主余震序列波下钢筋混凝土墩柱的抗震性能分析

Seismic Behavior Analysis of Reinforced Concrete Pier Columns under Main Aftershock Sequence Waves

地震主震之后常常伴随着余震,可能给结构带来二次破坏。文章以普通钢筋混凝土墩柱为研究对象,基于理论分析和二维有限元非线性动力时程计算的方法,采用修正的Park-Ang损伤指标为依据,在主余震作用下对钢筋混凝土墩柱损伤分析,研究墩柱损伤指数随配筋率的变化规律。在多种工况下结构双参数损伤指数分析表明:在主震后处于完好或者轻微损伤状态的墩柱可以不计余震的影响;在主震后处于中等损伤或严重损伤的混凝土墩柱,需要考虑余震的影响。结构抗震设计时,应计入余震的作用,结构的主余震相应大小与余震的峰值加速度和频率特征有关;对主震造成中等损伤、严重损伤和倒塌的钢筋混凝土墩柱,配筋率在一定范围内增加可明显提高结构抗主震及其余震能力。本研究为提高钢筋混凝土墩柱抗余震能力提供有力支撑。

The aftershocks often followed by the main shock may cause secondary damage to the structure. Based on the theoretical analysis and the two-dimensional finite nonlinear dynamic time history calculation method, the modified Park-Ang damage index is adopted in this paper. Under the action of main aftershock, the damage analysis of reinforced concrete pier column is carried out, and the variation law of damage index of pier column with reinforcement ratio is studied. The analysis of two-parameter damage index of the structure under various working conditions shows that: the pier column in intact or slight damage state after the main earthquake can ignored the effect of aftershock;the influence of aftershock should be considered for the concrete pier column with moderate or serious damage after the main earthquake, so the effect of aftershocks should be taken into account in the seismic design of structures, and the corresponding magnitude of the main aftershocks of the structure is related to the peak acceleration and frequency characteristics of the aftershocks;for the reinforced concrete pier columns with moderate damage, severe damage and collapse caused by the main shock, the reinforcement ratio can obviously improve the ability of structure resisting the main shock and its aftershocks by increasing the reinforcement ratio in a certain range. The conclusion of this paper provides a strong support for improving the aftershock resistance of reinforced concrete pier columns.