长周期地震动模型化及设计地震动研究

As a special type of earthquake ground motion, the long period ground motion (LPGM) has widely attracted the attention of researchers and engineers in Structural and Earthquake Engineering in recent years, since remarkable adverse effects of LPGM on engineering structures especially the super high-rise building structures had been verified by a great deal of earthquake damages. According to the research results and engineering practice experiences in Japan, LPGM cannot be simply represented by the long period segment of earthquake response spectrum. And increasing the code specified design response spectrum values is not a satisfactory solution to the input problem of LPGM. In China,since the number of super high-rise building structures subjected to the risk of LPGM is growing rapidly, and since the quantitative description method of LPGM characteristics and determination method of design earthquake ground motion have rarely been developed, a thorough study on LPGM will be carried out in this research program using theoretical analysis, numerical computation and experimental research based on the seismic fortification philosophy and seismic design method in China. This proposed research program aims to investigate: the engineering characteristics and description method of LPGM; elastic and elasto-plastic response characteristics of super high-rise building structures under LPGM input; the ground damage patterns caused by LPGM; the calibration parameters and modeling method of LPGM; the formation method of the LPGM design spectrum that can be incorporated into the current Chinese codes; and the generation method of artificial waves of LPGM. Rational LPGM input records for the seismic analysis of super high-rise building structures will also be provided.

作为一种特殊的地震动类型，长周期地震动对于工程结构尤其是超高层建筑所产生的显著影响已经被大量震害所证实并引起结构抗震界的广泛关注。日本的研究和工程实践表明，长周期地震动不等于地震动反应谱的长周期特征，长周期地震动输入问题不能通过提高规范设计反应谱的长周期谱值来解决。鉴于我国存在一些孕育长周期地震动的地区和我国超高层建筑飞速发展的客观事实，以及目前的研究在长周期地震动特性的定量描述和设计地震动确定等方面存在的不足，结合中国的抗震设防思想和抗震设计方法，本项目通过理论分析、数值计算和试验研究相结合的方法，研究长周期地震动的工程特性及其描述方法、长周期地震动输入下超高层结构的弹性和弹塑性响应特征，分析地震动的破坏势，建立长周期地震动输入的标定参数与模型化方法，提出与中国规范相接轨的长周期地震动设计谱的表述方法，建立长周期地震动的人造波方法，为超高层建筑的抗震分析提供合理的长周期地震动输入。

长周期地震动及其对超高层建筑的影响备受关注，日本已经开展了一定研究。国内部分大型城市具备长周期地震动的孕育机制，受到长周期地震动潜在威胁，但对长周期地震动的相关研究较少。鉴于此，本课题从长周期地震动的孕育机制和定量判别出发，建立了考虑面波频散特性和尾波卓越性的长周期地震动判别准则，明确了什么是长周期地震动；然后通过振动台试验和数值模拟分析长周期地震动的工程特性，提出了频率一致脉冲族应作为长周期地震动控制地面运动特征的主要参数，为形成长周期地震动反应谱和人造波提供了依据；针对实际工程的长周期地震动输入需求，提出了将大震级远场地震危险性分析与盆地放大延时效应相结合的确定超高层建筑校验长周期地震动的方法，可为盆地区域的超高层建筑提供额外的长周期地震动验算分析；基于本课题给出的校验长周期地震动确定方法，分析了国内超高层建筑在长周期地震动作用下的结构与非结构响应特性，给出了我国超高层结构长周期地震动响应控制方法建议。