Low-temperature effect on seismic performance of isolated highway bridges with high damping rubber bearings

The high damping rubber (HDR) bearing and lead high damping rubber (LHDR) bearing have been proven to be temperature-sensitive bearings in previous research, especially at low temperatures. However, this characteristic may affect the seismic performance of isolated bridges with HDR and LHDR bearings at low ambient temperatures. Due to the absence of explanations for the temperature-dependent mechanisms of rubber bearings, current seismic design codes for isolated bridges in Japan do not consider low-temperature environmental factors. To thoroughly evaluate the seismic performance of isolated bridges with HDR and LHDR bearings at low ambient temperatures and provide a reference for current seismic design codes, a nonlinear bridge model is established to conduct dynamic analysis at ambient temperatures of −20℃, 0℃, and 23℃. The multi-layer thermo-coupled Bouc-Wen (MTBW) model is adopted to replace the bilinear model and simulate the behavior of the HDR and LHDR bearings in the bridge model to account for the low-temperature effect. The ductility of the bridge pier and the shear strain of the isolation bearing are selected as two engineering demand parameters. The corresponding damage states are defined in incremental dynamic analysis (IDA) and seismic fragility analysis. The research outcomes show that low temperatures have significant effects on the seismic performance of isolated bridges, with a reduction in the maximum shear strain and energy dissipation of bearings and an increase in displacement of the pier. The effectiveness of the isolation system is weakened at low ambient temperatures. Moreover, the failure probability becomes higher at low ambient temperatures for both the bridge pier and bearing at each damage state. At low ambient temperatures, the probability of pier damage occurring before bearing damage increases, which becomes the dominant damage mode in most cases. The low-temperature effect is recommended to be thoroughly assessed for isolated highway bridges in cold earthquake-prone regions. • Low temperature effect on isolated bridge with high damping rubber bearing is evaluated. • Effectiveness of isolation system is weakened at low ambient temperatures. • Failure probability is higher at low ambient temperature for bridge pier and bearing at each damage state. • Likelihood of pier damage occurring before bearing increases in low-temperature environments. • Low temperature effect should be assessed for isolated bridges in cold earthquake-prone regions.