A Risk-Based Approach to Determine the Optimal Service Life of Steel Buildings in Seismically Active Zones

Abstract

The object of this study is to propose, develop and apply a risk-based approach to determine the optimal service life for steel framed buildings in seismically active zones. The proposed framework uses models for seismic hazards, structural fragility and loss functions to estimate the system-wide costs owing to earthquake retrofitting and recovery. With the seismic risk curves (i.e. the expected seismic loss and probability of exceeding the loss), the optimal service life can be determined according to the probable maximum loss (PML) defined by the building’s owner. The risk-based approach is further illustrated by examples of 6- and 20-story steel framed buildings. The buildings have three kinds of different lateral load resisting systems, including moment resisting frames, eccentrically braced frames and buckling restrained braced frames. The results show that for the considered PML (i.e. 40% initial construction cost) and risk acceptance (e.g. 90% reliability), steel braced frames can effectively improve seismic fragility and lengthen service life for a low-rise building. However, the same effects cannot be expected in a high-rise building.