远场地震动频谱特性与超高层结构响应相关性研究

Correlation between spectral characteristic of far-field ground motion and seismic response of super high-rise building

远场长周期地震动频谱特性对超高层结构的动力响应影响尤为显著,目前对其频谱特性研究很少。利用ANSYS软件建立超高层建筑弯-剪耦合连续化简化模型(Miranda模型),选取19条远场长周期地震动波,对不同高度结构进行时程分析,改变结构阻尼,得到结构顶点位移和最大层间位移。研究T_(PA)、T_(PD)、T_(PV)、T_c、T_g、T_g、T_(mh)、T_(mf)等8个频谱特性指标分别与结构顶点位移和最大层间位移的相关性随基本自振周期和阻尼比的变化规律。研究结果表明:T_(mh)与顶点位移相关性最强,最高可达0.75以上,建议采用T_(mh)指标作为频谱特性指标来表征超高层建筑的顶点位移;T_(mf)指标与层间位移相关性在各周期段内较稳定,保持在0.65左右,建议采用T_(mf)指标作为频谱特性指标来表征超高层建筑的最大层间位移。

Spectral characteristic of far-field long-period ground motion has particularly significant influence on the dynamic response of long-period structures, and there have been few study about it. In order to analyze the correla- tion coefficients between the eight spectral characteristic indices （ TPA, TPD, TOV, Tc , Tg ,Tg, Tmh, Tmf ） and the top displacement, the maximum story drift as well as their changing rule with fundamental natural period and damping ratio, ANSYS software was used to build the simplified flexural-shear coupling beam model （ Miranda model） of su- per high-rise buildings. 19 far-field long-period ground motions were input and change the structural damping, the top displacement and the maximum story drift were obtained. The results show that the correlation between Tmh and top displacement can be over 0.75, so the Tmh is recommend to characterize the top displacement of high-rise build- ings. The collection of Tmf is stable in the whole period, and remain about 0.65, so the Tmf is recommend to char- acterize the maximum story drift of high-rise buildings.