不平整度桥面下连续梁桥车桥耦合振动分析

Analysis of Vehicle-Bridge Coupling Vibration of Continuous Girder Bridge Under Uneven Deck

现行《公路桥涵设计通用规范》采用结构基频来计算桥梁结构的冲击系数,而基频的计算宜采用有限元方法,但如何计算,规范没有明示;而且规范给定的连续梁基频估算公式不分直桥和弯桥;再者按规范基频估算公式计算冲击系数的值有待商榷。采用一种基于有限元通用分析软件ANSYS来实现公路桥车桥耦合振动数值分析方法,对弯桥车桥耦合振动影响因素进行分析,然后分别对直线和曲线连续梁桥考虑了桥面不平整度后车桥耦合振动进行计算。分析结果表明,直桥和弯桥的动力系数不同,换算成冲击系数均大于连续梁按规范给定的基频估算值计算的冲击系数。

In the present ＂General Code for Design of Highway Bridges and Culverts＂, the structural base frequency is used to calculate the impacting coefficient of bridge structure while the base frequency is required to be preferably calculated by the finite element method. However, for the ways of how to make the calculation, there are no clear provisions in the Code, the estimation formula for the base frequency of the continuous girder bridge given in the Code do not make a difference between the straight bridge and curved bridge and hence, the values of the impacting coefficient calculated by the formula still need to be discussed. By using a numerical analysis method for the highway vehicle-bridge coupling vibration based on the general finite element analysis software ANSYS, the factors having influence on the coupling vibration of the curved bridge are analyzed and the coupling vibration of both the straight bridge and curved bridge is respectively calculated after the unevenness of the deck is taken into account. The results of the analysis and calculation show that the dynamic coefficients for the straight bridge and curved bridge are different and are all greater than the impacting coefficient calculated by the estimation formula for the continuous girder bridge in the Code when the former are converted into the impacting coefficient.