基于梁板子结构的爆炸下钢结构建筑连续倒塌研究

Steel structures are most widely used in tall building structures in China, but it still lacks in-depth research on progressive collapse of these structures under blast, and the corresponding codes for progressive collapse resistance design of buildings are not mature enough. In this project, in order to address the questions that the widely used alternate path method cannot reflect the real interaction process between the blast load and the structure members, the progressive collapse of steel structures under internal blast will be studied using the composite subassemblies and steel frames as the subjects. Based on the research on the behavior and damage evolution of subassemblies, and co-operative actions between steel beams and slabs, the development of flexural and catenary actions, the damage mechanism and progressive collapse mechanism of composite subassemblies under internal blast will be revealed, and an equivalent quantitative relationship between the blast loads and collapse resistances will be established. Based on this, an equivalent method that simulates the damages of steel beams and slabs will be studied, and an efficient method for progressive collapse analysis of steel structures under blast will be established. Based on this method, the progressive collapse mechanism of the steel frame under internal blast will be studied, and an efficient method for prediction of the progressive collapse will be proposed. The research results can be used as the theoretical basis and technological supports for progressive collapse resistance design of steel structures subjected to explosion.

我国的高层建筑常采用钢结构作为主体结构，但对爆炸荷载作用下钢结构连续倒塌的研究还不够深入，相应的抗倒塌设计规范还不够成熟。本项目拟针对目前研究中普遍采用的替代传力路径法存在不能反映爆炸荷载与结构间相互作用等问题，以钢框架梁板子结构及框架结构为研究对象，系统开展室内爆炸荷载作用下钢结构建筑的连续倒塌研究。通过对室内爆炸作用下子结构行为响应、损伤演化过程以及抗倒塌过程中梁板协同工作关系、梁和悬链线等机制发展转换情况的研究，揭示室内爆炸荷载作用下梁板子结构的损伤机理及抗倒塌机制，建立爆炸荷载与子结构最大抗力间的等效量化关系。在此基础上，通过对爆炸下梁板损伤等效模拟方法的研究，建立考虑爆炸作用的钢结构连续倒塌高效分析方法，揭示室内爆炸荷载作用下钢结构建筑的抗倒塌机制并提出倒塌快速预测方法。研究成果可为爆炸下钢结构建筑抗倒塌设计提供理论基础与技术支撑。

爆炸荷载作用下钢结构建筑的连续倒塌问题是当前国内外重点关注的研究课题。本项目基于中尺度受限空间燃爆实验及数值模拟得到的爆炸荷载，研究了钢筋混凝土板及钢框架梁柱子结构在爆炸下的行为响应和损伤演化过程，提出了爆炸下抗倒塌性能影响程度的评估方法；基于梁板子结构落锤冲击试验及精细化数值模拟，系统研究了钢框架梁板子结构在爆炸下的损伤机理及爆炸作用对抗倒塌过程中各机制峰值承载力的影响规律，揭示了爆炸下梁板子结构的抗倒塌机制，建立了子结构抗力折减系数与爆炸荷载间的量化关系，并开展了梁板子结构与板、梁柱子结构抗倒塌性能的对比研究；通过对子结构抗力折减系数的修正优化，提出了爆炸下梁板损伤简化模拟方法，开发了考虑爆炸下构件损伤的钢框架倒塌高效分析模型，研究了不同参数条件下的钢框架连续倒塌规律，揭示了爆炸作用下钢框架结构的抗倒塌机制，并提出了钢框架结构连续性倒塌的快速评估预测方法。研究成果可为高层钢结构建筑抗爆安全性的提升提供理论技术支撑。