钢筋混凝土框架结构抗连续倒塌性能评估简化方法研究

Based on single-degree-of-freedom displacement hypothesis, the progressive collapse-resisting capacity of reinforced concrete (RC) frame structures is studied using alternate path method and energy-based partial pushdown analysis, and a simplified assessment method of progressive collapse-resisting capacity of RC frame structures is proposed in this project. The progressive collapse-resisting mechanics and capacity of RC beams and slabs under single pillar removal are investigated based on theoretical analysis, model experiments and numerical simulation. And the simplified static response curves are presented, which demonstrate the relation between resisting force and response of RC beams or slabs at different stages of load-bearing. Then the progressive collapse-resisting capacity curves of RC beams and slabs are established based on conservation of energy principle and the simplified static response curves. Based on superposition principle and deformation compatibility condition at ultimate state, the progressive collapse-resisting capacity curves of RC frame structures are derived from the capacity curves of RC beams and slabs. Compare the capacity curves and the demand curves of RC frame structures, the progressive collapse-resisting performance can be obtained simply and accurately. And the assessment results are verified through the progressive collapse experiments of model structures and the records of progressive collapse accidents. The achievements of this project are of great significance in theory and engineering application, and they are beneficial to the progressive collapse-resisting design of RC frame structures.

本项目拟以竖向单自由度变形假设为前提，以APM和EPP相结合的分析方法为手段，研究钢筋混凝土框架结构抗连续倒塌性能的简化评估方法。通过理论分析、模型试验和数值模拟，明确在不同区域单个柱缺失条件下，钢筋混凝土梁和板构件在不同受力或变形阶段的抗连续倒塌受力机理和抗连续倒塌性能，建立其静力抗连续倒塌简化反应曲线，并基于能量守恒原理，建立其抗连续倒塌简化能力曲线。基于叠加原理，根据各个构件的抗连续倒塌简化能力曲线，及极限状态下构件间的变形协调，建立整体框架结构的抗连续倒塌简化能力曲线。将其与结构的需求曲线比较来判断结构的抗连续倒塌性能，并通过框架模型结构连续倒塌试验和已有连续倒塌事故记录进行验证。项目成果可用于不同钢筋混凝土框架结构在不同区域柱缺失情况下，抗连续倒塌性能的准确快速评估，具有重要的理论意义和工程应用价值；并可为此类结构的抗连续倒塌设计提供参考。

房屋结构在遭受偶然荷载与作用时，如发生连续倒塌，将造成人员伤亡和财产损失，是对安全的最大威胁。“9.11”事件的惨痛教训，已经引起全世界土木工程技术人员的极大震惊。因此，开展建筑结构连续倒塌研究，已引起世界各国政府和科技工作者的重视。本项目针对钢筋混凝土框架结构竖向连续倒塌的全过程、破坏模式和抗倒塌机制等问题开展系统深入的试验研究、数值模拟和理论分析。分别基于梁柱子结构（两跨梁、三根柱组成，且中柱缺失）和空间框架结构（中柱或边柱缺失），探讨了钢筋混凝土梁构件和板构件在不同竖向连续倒塌阶段的破坏模式和抗倒塌作用机制，建立了梁柱子结构和空间框架结构的抗连续倒塌力学模型，分别给出了其极限倒塌抗力的计算方法，并基于能量守恒原理，建议了钢筋混凝土框架结构抗连续倒塌性能简化评估方法。本项目研究成果对于进一步丰富与完善我国钢筋混凝土框架结构抗连续倒塌设计规程及连续倒塌评估理论提供重要的理论依据和技术支持。