The previous studies have shown that the internal force and deformation of long-span structures when considering the wave-traveling effect of seismic motion would have a greater difference from those when not considering it. For a large coal transport trestle across a long distance, there will be differences between the times when the seismic waves would reach to the different pillars of the trestle, so it is untrue to calculate the seismic effect according to the uniform excitation response spectrum method, in the structural design, the adverse impacts of the seismic wave-traveling effect should be considered. Here, by using the finite element analysis method and the dynamic elastic time-history analysis method in a practical bridge engineering, the effects of two different ways such as the uniform excitation and wave-traveling excitation on the structures are compared and analyzed. Because of the greater effects of the seismic waves and their apparent velocities on the large-span structure, three pieces of seismic waves and four kinds of seismic wave velocities are selected for calculation in order to ensure the valid and reliable results. The results show that when considering the wavetraveling effect of seismic motion, the impact on the large-span coal transport trestle would be significant, the internal force would be reduced wholly, at the same time, the internal force would increase as the wave velocity becomes larger and would trend to the uniform excitation. When the wave volocity reaches 3 000 m/s, the stress of individual rods would exceed that of the rods under the uniform excitation, which should be paid attention to and prevented.%已有研究表明,大跨度结构考虑地震动的行波效应时,结构构件的内力、变形与不考虑时可能有较大差别.对于超大跨长距离输煤栈桥结构,地震波到达栈桥不同支柱的时间会有差异,按一致激励反应谱法计算结构的地震作用是不真实的,在结构设计中应考虑地震波的行波效应对结构产生的不利影响.本文利用有限元分析程序,对某实际栈桥工程应用动力弹性时程分析方法,对比一致激励与行波激励两种不同方式对结构产生的效应.由于地震波和其视波速对结构作用效应影响较大,为了保证结果的有效及可靠,选取了3条地震波与4种波速进行计算.计算结果经分析后显示,大跨度输煤栈桥在考虑行波效应后对结构的影响明显,考虑行波效应后结构内力整体减小,内力随着波速的增加而变大并趋向于一致激励,当波速到达3000 m/s时,个别杆件应力值超过一致激励情况下杆件的应力值,应引起注意并防范.
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