多点输入下大跨空间结构动力稳定性分析

Dynamic stability analysis of large-span spatial structures under multi-support excitation

大跨空间结构属于缺陷敏感性结构形式,在进行地震动输入时需要考虑时空相干性对结构动力响应的影响。为分析这类结构的动力稳定性,将随机振动方法和时程分析方法结合,将包含了场地统计规律的功率谱函数转化为时程分析方法的荷载输入,人工合成具有概率意义且考虑空间相干性的地震波,对实际工程中的大跨空间结构进行多点输入。结果表明:多点输入下的地震相干效应使结构失稳峰值加速度明显小于一致输入对应的失稳峰值,该方法适用于大跨度空间结构的动力稳定分析。

Large-span spatial structure belongs to defect sensitivity structural type, and time-space coherence effects on structural dynamic response should be taken into account under seismic inputs. For analyzing the dynamic stability of the structure, random vibration was combined with time history analysis. Power spectrums which include law of site statistic were translated into load inpn of time history analysis. Seismic wave were synthesized including probability meanings and spatial coherence for large-span spatial structure of practical engineering projects under multi-support excitation. The results show that structural instability peak acceleration under seismic coherence effect of multi-support excitation is obviously smaller than instability peak under uniform excitation. The method can be used in structural dynamic stability analysis.