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基于车桥耦合振动的连续梁桥动力响应分析

Dynamic Response Analysis of Continuous Beam Bridge Based on Vehicle-bridge Coupling Vibration

  • 摘要: 为详细评定常见连续梁桥在车桥耦合作用下的动力响应,采用数值模拟的方法,利用桥涵通用图纸建立五跨连续梁桥的有限元模型,分析其在车辆荷载作用下的挠度、应力2个动力响应。并计算相应的动力放大系数,比较动力放大系数在车辆频率、桥梁频率、扰动频率3个因素影响下的变化规律。研究结果表明,通用图纸中连续梁桥的结构基频为4.44 Hz,当车辆频率与桥梁的基频接近时,将会产生共振的效果,产生更大动力放大系数;分析计算中所得的中跨跨中位置和次边跨跨中位置处动力放大系数变化规律和数值大小较为接近,而与边跨跨中位置处的动力放大系数则存在一定的差异,说明边跨处一端简支的结构对此处的动力放大系数存在较大的影响;车辆频率、桥梁频率和行车扰动频率等均对动力放大系数产生影响,故桥梁规范中的冲击系数仅作为桥梁基频的函数,与实际有较大的差距,有待改进。

     

    Abstract: In order to evaluate the dynamic response of common continuous girder bridges under vehicle-bridge coupling in detail, this paper uses numerical simulation method to establish the finite element model of five-span continuous girder bridges with general drawings of bridges and culverts, and analyzes its dynamic responses under vehicle loads: deflection, stress. The corresponding dynamic amplification factor is calculated, and the variation law of dynamic amplification factor under the influence of vehicle frequency, bridge frequency and disturbance frequency is compared. The research shows that the fundamental frequency of the continuous beam bridge in the general drawing is 4.44 Hz. When the vehicle frequency is close to the fundamental frequency of the bridge, the resonance effect will be produced and a larger dynamic amplification factor will be produced. The variation law and numerical value of the dynamic amplification factor at the middle position of the middle span and the middle position of the secondary side span obtained from the calculation are close to each other, but there are some differences with the dynamic amplification factor at the middle position of the side span, which shows that the structure with one end simply supported at the side span has a great influence on the dynamic amplification factor here. Vehicle frequency, bridge frequency and driving disturbance frequency all affect the dynamic amplification factor, so the impact coefficient in the bridge specification is only a function of the fundamental frequency of the bridge, which is far from the reality and needs to be improved.

     

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