多次侧向冲击下装配式钢管混凝土框架抗倒塌性能研究

Building structures would be under multiple lateral impacts by the boulders in debris flow or rockfall which are frequent natural disasters in mountainous areas. The loss of critical structural column caused by multiple lateral impacts may trigger the whole collapse of structure. Due to the advantages of short construction period, good seismic performance and high impact resistance, concrete filled steel tube is ideal for mountainous constructions. At present, few studies focus on the performance of concrete filled steel tubular column and the anti-collapse behavior of concrete filled steel tube frame structure under multiple lateral impacts. A converted drop-weight impact tester is adopted to conduct the multiple lateral impact test on concrete filled steel tubular column and the impact-collapse combined test on prefabricated beam-column sub-structure. Finite element models based on dynamic constitutive and damage-fracture model of materials are developed to conduct numerical parametric analysis. “Unified theory” and “Component Method” are adopted to conduct theoretical analysis by developing mechanical models. The damage mechanism of concrete filled steel tubular column under multiple lateral impact loads is studied. The coupling relation between the dynamic response of column under lateral impact and catenary action in beam-joint would be clarified. The whole transformation process of anti-collapse load-carrying mechanism of frame considering the failure modes of column is revealed. The methods for the damage assessment of concrete filled steel tubular column and for the anti-collapse optimization design of prefabricated concrete filled steel tubular frame under multiple lateral impacts would be proposed. The achievement of this project will improve the protective performance and design theory of prefabricated concrete filled steel tubular frame under multiple disasters, and guarantee the safe construction of cities in mountainous area.

泥石流、落石等山地频发的自然灾害往往会对建筑结构带来多次侧向冲击作用，造成关键柱构件损坏，甚至结构整体倒塌。钢管混凝土具有施工速度快、抗震和抗冲击性能好的优点，特别适用于山区建筑。本项目针对多次侧向冲击下钢管混凝土构件及体系抗倒塌性能研究的不足，采用改进后的落锤试验机进行方钢管混凝土柱的多次侧向冲击试验和装配式梁柱子结构的冲击-倒塌联合试验，进行考虑材料动力本构和损伤断裂模型的有限元参数分析，建立基于“统一理论”与“组件法”的结构体系力学分析模型，探索多次侧向冲击下钢管混凝土柱的损伤机理，阐明侧向冲击下柱的动力响应与梁-节点悬链线效应的耦合关系，揭示考虑柱失效模式影响的框架抗倒塌承载机制转换全过程，提出多次侧向冲击下钢管混凝土柱的损伤评价方法以及装配式钢管混凝土框架抗倒塌优化设计方法。本项目的研究成果将进一步完善装配式钢管混凝土结构的多灾害防护性能及设计理论，为山地城镇建设安全提供保障。

泥石流、落石等山地频发的自然灾害往往会对建筑结构带来多次侧向冲击作用，造成关键柱构件损坏，甚至结构整体倒塌。钢管混凝土具有施工速度快、抗震和抗冲击性能好的优点，特别适用于山区建筑。目前对于钢管混凝土抗冲击性能的研究大都是针对轴向冲击或者单次侧向冲击下的柱构件，对于钢管混凝土柱在多次侧向冲击作用下的动力响应、破坏模式以及受其影响的装配式框架抗倒塌性能研究较少。本项目针对多次侧向冲击下钢管混凝土构件及体系抗倒塌性能研究的不足，进行了方钢管混凝土柱的多次侧向冲击性能和装配式钢管混凝土结构的冲击-倒塌性能的研究。本项目完成了多次侧向冲击下方钢管混凝土柱的抗冲击性能试验研究和有限元参数分析，分析了柱的冲击过程、内力发展和分布、破坏模态以及冲击次数对方钢管混凝土柱冲击力和跨中挠度的影响，在考虑影响多次侧向冲击方钢管混凝土柱动力响应的关键参数有限元分析的基础上，提出了考虑高敏感性参数的方钢管混凝土柱受反复侧向冲击的动态弯矩承载力以及剩余承载力的简化计算方法；对连续倒塌工况下装配式钢管混凝土节点中的角钢连接件和T型件的极限抗拉性能进行了试验研究、数值模拟和理论分析，提出了非加劲/加劲的T型件和角钢连接件的极限抗拉承载力、初始刚度和极限变形能力的预测公式以及荷载-位移全过程理论力学模型；对高强螺栓高温作用后静力性能及低温冲击韧性进行了研究，提出了相应的应力-应变全曲线模型并验证了Boltzmann函数；对装配式钢管混凝土结构体系中新型钢-混凝土组合梁力学性能进行研究，提出了拼接式钢-混凝土组合扁梁抗弯承载力设计方法；对考虑柱侧向冲击损伤的钢管混凝土框架抗连续倒塌性能的进行了评估，根据倒塌判断准则，单一因素不能造成经过合理设计的结构在冲击作用下的连续倒塌，结构倒塌是由是多种因素综合引起的。本项目的研究成果将进一步完善装配式钢管混凝土结构的多灾害防护性能及设计理论，为山地城镇建设安全提供保障。