多点地震激励对大跨度结构抗震设计的影响

The effect of multiple-support seismic excitation on seismic design of long-span structures

以上海浦东机场(二期)候机楼为例,讨论了大跨结构多点激励效应对结构抗震设计值的影响。文中首先进行了结构静力荷载作用下的反应分析,并与上海浦东机场(二期)候机楼在一致激励下的地震反应相组合,得到一致地震作用下结构抗震设计值;然后根据工程场地二维地震动场反应分析结果,进行了上海浦东机场多点输入下的地震反应分析,将其与静力反应组合得到多点地震激励下结构抗震设计值。考察在一致输入和多点输入下得出的抗震设计值之间的差异,分析了不同的地震激励方式对控制结构抗震设计值以及结构动力位移和加速度值的影响。研究结果表明:多点地震输入对浦东机场二期工程候机楼的抗震设计影响较大,特别是对承力柱的影响最大,可以使一些柱的控制截面内力的抗震设计值比一致地震输入时的数值增大10～50%,同时使另外一些柱的控制截面内力的抗震设计值减小40%左右。因此,为合理地进行这类结构的抗震设计,在结构抗震分析中考虑地震动的多点输入的影响是非常必要的。

Taking Shanghai Pudong International Airport（Phase II）terminal as an example,the effect of multi-support excitation on seismic design value of long-span structures is discussed.First,the static response of the Pudong Airport（Phase II）terminal is analyzed and then combined with the seismic response of the structure under the uniform excitation to obtain the seismic design values of the structure.At the same time,according to the results of the seismic response analysis of the engineering site with two-dimensional model,the seismic response analysis of the Pudong Airport（Phase II）terminal under multi-support excitation is carried out and then combined with its static response to obtain the seismic design value of the structure under the multi-support excitations.The influence of the different types of seismic excitations on the seismic design value,including the seismic displacement and acceleration values,of the structure are analyzed by comparing the difference of the seismic design values obtained from two types of seismic excitations.The obtained results show that the effect of multi-support excitation on the seismic design of Shanghai Pudong International Airport（Phase II）terminal is significant,especially for some important columns in the structure.The seismic design values at some column cross sections under multi-support excitations increase 10%-50% relative to the ones under the uniform excitations.Meanwhile,the seismic design values at other column cross sections decrease about 40%.Therefore,it is necessary to consider the influence of the multi-support excitation in the seismic response analysis for the reasonable seismic design of such long-span structures.