Analysis on the seismic responses of isolated skew bridges considering the ambient temperature effect and lead core heating of LRB under near-fault ground motions

Low temperature environment and lead core heating can cause the change of mechanical properties of lead rubber bearings (LRBs) . The performance of the bearing was modified from the aspect of lead and rubber material characteristics and then, the influence of low temperature on the mechanical properties of the bearing was considered. A strength degradation model was used to consider the influence of lead core heating on the mechanical properties of the bearing. Based on the OpenSees seismic analysis platform, a dynamic analysis model was established to study the relationships between the seismic response and the ambient temperature, lead core heating and skew under near fault ground motions. The results show that the rotation of the beam body and the displacement of the bearing are significantly reduced under low temperature environment, while the seismic responses of piers are significantly increased. The lead core heating has little influence on the seismic responses of piers and bearings. Under the combined action of ambient temperature and lead core heating, the shear force and torque of the piers are significantly amplified, and the low temperature environment plays a leading role in its seismic responses. At the same low temperature, the amplification degrees of longitudinal shear force and torque at the bottom of piers increases with the increase of a skew. At - 30 °C, the longitudinal shear force and torque of the piers of a skew bridge with the skewness of sixty are amplified by 20% and 39% respectively. © 2022 Chinese Vibration Engineering Society. All rights reserved.