桥墩截面形式对弯连续刚构桥地震响应的影响

Effect of Pier Section Type on Seismic Response of Curved Continuous Rigid Frame Bridge

为了研究桥墩截面形式对弯连续刚构桥动力及地震响应的影响,以某工程实例为背景,建立了空间有限元分析模型,研究了桥墩外形尺寸、截面面积、截面纵向刚度等参数对结构自振特性的影响,在此基础上,利用线弹性时程法,对比分析了这些参数变化对空心墩与实心墩结构地震响应的影响。研究结果表明,桥墩截面形式的不同使得结构的振型系列发生了改变,具有空心墩的连续刚构桥与具有实心墩的连续刚构桥相比,当两者的外形尺寸相同时,前者的频率较低,当两者桥墩面积相同时,前者频率较高,在纵向刚度相同的情况下,前者频率稍低;采用空心墩时,墩底应力及主梁位移比相应实心墩的小,当桥墩纵向刚度相同时,空心墩和实心墩的地震响应基本相同。

In order to study the influence of pier section on the dynamic and seismic responses of curved continuous rigid frame bridge, a current bridge was taken as an example, and its finite element model was set up to analyze three parameters＇ effects on the structure＇s natural vibration characteristics.The parameters include external dimensions, section area and section longitudinal rigidity of the pier. Then liner elastic time history analysis method was adopted to deduce the effects of the parameters on the seismic response of hollow pier or solid pier structure. The results show that the mode shape sequence changes with different section types of the pier： for the continuous rigid frame bridges, （1） if the external dimensions of the hollow pier is the same to that of the solid pier, the frequencies of the former are lower than those of the latter; （2） if the section areas of the two kinds of pier are the same, the frequencies of the former are higher than those of the latter; （3） if the two kinds of pier have the same longitudinal rigidity, the seismic response of the former is basically as same as that of the latter. （4） under the earthquake excitation, the stress at the bottom of the hollow pier and the displacement of the superstructure are less than those of bridge with solid pier.