Report - PEER - University of California, Berkeley

Table 10. Problems of performance-based designWhat do you think the barriers for performance-based seismic design?Choose from the followings based on the assumption that necessary costupof design by increasing steps and times is paid by clients.Number andpercentage(1) It is trouble because many decisions have to be made 7 (7%)(2) Time for design increases 2 (2%)(3) Current technology is insufficient to meet realistic and practical10 (10%)demands and requirements(4) Require engineers with higher engineering background, knowledge30 (30%)and skill(5) Design is controlled by a designer or a design group with high21 (21%)technical background, and the design cannot be approved by others(6) Risk and responsibility increase 20 (20%)(7) Others 10 (10%)(8) No answers 0Total 100 (100%)static analysis provides good application” (46%). Subsequent opinion is that theyintend to “use dynamic response analysis more extensively, because input data forpushover analysis are nearly the same to the input data for dynamic response analysis.Furthermore, pushover analysis is inconvenient because it takes more man-power andit cannot be used for some types of bridges with predominant higher modes, whiledynamic response analysis can be used for all bridges regardless the types” (28%). Onthe other hand, few opinions were directed to “current level of balance betweenpushover analysis and dynamic response analysis is appropriate” (9%) and “usepushover analysis more, because dynamic response analysis is inconvenient fordetermination of sections” (9%).Table 10 shows problems which the engineers are concerned about in theperformance-based seismic design. The largest problem was that “engineers withhigher engineering background, knowledge and skill are required” (30%). This isfollowed by “design is controlled by a designer or a design group with high technicalbackground, and the design cannot be approved by others” (21%), “risk andresponsibility increase” (20%), and “current technology is not matured to meetrealistic and practical demands and requirements” (10%). On the other hand fewpointed out “it is trouble for having several decisions” (7%) and “it increases time fordesign” (2%).CONCLUSIONSSeismic performance criteria and levels were clarified based on a questionnairesurvey to 100 civil engineers. The following conclusions may be deduced based onthe results presented herein:87