强柱系数基于结构易损性的抗震性能评估

Evaluation of Structural Fragility-based Seismic Performance for Strong Column Factors

摘要:

增大柱端抗弯承载力是抗震"能力设计"措施中引导钢筋混凝土框架结构形成梁铰型有利耗能机构的关键措施。本文以6层确定性钢筋混凝土框架结构为分析对象,通过结构易损性分析评估了不同强柱系数取值对钢筋混凝土框架结构抗震性能的影响。结构易损性分析表明增大柱端抗弯承载力是改善结构抗震性能的有效措施,增大强柱系数提高了结构的变形能力,使不同破坏极限状态之间形成较大的"梯度",对防止强烈地震作用下结构的突然倒塌提供了预示。结构易损性曲线对评估结构抗震性能、选用合适的目标强柱系数提供了量化标准。

Abstract:

Augmenting the flexural strength of columns in the seismic design of reinforced concrete （RC） moment resisting frames is a key measure among all the detailing procedures of capacity design, which induces the desirable beam sidesway mechanism for the structure to dissipate energy during a strong earthquake. The objective of this paper is to assess the influence of various strong column factors which is employed to perform seismic fragility analysis to the seismic performance of a 6-storey deterministic RC frame structure. Seismic fragility analyses indicate that augmenting the flexural strength of columns is an effective measure to improve seismic performance of RC frame structures. Increasing strong column factor improves the displacement capacity of structure and induces the biggish grads between the different damage limit states, which provide caution to prevent the abrupt collapse of structure during a strong earthquake. Seismic fragility curves provide the quantitative criterion for evaluating the seismic performance of structure and choosing appropriate target strong column factor.