8/4/2019 EC Newsletter August08-Earthquake
1/1
SEISMICZONESINCENTRALAMERICA
The isthmus of Central America, astrip of continental territory
ofapprox. 522,000 km2 borderingMexico, Colombia, the
CaribbeanSeaandthePacificOcean,islocatedin a highly seismic zone,
whereearthquakesproducedeitherbytheinteraction of tectonic plates
or byvolcanoactivity inthe interiorpartsof the isthmus, have
produced inthelast50yearsmanyhumanlosseswithup to the37
thousandvictimsandmaterial damages that
exceedthe47,000millionsUSD.
Fig.1: Continetal Plates in the
region of Central America. Red:
seismicactivity.
ElasticResponseSpectra,whicharethebasisforcomputingdesigndisplacementsand
forces insystems thatareexpected
toremainelasticandtodevelopdesignforcesanddisplacementsinsystemswithinelasticresponse.TheElasticResponseSpectrashowninfig.3werecalculatedforeachcountryofCentralAmerica,usingrockysoil,
elasticbehavior and the greatest seismic zone factor of thecountry.
The obtained graphs are compared to their equivalentobtained for
UBC zone 4. As an important conclusion for
theregion,theuseofindividualcountrycodesgenerallyleadstomorecost
efficient seismic designs, as the use of UBC zone 4
designparametersprovidesratheroverestimatedseismicdesignloads.
Fig. 3 Elastic response Spectra, illustrated as maximum
accelleration Ac
(expressed in g) vs. wave periods T (in seconds) for El Salvador
(SV),
Guatemala
(GT),Nicaragua(NI),CostaRica(CT),Honduras(HN),Panama
(PN).UBC:CorrespondingvaluesaccordingtoUBCforseismiczone4.
Seismicdesigncodes
inCentralAmericausedifferentnomenclaturetorefertotheseismichazardofaspecificzone.Inordertocontributetoageneral
overview of the seismic hazards of the region, two
followingmainparametersarepresented:TheSeismicZoneFactor(Ao),ameasureofthepeakaccelerationtobeusedforaspecificsiteandcorrespondstoadesignearthquakethathasa90%probabilityofnotbeingexceededwithin50
years. Inorder
toobtainauniformmapfortheregion,whichrespectsthezonesdefinedby each
country, specific extrapolation criteria were
used.Correspondingresultsaredepictedinfig.2.
Fig.2.SeismicZonesinCentralAmerica.
Left:Seismiczones,asdefinedbyeach
individualcountry.Somezoneshave
beenslightlyreduced(caseforHondurasterritoryborderingElSalvador).As
observedinthemap,seismiczonesinmostcountriesreflecttheinfluenceof
thesubductiontrenchcreatedbytheinteractionoftheCocosplateandthe
Caribbeanplate.Right:Proposalforseismiczoneunificationfortheregion,obtainedthrough
graphicalextrapolationcriteria,takingintoaccounttheseismiczonesdefined
by each individual country. Aovalues are grouped into a maximum
of five
zones,followingtheUBCformat.
PROJECTHIGHLIGHT
EC has completed thestructural design of theWorld Trade Center
IIIexpansion, including theTorre Futura, one of thetallest
buildings in SanSalvador.TheWTCcomplex,with a total
constructionareaof64000m2,islocatedon the slopes of the
SanSalvadorvolcano,oneofthehighest seismic
hazardzonesofCentralAmerica.ECprovided the structuraldesign
in
accordance
with
the highest internationalseismic design standardsand is
presently performingas the structural supervisorofthisproject.
Fig. 4: Overview of the WTC III
expansion project, including Torre
Futuraandadjacentbuildings.
Torre Futura, a 20 level,aprox.90 m
high building with 5 underground
parking levels, rests on a
foundationslab.Thestructuraldesignisbasedon
concrete frames combined with high
strengthconcreteshearwalls.
Completion of the civil/structural works, with an aprox.
Concretevolumeof 32000m3,isduebytheendof2008.
EngineeringCompanyofCentralAmerica,Col.YAv.VistaHermosa434,SanSalvador,ElSalvador
PHONE:(+503)22422476/22423808FAX:(+503)22421300
EMAIL:[email protected];
WEBSITE:www.eccentralamerica.com
SupportOfficeinArgentina
Montevideo1777CordobaArgentina
[email protected]
SupportOfficeinPanama
Balboa,Panam#2362CallePearsar
[email protected]
SupportOfficeinMexico
CalculistasNm.19,Col.Sifn09400Mxico,D.F.
[email protected]
USAPostalAddress
LOGSAL4080NW56Street
Miami,Florida33166
ENGINEERINGCOMPANYOFCENTRALAMERICA
ConsultingEngineeringSupervisionIndustrialPlantsBuildingsInfrastructure
August2008v1.1 NEWSLETTER
ELASTICRESPONSESPECTRAFORCENTRALAMERICANCODES
