This paper presents a highly efficient and accurate analytical method for the dynamic analysis of subjected to moving loads. Bridges with complex cross section and considering damping are modelled as plate built-up structures by the dynamic stiffness method with few degrees of freedom. Different moving loads with time-varying amplitudes travelling at different speeds can be modelled semi-analytically: The moving vehicle loads with varying amplitude are transformed into the frequency-wavenumber domain by the analytical sine transform combined with the fast Fourier transform; then the time-spatial domain dynamic response of the bridge is computed by the associated inverse transforms from the frequency-wavenumber domain response of the dynamic stiffness model. The most commonly used box girder railway bridge is taken as an example, and the results of both free vibration and dynamic response subject to moving train wheel loads computed by the proposed method are validated well by the finite element software ANSYS. The proposed method uses about 1.2% time of that taken by the ANSYS but achieves a similar level of accuracy. The proposed method can serve as an efficient alternative tool of modal and dynamic response analysis for the design and optimization of a wide range of complex bridges.

本文提出了一种高效、准确的分析方法，用于运动载荷的动态分析。采用少自由度动刚度法将复杂断面且考虑阻尼的桥梁建模为板组合结构。可以对以不同速度行驶的时变幅值的不同运动载荷进行半解析建模：通过解析正弦变换结合快速傅里叶变换，将幅值变化的运动车辆载荷变换到频率-波数域；然后，通过动态刚度模型的频率-波数域响应的相关逆变换来计算桥梁的时空域动态响应。以最常用的箱梁铁路桥为例，有限元软件ANSYS很好地验证了该方法计算的自由振动和动轮荷载作用下的动力响应结果。所提出的方法使用的时间大约是 ANSYS 的 1.2%，但达到了相似的精度水平。该方法可以作为模态和动态响应分析的有效替代工具，用于各种复杂桥梁的设计和优化。