行人激励载荷下大跨径异形天桥抗震支座设计研究

Research on Aseismatic Bearing Design of Long-span Special-shaped Flyover under Pedestrian Excitation Load

摘要:

为了解决抗震支座弯矩受到行人不确定激励载荷影响，出现参量获取不全面的现象，导致支座抗震效果不佳这一问题，进行了行人激励载荷下大跨径异形天桥抗震支座设计研究。首先，考虑到行人对桥梁激励的不确定性，设置了多种载荷激励类型，并提出利用区间过程法来描述桥上行人的不确定激励，使用自相关系数函数分析在行人激励载荷作用下的桥梁非随机振动情况；其次，利用有限元软件中的单元构造了抗震支座模型，并对桥梁位移、桥墩弯矩、桩基弯矩进行数值模拟；最后，将支座参量数值模拟结果代入有限元模型中，设计出一种双曲面球抗震支座结构。结果表明，设计的支座在慢跑、快跑情况下纵向弯矩与实际数据之间的最大误差分别为25 kN·m、250 kN·m，横向弯矩与实际数据一致，说明根据数值模拟结果设计的支座能够起到良好减震效果。

Abstract:

In order to solve the problem of the bending moment of the aseismatic bearing affected by the uncertain excitation load of pedestrian to cause the phenomenon of incomplete parameter acquisition and the poor seismic effect of the bearing, the aseismatic bearing design of long-span special-shaped flyovers under the pedestrian excitation load is studied. Firstly, by considering the uncertainty of pedestrian excitation on the bridge, multiple load excitation types are set. The interval process method is used to describe the uncertain excitation of pedestrians on the bridge. The autocorrelation coefficient function is used to analyze the non-random vibration of the bridge under the excitation load of pedestrians. Secondly, the aseismatic bearing model is constructed by using the elements in the finite element software. And the bridge displacement, pier bending moment and pile foundation bending moment are numerically simulated. Finally, the numerical simulation results of the bearing parameters are substituted into the finite element model to design a hyperboloid spherical aseismatic bearing structure. The results show that the maximum errors between the longitudinal bending moment and the actual data of the designed bearing are 25 kN·m and 250 kN·m respectively under the conditions of jogging and fast running. The transverse bending moment is consistent with the actual data, which shows that the designed bearing can play a good anti-seismic effect according to the data.