风与地震载荷作用下集装箱小车低架桥结构耦合振动分析

CONTAINER VEHICLE-TRUSS BRIDGE COUPLED VIBRATION ANALYSIS UNDER WIND AND SEISMIC LOAD

  • 摘要: 外部环境激励下的车桥耦合振动严重影响着自动化码头集装箱小车-低架桥结构的安全和使用效率。针对该问题, 基于一元多维平稳随机过程数值模拟法实现轨道不平顺、风速场的时程模拟, 利用双协调自由界面模态综合法求解了车桥结构在轨道不平顺、轮对蛇行运动以及风、地震载荷激励下的耦合振动时域响应, 分析了风、地震载荷等对车桥耦合振动响应的影响, 并设计结构模型试验验证自激激励仿真结果。结果表明:1) 自由界面模态综合求解车桥耦合振动响应的仿真方法合理;2) 车桥竖向振动主要由小车移动加载引起, 自激激励是主因;风、地震载荷会大大增强横向振动, 车桥耦合振动响应随着小车速度、脉动风平均风速的增大而增大, 且对地震载荷的敏感程度大于工作状态风载荷;3) 小车复线运行时车桥耦合振动响应最大值大于小车单线运行时, 铅芯橡胶支座可有效减小车桥加速度响应。

     

    Abstract: The container vehicle-truss bridge coupled vibration inspired by the external environmental load greatly affects the automated container terminals’ (ACT) structural-safety and handling-efficiency. To solve this problem, firstly, the stochastic simulation of track irregularity and fluctuating wind time-history were generated, based on the numerical simulation method of a multidimensional homogeneous process. Then using a free-interface component mode-synthesis (CMS) method, the coupled vibration time-domain responses inspired by the self-excitation including track irregularity and hunting movement as well as wind and seismic load were obtained. Furthermore, the influences of wind load, seismic load etc. on the dynamic responses were studied. Finally, a miniature model test was designed to validate the simulation results. The following conclusions can be drawn: 1) the technique of applying free-interface CMS to solve a vehicle-bridge coupled-vibration problem is feasible. 2) The vehicle-bridge vertical vibration is caused mainly by the vehicle moving load, and the self-excitation is a major factor. Wind and seismic loads will greatly enhance the lateral vibration. As fluctuating wind mean velocity or vehicle velocity increases, the response increases too. And the sensitivity of the response to the seismic load is greater than that of the working-condition of wind load. 3) When vehicles are double-running, the maximal response is significantly greater than that due to single-running. Lead rubber bearing (LRB) can effectively reduce the acceleration response of both vehicle and bridge.

     

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