近场地震作用下 RC 框架鲁棒性分析

摘要

基于地震作用下结构的受力的特征，提出构件易损性及重要性系数的改进计算方法，以此定量分析结构在近场地震作用下的鲁棒性。通过分析比较 RC 框架在近场有无速度脉冲两组地震动，不同强度下的构件易损性系数、重要性系数和结构鲁棒性系数，揭示了 RC 框架结构在近场地震作用下抗连续倒塌鲁棒性的特点，并依此提出增强结构鲁棒性的措施。研究表明：相比于层间位移角等结构的整体响应指标，鲁棒性则更能具体地反应出结构在近场地震下的状态；与近场无速度脉冲型地震动相比，速度脉冲型地震动会对结构构件的易损性与重要性造成更为明显的影响，从而降低了整体结构的鲁棒性，对结构安全存在更为不利的影响。%Based on the mechanics characteristics of structure subjected to seismic action,an improved calculation method for the coefficients of vulnerability and importance of constructional element was proposed in order to analyze the structural robustness under near-field earthquake.Two groups of ground motions,namely the motions with and without velocity pulses,were applied to a reinforced concrete frame structure and the coefficients of vulnerability,importance and robustness of elements were compared under different seismic intensities,aiming at revealing the characteristics of structural robustness representing the ability of resisting progressive collapse.Some correspondent measures to enhance the structural robustness were proposed.The results show that the robustness can reflect the state of structure subjected to seismic action better than other response indexes such as the story-drift angle.The seismic action with velocity pulses has more evident impact on the vulnerability and importance of structure than that without velocity pulses and can reduce the structural robustness,causing a more adverse effect on the structural safety.