System-Level Calibration of Bridge Component Damage States

Post-earthquake repair costs and repair times are important for evaluating the performance of bridges in a fundamentally different way than the traditional component-level metrics such as bearing displacements and column ductility demands. Repair costs and times are metrics that address the system-level response of bridges to a suite of seismic events, especially when cast probabilistically in the form of fragility curves. Traditionally, bridges are assessed and fragilities are generated according to enumerated component damage states (e.g., DS1 is minor damage). However, the level of system functionality that corresponds to each component damage state and whether individual components have risk or performance consistent with the system are of considerable interest in seismic assessment. In this paper, repair costs and times are calculated for a typical multi-span reinforced concrete highway overpass bridge in California. This system-level information is then used to back calculate consistent component damage states. The initial damage states are compared to the back-calculated states for forward prediction on different bridge configurations, and it is shown that it is difficult to achieve consistent performance using constant component damage states.