Risk as a measure of performance: the next step in performance-based engineering procedures

The US Federal Emergency Management Agency (FEMA) is supporting the Applied Technology Council (ATC) to develop a next generation of performance- based seismic design guidelines for buildings. The project, ATC-58, will result in the capability to base design decisions explicitly on the expected performance of the building in future earthquake events. Performance is measured explicitly as the risk of experiencing three types of losses: • Deaths and serious injuries. • Direct capital losses attributable to damage to the building and contents. • Indirect losses attributable to the loss of use for repair or reconstruction. This characterization of performance provides a common framework for design decisions that can be readily adapted to the perspectives of all stakeholders (e.g. owner, architect, engineer, contractor, regulator, lender, insurer). It also facilitates efficient planning and design decisions through comparison of costs and benefits of various alternatives. This paper describes a procedure to assess risk and potential losses for individual buildings. A practical example is included to illustrate application of the procedure.