Decision process and optimization rules for seismic retrofit programs

In earthquake-prone areas public authorities are dealing with the decision process of initiating retrofitting programs for a large building stock. By means of a cost-benefit-analysis decision makers can quantify all impacts of various investment alternatives to a society in monetary terms and make recommendations based on the net present value. In the case of seismic retrofit decisions the input variables, such as costs of alternative seismic upgrade levels, direct and indirect damage, and casualties, are influenced by many uncertain factors.
This paper will analyse standard decision criteria under the aspect of uncertainty and introduce a probabilistic cost-benefit-analysis for seismic retrofit programs. The implication of influencing factors is analysed with Monte Carlo simulation and sensitive analysis. The presented methodologies are integrated in the loss estimation software EQSIM which has been developed by the Collaborative Research Center 'Strong Earthquakes: A Challenge for Geosciences and Civil Engineering' at the University of Karlsruhe in Germany.