Performance-based seismic design and optimization of damper devices for cable-stayed bridge

The seismic vulnerability of cable-stayed bridges located in seismically active regions can be of great concern to the regional safety and resilience. A promising design practice for cable-stayed bridges lies in decoupling the deck from deck-pylon connection and incorporating energy dissipation devices to reduce the dynamic responses. In this study, the performance-based seismic design (PBSD) procedure is adapted to the optimal design of damper devices at the deck-pylon connections in a benchmark cable-stayed bridge. The benchmark cable-stayed bridge was modeled in the OpenSees platform, which was calibrated against the previous finite element models. Then it was seismically designed with viscous and metallic dampers in the longitudinal and transverse direction, respectively. The component-level fragility functions of the cable-stayed bridge were first derived based upon the multiple stripe analysis (MSA) method, and then the system-level repair cost ratio (RCR) surfaces were built under the PBSD framework. Finally, the genetic algorithm based on parallel computation was utilized to identify the optimal parameters of the damper devices. The analysis results illustrate that the optimal design parameters can be effectively obtained through the proposed method, and the damper devices with optimal parameters lead to a significant reduction of the overall repair cost. The study also demonstrates that if the device parameters are not selected appropriately, the dampers can have negative effects on bridge responses. The design framework and the findings could provide the guidance for the designing and retrofitting of cable-stayed bridges in practice.