不同抗震设防RC框架结构抗倒塌能力的研究

STUDY ON THE COLLAPSE-RESISTANT CAPACITY OF RC FRAMES WITH DIFFERENT SEISMIC FORTIFICATION LEVELS

地震作用下建筑结构的抗倒塌能力是基于性能抗震设计的核心目标。建筑结构需要足够的抗倒塌安全储备,以避免大震或特大地震的倒塌破坏。我国现行抗震设计尚缺乏大震抗倒塌定量设计方法和抗地震倒塌能力的定量评价指标。该文基于IDA的结构抗倒塌易损性分析方法,定量评价了按现行规范设计的不同抗震设防烈度多层RC框架结构的抗地震倒塌能力和抗倒塌安全储备,讨论了轴压比和倒塌机制对RC框架结构抗地震倒塌能力的影响,并根据分析结果提出了有关建议。

Collapse safety is the most important objective of performance-based aseismic design.Buildings should have an enough safety margin to avoid collapse subjected to a severe or mega earthquake.However,current Chinese seismic design code for building structures does not provide an explicit design or a quantitative evaluation method for collapse-resistant capacity.In this paper,the collapse-resistant capacities and safety margins against collapse of multi-story reinforced concrete（RC） frames with different seismic fortification levels are quantitatively evaluated,with a collapse fragility analysis based on an incremental dynamic analysis（IDA）.The influences of the axial compression ratio and the failure mode to the collapse-resistant capacity are discussed,and suggestions are proposed to improve the current design.