Seismic resilience assessment of bridges considering both maximum and residual displacements

The residual displacement of the bridge column has a great influence on evaluating earthquake damage and seismic resilience of bridges. However, the residual displacement is rarely considered when assessing post-earthquake functionality and seismic resilience of bridges. An evaluation method for seismic damage of bridges is proposed in this paper by introducing both the maximum drift (MD) and residual drift (RD) of the bridge column as engineering demand parameters. The damage states and damage probability of bridges under earthquakes are determined through the joint probability density function and used to evaluate the functionality loss and recovery of bridges after earthquakes. A seismic resilience assessment framework of bridges considering both MD and RD is proposed and applied to assess the seismic resilience of a two-span reinforced concrete (RC) bridge. The results indicate that RD greatly impacts the probability of collapse damage of bridges. The evaluated functionality loss of the bridge considering both MD and RD is larger than that considering the single MD index after the earthquake. When both MD and RD are taken into consideration, the evaluated seismic resilience is smaller than the result considering the single MD index. The maximum reduction of seismic resilience is 14.1% at the peak ground acceleration (PGA) of 0.7 g. With the increase of PGA, the seismic resilience considering both MD and RD is similar to that only considering MD. The seismic resilience can be overestimated when RD is not taken into consideration.