Report - PEER - University of California, Berkeley

Table 2. Seismic performance goalsChoose two among the following six goals which are closeto your professional opinion on the seismic performancelevels(1) Since the roads and railways are essentialinfrastructures in urban areas, socio-economic damage(indirect damage) resulted by damage of bridges must beextensively larger than the direct damage. Furthermore, ittakes several weeks even to arrange materials and humanresources once an urban area is extensively deteriorated byan earthquake. Therefore it is required to design bridges sothat they do not suffer extensive damage in an extend thatthey require emergency repair even under the Kobeearthquake.(2) It is not economically feasible to design bridges so thatthey do not suffer damage under a rare earthquake such asthe Kobe earthquake. It must be thus allowed for engineersto design bridges so that collapse can be avoided no matterhow extensive damage which results in long termsuspension of traffic occurs. Saving lives must be the goal.(3) It is not meaningful for bridges to be functional whenan urban area is extensively and widely deteriorated.Consequently, Sustaining extensive damage on bridges isacceptable.(4) Criticism was raised by public after the 1995 Kobeearthquake on the collapse of bridges. Public expects thatbridges are so designed that they do not collapse. Thephilosophy that only collapse should be prevented withallowing extensive damage to occur is realized only amongengineers.(5) The seismic performance depends on the amount ofinvestment. Engineer’s mission is to do their best withingiven investment and boundary conditions. Because budgetis limited, it is difficult to prevent extensive damage duringdestructive earthquakes such as the 1995 Kobe earthquake.(6) The seismic performance level depends on the amountof investment. However it is civil engineers who decide thedesign force levels and the performance goals. We makedesign calculations according to design codes, but are wereally trying to design bridges so that damage can beavoided? We should deliver our engineering knowledge for(1)Experiencedthe Kobeearthquake(2) Noexperienceto Kobeearthquake(3) Total19(17.9%) 10(10.6%) 29(14.5%)25(23.6%) 19(20.2%) 46(23.0%)2(1.9%)3(3.2%)5(2.5%)10(9.4%) 10(10.6%) 20(10.0%)14(13.2%) 13(13.8%) 27(13.5%)19(17.9%) 11(11.7%) 30(15.0%)preventing damage.(7) No answer 17(16.0%) 26(27.7%) 47(23.5%)Subtotal 106(100%) 84(100%) 200(100%)80