摘要
建筑结构的破坏具有离散性和系统性的特点,该特性决定结构抗地震倒塌的研究需多参数、多层次考虑问题。文章结合结构地震倒塌破坏模式的研究,完成了三榀钢筋混凝土平面框架的低周反复荷载试验,通过对模型框架破坏过程、破坏形态、滞回耗能及刚度退化的分析,探讨轴压比和梁柱线刚度比对RC框架结构抗震性能的影响,以期为后续结构地震倒塌破坏机理的研究提供参考。分析结果表明:降低结构的竖向荷载和梁柱线刚度比,有利于梁端塑性铰的充分发育,从而更易实现理想的"梁铰"破坏机制;试验框架的最终破坏是由底层柱下端塑性铰充分发育后、混凝土突然压溃所致,底层构件的耗能能力得到充分发挥,而中间层构件和顶层构件所耗散的能量较少;KJ-2的峰值荷载及极限荷载比KJ-1的峰值荷载及极限荷载分别大约9.9%和8.7%、等效黏滞阻尼系数比KJ-1大约16.5%,但位移延性系数比KJ-1小约57.1%,说明增大结构的竖向荷载可以提高其承载能力及耗能能力,但会降低延性及变形能力,同时,一定程度地增大竖向荷载,有利于强化结构的初始抗侧刚度,延缓刚度退化趋势,但在层间位移角较大情况下P-Δ效应的影响凸显;结构梁柱线刚度比的增大可以提高其耗能能力,但会降低结构的承载能力、延性及初始抗侧刚度;对于轴压比及梁柱线刚度比较小的"梁铰"结构,临近倒塌时的层间位移角可达1/25,此时结构仍具有一定的竖向承载能力。
The collapse of building structure is characterized with discrete and systematic features, indicating that the study of seismic collapse of buildings shall be conducted from multi-parameter and multi-level aspects. Three 1/3-scale models of three-story, three-bay reinforced concrete plane frames were fabricated and tested under low-cycle loading, based on the research of structural collapse and failure mode. The effects of axial compression ratio and beam-to-column linear stiffness ratio on the seismic performance of RC frame structures were discussed through the analyses on failure process, failure pattern, energy dissipation capacity and stiffness degradation of model frame, which provides references for further researches. Test results indicate that the ideal beam-hinge failure mechanism of RC frame structures can be easily attained by reducing vertical axial force and beam-to-column linear stiffness ratio, which shall be beneficial to the full development of plastic hinges at beam ends. The ultimate failure of test frames was caused by the sudden crushing of concrete owing to the full development of plastic hinges at column bottoms in the first floor, and the energy dissipation capacity of components in the first floor was fully utilized, while those of second floor and third floor were relatively less.The peak load, ultimate load and equivalent viscous damping coefficient of KJ-2 were about 9.9%, 8.7% and16.5% larger than those of KJ-1 respectively, but the displacement ductility coefficient of KJ-2 was about 57.1%smaller than that of KJ-1, indicating that the bearing capacity and energy dissipation capacity of a structure can be increased by increasing its vertical load, but the ductility and deformation capacity may be decreased.Meanwhile, increasing the vertical load to some extent shall be beneficial to enhancing the initial lateral stiffness of structures and postponing the structural stiffness degradation, but the P-Δ effect appears to be prominent in the case of large inter-story drift angle. By increasing the linear stiffness ratio of RC frame structures, the energy dissipation capacity can be enhanced, but the bearing capacity, ductility and initial lateral stiffness of structure may be reduced. For the beam-hinge structure with small axial compression ratio and beam-to-column linear stiffness ratio, the inter-story drift angle of structure when approaching to collapse can reach 1/25, and the structures still possess a certain load-bearing capacity at this stage.
作者
刘伯权
苏佶智
马煜东
奚凯麟
邢国华
Liu Boquan;Su Jizhi;Ma Yudong;Xi Kailing;Xing Guohua((Chang'an University, Xi'an 710000, China))
出处
《土木工程学报》
EI
CSCD
北大核心
2019年第8期24-39,共16页
China Civil Engineering Journal
基金
国家自然科学基金（51578077）
陕西省国际科技合作与交流计划项目（2016KW-056）
关键词
钢筋混凝土框架结构
拟静力试验
轴压比
梁柱线刚度比
reinforced concrete frame structure
pseudo-static test
axial compression ratio
beam-to-column linear stiffness ratio
