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8/11/2019 Paper Pique Martel

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13th World Conference on Earthquake EngineeringVancouver, B.C., Canada

August 1-6, !!"#a$er %o. 1&'

HOW PERUVIAN SEISMIC CODE GREATLY IMPROVED BUILDING RESPONSE TO REALEARTHQUAKES

Javier PIQUE1, Peer MARTEL!

SUMMARY

Actual response of school buildings, with almost identical architecture and configuration, subjected to amoderate to severe shaking was analyzed. A group of these was designed with 1977 eruvian !tandardwhile another was designed with 1997 updated !tandard. "hose designed with the former 1977 #odesuffered damage while the ones designed with modern 1997 !tandard did not e$perience damagewhatsoever. "his evidences eruvian practice has achieved real protection of essential and other buildingstructures due to an strategy based on drastically limiting displacements. Although allowable displacementsare similar to worldwide practice, computed displacements are large based on large % values.

INTRODUCTION

After &' years, in 1997 the eruvian "echnical #ommittee for !eismic %esistant (esign issued a newstandard which profited from e$periences from earth)uakes worldwide between 19*+ and 199. -ne of itskey features was the increase on computed lateral displacements over / fold0. uilding structures so

designed became much more rigid than those obtained using specifications from the former 1977 code."his paper presents a comparison of the seismic response of actual state school buildings to the 2une &1 st,&''1 Atico Are)uipa0 earth)uake 3w4*,50 in southern eru. "his structures are located at the sameregion thus assuming were subjected to the same shaking, with identical architectural distribution & story0in which the only variable is the seismic design code and more precisely the procedure for calculatinglateral displacements. 6ield information was collected after the earth)uake, dynamic analysis wereperformed. t could be observed that buildings designed using the higher displacement re)uirements fromthe 1997 code evidence no damage al all whereas those designed using the former code, with re)uirementssimilar to world standards had short column failures almost widespread in spite of being separated frompartition walls. "his strongly suggest the current eruvian !tandards produces buildings that fully respondto the re)uirements for essential buildings, that is to maintain operation after a strong earth)uake, limitingdamage and precluding collapse.

EARTHQUAKE MOTION

1rofessor of #ivil 8ngineering, eru 2apan #enter for 8arth)uake 8ngineering %esearch and (isaster3itigation, #!3(, 6aculty of #ivil 8ngineering, ational :niversity of 8ngineering, ;ima, eru.resident of the eruvian !eismic #ode #ommittee. 8mail< jpi)ue=uni.edu.pe& %esearch assistant, eru 2apan #enter for 8arth)uake 8ngineering %esearch and (isaster 3itigation,#!3(, 6aculty of #ivil 8ngineering, ational :niversity of 8ngineering, ;ima, eru. 8mail"he earth)uake occurred in Are)uipa on 2une &/rd &''1 at 1+ hours // minutes local time causedimportant damages in (epartments of Are)uipa, 3o)uegua and "acna and to the cities of Arica and)ui)ue in #hile. ational nstitute for #ivil (efense (8#0 indicates the earth)uake produced 75 deadpeople, in addition to 5 dissapeared, &,*9 injured and &17,59+ homeless in the whole affected region.eople disappeared due to the effects of a tsunami caused by the earth)uake and was responsible for the

destruction of around &''' housing units at beaches of #amana city?. @amudio 1B

Ceophysical nstitute of eru C0 located the epicenter of this earth)uake at coordinates ituto CeofDsicodel erE C0 1.&'F !, 7/.7+F GH that is at *& km G of the town of -coIa, closer to Atico, as shown in6igure 1.

/i*$re 10 /'a2 Me"a&i34 a&- 3re33 'rie&ai'&0 Ear"#$a%e '5 J$&e !r-, !..10 Are#$i)a, Per$0

ational !eismic etwork registered a total of 1/5 aftershocks in the first &5 hours, many of themproducing intensities between and J in 3odified mercallu !cale 330 in the city of Are)uioa, which is

the largest city in southern eru. 1 ''' ''' inhabitants0.

I&e&3iie3 a&- 3ei34ii6 '5 "e re*i'&eru 2apan #enter for 8arth)uake 8ngineering %esearch and (isaster 3itigation #!3(0 of the 6acultyof #ivil 8ngineering of the ational :niversity of 8ngineering :0 maintains a network ofaccelerographs having registered the main event in the 3o)uegua !tation, a city south of Are)uipa, around5''km away from the epicenter0. eak acceleration value obtained for the 8KG direction was &9+./ gals, inthe K! direction &&' gals and 1'. gals in the vertical component. n 6igures & and / the registeredaccelerographs are plotted.

>(amage produced by this seismic event showed once again that structures built which do not followtechnical standards and are built without technical supervision, with poor workmanship and low )uality

materials will have a high level of seismic vulnerability?, #!3( &B.


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/i*$re !0 Ae2erai'& Re'r- i& M'#$e*$a, Per$0 E7W C'4)'&e&0 Ear"#$a%e '5 J$&e !r-, !..1Are#$i)a0 (M89:0;+ PGA9 ! AND 1


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Ba3e S"earn 1977 !tandard base shear was computed through the classical e$pression Sa&-ar- a&- 1


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/i*$re > C'4)ari3'& i& Di3)2ae4e& S)era, 1> Sa&-ar- a&- 1


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/i*$re > Are#$i)a Re*i'& i& 3'$"er& Per$ 8i" 2'ai'& '5 3"''2 ?$i2-i&*3 i& "i3 3$-60

!tructures shown in 6igure * 1977 !tandard0 are built with reinforced concrete frames in the longitudinal

direction, although, as can be seen in the plan view, columns are oriented with the strong a$es in thetransverse direction, because of gravity load framing. "his is a fle$ible direction.n the transverse direction seismic resistance is provided by solid confined masonry, being this a very stiffsystem.

/i*$re : E2evai'& a&- 5ir3 52''r )2a& '5 3"''2 ?$i2-i&*3


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!chools shown in 6igure 9 were designed with 1997 !tandard and columns have now small flanges in thelongitudinal direction giving the structure a higher stiffness. n the transverse direction the seismicresistance system is the same based on masonry walls.

/i*$re < /ir3 a&- 3e'&- 52''r )2a& '5 3"''2 ?$i2-i&*3 -e3i*&e- 8i" 1


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/i*$re 1.0 Da4a*e ' ?$i2-i&* -e3i*&e- $3i&* 1> Sa&-ar-0

8ven when peak ground acceleration must have been higher than design acceleration record showed abovewith almost o./g was registered 1''km south from Are)uipa region where schools were located, even

further from epicenter0 , there was no damage and the schools continue to operate unharmed.

/i*$re 110 P'3 ear"#$a%e '&-ii'& '5 3"''2 ?$i2-i&* -e3i*&e- $3i&* 1


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periods0

%eduction 6actor %d 4 5 % 4 1'

ase !hear N 41*.&M , or P 4 &1M

Ta?2e :0 Rai' (1+ '5 '4)$e- i&er3'r6 -i3)2ae4e&3 i& 2'&*i$-i&a2 (+ -irei'&

!tory (iaphragm ;oad R 1977 R 1997 R 1997LR 1977& (& !R '.'&*9* '.'1/&* '.5+*'7+1 (1 !R '.'51*5 '.'1+/ './711/

CONCLUSIONS

Sei34i Sa&-ar-3#hange in eruvian !eismic !tandards resulted in higher computed lateral displacements. Around threetimes that specified in the older 1977 !tandard. !tructures designed using 1997 new !tandard have to bemuch more rigid than before.A&a263i3!pectral dynamic analysis performed on all school building structures showed a reduction to one third incomputed displacements.

Re3)'&3eAll buildings designed with 1977 !tandard e$perienced structural and nonstructural damage. one of theschools in the region designed and built under the 1997 !tandard suffered damage. !tiffness was largerenough as to make seismic separation unnecessary. 8ven when peak ground acceleration must have beenhigher than design acceleration record showed above with almost o./g was registered 1''km south fromAre)uipa region where schools were located, even further from epicenter0 , there was no damage and theschools continue to operate unharmed. "herefore seismic response improved greatly with 1997 !tandard.C'33#hanges in structural element dimensions to achieve additional stiffness increase costs by 1+M. o costwas involved after the earth)uake because of absence of damage. Nowever structures designed with 1977!tandards had to be repaired, they could not be used for several months and cost of retrofitting an stiffeningreach up to 5'M of initial cost.

#learly designing and building stiffer structures has resulted in a much better performance, no damage andcontinuity of service. eruvians have achieved what was always e$pected of seismic standards.

RE/ERENCES

1. @amudio J, Paldivia . >ntensities 8valuation in #araveli and #amana Are)uipa0 rovinces due tothe 2une &/rd. &''1 8arth)uake?. ational #enter for Ceophysical (ata.. Ceophysical nstitute of eru.;ima. eru. &''1 in !panish0&. eruK2apan #enter for 8arth)uake 8ngineering %esearch and (isaster 3itigation, #!3(, 6acultyof #ivil 8ngineering, ational :niversity of 8ngineering, >reliminary %eport of the 1st. Pirtual #ongressAre)uipa 8arth)uake of 2une &/rd 8arth)uake &''1T A year later. ;earned ;essons? . ;ima T eru in

!panish0/. 3inistry of "ransportation, #ommunications and Nousing. ational "echnical !tandard 8K'/'>8arth)uake %esistant (esign?. ;ima, eru. 1997 in !panish05. 3inistry of Nousing, >asic !tandard for 8arth)uake %esistant (esign?. ;ima, eru, 1977 in!panish0+. 3uIoz, A. >(esign 6orces and (isplacement #ontrol in the eruvian !tandard for 8arth)uake%esistant (esign?. 8l ngeniero #ivil. 199*. in !panish0. 3artel, . >#omparison of !eismic %esponse of !chool uildings designed with 1997 and 1977!tandards subjected to the &''1 Are)uipa %egion earth)uake? "hesis to fulfill re)uirements to the of #ivil


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8ngineer degree. 6aculty of #ivil 8ngineering. ational university of 8ngineering. ;ima. eru.&''5 n!panish0

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