行波效应对大跨度空间结构随机地震响应的影响
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摘要
深入研究了行波效应对大跨度空间结构随机地震响应的影响,进一步完善了大跨度空间结构随机地震响应分析理论。推导了双支座、单自由度体系地震响应功率谱密度函数的解析表达式,研究了不同频率体系的响应峰值随地面视波速的变化规律,分析了多支撑点、多自由度体系的地震响应功率谱矩阵的特点,发现多自由度体系地震响应随地面视波速的变化规律与单自由度体系相似。数值模拟了某体育馆网壳结构在不同地面视波速情况下的随机地震响应,结果表明,考虑地震动行波效应后,结构地震响应随地面视波速的变化而显著变化,当视波速较低时其变化规律很复杂;且支撑点附近、受拟静力位移影响较大的部分杆件的地震响应明显增大,远离支撑点处、受拟静力位移影响较小的部分杆件的地震响应稍有减小。由此得出结论,对于大跨度空间结构的随机地震响应分析,必须考虑地震动的行波效应,尤其当受拟静力位移影响较大的部分杆件对结构抗震设计起控制作用时;且应对可能出现的地面视波速进行全面分析,作为结构抗震设计依据。
The influence of wave travelling effect on random seismic responses of long-span spatial structures is studied in detail,which may further complete the theory of random seismic analysis for long-span spatial structures.The analytical expression of the power spectrum density functions of seismic responses of an SDOF system with two supports is derived.The variation law of the peak response of the system with different frequencies with the ground apparent wave velocity is investigated.The characteristic of the power spectrum density matrix of seismic responses of an MDOF system with multiple supports is analyzed.It is found that the variation law of the seismic responses of the MDOF system with ground apparent wave velocities is similar to that of the SDOF system.The random seismic responses of the reticulated shell structure of a gymnasium at different ground apparent wave velocities are numerically simulated.The results show that when considering the wave travelling effect of ground motion,the seismic responses vary significantly with the variation of the ground apparent wave velocities,and the variation law is very complicated when the apparent wave velocity is low.The seismic responses of the members near the supports more influenced by the pseudo-static displacements are obviously increased.And the seismic responses of the members far from the supports less influenced by the pseudo-static displacements are slightly reduced.Some conclusions are drawn that the wave travelling effect of the ground motion must be considered for the random seismic response analysis of the long-span spatial structures,especially when the members mainly affected by the pseudo-static displacements control the seismic design of the structures.The comprehensive analysis should be performed for possible apparent wave velocities as the reference for seismic design of the structures.
The influence of wave travelling effect on random seismic responses of long-span spatial structures is studied in detail,which may further complete the theory of random seismic analysis for long-span spatial structures.The analytical expression of the power spectrum density functions of seismic responses of an SDOF system with two supports is derived.The variation law of the peak response of the system with different frequencies with the ground apparent wave velocity is investigated.The characteristic of the power spectrum density matrix of seismic responses of an MDOF system with multiple supports is analyzed.It is found that the variation law of the seismic responses of the MDOF system with ground apparent wave velocities is similar to that of the SDOF system.The random seismic responses of the reticulated shell structure of a gymnasium at different ground apparent wave velocities are numerically simulated.The results show that when considering the wave travelling effect of ground motion,the seismic responses vary significantly with the variation of the ground apparent wave velocities,and the variation law is very complicated when the apparent wave velocity is low.The seismic responses of the members near the supports more influenced by the pseudo-static displacements are obviously increased.And the seismic responses of the members far from the supports less influenced by the pseudo-static displacements are slightly reduced.Some conclusions are drawn that the wave travelling effect of the ground motion must be considered for the random seismic response analysis of the long-span spatial structures,especially when the members mainly affected by the pseudo-static displacements control the seismic design of the structures.The comprehensive analysis should be performed for possible apparent wave velocities as the reference for seismic design of the structures.
引文
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[7]李忠献,林伟,丁阳.行波效应对大跨度空间网格结构地震响应的影响[J].天津大学学报,2007,40(1):1-8.
[8]丁阳,林伟,李忠献.大跨度空间结构多维多点非平稳随机地震反应分析[J].工程力学,2007,24(3):97-103.
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[10]Kiureghian A D,Neuenhofer A.Response spectrum method for multi-support seismic excitations[J].Earthquake Engineering and StructuralDynamics,1992,21(8):713-740.
[11]Dumanogluid A A,Soyluk K.A stochastic analysis of long span structures subjected to spatially varying ground motions including the site-re-sponse effect[J].Eng Struct,2003,25(10):1301-1310.
[12]范立础,王君杰,陈纬.非一致地震激励下大跨度斜拉桥的响应特征[J].计算力学学报,2001,18(3):358-363.
[2]梁嘉庆,叶继红.结构跨度对非一致输入下大跨度空间网格结构地震响应的影响[J].空间结构,2004,10(3):13-18.
[3]林家浩,张亚辉.随机振动的虚拟激励法[M].北京:科学出版社,2004.
[4]张亚辉,李丽媛,陈艳,等.大跨度结构地震行波效应研究[J].大连理工大学学报,2005,45(4):480-486.
[5]Zhang Y H,Lin J H,Williams F W,Li Q S.Wave passage effect of seismic ground motions on the response of multiply supported structures[J].Structural Engineering and Mechanics,2005,20(6):655-672.
[6]曹资,薛素铎.空间结构抗震理论与设计[M].北京:科学出版社,2005.
[7]李忠献,林伟,丁阳.行波效应对大跨度空间网格结构地震响应的影响[J].天津大学学报,2007,40(1):1-8.
[8]丁阳,林伟,李忠献.大跨度空间结构多维多点非平稳随机地震反应分析[J].工程力学,2007,24(3):97-103.
[9]Clough R W,Penzien J.Dynamics of structures.3rd edition[M].Berkeley,CA:Computers&Structures,Inc.,2004.
[10]Kiureghian A D,Neuenhofer A.Response spectrum method for multi-support seismic excitations[J].Earthquake Engineering and StructuralDynamics,1992,21(8):713-740.
[11]Dumanogluid A A,Soyluk K.A stochastic analysis of long span structures subjected to spatially varying ground motions including the site-re-sponse effect[J].Eng Struct,2003,25(10):1301-1310.
[12]范立础,王君杰,陈纬.非一致地震激励下大跨度斜拉桥的响应特征[J].计算力学学报,2001,18(3):358-363.
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