主余震序列型地震动作用下RC框架结构损伤耗能研究

Damage energy dissipation analysis of RC frame structure under mainshock-aftershock sequence-type ground motions

强震发生后通常伴随着余震,余震的发生会加重结构损伤甚至引发倒塌。为了量化研究主余震序列型地震动对结构损伤的影响,以一栋3层钢筋混凝土框架结构为研究对象,选取了10条实际的主余震记录作为地震动输入,采用ABAQUS非线性有限元软件对该框架结构进行非线性动力时程分析,并依据结构局部和整体损伤耗能指标来评价主余震序列型地震动对框架结构累积损伤的影响。研究结果表明:序列地震会加剧结构底层柱的局部损伤耗能,特别是对底层中柱的影响更加明显;序列地震作用下的结构整体损伤耗能平均值相对于单主震作用下增加约30%;当余震与主震的第一周期谱加速度指标的比值Sa(T_1)_(余震)/Sa(T_1)_(主震)较大时,序列地震对结构损伤需求的影响更为显著。

Strong earthquakes are always followed by aftershocks which could aggravate the structural damage or even induce collapse. To quantify the effect of mainshock-aftershock sequence-type ground motions on the structural damage, a 3-story reinforced concrete (RC) frame structure is taken as the research object in this paper. For this purpose, a total number of 10 as-recorded mainshock-aftershock seismic records are selected as seismic input, and nonlinear dynamic time history analysis of the structure subjected to the seismic sequences is performed using ABAQUS software. In addition, both the local and global damage energy dissipation indices are used. The results indicate that sequence-type ground motions have a significant influence on the bottom columns, especially the middle columns, in terms of local damage energy dissipation. The global damage energy dissipation index increases by approximately 30% due to the effects of the aftershocks. When the ratio of the first-order-period spectral accelerations between the aftershock and mainshock is larger, the aftershock will induce a more demand on the structural global damage energy dissipation.