单车荷载作用下T型刚构桥车致振动响应研究

根据车辆-桥梁结构振动特性，研究单车移动荷载作用下，T型刚构桥考虑桥面不平顺影响时桥梁振动响应及冲击特性。通过将T型刚构桥离散为三维梁单元有限元模型，车辆简化为九自由度整车模型（考虑车辆俯仰及侧翻），桥面不平顺激励采用实测和数值模拟（根据国标GB／T7031—86给定功率谱密度曲线采用三角级数叠加法模拟）两种激励；以车轮与桥面相互接触处保持不脱离为条件，建立车辆与桥梁耦舍振动方程，利用模态综合法并结合Newmark—β数值积分方法进行迭代求解。以乔木湾乐安河T型刚构桥为工程背景，研究了单车荷载下，最不利位置处的冲击系数随桥梁结构阻尼、行车速度、桥面不平顺及车辆特性的变化关系，并将数值模拟结果与实测结果对比。研究结果表明，实测冲击系数与数值模拟的冲击系数较好吻合，乐安河大桥冲击系数满足04《桥规》要求。

Vehicle-induced Dynamic Response Analysis of T-type Rigid-frame Bridge under a Vehicle Load

This paper is to present the results of an investigation of the dynamic and impact characteristics of T-type rigid-frame bridge with rough decks caused by vehicle moving across it. By separating T-type rigid-frame bridge into three-dimensional finite element model, the vehicle is reduced to freedom model of nine degrees （considering pitch and roll of the vehicle）. Incentives of bridge irregularity include practical measuring and digital simulating （according to the international standard GB/T7031 - 86）. By establishing the equations of motion for the bridge and the vehicles respectively, an iteration solution method is presented to analyze the coupling vibration response of vehicle bridge system based on the same displacement and coupling force at the interface. The Newmark - β method is used to solve the motion equations and the results of a parmetric study are presented. Based on the numerical analysis of T-type rigid bridge of the Le＇an river which locates in Qiaomuwan town,compared with the experimental results,the DAFs of the Ttype Rigid Bridge vary with its structural damping,the vehicle speed,the rough decks,and the frequency of the vehicle are studied. The results indicate that the DAFs obtained from numerical simulation are in line with experiment results and the DAFs of the T-type rigid bridge meet a criterion of Chinese Bridge Standard in 2004.