首先建立了考虑预应力影响的渡槽竖向地震反应分析的变系数微分方程。然后应用模态摄动法和振型叠加法,提出了预应力渡槽竖向动力特性和地震反应的计算方法。最后通过典型工程实例分析,讨论了渡槽竖向地震反应分析中的预应力和槽内水体对渡槽动力特性和抗震性能的影响及渡槽竖向高阶振型对渡槽地震反应的贡献等。算例结果表明,施加预应力使渡槽的自振频率升高、抗震能力增强,渡槽的竖向地震反应中高阶振型的贡献可以忽略,槽内水体对渡槽的自振特性和地震反应有很大影响。在渡槽的抗震设计中应考虑渡槽竖向地震反应的影响。
Based on the modal perturbation method and the mode superposition method, an approach is established for vertical seismic response analysis of prestressed aqueducts. Several problems occurred to the analysis of vertical seismic response of aqueducts are discussed by analyzing a typical example. The numerical result shows that the natural frequencies are elevated and the seismic responses are reduced when the preloading is applied on the aqueduct. The water filled in the aqueduct has important effect on natural frequencies and seismic responses, but the contributions of high-order mode responses can be ignored . It is suggested that the vertical seismic responses must be considered in aqueduct design.