• Earthquakes and Structures
• /
• v.27 no.5
• /
• pp.385-399
• /
• 2024

Highway bridges usually extend over long distances and are vulnerable to the variation of ground motions. In this paper, a 5-link continuous bridge with a total length of 510 m was selected for seismic vulnerability analyses under consistent and multi-support excitations. Fragility curves for piers and bearings considering both the non-isolated and isolated conditions are generated through incremental dynamic analysis (IDA). The results show that for the non-isolated condition with elastomeric bearings (EBs), the junction piers between adjacent links are more vulnerable than interior piers within links under consistent excitation, whereas it is exactly the opposite for the bearings. Under the multi-support excitation, the fragility of the bearings at junction piers significantly increases due to the unsynchronized movement of adjacent links. For the isolated condition with lead-core rubber bearings (LRBs) and friction pendulum bearings (FPBs), the fragility of piers is effectively reduced compared to EBs, especially for FPBs and under multi-support excitation. The fragility of LRBs is lower than that of EBs under both excitation modes. The fragility of FPBs is apparently higher than that of the piers, controlling the vulnerability of the bridge. This study provides a reference for the seismic design of highway bridges.