinceboth theapproacheshave theirown
strengths andweaknesses, they are required to be used in combination to arrive at themost
appropriateengineeringdecisions. Itmaythusbeadvisabletoprovidetheresultsfromboththe
approachesandtheCommitteemaytakeaview ineveryparticularcase.Therefore,anattempt
hasbeenmade to formulate a document: Guidelinesfor Preparation and Submission of SiteSpecificSeismicStudyReporttoNationalCommitteeonSeismicDesignParameters(NCSDP)forRiverValleyProjects,tohaveingeneral,auniformapproachbydifferentexpertorganizationsforcarryingoutsitespecificseismicstudies.Astheinputdataontectonicfeatures,pastseismicityand
strong groundmotion characteristics required for such studiesare scanty inmany cases, these
guidelinesshallgoalongwaytoovercometheselimitationstilltherequiredinformationbecomes
availableintimestocome.
Iexpressmysincere thankstoall thepresentandExMembersofNCSDP,officers fromCWPRS,
Pune, IIT,RoorkeeandCWCfortheir invaluablecontributionandcooperation inhelpingCWCto
preparetheseguidelines.
For thismeticulouswork, Iexpressmygratitude forsincereanduntiringeffortsmadebyDr ID
Gupta,Director,
CWPRS,
Pune,
Dr
H
R
Wason,
Prof
&
Head,
DEE,
IIT
R,
Dr
M
LSharma,
Prof
IIT
R,
ShriManishShrikhande,AssociateProf,IITR,ShriCSMathur,ChiefEngineer(DSO),CWC,DrBRK
Pillai, Director, CWC and Shri S S Bakshi, Director, CWC & Member Secretary NCSDP for
formulationoftheseGuidelines.Iamalsohappytoacknowledgethesupportandcooperationof
officersandstaffofFE&SADirectorateofDamSafetyOrganization,CentralWaterCommissionin
preparationofthisdocument.
IamsurethattheseGuidelineswillbehelpfulforthedesignsofvariousrivervalleyprojectsofthe
country.
NewDelhi
October,2011
-
7/31/2019 Guidelines EQ
3/34
CentralWaterCommission
NCSDPGuidelines:2011
ContentsPageNo.
Abbreviations1.0 Scope 1
2.0 GeneralConceptsandGuidingPrinciples 2
3.0 DataRequirements 5
4.0 Methodology 7
5.0 RecommendationsonDesignApproach 17
6.0
Submissionof
Study
Report
for
NCSDP
Approval
19
7.0 PresentationofStudyReportBeforeNCSDP 20
AnnexureA
IllustrativeExample:DSHAMethodforDevelopingTargetResponseSpectra 21AnnexureB
IllustrativeExample:PSHAMethodforDevelopingTargetResponseSpectra 23AnnexureC
ProformaforSubmissionofStudyReporttoNCSDP 27AnnexureD
Bibliography 29
-
7/31/2019 Guidelines EQ
4/34
CentralWaterCommission
NCSDPGuidelines:2011
ABBREVIATIONS
DBE DesignBasisEarthquake
DSHA DeterministicSeismicHazardAnalysis
ICOLD InternationalCommitteeonLargeDams
IS IndianStandard
LET LocalEarthquakeTomography
MCE
MaximumCredible
Earthquake
MCM MillionCubicMeters
MPa MegaPascal
MT Magnetotellurics
NCSDP NationalCommitteeonSeismicDesignParameters
NGA NextGenerationAttenuation
OBE OperatingBasisEarthquake
PGA PeakGroundAcceleration
PSHA ProbabilisticSeismicHazardAnalysis
Sa Spectralacceleration
SEE SafetyEvaluationEarthquake
SGM StrongGroundMotion
SSZ SeismicSourceZones
-
7/31/2019 Guidelines EQ
5/34
NCSDPGuidelines:2011 Page1
GUIDELINESFORPREPARATIONANDSUBMISSIONOF
SITESPECIFICSEISMICSTUDYREPORTOFRIVERVALLEYPROJECTTO
NATIONALCOMMITTEEONSEISMICDESIGNPARAMETERS
1.0
SCOPE
1.1 Theseguidelinesdealwiththepreparationofsitespecificseismicstudyreportofarivervalley
projectanditssubmissiontotheNationalCommitteeonSeismicDesignParameters(NCSDP)
fornecessary approval. The guidelineswill help in estimationof parameters tobe used in
seismicdesign,analysisandsafetyevaluationofneworexistingdamsandtheirappurtenant
structures. It isalsoexpectedthattheguidelineswillbringuniformity insitespecificseismic
studiesbeingcarriedoutbydifferentexpertorganizations.
1.2 The site specific seismic studies need tobe carried out and submitted for the approval of
NCSDP in respect of all such river valley project/dams that are classified under high or
extremehazardpotentialcategories.However, theuniformhazardpotentialcategorization
criteriafordams inIndiaareyettobeformulatedandapprovedbytheNationalCommittee
on Dam Safety. Till such time the hazard categorization criteria is not in place, it will be
mandatory, for the large dams1 that fall in seismic zone III, IVorV to get the approvalof
NCSDP forsitespecificseismicstudies fortheassessmentofdesignearthquakeparameters.
However,fortheprojectsinseismiczoneII,theapprovalofNCSDPforthesitespecificseismic
studieswillbemandatoryforsuchdamsthataremorethan30metersinheight.
1.3 The basic provisions of the guidelines are applicable for the river valley projects and its
appurtenantsstructures,andalsoforthepowerhouseandsuchotherstructureslocatedinthe
vicinityofdamwhosefailurecanresultinanuncontrolledreleaseofwaterfromthereservoir.Thetermdamusedhereshallmeananyartificialbarriermeanttoimpoundordivertwater,
and is inclusive of gravity dam, arch dam, embankment dam, barrage, weir, bund etc.
However, theprovisionsof theguidelinesneednotbeapplied incaseofprojectcanalsand
canalstructures,andalsonotincaseoftemporarystructuressuchascofferdams.
1.4 There isno intrinsicdifference in themethodology of selecting earthquake parameters for
design of new dams or safety evaluation of older dams. The rehabilitation of existing
structureswhicharedesignedonthebasisofstandardearthquakeprinciplesmaynotcallfor
fresh site specific seismic studiesunlessnew seismic activity are reported inor around the
project
sites.
However,
rehabilitation
cases
involving
dams
that
are
not
investigated
or
designedasperthemodernengineeringpracticesmayrequiresitespecificseismicstudies.
1.5 Thesitespecificseismicstudieswhicharenotmandatedasperaboveconditionsneednotbe
referredtoNCSDPunlessdirectedotherwisebyagovernmentorjudicialauthority.Inallsuch
exemptcases,theselectionofseismicdesignparameterswillcontinuetobegovernedbythe
IndianStandard1893(Part1)CriteriaForEarthquakeResistantDesignOfStructures2.
1Alargedamisonemorethan15mhigh(abovethedeepestfoundationlevel)oronebetween10mand15mhighsatisfying oneofthefollowingcriteria:
(a)
more
than
500m
long;
(b)
reservoir
capacity
exceeding
1x106
m3;
(c)spillway
capacity
exceeding
2000
m3/sec
2PendingfinalizationofParts2to5ofIS1893,provisionsofPartIwillbereadalongwiththerelevantclausesof IS1893:1984forstructuresotherthanbuildings
-
7/31/2019 Guidelines EQ
6/34
CentralWaterCommission
NCSDPGuidelines:2011 Page2
1.6 Fordesigncriteriaotherthanthoserelatedtoseismicdesignparameters,referencemaybe
madetotheIndianStandardIS1893(Part1)3
.
2.0 GENERALCONCEPTSANDGUIDINGPRINCIPLES
The site specific seismic study for a river valley project requires an understanding of the
seismic scenario with regard to dam site, which includes geological setting of the area,
tectonic featuresand thehistoryofearthquakeoccurrence in theregion.Thestudyenables
evaluation of design ground motion based on identifiable seismic source zones and
appropriategroundmotionattenuationlaws.Thegeneralconceptsandprinciplesusedinsuch
studyaregivenbelow.
2.1 SeismicSourceZones
For the assessmentofdesignearthquake sourceparameters, it isnecessary to identify the
probableSeismicSourceZones(SSZ)wherecatastrophicruptureswillgenerateearthquakesat
a
site
in
prevailing
tectonic
environment,
and
adopt
a
pragmatic
approach
to
evaluate
the
likelymaximummagnitudeoftheeventwhichcouldoccurinfuture.
ThedelineatedSSZhastobeconsideredtorepresentazoneofstructural(tectonic)features
foroccurrenceoffutureearthquakes.TheprobablemaximumseismicpotentialoftheSSZ is
generallycontrolledbytheareaunderstrainbuildup,governingthelengthandbreadthofthe
seismicrupture,strengthanddeformationcharacteristicsoftherock,stressdrop,andfailure
mechanism.Theseismicpotential is rated in termsofthemagnitudeoftheevents,andthe
maximummagnitudethuscorrespondstotheprobablemaximumruptureparameters.Ifthere
are two, threeormore seismogenic featureswhichcan influence thegroundmotionat the
site,alltheseshouldbeconsideredaspotentialsourcesforthepurposeofanalysis.
Thedamagedue toearthquake isameasureof theearthquake intensityatany site,and it
dependsonthedistanceandenergyreleasedfromtherupturewithinSSZ.
2.2 DesignEarthquakes
2.2.1 Thelargestbelievableearthquakethatcanreasonablybeexpectedtobegeneratedbyspecific
seismicsources(SSZ)inagivenseismotectonicframeworkisreferredtoasMaximumCredible
Earthquake(MCE)forthatSSZ.Thisisthelargesteventthatcouldbeexpectedtooccurinthe
regionunderthepresentlyknownseismotectonicenvironment;andthestructuralsystem,if
designed on this basis, would prove to be highly uneconomical. Therefore a Design Basis
Earthquake(DBE),whichwouldhaveareasonablechanceofoccurrenceduringthelifetimeofthestructure,isalsoevaluatedkeepinginmindthedegreeofsafetyrequired.
2.2.2 Maximum magnitude of the events which could occur in a SSZ is evaluated from data on
earthquake occurrences. If data is available for sufficiently long duration, the highest
magnitudeof the knowneventofpastwith suitable increment is generally adopted as the
maximum magnitude of MCE for that source. For regions with poor documentation of
historicalevents,anappropriate increment isaddedtothehighestmagnitudeoftheknown
event for evaluation of MCE to account for the incompleteness of seismicity catalog The
deterministicapproachfordeterminationofMCEpractically ignoresthereturnperiodofthe
3ibid2
-
7/31/2019 Guidelines EQ
7/34
CentralWaterCommission
NCSDPGuidelines:2011 Page3
event.TheMCE levelofgroundmotioncanalsobeevaluatedusinganappropriateapproach
similartothatgiveninICOLDbulletin89(revised).
2.2.3 TheDBE represents that levelofgroundmotionatdam siteatwhichonlyminorandeasily
repairable damage is acceptable. Since the consequencesof exceeding theDBE aremainly
economic, theoreticallyDBEshallbedetermined fromaneconomicanalysis.However, frompracticalconsiderations theDBE ischosen foracertain returnperiodofthegroundmotion.
For the occurrence of earthquake shaking not exceeding the DBE, the dam, appurtenant
structuresandequipmentshouldremainfunctionalanddamagesshouldbeeasilyrepairable.
2.2.4 IntherecentlyadoptedICOLDguidelines(SelectingSeismicParametersforLargeDams,2009),
theterminologiesofSafetyEvaluationEarthquake(SEE)andOperatingBasisEarthquake(OBE)
havebeenused inplaceofMCEandDBE.There isno intrinsicdifference inthedefinitionor
usageofOBEvisvisDBE.However, theusageof SEEhasbeen characteristicallydifferent
thanMCEonaccountofapplicationofaprobabilisticapproachwhereinthechoiceofreturn
periodofevent
islinked
with
hazard
potential
categorization
ofdam.
Change
over
from
MCE
DBEterminologiestoSEEOBEterminologies isconsidereddesirable;but,thesamehasbeen
deferredtilladoptionoftheuniformhazardpotentialcategorizationcriteriafordamsinIndia.
2.3 SeismicEvaluationParameters
2.3.1 Groundmotionatanysiteisinfluencedbysource,transmissionpathandlocalsiteconditions.
Thefactorsresponsibleforsourceeffectincludefaulttype,rupturedimensions,mechanism
anddirection,focaldepth,stressdropandamountofenergyreleased.Thetransmissionpath
effectrelatestothegeometricspreadingandabsorptionofearthquakeenergyastheseismic
wave travel away from the source; and the responsible factors include rock type, regional
geological structures including surface faults and folding, crustal inhomogeneities, deep
alluvium, and directivity effects (direction of wave travel vs direction of fault rupture
propagation).Thelocalsiteeffectresultsfromthetopographicandsoilconditionspresentat
thesite.
Groundmotioncanbecharacterizedbypeakvaluesofexpectedacceleration,velocity,and/or
displacement.Ideally,allfactorsaffectinggroundmotionshouldbeconsideredforevaluation
oftheseparameters;butthisisnotpractical.Generally,onesourcefactor(magnitude)anda
singletransmissionpathfactor(distance)onlyareconsidered.The localsiteeffectsareoften
disregarded, or limited to simple distinction between rock and alluvial sites and possible
considerationofnearfieldeffects.Empiricalrelationsderivedfromavailableearthquakedata(attenuation relations) relategroundmotionparameterstodistance from thesourceandto
magnitude.
2.3.2 Attenuation relations:Attenuation relations are empirical relationsdeveloped from Strong
GroundMotion (SGM)measurements, and areused for the predictionof expected ground
motionanditsintrinsicvariabilityattheprojectsite.Suchpredictions aregenerallyperformed
usinggroundmotionmodelsthatdescribe thedistributionofexpectedgroundmotionsasa
functionofafewindependentparameters,suchasmagnitude,sourcetositedistanceandsite
classification. The distribution of expected ground motions described by any one ground
motion model is given in terms of median spectral amplitudes and associated standarderror/deviationusuallyreferredtoasaleatoryuncertainty.Theseismichazardstudiesshould
-
7/31/2019 Guidelines EQ
8/34
CentralWaterCommission
NCSDPGuidelines:2011 Page4
needtoaccountforboththeseuncertaintiesintherelations.
Ideally,theattenuationrelationtobeusedforaparticularsiteshouldbedevelopedusingthe
recorded strongmotion data in the region around the site of interest. However, due to
paucityofstrongmotiondata in India,such relationsarenotavailable fordifferentpartsof
the country. In practical engineering applications, it thus becomes necessary to identify
suitablerelationsfromthepublishedliterature.
2.3.3 Duration of shaking: The strong motion duration is important from the point of view of
responsebehaviorofthestructurebeingexamined,anditlargelydependsontheearthquake
magnitude and alsoon thedistance and site condition to some extent. The strongmotion
durationisafunctionofthefrequencyandrepresentsthesumtotalofthedurationsofallthe
strongmotion segments contributing 90%of the energyof completemotion (Trifunac and
Brady,1975).Durationofstrongshakingisanimportantparameterfordamsafetybecauseof
itsdirectrelationtodamages,especiallyincaseofembankments.
2.3.4 Responsespectrum:Theresponsespectrum representsthemaximumresponse (inabsolute
acceleration and relative velocity or relative displacement) as a function of natural time
period, for a given damping ratio, of a set of singledegreeoffreedom (SDOF) systems
subjectedtoatimedependentexcitation.
ItiscustomarytorepresentcomputedresponseofSDOFsystemtoaparticulargroundmotion
in the form of elastic spectra. These spectra show the response quantity (e.g. absolute
acceleration) against the natural periods of SDOF systems for different values of damping.
Sincetherearepeaksandvalleysinthespectrathuscomputed,thevagariesareironedoutas
faraspossiblebythesmoothenedspectra.ResponsespectrumcharacterizingtheMCEorDBE
hastobesitespecific.
Thenumberofdampingvalues forwhichresponsespectrashouldbespecified to represent
theMCEorDBElevelofgroundmotionshouldencompassarangeofvaluesapplicabletothe
typeofdamand levelofgroundmotionconsidered.Dampingvaluesforanalysisofconcrete
and masonry dams may be taken as 5 and 7 percent respectively when the response is
assumedtobepredominantlyelastic.Dampingvaluesfortheanalysisofembankmentdams
maybetakenas10to15percent.
2.3.5 Acceleration time histories: The seismic parameters in terms of peak values and spectral
characteristicsaresufficientforanalysisofmanydams.However,incaseofdamswithhighor
extremehazardpotentials,andforuseofnonlinearanalysistechniques,thespecificationof
earthquake motion in time domain (as acceleration time history records) is also required.
Accelerationtimehistoriesmaybespecifiedforhorizontaland/orverticalmotionandshould
preferablyberepresentedbyrealaccelerogramsobtainedforsiteconditionssimilartothose
present at the dam site under consideration. However, since strong ground motion data
currentlyavailabledonotcoverthewholerangeofpossibleconditions,this isessentiallyan
exercise in generation of random waveforms (keeping in view the duration of the ground
motion and the general pattern of ground motion history) which are synthetic in nature.
Severaltimehistoriescouldbegeneratedtomatchthesametargetresponsespectrum,and
allofthesewouldbeequallyacceptablefromthepointofseismicconsiderations.
-
7/31/2019 Guidelines EQ
9/34
CentralWaterCommission
NCSDPGuidelines:2011 Page5
2.4 DeterministicandProbabilisticAnalysisApproaches
The two general approaches for developing the sitespecific response spectra are the
deterministic seismic hazard analysis (DSHA) and the probabilistic seismic hazard analysis
(PSHA) methods. The basic inputs required for both the approaches are the same, which
include data on past seismicity, knowledge of the tectonic features, geological and
morphological setup, geophysical anomalies, information on site soil condition and the
underlyinggeologyofthesurroundingarea,andtheattenuationcharacteristicsofthestrong
motionparametertobeusedforquantifyingthehazard.Thetreatmentofseismicitydatafor
homogenization,completenesswithrespect to timeandsize,anddeclusteringarerequired
beforeproceedingwithanyoftheapproaches.
2.4.1 In its most commonly used forms, the DSHA approach proposes design for the socalled
"scenario"earthquakes(MCE).Theunderlyingphilosophyisthat"scenario"earthquakeofthe
seismic source is scientifically reasonable and is expected to produce most severe strong
groundmotionatthedamsite.OneofthemostimportantissuesisthereliableestimationoftheMCE,foreachoftheidentifiedseismicsourcezones,onthebasisoftheavailabledataon
past earthquakes and the seismotectonic and geological features of a SSZ. However, the
delineationof theSSZ, theestimationofMCEmagnitudes,aswellas theestimationof the
corresponding ground motion at a certain distance from the earthquake source, are
commonlyassociatedwithlargeuncertainties.TheDBElevelofdeterministicgroundmotionis
generallytakenasanappropriatefraction(say0.5)oftheMCElevelofmotion.
2.4.2 ThePSHAapproachprovidesastructure inwhichuncertaintiescanbe identified,quantified
andcombinedinarationalapproachtoprovideacombinedeffectofseveralalternateseismic
sourceson
seismic
hazard
atasite.
Thus,
there
are
multiple
scenarios
and
models
for
hazard
analysisapplicableatagiven site.ThePSHAcarriesout integrationover the totalexpected
seismicitytoprovidetheestimateofagroundmotionwithaspecifiedreturnperiod.TheMCE
levelofgroundmotion isproposed tobedefinedwithareturnperiodofabout2500years,
whereasDBElevelofgroundmotionisdefinedwithamuchlowerreturnperiodofabout145
years.
3.0 DATAREQUIREMENTS
Theprimarydataforidentificationofpotentialsourcesofearthquakesandevaluationoftheir
characteristicspertaintothetectonic,geologicandseismicactivityconditionsat,and inthe
vicinityof,thedamsite.Thestudyshouldconsidertheregionalaspects,andthenfocusonthelocalsiteconditions,soastofullyunderstandtheoverallgeologicsettingandseismichistory
ofaparticularsite.
The below mentioned information need to be compiled by getting inputs from various
organization or institute and published standard literature for the assessment of seismic
designparameters.
3.1 RegionalGeologic/Seismotectonic Setting
Seismotectonic map: A seismotectonicmapof1: 1000,000or comparable scale,depictinggeology,structures(withemphasisonnatureandextentofmajorfaults,shearzonesetc)and
seismicity(asdetailedinpara6.2&7.1)foranareaabout300kmradiusfromdamsiteshould
-
7/31/2019 Guidelines EQ
10/34
CentralWaterCommission
NCSDPGuidelines:2011 Page6
beused ( i.e.about60 latitudex6
0 longitudewiththedamsiteatthecentre).Locationand
descriptionof faultsand shear zonesandassessmentof the capabilityof faults togenerate
earthquakesshouldbe furnished.This should includedocumentationon theexistenceofor
thelackofhistoricalorprehistoricalactivity(paleoseismicity)foreachmajorfault.
Seismotectonicsection: At leastoneregionalseismotectonicsection throughthedamandacrossthemajortectonictrend(basedon6.1.1)oftheregionshouldbeprepared.Thesectioncoveringaminimum50kmreachoneithersideofthedamshouldclearlyshow(ifnecessary,
by vertical exaggeration) the subsurface disposition of the major faults and earthquake
hypocenters.
3.2 SeismicHistory
Earthquake catalogue: Theearthquake catalogue should contain informationaboutorigintime (date/ time), location (latitude/ longitude/ depth), and size (magnitude / type of
magnitude/ intensity)ofearthquake fromthehistoricaltimetopresent time foranareaof
about300kmradiusfromdamsite.ThisdatamaybeobtainedfromIMDandupdatedonthebasisofotherauthenticsources.Totheextentpossible,informationonfocalmechanism,felt
area,accompanyingsurfaceeffects,knownorestimated intensityofgroundmotion induced
atthedamsite,andthesourceofdataanditsreliability,shouldalsobepresentedforallmajor
events.
Micro earthquake investigations: Fordams exceeding the heightof 100m, thedetails ofmicroearthquakedata recordings around thedam sitewithin a radiusof50 km shouldbe
providedincorporatingfullcatalogueinformationforaperiodofatleastsixmonths.Suchdata
shouldbeobserved/collectedbytheprojectauthorities.
3.3 LocalGeologic
Setting
Geologicalmap: Fordamshigher than200mand located inseismiczone IVorV (asper IS1893 Part 1 (2002) a geologicalmap (based on photogeology/imagery studies and ground
mapping)on1:50,000to1:60,000scalesshouldbepreparedforanareaof50kmradiusfrom
the dam site with special emphasis on gross lithological (or stratigraphical/tectono
stratigraphic)domains,structuraldetailslikefaults,folds,shearzones,masterjoints,structural
trendlinesandlineamentsetc.Geomorphicand/orevidencefromQuaternaryGeology(ifany)
withintheinfluenceareaindicatingpresenceofactivefaultshouldbedocumented.Geological
evidenceswhereveravailableonthenatureofmovementalongthefaultvisvistheageof
such movement should be indicated. A short descriptive account on the various lithostratigraphicunitsandstructuralelementsshouldbeincluded.
Surfaceandsubsurfaceexploration:Thereportofexplorationshouldcontainlocalgeologicalmap(s)ofthedamsiteandotherappurtenantstructureson1:1000orlargerscalealongwith
topographiccontours.Thereportshouldalsoincludegeologicalsectionsalongandacrossdam
axisThegeologicalsectionsshouldbederivedthroughdrillingandothergeophysicalprobing,
andtheyshouldshowdepthtooverburden,faults,shearzonesetc.Thecompressionalwave
velocity (Vp)andshearwavevelocity (Vs)ofat least30mbelow themajorstructures (dam,
powerhouseetc.)shouldbeprovided.
-
7/31/2019 Guidelines EQ
11/34
CentralWaterCommission
NCSDPGuidelines:2011 Page7
Additionalinputsonsubsurfaceconfigurationofmajorfaults: Fordamsofheightexceeding200 m and located within seismic zone IV or V, additional inputs on the subsurface
configurationofmajorfaultswithin50kmradiusofthedamsiteshouldbeprovidedbasedon
Local Earthquake Tomography (LET) / Magnetotelluric (MT) studies or any suitable
methodologymaybeadopted,detailsofwhichshouldalsobefurnished.
4.0 METHODOLOGY
The site specific seismic design parameters will depend on many variable factors. It is an
extremelydifficulttasktodeterminetheexactparametersinviewofuncertaintiesrelatedto:
[a] choice of earthquake parameters (namely magnitude, distance, focal depth and
mechanism)relatedtoMCEandDBE;[b]choiceofgroundmotionattenuationrelationshipfor
computing spectral accelerations and [c] the elastic modulus, shearmodulus and damping
characteristics of the material used in construction. In view of above, it is important to
exerciseajudiciousbalance invarioussteps involved inthestudy.Thementionedguidelines
beloware
expected
to
facilitatethis
process
for
the
meaningful,
reliable
and
safe
design
of
rivervalleyprojectsinthegivenseismicenvironment.
4.1 SelectionofEarthquakesforAnalysis
All geological maps and data (as specified in section 6) should normally be studied to
determineactiveseismicfeatures.
A tablegiving the listofearthquakeswithperiodwisebreakup (historical to1900;1901 to
1963;1964topresent)shouldbeprepared.Forearthquakedatasubsequentto1964,thetype
ofmagnitude (i.e.MW,Ms,mb,ML,MDetc)and focaldepth shouldbegiven; the aand b
values from GuttenbergRichter (GR) relation should be calculated through regression
analysis,preferablyusingmaximumlikelihoodmethodandtheMmaxforaspecifiedrecurrence
periodshouldbe indicatedusingaand bvaluesforeach identifiedseismicsourcezoneas
wellasfortheregionasawhole.
Theappropriatedistanceconsistentwithattenuation relationship frompostulatedscenario
earthquake from dam site should be tabulated. Efforts should be made to classify the
correspondingfaultsbasedon itstypesofmovement(i.e.normal,thrust,strikeslip[dextral/
sinistral])visvisthelocationofthestructure(e.g.,hangingwall,footwall,directivityincase
of strikeslip etc.). A floating earthquake approach should be adopted where seismogenic
featuresinthevicinityofdamsitearenotknown.
4.1.1 Magnitude of MCE: TheMCE for aparticular SSZ canbe estimated from the catalogueof
earthquakes in the area of 300 km radius around the dam site (i.e. about 60 latitude x 6
0
longitude with the dam site at the centre), using several different methodologies. The
magnitudeforMCEcanbeestimatedusingmethodsasunder:
incrementingtheworstrecordedearthquake,toaccountforincompletenessofcatalogusingaandbvaluesofGuttenbergRichterrelationshipextremevaluedistributionusingempiricalrelationship
-
7/31/2019 Guidelines EQ
12/34
CentralWaterCommission
NCSDPGuidelines:2011 Page8
predictingmagnitudeofearthquakebasedonfaultrupturedimensions4Thesimplestmethodistosuitablyenhancetheworstrecordedearthquakebyanappropriate
incrementtoaccountforincompletenessofdataforarrivingatMCE.
4.2 SelectionofAttenuationRelations
HavingchosenthedesignearthquakeparametersofMCEorDBEshock inrelationtoproject
site, thenext task is toobtain thegroundmotion characteristicsat the siteusingempirical
groundmotionmodels(attenuationrelations)whichrelatetheresponsespectralamplitudes
atdifferentnaturalperiodsor frequenciesof the structure to thegoverningparameter like
earthquakemagnitude,sourcetositedistanceandsitegeologicalconditions.
The selectionof appropriate groundmotionmodels for aparticular target area from large
numberofpublished attenuation relations forother regions isnot thateasy.The selection
process becomes complicated because there may be systematic differences in terms of
seismicsources,wavepropagationorsiteresponsebetweenthetargetregionandhostregion
fromwherethedatausedtoderivethemodelwasobtained.
The goal is to identify the smallest setof independentmodels (outof the largenumberof
modelsavailableinpublishedliterature)thatcapturetherangeofpossiblegroundmotionsin
the region under study. The criteria recommended for shortlisting the ground motion
predictionmodel,arrangedintheorderofdescendinghierarchy,areasunder:
Modelshouldbeforasimilartectonicregimeasitwouldclearlynotbeappropriatetouseanequationderivedforasubductionzoneforhazardanalysisinaregionofcrustal
seismicity,andviceversa.
Model ispublished inan internationalpeerreviewedjournal.Thepeerreviewprocessusuallyensures that themodelsareclearlydescribedand thatbasic tests (analysisof
residuals, comparisonwithprevious studies, etc.)havebeenperformed. Themodels
whichhavebeenextensivelyusedandtestedshouldbefavoured.
Documentationofmodeland itsunderlyingdataset shouldbecomplete.Theoriginaldatasetusedinthestudymustbepresentedinthepublicationandthedataprocessing
mustbedescribedandtheparametersusedinregressionstabulated.
Frequencyrangeofthemodelshouldbeappropriateforengineeringapplications.Forsomeengineeringapplicationswherehighfrequencies(>10Hz)or lowfrequencies(
-
7/31/2019 Guidelines EQ
13/34
CentralWaterCommission
NCSDPGuidelines:2011 Page9
SometypicalattenuationrelationsbeingusedarelistedinBibliography.
The choice of any particular attenuation relationship should be explained with complete
references and narration of itsmerits. Further, the final selection should be based on the
rankingcriteriaduetoScherbaumetal.(2004)usinglimitedstrongmotiondata,ifavailablein
theregionofinterest.Forthispurpose,itisproposedtodividethecountryintothreeregionsfortheidentificationofseparatesetsofattenuationrelationshipsthatarebestsuitedforeach
region.Thetargetedthreeregionsare(i)Himalayas,(ii)Gangabasinand(iii)Shieldregions.
Such anexercisewill call fordetailed examinationof the geophysical criteria regarding the
degreeofsimilarity,orotherwise,betweenthehostregionsfromwherethecandidatemodels
havebeenderivedandthethreetargetregions.
Till the detailed study is carried out to identify the attenuation relations for the above
mentioned threeregionsof India,the following informationmaybeconsidered forthetime
being:
The spectral acceleration values computed at various natural periods from differentpublished attenuation relations when compared with the limited observed spectral
amplitudesfromafewHimalayanearthquakes,therelationshipsduetoAbrahamsonand
Silva(1997)andTrifunacandLee(1989)areseentohavetheoverallbestmatchingwith
theobserveddataandmaythusbeconsideredsuitablefortheHimalayanregion.
Abrahamson and Silva have recently updated their relationship as a part of the NextGeneration Attenuation (NGA) project using the PEER NGA database. The updated
relationshiphasincludedthefaultdirectivityandsiteeffectsmorecomprehensively,but
itneeds exact information about the fault rupture geometry,which isnot available in
most cases. TheotherNGA relations alsoneed informationon faultdetails to varyingextent. Hence the NGA attenuation relations cannot be used without making some
subjectiveassumptions leadingtobiasedresults.TheearlierrelationofAbrahamsonand
SilvamaythereforehavetobeusedfortheHimalayanRegion.
Based on world wide data, Graizer and Kalkan (2009) have proposed an approach toobtaintheresponsespectralshapeconsideringthedependenceonmagnitude,distance,
and site condition which can be scaled by the PGA. They have also developed an
attenuation relation for PGAusing the samedatabase (Graizer and Kalkan, 2007). This
approach is also considered suitable for the Himalayan region, because the PGA
attenuationofGraizerandKalkan (2007) is found todescribe theavailablePGAdata in
Himalayanregionquitewell
The relationshipdue toTrifunacandLee (1989)hasconsidered thedependenceon themagnitudeanddistance inaphysicallyrealisticway inthat themagnitudeanddistance
saturationeffectsaswellasthegeometricspreadingwithdistanceareaccounted forat
each frequency. Also the influences of both the shallow local soil, as well as deep
geological formationsat the site,are included in this relationship.Asno strongmotion
data isavailable for the IndoGangeticplains, the relationshipof Lee isproposed tobe
used for the region due to physically realistic dependence on various governing
parameters.
-
7/31/2019 Guidelines EQ
14/34
CentralWaterCommission
NCSDPGuidelines:2011 Page10
4.3 DevelopmentofTargetResponseSpectra
Forestimatingthesitespecificdesigngroundmotionbydeterministicaswellasprobabilistic
approach, it is first necessary to obtain the response spectra of horizontal and vertical
componentsofmotionseparately foradampingratioof5%.Suchspectraareknownasthe
target response spectra, and the ground motion acceleration time histories required fordetailed dynamic response analysis are generated synthetically to be compatible with the
target response spectra.Response spectra forother valuesofdamping are then computed
from these acceleration time histories. Target response spectra can be developed by the
followingthreeapproaches:
(i) ScalingastandardspectralshapebyPGA:
Theresponsespectraofhorizontalandverticalcomponentsofgroundmotioncanbeobtained
conveniently by scaling a mean plus one standard deviation normalized spectral shape
appropriate for thesiteof interestwiththemedianpeakgroundacceleration.Thestandard
spectralshapeshouldbebasedonsufficiently largeensembleofstrongmotionrecordswithmagnitude and sourcetosite distance close to the desired magnitude and distance of
controllingMCE.ThePGAcanbeestimatedbydeterministicorprobabilisticapproach.
(ii) Usingspectralamplitudeatselectedperiods(say0.2and1.0sec):
Theresponsespectralamplitudesatnaturalperiodsof0.2secand1.0secalongwithPGAcan
be estimated using an appropriate attenuation relation from deterministic or probabilistic
approach. Median or median plus one standard deviation values (depending upon the
seismicityoftheregion)ofalltheseparametershastobeusedinthedeterministicapproach
andwithareturnperiodof2500years intheprobabilisticapproachtogettheMCE levelof
spectra.
The control period T2 which marks the beginning of the constant velocity range is then
obtainedastheratioofthepseudospectr ac ionat1.0and0.2secasfollowsal celerat
T S 1.0sS 0.2s5
:
x 1sThecontrolperiodT1whichmarksthebeginningofconstantaccelerationrangeisobtainedas
afractionofT2dependingonthesoilclassific tion s:a a
T 12 to 15 x Twiththefactor1/2correspondingtoverysoftsoiland1/5correspondingtomassiverocks.For
mostoftheprojectsitestheactualfactorwillbebetweenthesetwoextremevalues(0.20.5).
Thepsuedospectralacceleration isconsidered to increase linearly fromPGAvalueatperiod
T0= 0.03 sec to its maximum value at T1. The maximum value of the psuedospectral
accelerationobtainedatTn=0.2secisheldconstantfromperiodT1toT2.Forperiodslessthan
5P K Malhotra- Return period design ground motions. Seismological Research Letters, 76(6):693-699,2005.
-
7/31/2019 Guidelines EQ
15/34
CentralWaterCommission
NCSDPGuidelines:2011 Page11
T0thepsuedospectralaccelerationisconsideredtobethesameasthePGA.
The psuedospectral velocity is held constant at ST STx in the range fromperiodsT2toT3.Theconstantvelocityrange isconsideredtoextenduptoT3=(6to9)T2 ,
withthefactor6correspondingtomassiverocksand9correspondingtoverysoftsoil,afterwhichtheconstantdisplacement(orlinearpsuedospectralvelocitywithnegativeslope)range
begins.Forstrongearthquakes,theconstantdisplacementrangeoftheresponsespectrumin
the near field generally begins between 3sec and 4sec. The constant psuedospectral
displacementisobtainedfromthepsuedospectralvelocityatT3as
ST ST x T2 ST x T2 x T2Thetripartiteplotofresponsespectrumisshowninfig1
Figure1:Responsespectrumtripartiteplot(logscale)
-
7/31/2019 Guidelines EQ
16/34
CentralWaterCommission
NCSDPGuidelines:2011 Page12
The tripartite format of design spectrum is not very convenient to use in practice and
therefore,itisnecessarytotranslateitintoalinearplotofpseudospectralacceleration(Spa)
versusnaturalperiod (T).Foraresponsespectrum intripartite format (asshown inFig.1),thepseudospectralacceleration(S)maybep as nctionofthenaturalperiod(
T)as:
rescribed afu
ST PGA x
1 ; T TT T ; T T TA ; T T TV T ; T T TD T ; T T
Theparameters ,A,VandDaredescribedasbelow:
1;
A ;V 2 x D 2 x T x STPGA
;
Thepseudoaccelerationdesignspectrumspecifiedbytheaboveequationandcoefficients is
shown in Fig.2. Thepositionsof the controlperiodsof theequationhavebeenmarked in
thesefigures.Itmaybeseenthatwhilethepseudoaccelerationspectrumplotinlinearscale
hasdifferentcurves,thetripartiteplotinlogarithmicscalesiswelldefinedbyasetofstraight
linesbetweendifferent pairsof control periods. Therefore, the above equation of pseudo
accelerationdesignspectrum isderivedfromthecorrespondingequationsofstraight linesof
pseudovelocityspectrumonthetripartiteplot.
Figure
2
:
Pseudo
spectral
acceleration
(linear
scale)
-
7/31/2019 Guidelines EQ
17/34
CentralWaterCommission
NCSDPGuidelines:2011 Page13
(iii) Usingfrequencydependentattenuationrelationships:
TheattenuationrelationsusedforestimatingthePGAorspectralamplitudeat0.2and1.0sec
intheabovetwomethodsaregenerallydefinedforalargenumberofnaturalperiodscovering
the entire frequency range necessary to define the complete response spectrum. Thus, by
estimatingthespectralamplitudeatallthenaturalperiodsforwhichtheattenuationrelation
is defined, it is possible to obtain the complete response spectrum without making any
assumptions. This can be done by using both deterministic as well as probabilistic
methodologies.
4.3.1 DSHAMethodologyforDevelopingTargetResponseSpectra
Incommonlyuseddeterministicapproachfordevelopingtheresponsespectraforadamsite,
onehastofirstassessthemaximumpossibleearthquakemagnitude foreachof theseismic
sources (important faults, shearzones, thrustsetc) in theprojectareaof interest (generally
about 60 latitude x 60 longitude with the dam site at the centre). Such an earthquake is
commonly termedasMaximumCredibleEarthquake (MCE),which isthe largestearthquake
thatcanbesupportedbyeachsourceunderthesitespecificseismotectonicframework.The
MCEforeachseismicsourceisthenpresumedtooccurata locationthatplacesthefocusat
theminimumpossibledistance to theprojectdamsitewhich thesourcegeometrypermits.
TheresponsespectraforeachMCEcanthenbedevelopedusinganappropriateattenuation
relation. The zeroperiod spectral value is the peak ground acceleration, i.e., zeroperiod
spectralacceleration (ZPA)=PGA.Theworstcombinationof themagnitudeanddistanceof
MCEisnormallyconsideredtogettheMCElevelofdesigngroundmotion.
ThetargetspectrumforMCEconditionmaybetakenasatmedianplusonestandarddeviation
levelforprojectsitesinregionsofhighseismicity(SeismicZoneIVandVasperIS:18932002)
becauseofrelativelyshortreturnperiodsoflargeearthquakesandtoaccountforthescatter
in recordedearthquakedata.For the low seismicity regions (Seismic Zones IIand IIIasper
IS:18932002), the recurrence intervalofMCE levelearthquakes isvery largeand therefore
theMCEtargetspectrumforprojectsitesintheseregionsmaybetakenasmedianestimates.
Thisistomaintainapproximatelyuniformlevelofseismicriskacrosstheentirecountry.
ThetargetresponsespectraforDesignBasisEarthquake(DBE)conditionmaybetakenasone
standard
deviation
less
than
the
corresponding
MCE
target
spectra,
or
half
of
MCE
target
spectra,whichevergivehigheramplitudeatnaturalperiodofinterest.
AnillustrativeexampleoftheforegoingmethodologyisgiveninAnnexureA4.3.2 PSHAMethodologyforDevelopingTargetResponseSpectra
Theprobabilisticseismichazardanalysis(PSHA)approach isbasedonanaltogetherdifferent
philosophy and concept compared to the deterministic seismic hazard analysis (DSHA)
approach for arriving at sitespecific design earthquake ground motion for important
engineeredprojects.TheDSHAaimsatestimatingthepossiblemaximumvalueoftheground
motion
amplitudes
by
considering
a
maximum
magnitude
of
earthquake
to
occur
at
the
shortestsourcetositedistance, irrespectiveoftheprobabilityofsuchanoccurrence,which
-
7/31/2019 Guidelines EQ
18/34
CentralWaterCommission
NCSDPGuidelines:2011 Page14
remains unknown and unquantified. The PSHA on the other hand aims at estimating the
groundmotionamplitudeshavingadesiredannualprobability(p)ofexceedanceduetoanyof
theearthquakesexpectedtooccuranywhereintheregionaroundtheprojectsite.Thereturn
periodTr (years) isequal to reciprocalof the annualprobability (p)ofexceedance.Thus, a
probabilityof exceedance equal to 0.001 represents a return periodof 1000 years for the
groundmotion.TheICOLDguidelines(2010)specifythereturnperiodsof10,000years,3,000
yearsand1,000yearsfortheMCE levelofgroundmotionfordamswiththreedifferentrisk
levels to the downstream population. The PSHA approach can also be used to obtain the
return period corresponding to the deterministic estimate of the ground motion for
comparison with the return periods proposed by ICOLD guidelines and taking appropriate
decisionsaboutthesuitabilityofthedeterministicestimate.
Detailson the currentlyusedPSHAapproach canbe read fromCornell (1968),EPRI (1987),
Reiter(1990),SSHAC(1997),USACE(1999),Gupta(2002),McGuire(2004),etc.ThebasicPSHA
approachisbasedoncomputingthefollowingannualprobabilityofexceedanceofaspecifiedmeasureofthegroundmotionamplitude(e.g.theaccelerationresponsespectrumamplitude
SA(T)atnaturalperiodT):
Here,istheannualprobabilityofexceedingaspectralamplitudeSA(T)duetoanyofthe earthquakes in any of the source zones, n (, ) is the annual occurrence rate ofearthquakesofmagnitudeatsourcetositedistanceineachoftheseismicsourcezonesaround the project site, and
| , is the probability of exceeding the spectral
amplitudeSA(T)duetomagnitudeanddistancecombination(,) inthenthsourcezone.Theplotof SA(T)vsisknownastheHazardCurve.Bycomputingthehazardcurvesforall thenaturalperiodsT, thedesign response spectrum canbeobtainedwithadesired
annualprobabilityofexceedance(orrecurrenceperiod)atalltheperiods.Suchaspectrumis
knownasUniformHazardResponseSpectrum.
1 | , . ,
The various steps involved in computing the hazard curves to implement the PSHA
approachcanbesummarizedasbelow:
Step1:DelineationofSeismicSourceZones
Thefirststep inPSHA isto identifyanddelineatevariousseismicsourcezones(SSZ)withina
regionof6lat6longwiththedamsiteatthecenter,whereaSSZrepresentstheportion
of earths crustwith distinctly different characteristics of earthquake activity ( in terms of
frequency&maxpotential) from thoseof the adjacent crust.Though fault specific seismic
sourcescanbeusedinsomecases,duetolackofclosecorrelationofobservedseismicitywith
knownfaults,extendedareatypeofsourcesisusedmorecommonlyinpracticalapplications.
Itmaybe noted thatdelineation of seismic sources cannotbe considered free from some
elementofsubjectivity.
-
7/31/2019 Guidelines EQ
19/34
CentralWaterCommission
NCSDPGuidelines:2011 Page15
Step2:EstimatingSeismicityofaSourceZone
TheGutenbergandRichters(1944)recurrencerelationship log ,whereN(M)representsthecumulativenumberofearthquakesperyearwithmagnitudeMorgreater, is
fitted toeach seismic source in step 2using availablepastearthquakedata.The catalogue
datamaybetreatedforremovalofforeshocksandaftershocks,homogenizationofmagnitudetoeitherMworMsandcorrection for incompleteness in sizeand time.This is thenused to
obtaintheoccurrenceraten()ofearthquakesinmagnitudeinterval( ,+ )bydiscretizingthecompletemagnituderangebetweenaminimumthresholdmagnitudeandthe
maximum upper bound magnitude. These numbers are finally distributed over the entire
source zone by dividing it into a large number of small size elements to get the annual
occurrence rate (, ), where refers to the distance to the center of the ith sourceelement.
Step3:EstimationofProbabilityqn[SA(T)I
,
]
An attenuation relationship suitable for the region of interest is selected in step 3,which
describestheresponsespectralamplitudes intermsofearthquakemagnitude,sourcetosite
distance, and site geologic condition. Such a relation is able to provide the least squares
medianestimateandthecorrespondingprobabilitydistributionoftheresidualsforspecified
earthquake magnitude and sourcetosite distance , which can readily be used toestimate the probability qn[SA(T) IM,R ].A single attenuation relationmay normally beapplicabletoallthesourcezones,butdifferentrelationsmayalsobeused,ifnecessary.
Step4:ComputationofUniformHazardSpectrum
The fourth and the final step in the PSHA approach is to compute the hazard curves, i.e.probabilitydistributionp[SA(T)],bycarryingoutthesummationsoverallthemagnitudesand
distances in all the source zones. A uniform hazard response spectrum is obtained by
computing the p[SA(T)] for all the natural periods of interest and estimating the
correspondingspectralamplitudeswithadesiredannualprobabilityofexceedance(orreturn
period).
AnillustrativeexampleoftheforegoingmethodologyisgiveninAnnexureB
4.4 DeterminationofSitespecificSeismicCoefficients
With theknowledgeof thenaturalperiodof thedam section, the response spectra canbe
used toobtain thesitespecificseismiccoefficients.The typeandpreliminary sectionof the
dam,thecomputational formula,andotherassumptionmade inthecomputationofnatural
periodshouldbefurnishedinthestudy.
4.4.1 Horizontalseismiccoefficient:Forthecomputednaturalperiodofthedamsection,findthe
spectralamplitudeforDBEusingthe5%dampedspectrumfortheconcrete/masonrydamand
10%damped spectrum forearthenand rockfilldams.Thehorizontal seismic coefficienthmaybetakenasafraction(say0.5)ofthespectralamplitudeobtainedasabove,howevernot
lessthanthatobtainedasperIS1893(1984).
-
7/31/2019 Guidelines EQ
20/34
CentralWaterCommission
NCSDPGuidelines:2011 Page16
4.4.2 Vertical seismic coefficient: Similar steps (as for h) should be applied on the response
spectrum for the vertical seismic component for the determination of vertical seismic
coefficientv.Thealternativeapproach (asper IScode)shouldalsobeappliedwherein the
verticalseismiccoefficientistakenas2/3rdsofthehorizontalseismiccoefficient(i.e.v=2/3
h).Thehigherofthetwovaluesshouldbetakenasthedesigncoefficient.
4.5 EstimationofDurationofShaking
Thedurationof strong shakingbeingan important seismicevaluationparameter,shouldbe
reflected explicitly in the study, alongwith the total duration. Both these durations can be
estimated using the scaling relations (e.g.Novikova and Trifunac, 1994),which defines the
strongmotiondurationateachfrequencyasafunctionofearthquakemagnitude,sourceto
sitedistanceand site condition.Forgenerationofdesignaccelerograms, the strongmotion
durationmaybetakenastheaveragedurationcorrespondingtothehighestfrequencyband
(1825Hz)and the totalduration canbe takenas theaverageplusone standarddeviation
valuecorrespondingtothelowestfrequencyband(0.100.15Hz)butnotlessthan20seconds.
Localconditionsmayalsoaffecttheexpecteddurationofearthquakeshakingandshouldbe
consideredonacasebycasebasis.
4.6 DevelopmentofAccelerationTimeHistories
The acceleration time histories should preferably be represented by real accelerograms
obtainedforsiteconditionssimilartothosepresentatthedamsiteunderconsideration.Since
thestronggroundmotiondatacurrentlyavailabledonotcoverthewholerangeofpossible
conditions, such records may be supplemented by synthetic motions representing any
earthquakesizeandseismotectonicenvironment.Syntheticearthquakescanbedevelopedby
superpositionmethods6.
It is recommended thatseveralacceleration timehistoriesbeused to represent theground
motionascertaintimehistorieshavelowerenergycontentatsomefrequenciesandtheiruse
mayresultinanunconservativeanalysis.Whendetailedtimehistoryanalysisisnecessaryitis
proposed to use atleast three sets of uncorrelated time histories of horizontal & vertical
motionsandthemaximumresponsetoallthethreesetsbeconsideredfordesignpurposes.
Acceleration time histories should be specified separately for the horizontal and vertical
motions.
4.7 FactorstobeconsideredwhiledecidingthesitespecificTargetResponseSpectrum
Having obtained the target response spectrum from Deterministic as well as Probabilistic
approach,thefollowingconsiderationsmaybehelpfulinadoptingthetargetresponsespectra
inpracticalapplications:
ForMCEcondition:If the spectral amplitudes obtained by the two approaches differ by 25% or less, the
envelopeofbothmaybeadoptedasthedesigntargetspectra.Inothercasesaweighted
average of both the spectra may be adopted as the target spectra, with weights
6Gupta&Joshi (1993).Onsynthesizingresponsespectrumcompatible accelerograms,JournalofEuropeanEarthquakeEngineering,2,2533.
-
7/31/2019 Guidelines EQ
21/34
CentralWaterCommission
NCSDPGuidelines:2011 Page17
appropriatelyjustified. Ifthedifference inthespectralamplitudevaluesobtainedbytwo
approacheshappens tobevery large (saymore than100%), then thepossible technical
reasonsforsuchdiscrepanciesshallbeexplainedinthereport.
ForDBEcondition:Intheseismiczones IVandV, ifthespectralamplitudesobtainedbythetwoapproaches
differby25%orless,attheperiodsofinterest,thedesigntargetresponsespectrumshall
beobtainedastheenvelopeofDSHAandPSHADBEestimate(asdescribedinparas4.3.1&
4.3.2).Inothercasesaweightedaverageofboththespectramaybeadoptedasthetarget
spectra,withweightsappropriatelyjustified.However,forseismiczonesII&III,thedesign
target responsespectrum shallbeobtainedas theenvelopeof theDSHAandPSHADBE
estimates.
Theabovecomparisonsaretoberestrictedfornaturalperiodsupto1.0sec
5.0 RECOMMENDATIONSONDESIGNAPPROACH
Thesitespecificseismicstudyreportshouldmentionthedesignapproachtobeadoptedfor
checking the stability of the dam and should also contain recommendations regarding the
permissiblestressesandslidingfactorstobeadopted.Theearthquakeperformanceofgravity
damshastobeevaluatedonthebasisofstresses,slidingfactor,demandcapacityratiosand
the associated cumulative duration. The below mentioned points should be taken in to
accountwhileformulatingrecommendations.
5.1 Seismicanalysisofconcretegravitydamscanstartwithsimplifiedmethodsusingsitespecific
seismiccoefficientforslidingandoverturningstability,andprogresstoamorerefinedanalysis
asneeded. The pseudostaticmethod of analysismaybeused for computationof forces.
Regardingpermissiblestresses,BIScode6512:CriteriafordesignofSolidGravityDamsmaybe
madeuseof.
TheDBElevelofgroundmotionisusedfortheevaluationoftheactualperformanceofgravity
dams. Under DBE, the dam is required to be within linear elastic range with little or no
damage. The spectra and timehistories for DBE level of ground motion can be used to
evaluatethedynamicresponseofgravitydamsbylinearelasticresponsespectrummethodor
thetimehistorymethod.UnderDBEcondition,thedemandcapacityratios(DCR)arerequired
to
beless
than
orequal
to
1.0.
The
DCRisdefined
as
theratio
ofinduced
tensile
stress
to
tensilestrengthoftheconcrete.Forthispurpose,thetensilestrengthorcapacityoftheplain
concrete can be obtained from the uniaxial splitting tension tests or from the static
compressivestrength,fc,usingtherelationduetoRaphel(1984),ft=1.7fc2/3 wherefcisinpsi
orft=0.324fc2/3 wherefcisinMPa,asrecommendedinUSACEManualEM111026051.
UnderMCEcondition,damsshouldnotexperienceacatastrophiclossofthereservoir.Under
therapid loadingofMCEconditions,slidingmayoccuratthedamfoundation interfaceorat
upper elevations at liftjoints.Dams subjected to large lateral forcesproducedby theMCE
groundmotionmaytipandstartrockingandtheresultingdrivingforcemaybecomesolarge
that the structurebreaks contactwith the foundationor cracksall theway through at theupperelevation.
-
7/31/2019 Guidelines EQ
22/34
CentralWaterCommission
NCSDPGuidelines:2011 Page18
ThedynamicresponseunderMCEconditionmay firstbeevaluatedusing linearelastictime
historyanalysis.The levelofnonlinear responseorcracking isconsideredacceptable ifDCR
are less than2.0,and limited to15percentof thedam crosssection surfacearea,and the
cumulative duration of stress excursions beyond the tensile strength of the concrete falls
below the performance curve given in Figure 3. DCR of 2.0 corresponds to the apparent
dynamic tensile strength of concrete (Raphel, 1984). The cumulative duration beyond a
certainlevelofDCRisobtainedbymultiplyingthenumberofstressvaluesexceedingthatlevel
bythe timestepused in the timehistoryanalysis. When theseperformanceconditionsare
notmet,anonlineartimehistoryanalysisisrequiredtoestimatethedamagemoreaccurately
underMCEcondition.
Fig.3:Performancecurveforgravitydams
5.2 Incaseofearthendams, the seismic slope stabilityanalysis involves startingwitha simpler
analysis(Pseudostatic)andmovingontoSlidingBlockanalysisandDynamicanalysis,where
complexity of analysis increases in each stage. In pseudostatic slope stability analysis,
earthquake forces are represented by the site specific seismic coefficient. Seismic inertial
forces are estimated by multiplying weight of the potential sliding mass (W) with seismic
coefficientasper IS1893 (1984).Undrainedshearstrengthofthesoil istobeconsidered in
theanalysis.An indexofstability,calledfactorofsafety(FOS) iscomputedfromtheratioof
resistingmomenttodisturbingmoment,forapotentialslidingmass.AFOSof1.0oraboveis
consideredacceptableunderearthquakecondition.Seedssimplifiedapproachmaybeused
todetermine liquefactionpotentialof cohesionless soil strata. The liquefactionpotential is
ascertainedfromindexpropertiesasrecommendedbySeed(2003).
Inslidingblockanalysis,permanentdeformation inanearthendam,duetoanearthquake is
evaluatedbasedonNewmarkconcept.Inthismethod,apotentialslidingmassisassumedasa
-
7/31/2019 Guidelines EQ
23/34
CentralWaterCommission
NCSDPGuidelines:2011 Page19
rigidbodyonarigidbaseandcontactbetweenthemasarigidplastic.Theanalysis involves
determination of Yield acceleration (Ky) from slope stability analysis, maximum crest
acceleration (Umax) and average acceleration time history [Kav(t)] of sliding mass and
estimationofpermanentcrestdisplacementbydouble integrationofaccelerationdifference
[Kav(t)Ky]. If the crestdisplacement iswithinpermissible limit (w.r.t FreeBoard)no further
analysis is required. In case the sliding block analysis shows excessive deformation, the
detaileddynamicanalysismaybecarriedout.
Dynamicanalysis iscarriedoutfordams, failureofwhichmay leadtohigh levelofrisk.The
analysisinvolvesdeterminationofcyclicstrengthofsoilfromcyclictriaxialsheartests,induced
shearstressesfromdynamicfiniteelementresponseanalysis(equivalent linearornonlinear)
using site specific earthquake,evaluationof strainpotential in eachelementby comparing
induced shear stresses with shear strength of soils and then determination of overall
deformationofdamfromstrainpotential,whichshouldbewithinpermissiblelimit(w.r.t.Free
Board
provided).
Thedynamicanalysisprocedureisfollowedtodetermineliquefactionpotentialofsoil.Incyclic
triaxialtestsonundisturbedsoilsamples,thecyclicshearstressrequiredtocauseliquefaction
isdetermined.Thestressesthatare likelytobe induced inthegroundaredeterminedfrom
dynamicresponseanalysis.Comparing theinducedstresseswithstressrequired tocause
liquefactionwillindicatesusceptibilityforliquefaction.
6.0 SUBMISSIONOFSTUDYREPORTFORNCSDPAPPROVAL
Thesitespecificstudiesfordeterminationofdesignearthquakeparametersshallhavetobe
carriedoutbyDeterministicaswellasProbabilisticapproach.However,wheretheavailable
data on past seismicity is scanty, and even the data on tectonic features and geological
processes are inadequate to have any meaningful application of probabilistic analysis, the
deterministic analysisonly shallbe carriedoutby recording theproperjustification fornot
adoptingtheprobabilisticapproachforanalysis.
Thereportshouldalsoincludeasection/chaptergivingthefollowinginformation:
Comparison of target response spectra obtained from Deterministic as well asProbabilistic approach forMCE andDBE conditions alongwith final target response
spectra
selected
with
justification
CompatibleaccelerationtimehistoriesforMCE&DBEtargetresponsespectra Computedresponsespectrafordifferentdampingvalues ie2%,3%,5%,10%and15%
atleast
SitespecifichorizontalandverticalSeismiccoefficientsAftercompletionofthesitespecificseismicstudy,thefullstudyreportshouldbecompiledin
asingledossierasperproformagiveninAnnexureC.Thesaidproformashouldalsobefilled
upreflectingthestatusofcompliances(alongwithreasonsfornoncompliances)fordifferent
itemsofthestudy.Thisproforma,dulyfilledandsigned,shouldbefurnishedasachecklistin
thebeginningofthestudyreport.
-
7/31/2019 Guidelines EQ
24/34
CentralWaterCommission
NCSDPGuidelines:2011 Page20
Fifteen(15)boundvolumesandonesoftcopyofthestudyreportshouldbesubmittedtothe
NCSDP secretariat (Foundation Engineering & Special Analysis Directorate, Central Water
Commission,712(S),SewaBhawan,R.K.Puram,NewDelhi).Inordertoensureconsideration
of study report in a particular meeting of the NCSDP, the study report should reach the
secretariat at least twomonths aheadof thatmeeting.Only such study reports,which are
foundsatisfactory(intermsofcompliancesoftheguidelines)onpreliminaryinspectionbythe
Secretariat,willbeputuptotheNCSDPforconsiderationandapproval.
7.0 PRESENTATIONOFSTUDYREPORTBEFORENCSDP
Thedateonwhich study report of aparticular projectwill comeupbeforeNCSDPwillbe
intimated by the Secretariat to the project authorities. It will be the responsibility of the
projectauthorities toensurepresenceofexperts/consultantsconnectedwith the studyon
thestipulateddateandtime.TheprojectauthoritieswillmakeaPowerPointpresentationof
thestudyreportbeforeNCSDP,andanswertothequeriesofthemembersoftheCommittee.
The presentation should cover: (i) details of the project; (ii) regional geological & seismo
tectonic setting; (iii) seismichistory; (iv) localgeological setting; (v) studymethodologyand
deviation, if any, from the recommended approach; (vi) evaluated parameters of the site
specificseismicstudy;and(vii)recommendationsondesignapproach.
-
7/31/2019 Guidelines EQ
25/34
CentralWaterCommission
NCSDPGuidelines:2011 Page21
AnnexureA
IllustrativeExample: DSHAmethodfordevelopingtargetresponsespectra
Consideringascenarioearthquakeofmagnitude7.5withclosestdistancefromthesitetozoneofenergy releaseas14kmandwith localgeologicalconditions indicatingmassive rock, the
following isestimated fromagroundmotionpredictionequation for5%dampedhorizontal
accelerationspectrum:
PeakGroundAcceleration(atmeanplusonestandarddeviationlevel) =3.934m/s2
7Ps s accel at woperiodsie0.2secand1.0secuedo pectral er ionvaluefort
S 0.2s 8.63m/s2; S 1.0s 5.782m/s2Thusthecontrolperiod(T2)forstartofconstantvelocityr utto0.67sec.ange workso
T . .
x 1s; T .. x 1s 0.67sThecontrolperiodforthebeginn o tacceleration(T1)isobtainedasafractionofingofc nstan
T2as: =0.134secThepseudospectralaccelerationisconsideredtobesameasthepeakgroundaccelerationat
controlperiodT0=0.03s.
Thecontrolperiodforconstantdisplacement(T3)(generallybetween3secto4secforstrongearthquakesinnearfieldconditions) obtained scalingtheconstantvelocitycontrolperiod
(T2)as
is by
=6.25=4.2secThuswehave:
PGA T .934 m s
ST=
8.63 m s
ST
S 3 ;
Thecorrespondingpseudospectral v it eloc ies maybeobtainedas:
S T S Tx T2 0.0188 m/s
S T S Tx T2 0.1868 m/s S T S Tx T2 0.9315 m/sST STx T
2
0.9315 m/s
7Boore-Atknison -Ground motion Prediction equations for the average horizontal component of PGA, PGV and 5%-damped PSA at spectralperiods between 0.01s and 10.0s, Earthquake Spectra, 24(1):99-138,23008
-
7/31/2019 Guidelines EQ
26/34
CentralWaterCommission
NCSDPGuidelines:2011 Page22
From these numerical values of pseudospectral velocity and the control periods, the
parametersofthesmoothaccelerationdesignspectrummaybeobtainedas
1 0.534;A 2.194;V 2 x 88;1.4
D 2 x T x STPGA 6.248
TargetResponsespectrumforHorizontalAcceleration(5%dampingLevel)
-
7/31/2019 Guidelines EQ
27/34
CentralWaterCommission
NCSDPGuidelines:2011 Page23
77 78 79 80 81 82 83
Longitude, E
27
28
29
30
31
32
33
Latitude,
N
Lineaments Faults Sub-surfacefault
Thrust Gravity fault Suture zone
Gartok (Tibet)
Delhi
Haridwar
Deharadun ProjectSite
Chamoli
Uttarkashi
Nainital
Pithoragarh
Manali
4.0 M < 4.8 4.8 M < 5.6 5.6 M < 6.4 M 7.26.4 M < 7.2
AnnexureB
IllustrativeExample: PSHAmethodfordevelopingtargetresponsespectra
To illustrate the application of the PSHA approach, a typical site shownby solid triangle is
consideredinthe
highly
seismic
Kumaun
Garhwal
Himalayan
region
(Fig.
1).
The
major
tectonic
features in the region canbe divided longitudinally into fivemajor crustal formation zones
identified fromsouth tonorthas (i)outerzoneof the foredeep, (ii) innerzoneof the fore
deepformingtheHimalayanfoothills(iii)LesserHimalayaformedbysuperpositionofaseries
of tectonicnappesandprobably thrustedover the foredeep, (iv) theHighHimalayaand (v)
the IndusTsangpoSuturezone (Dasgupta,2000).The first fourofthesezonesareseparated
fromeachotherby large thrust faults.TheMainFrontalThrust (MFT) runsat theboundary
between theouterand the inner zonesof the foredeep.TheMainBoundaryThrust (MBT)
separatesthenappedfoldedcomplexoftheLesserHimalaya fromthe Himalayan foothills.
A thick strata of crystalline rock comprising the High Himalaya is thrusted over the
metamorphosed deposits of the Lesser Himalaya along the MCT. The belt north of High
Himalayaand
bound
byIndus
Tsangpo
Suture
isknown
asTethys
Himalaya,
which
consists
of
fossiliferroussedimentaryrocks.
Fig.1:Majortectonicfeaturesintheregionoftheprojectsitealongwith
theepicentersofavailablepastearthquakes
-
7/31/2019 Guidelines EQ
28/34
CentralWaterCommission
NCSDPGuidelines:2011 Page24
77 78 79 80 81 82 83
Longitude, E
27
28
29
30
31
32
33
La
titude,
N
Project site
Source - 1
Source - 3
Source - 2
Sub-Source - 3
Source - 4
Source -5
Source - 3
4.0 M < 4.8 4.8 M < 5.6 5.6 M < 6.4 M 7.26.4 M < 7.2
InadditiontothemajorstructuraldiscontinuitiesoftheHimalayanregion,thereareanumber
of other faults/lineaments in the region. Within the main Himalayan belt, the high grade
complex of thecentralcrystallines is bound tothenorthandthesouth by MartoliThrust
andMCT,respectively. Asimilarhighgradecomplex,theAlmoracrystallines, isdelimitedon
eithersidebytheNorthAlmoraThrust(NAT)andtheSouthAlmoraThrust(SAT).Furthernorth
oftheMartolithrustisthedextralKarakoramFault,subparalleltotheIndusSutureZone(ISZ).
The belt between the Karakoram Fault and ISZ is occupied by cover rocks affected by the
Himalayanorogeny.Neotectonicactivityhasbeen recordedalong theKarakoramFault, ISZ,
MBTaswellasMFT. AnumberoftransversefaultsalsoexistwithintheHimalayanrangesas
wellastothesouth in the IndoGangeticplanes.Thetransverse featuresarealsoassociated
withvaryinglevelsofseismicity.
ThefirststepinPSHAistoidentifyanddelineatethevariousseismogenicsourcezones(SSZ)in
theregionofabout6lat6longaroundtheprojectsite.Consideringthespatialdistribution
andcorrelationofseismicactivitywiththetectonicfeatures intheregionoftheproject,five
broad seismic sources have been identified, viz. (i) TransHimalayan (TRH) area north of
KarakoramFault, (ii)HimalayanFold (HF)areabetween ISZandKarakoramFault, (iii)Tethys
Himalayan(THH)areabetweenMCTandISZ,(iv)MainHimalayanThrusts(MHT)areaofMCT,
MBT,etc.,and (v)AreaofAravalliFoldBelt (AFB) in the IndoGangeticPlains.These source
zonesareshowndemarcatedbythicksolidlinesinFig.2alongwiththeepicentersofthepast
earthquakes. There is a marked concentration of epicenters along the Kaurik Fault system
(KFS)intheTHHmainsource,whichhasbeenthereforedefinedbyaseparatesubsource.The
othermainsourcesarealsocharacterizedbyvaryingconcentrationsofepicenters,whichhas
beensuitablyaccountedindistributingtheexpectedseismicityoverthecompletesourcezone
toestimatetheoccurrencerate (
,
)ofearthquakesindifferentmagnitudeanddistance
intervals
Fig.2:Possibleseismicsourcezonesintheregionoftheprojectsite
-
7/31/2019 Guidelines EQ
29/34
CentralWaterCommission
NCSDPGuidelines:2011 Page25
The second step is to obtain ij RM , for each source zone. For this purpose, first the
GutenbergRichtersearthquake recurrence relationship isdefined for
each source zone, by estimating the constants a and b using maximum likelihood method
(Weichert,1980).TheN(M)isobtainedusingavailablepastearthquakedatainthesourcezone
byhomogenizationof themagnitude (Scordilis,2006),declustering the catalogby removing
fore andaftershocks(GardnerandKnopoff,1974),andaccountingfortheincompletenessof
earthquakes in different magnitude ranges (Stepp, 1973). The recurrence relation is then
suitably modified to consider an upperbound magnitude Mmax (Chinnery and North, 1975).
Typicalrecurrencerelationshipthusobtainedforsourcezone4isshowninFig.3
bMaMN =)(log
Fig.3:Recurrencerelationforsourcezone4
From the recurrence relationship for a source zone with an upper bound magnitude, the
occurrence rateofearthquakeswithina smallmagnitude range ),( jjjj MMMM + aroundcentralmagnitude canbeobtainedasjM
)()()( jjjjj MMNMMNMn +=
Thesenumbersaredistributedappropriatelyusingspatialsmootheningofpastseismicityover
theentire source zone, toget the requirednumber ( )ij RM , withina small sourcetosite
distancerange ),( iiii RRRR + .
In step three, theprobability, ( )ij RMTSAq ,)( ,ofexceedinga responseamplitudeSA(T)atnaturalperiodTduetomagnitude atsourcetositedistance isobtainedbyassuming
the tofollowaGaussianprobabilitydistributionas:jM iR
)(ln TSA
[ ]
=
)(ln 2
)(
)(ln
2
1exp
)(2
1)(
TSA
dxT
TSAx
TTSAF
In this expression )(ln TSA is the least squares estimate and )(T is the associated
standarddeviationof ,whichhavebeenobtained from theempirical attenuation
relationduetoAbrahamsonandSilva(1997),definedat28naturalperiodsbetween0.01sec
and5.0sec.Thecomplementaryof theprobability
)(ln TSA
[ ])(TSAp gives therequiredprobability,ij RMTSAq ,)( .
Fromknowledgeof iR, andthenuMTSAq )( mber ( )in R,M obtainedasaboveforall
-
7/31/2019 Guidelines EQ
30/34
CentralWaterCommission
NCSDPGuidelines:2011 Page26
ted
Fig.4:Typicalhazardcurvesatselectednatural riods
TheMCEleveloftargetresponsespectraofhorizontalandverticalcomponentsofmotionwith
Fig.5:The5%dampedtargetspectraforMCEcondition
themainandsubsourc ctionofeqn.(1)is instepfourforallthe28
naturalperiodsforwhichtheselectedattenuationrelationshipisdefined.Fig.4showstypical
hazardcurvesforT=0.02,0.2,1.0and3.0secperiods,where0.02secperiodcorrespondsto
thePGA.
e,thehazardfun compu
pe
damping ratio of 5% are finally obtained by estimating the spectral amplitudes at all the
natural periodswith annualprobabilityof exceedance equal to 0.0004 (returnperiod 2500
years).Theprobabilistic response spectrumof thehorizontalmotion thusobtained for rocktypeofsiteconditionisshowninFig.5.Thecorrespondingmeanplusonestandarddeviation
deterministic response spectrum forMCEmagnitudeof7.5atshortestdistanceof14km to
thefaultruptureplaneisalsoshowninFig.5forthepurposeofcomparison.
0.0001
0.001
A
nnualP
0.01
0.1
robabilityofExceedance
P=0.0004
1E-006 1E-005 0.0001 0.001 0.01 0.1 1
Spectral Acceleration, g
T=0.02s(P
GA)
T=0.2s
T=1.0
sT=3.0s
-
7/31/2019 Guidelines EQ
31/34
AnnexureC
PROFORMAFORSUBMISSIONOFSTUDYREPORTTONCSDP
Thestudyreportshouldbecompiledinasingledossierasperproformagivenbelow.
Theproforma,dulyfilledandsigned,shouldbefurnishedasachecklistinthebeginningofthestudyreport.
Sl
No.
Description Compliance(Yes/No)
w.r.t.Guidelines&
ReasonsforNon
compliance
1 ProjectDetails
(a) NameoftheProject
(b) NameoftheRiveroverwhichtheprojectisproposed
(c) BriefDescriptionoftheProjectComponents
(d) LocationoftheProject:State,District,Longitude&LatitudeandToposheetno.ofeachoftheProject
component (e.g. Dam/Barrage/Power House etc.)for which design seismic
coefficientisrequired.Informationtobegivenintabularformat.
(e) TypeofProject:
Multipurposeor irrigationStorage (area/volumeof reservoir)orRunof the
RiverSchemeorHydroPowerProject(surface/subsurface,InstalledCapacity,
numberofunitsetc.)
(f) Detailsofotherprojectsinthevicinity(within 100km):
Name of project, Type of hydraulic structures, and seismic parameters
(expectedPGAforMCE)forprojectsconstructed/underconstruction.
(g) PresentStatusofInvestigation:DPRsubmitted/approved;Salientcomments/observationsonDPRforground
exploration,relevanttoSeismicdesign;statusonenvironmentclearance;pre
construction/constructionstageetc.
(h) NatureofFoundationMaterial:
Natureoffoundationmaterial(includinggeotechnicalpropertiesofrock/soil
etc.)belowdifferentsegmentsofdamandotherprojectcomponents.
(i) NameandaddressoftheProjectAuthorityandConsultants/ Advisors:
Completepostaladdresswith telephone/fax/email of ProjectAuthority and
Consultants/Advisor engaged by the ProjectAuthorityfor various types of
inputs[geological,
geophysical,
geotechnical,
seismotectonics,
seismic
design
etc]shallbegiven.
2 RegionalGeologicalandSeismoTectonicEvaluation
(ReferSection3.0oftheguidelinesfordetails)
(a) TectonicMap:
(b) Seismotectonicsection:
(c) Interpretationofregionaltectonicmechanismandotherdetails:
(d) Earthquakecatalogue:
(e) Microearthquakeinvestigations:
NCSDPGuidelines:2011 Page27
-
7/31/2019 Guidelines EQ
32/34
CentralWaterCommission
NCSDPGuidelines:2011 Page28
3 LocalGeologicSetting
(ReferSection3.0oftheguidelinesfordetails)
(a) Geologicalmap:
(b) Surface&subsurfaceexploration:
(c) Additionalinputsonsubsurfaceconfigurationofmajorfaults:
4 Evaluationofsitespecificseismicparameters
(a) Methodologyofthestudy:
Theadopted studymethodology,confirming to section4.0of theguidelines,
shouldbebrieflydescribed.Anydeviationfrom the recommendedapproach
shouldbepointedoutwithadequatejustifications.
(b) Evaluatedsitespecificseismicparameters:
The study should furnish the identified MCE (deterministic); recommended
response spectrafor theMCE andDBE conditions; recommended horizontal
andvertical
seismic
coefficients
along
with
computed
natural
period
of
the
dam;estimateddurationofshaking;andacceleration timehistoriesforboth
horizontalandverticalmotions.
5 Recommendationsondesignapproach
(ReferSection5.0oftheguidelinesfordetails)
6 SubmissionofstudyreportforNCSDPapproval
(ReferSection6.0oftheguidelinesfordetails)
Date:
Signature&Seal
ofauthorizedrepresentative
ofProjectAuthority
-
7/31/2019 Guidelines EQ
33/34
CentralWaterCommission
NCSDPGuidelines:2011 Page29
AnnexureD
Bibliography
BasicEngineering
Seismology
1. Scordilis,EM(2006).EmpericalglobalrelationsconvertingMs amdmb tomomentmagnitude.Journalof
Seismology,10,225236.
DesignCriteria
2. FEMAUsersManualforRiskPrioritisationToolforDams. (2008).
3. Raphael,J.M.,1984.,Tensilestrengthofconcrete., Jour.ofAm.ConcreteInst.,81(2),158165.
4. USACE 2003. TimeHistory Dynamic Analysis of Concrete Hydraulic Structures, US Army Corps of
Engineers,Manual No.EM111026051
5. USACE 2007. Earthquake Design and Evaluation of ConcreteHydraulic Structures,US Army Corps of
Engineers,ManualNo.EM111026053
6. Wieland, M., 2006., Earthquake Safety of Existing Dams, First European Conference on Earthquake
EngineeringandSeismology.
GenerationofSpectrumCompatibleAccelograms
7. Gupta,I.D.,Joshi, R.G.,(1993).Onsynthesizingresponsespectrumcompatibleaccelerograms,Journalof
EuropeanEarthquakeEngineering,2,2533
8. Novikova, E.I. and Trifunac.M.D., 1994., Duration of strong ground motion. Scaling in terms of
earthquake magnitude, epicentral distance and geological and local soil conditions. Earthquake
Engineering&StructuralDynamics,23(6),10231043
9. Shrikhande, M and Gupta, V.K., 1996., On generating ensembles of design spectrum compatible
accelerograms. EuropeanEarthquakeEngineering,X(3):4956.
10. Trifunac,M.D.andBrady,A.G.,1975., Astudyonthedurationofstrongearthquakegroundmotion.
Bull.Seism.Soc.Am.,65,581626.
GroundMotionPredictionEquations
11 Abrahamson,N.A.andSilva,W.J.,1997. Empirical response spectralattenuation relations for shallow
crustalearthquakes.Seismological ResearchLetters,68(1):94127.
12. Boore,D.M.andAtkinson,G.M.,2008., Groundmotionpredictionequationsfortheaveragehorizontal
component of PGA, PGV, and 5%damped PSA at spectral periods between 0.01 s and 10.0 s.
EarthquakeSpectra,24(1):99138.
13. Cotton, F., Scherbaum, F., Bommer, J.J. and Bungum, H., 2006., Criteria for selecting and adjusting
groundmotionmodelsforspecifictargetregions:ApplicationtoCentralEuropeandrocksites.Journal
ofSeismology,10(2):137156.14. Graizer,V.and Kalkan.E,2007.,Groundmotionattenuationmodelforpeakhorizontalaccelerationfrom
shallowcrustalearthquakes.EarthquakeSpectra,23(3):585613.
15. Graizer,V.and Kalkan.E,2009., Predictionof spectralacceleration responseordinatesbasedonPGA
attenuation.EarthquakeSpectra,25(1):3969.
16. Scherbaum,F., Cotton.F.,and Smit.P.,2004., On theuseof response spectral referencedata for the
selection and ranking of ground motion models for seismic hazard analysis in regions of moderate
seismicity:thecaseofrockmotion.BulletinoftheSeismological SocietyofAmerica,94(6):21642185.
17. Trifunac,M.D.and Lee,V.W.1989., Empiricalmodels for scalingpseudo relative velocity spectraof
strong earthquake accelerations in terms of magnitude, distance, site intensity and recording site
conditions.
-
7/31/2019 Guidelines EQ
34/34
CentralWaterCommission
MethodologyofHazardAssessment
18. Anderson,J.G.,1997,Benefitsofscenariogroundmotionmaps,EngineeringGeology,48(1),pp.4357.
19. Anderson, J.G.,Brune, J.N.,Anooshehpoor,R.,Ni,S.,2000,Newgroundmotiondataandconcepts in
seismichazardanalysis,CurrentScience,79(9),pp.12781290.20. EPRI.,1987. SeismichazardmethodologyfortheCentralandEasternUnitedStatesVolume1,Part1,
Theory,andPart2,methodology,ReportNP4726,ElectricPowerResearchInstitute,PaloAlto,CA
21. Gupta, I.D. ,2002., Stateof theart inseismichazardanalysis, ISET J.EarthquakeEngineering,39(4),
311346
22. ICOLD ,2010., Selecting seismicparameters for largedams, Bulletin72, InternationalCommitteeon
LargeDams.
23. Malhotra,P.K. 2005., Return period of design ground motions. Seismological Research
Letters,76(6):693699.
24. McGuire,R.K.2004., Seismichazardand risk analysis. MonographMNO10,Earthquake Engineering
ResearchInstitute,Oakland,California.
25. Reiter,L.,1990.,EarthquakeHazardAnalysis. IssuesandInsights, ColumbiaUniversityPress,NewYork,
254p.26. SSHAC.,1997.,Recommendationsforprobabilisticseismichazardanalysis: Guidanceonuncertaintyand
use of experts, Report NUREG/CR6372, Senior Seismic Hazard Analysis Committee, US Nuclear
RegulatoryCommission,WashingtonDC.
27. Stepp, J.C., 1973. Analysis of completeness of the earthquake sample in the Puget sound area, in
`SeismicZoning(editedbyS.T.Harding),NOAATech.ReportERL267ESL30,Boulder,Colorado,USA
US Army Corps of Engineers., 1999., Response spectra and seismic analysis for concrete hydraulic
structures,EngineerManual,No.EM111026050,WashingtonDC