现浇楼板对钢筋混凝土框架结构倒塌模式的影响

地震作用下钢筋混凝土框架结构通常呈现弱柱型破坏模式而倒塌。针对其破坏特征，将钢筋混凝土框架结构离散为“板-柱”和“梁-柱-节点”体系，结合块体间碰撞作用的冲量模型，基于离散单元法建立考虑构件间碰撞作用的钢筋混凝土框架结构空间倒塌反应计算机仿真系统，并通过2个框架结构模型的倒塌试验对其进行了验证。利用计算机仿真系统模拟分析了现浇楼板对钢筋混凝土框架结构倒塌模式的影响。结果表明：考虑块体间碰撞作用的框架结构倒塌仿真系统可以真实再现地震作用下框架结构的倒塌过程和废墟堆积情况；考虑楼板影响时，强柱型框架结构可能会出现弱柱型倒塌，局部倒塌型框架结构则可能不倒或呈弱柱型倒塌；框架结构抗震设计或评定中应充分考虑现浇楼板对框架抗震性能的影响。

Effect of cast-in-situ floor slab on collapse modes of RC frame structures under earthquake

RC frame structures severely damaged, even collapsed in weak column mode were well documented during the past post-earthquake investigations. A collapse simulation system for RC frame structures based on discrete element method was established by discretizing a structure into slab-column discrete system or beam-column-joint discrete system according to the failure characteristic of RC frame structures, and revised with consideration of collision behaviors among fractured components with impulse-based impact model between concrete blocks. The proposed collapse simulation system was effectively verified with two collapse experiments on small-scale frame models. Further simulation was carried out to explore the effect of cast-in-situ floor slab on the collapse performance of RC frame structures under earthquake. The results indicate that, the whole collapse process of a frame structure including debris stacking can be visually simulated by the collapse simulation system with consideration of collision actions among fractured components; due to the effect of cast-in-situ floor slab, RC frame structures with strong column collapse mode may turn into weak column collapse mode, and RC frame structures with partial collapse mode may not collapse or be in weak column collapse mode; the effect of floor slab should be well considered in structural design or appraised for RC frame structures under earthquakes.