Life-cycle cost analysis based on a renewal model of earthquake occurrences

摘要

A decision methodology for the management of seismic risk of a single building is presented. The decision criterion aims at minimizing the expected life-cycle cost, including the initial cost of the design and the expected cost of damage due to future earthquakes. The expected life-cycle cost of each design alternative is formulated using a renewal model for the occurrence of earthquakes in a seismic source, which accounts for the temporal dependence between the occurrence of 'characteristic' earthquakes. The formulation involves the expected damage cost from an earthquake of specified magnitude in a given source. This term is estimated by simulating the processes of fault rupture, elastic wave propagation, surface soil amplification, dynamic structural response and generation of damage costs. As an example, the methodology is applied to an actual office building in Tokyo. A simple decision problem between two design alternatives is set: a bare steel moment frame, and the same frame equipped with oil dampers. Through this case study, the installation of the oil dampers is demonstrated to be effective in reducing the life-cycle cost of the building under consideration.