【摘要】 在加速度反应谱一致的前提下,研究了近断层速度脉冲的工程特性。首先,构造两组加速度反应谱一致的地震动时程:第一组时程为实际强震观测记录且含有明显的速度脉冲;第二组时程为以第一组时程的反应谱为目标谱合成的模拟地震动时程,在合成过程中,利用窄带时程叠加法,通过控制峰值速度可以使得这些时程不再含有速度脉冲。其次,通过分析钢筋混凝土框架结构在这两组输入地震动作用下动力响应的差异,研究了在加速度反应谱一致的前提下,速度脉冲对结构地震反应、尤其是弹塑性地震反应的影响。分析结果表明:对于层剪力、层间位移、各层最大位移等结构动力响应参数,当结构地震反应进入弹塑性阶段后,与不含速度脉冲地震动作用下的反应相比,在含有速度脉冲的地震动作用下,结构的反应有较大幅度的增大,尽管这两组输入地震动的加速度反应谱相同;在这种情况下,加速度反应谱将不能充分地体现出速度脉冲对结构地震反应的影响。更多还原

【Abstract】 Under the condition of acceleration response spectrum being consistent, the engineering properties of near-fault velocity pulse are studied. Firstly, two groups of ground motions that have same response spectra are generated; the first one contains field recorded seismograms with distinct velocity pulses while the other contains the simulated ground motion time histories synthesized with the response spectra of the ground motions in the first group as target spectra. During synthesizing, these ground motions can be generated to contain no velocity pulses by using the method of superimposing narrow-band time-histories to control the velocity peaks. And then, the differences were analyzed between the dynamic responses of reinforced concrete frames excited by these two kinds of ground motions, and the influences of velocity pulse on the seismic responses, especially the elastic-plastic seismic responses, of structures are studied with the response spectra being the same. The results show that in terms of some structural dynamic response parameters, such as the storey shear force, the inter-storey displacement, and the storey maximum displacement et al., the structural responses to the ground motion with velocity pulse are increased by considerable magnitudes when the seismic responses of structures step into the elastic-plastic stage, compared with the ground motion without velocity pulse, although the spectral accelerationsof the two groups of input ground motions are the same. Under such circumstance, the response spectrum cannot fully reflect the influence of velocity pulse on the seismic responses of structure.更多还原