Evaluation of Expected Losses and Total Present Cost: Further Preliminary Sensitivity Analyses. Optimum Seismic Protection for New Building Construction in Eastern Metropolitan Areas

摘要

Results of computer program runs which evaluate expected future losses due to earthquakes and which choose an optimal seismic design strategy are reported. Four cases were investigated, each for three different assumptions concerning the dependence of initial cost on design strategy and for three different assumptions regarding physical and associated costs. Sensitivity of the output was studied primarily with respect to earthquake occurrence probabilities, damage probability matrices, damage cost fractions, and initial cost penalties. The case histories are described and the results summarized. The study concludes that there are only slight differences among three of the cases with respect to optimal strategies. Small to moderate changes in earthquake occurrence probabilities, or in the elements of damage probability matrices are unlikely to markedly affect the optimum decision. Much higher occurrence probabilities in one case lead to the choice design for a maximum degree of protection if non-physical costs are included in the objective function. For the Boston setting, the input parameters which appear to affect the decision most are the initial cost increments. Extensive tabular data are included.