预制装配式混凝土结构抗倒塌机制和防控技术研究

The post-tensioned prestressed technique used in the connection of the prefabricated concrete frame that was constituted the whole structural system ,strengthening the beam-column joints and improving the robustness of the fabricated structure as well as preventing progressive collapse of fabricated concrete frames.Based on the collapsed experiment of post-tensioned prestressed fabricated concrete frames to simulate the sudden column loss, the test investigate the failure mechanism and the residual resistance ability of frames, as well as the alternative load paths. The research includes the collapse process internal force conversion pattern and collapsed judgment standard..The numerical model and simulation analysis were applied on the collapse of fabricated concrete frames.Research on dynamic response and the control parameters in the structure collapsed process, the collapse mechanism and alternative load paths were analyzed on both the qualitative method and the numerical analysis. The progressive collapse resistant capability of post-tensioned prestressed fabricated frame was studied on influence about redundancy index, ductility, connection property, prestressed degreescapability and etc.The collapse resistant constructional measures and design principles was suggested for fabricated concrete frames..The progressive collapse resistant theory and design principles of prefabricated concrete structures were proposed by the experimental study and theoretical analysis. The progressive collapse control measures and design methods were recommended to engineering application of prefabricated concrete structures. The research can form a new progressive collapse resistant technique for prefabricated frame, and the reference for other prefabricated structures.

将预应力技术应用于装配式混凝土框架结构的连接，构成整体受力节点和连续受力框架，提高装配式结构的鲁棒性，增强抗连续倒塌的能力。拟通过预制装配式框架倒塌试验，了解毁损结构的传力机制、局部抵抗能力和荷载替换路径，研究预制装配式混凝土结构倒塌过程中内力转换途径和倒塌判定标准。.对预制装配式框架结构进行精细化建模的倒塌数值模拟和图形仿真，研究结构在倒塌过程中的动力效应和控制参数，从定性和定量两个层面分析倒塌传力途径和倒塌机理。探讨结构冗余度、构件延性、节点连接性能、连接筋预应力度等因素与结构抗连续倒塌能力的关系。提出预制装配式框架结构抗倒塌破坏的主要措施和设计原则。.通过倒塌试验研究和理论分析，建立预制装配式混凝土框架结构倒塌破坏的防控理论和设计原则，提出抗倒塌防控措施和工程设计方法。该项目的研究可以形成预制装配式框架结构抗倒塌新技术，可为类似装配式结构提供可以借鉴的抗倒塌设计方法。

与现浇混凝土结构相比，装配式混凝土结构在意外荷载作用下，结构更容易发生连续倒塌。目前国内外学者关于装配式混凝土结构连续倒塌研究较少有人涉及。本项目在前期进行了4榀多跨多层预压装配式框架抗震性能试验研究的基础上，进行了三榀2层2跨预压装配式预应力混凝土平面框架连续倒塌试验，其中2榀拆除中柱，1榀拆除边柱。系统研究了预压装配式预应力混凝土框架结构的连续倒塌机制，探究了预应力筋拉结作用的影响，分析了当边柱或者中柱丧失竖向承载力时的荷载替代路径。通过试验研究和理论分析，提出了预压装配式预应力混凝土框架结构抗连续倒塌的基本要求、防控理论和设计原则，实现了预压装配式预应力混凝土框架结构抗连续倒塌分析的基础研究。.本项目突出的研究进展和创新性的研究成果在于：.（1）采用有粘结预应力手段加强预制装配式混凝土（PC）结构的鲁棒性，形成预压装配式预应力混凝土框架结构，预应力筋不仅作为PC结构拼装手段，在连续倒塌中还提供了水平和周边拉结作用。项目从定性和定量两方面探讨预压装配式预应力混凝土框架结构倒塌机制、传力途径和倒塌判定标准，探讨了节点连接性能、有粘结预应力筋和梁间荷载等因素对结构抗连续倒塌能力的影响，提出了预压装配式预应力混凝土框架结构倒塌破坏的防控措施和设计原则。.（2）以PC框架结构抗连续倒塌研究为切入点，为其他PC结构倒塌分析提供可以借鉴的防控倒塌措施和工程设计方法。与无粘结预应力筋相比，采用有粘结预应力筋作为PC框架节点连接较少，采用有粘结预应力筋连接的结构抗弯性能、裂缝宽度和极限强度均有较大提高，首次在抗倒塌性能试验中使用智能钢绞线实时监测，研究了有粘结预应力筋在预压装配式预应力混凝土框架结构连续倒塌中预应力的变化。