桥墩高度对桥梁隔震性能的影响研究

Study of influence on isolation performance of bridge by pier height

以我国近海交通工程某隔震连续梁桥为研究对象,通过考虑影响隔震桥梁隔震性能的主要因素,建立其简化隔震计算力学模型,并采用有限元程序对隔震桥梁模型进行地震动时程响应模拟,以验证所采用简化力学计算模型的合理性。根据该模型研究桥墩高度对混凝土桥隔震性能的影响,分析表明:随桥墩高度逐渐增加,桥墩质量相应增加,桥梁结构自振周期延长,隔震桥的第二阶自振周期趋近于第一阶自振周期。对于低墩桥梁而言,桥墩高度对桥梁隔震性能影响显著,随着桥墩高度的不断增加,桥墩高度对桥梁隔震性能仍具有影响,但其影响程度逐渐下降。

A great traffic engineering of isolated continuous girder bridge in Chinese offshore area is taken as an example. By considering the main factors influencing of isolation performance of the isolation bridge, the simplified isolation computational mechanical model is established. The general finite element program is adopted to stimulate the ground motion time history response of isolation bridge model for verifying the rationality of simplified mechanical model. Then the effect on the performance of isolation bridge by the pier height has been studied based on the simplified mechanical model. The analysis results show that the period of bridge structure is extended, the second natural periods of isolation bridge is constantly approaching to the first natural period with the height of pier and bridge pier quality gradually increasing. The height of pier have a significant effect on the isolation performance of bridge for the low pier bridge, and with the increase of the pier height, it still has an impact on the isolation performance, but the influence gradually diminishes.