预制UHPC壳局部增强装配式混凝土框架结构的抗震性能和设计方法

Connecting zones in precast concrete frames are easy to be damaged, affecting the structural performance of the whole structure significantly. Thus, the development of precast concrete frames is hindered to some degree. Ultra-high performance concrete (UHPC) is scarcely used in architectures for the inherent characteristics. In order to break through the restriction of these problems, a novel precast concrete frame strengthened locally by prefabricated UHPC shells is proposed, of which the prefabricated UHPC shells are used in the regions bearing the maximum forces. Firstly, pull-off tests and theoretical analysis are conducted to research the shear performance between precast UHPC and conventional monolithic concrete. The theoretical model of shear capacity vs slip between the interface is expected to be put forward. Then, structural performances of connections enhanced locally by precast UHPC shells are studied by theoretical analysis and seismic tests, aimed at establishing the mechanical analysis models of the connections. Finally, the seismic responses of the precast frame structures based on precast UHPC shells are researched and discussed by numerical analysis. As a result, the design method of the proposed structure will be developed. In this project, the structural form of precast frames is innovated to exploit the advantages of UHPC and precast techniques, promoting and improving the development of precast concrete frames in China. The theoretical mechanical models of composite structures, consisted of UHPC and conventional concrete, are proposed to enrich the missing knowledge.

装配式混凝土框架结构在构件连接区域易发生局部破坏，大大影响结构性能，阻碍其发展；超高性能混凝土（UHPC）由于其自身特点，难以在建筑结构中大量应用。为突破上述问题的制约，本项目拟提出并研究一种预制UHPC壳局部增强装配式混凝土框架结构，该结构在连接区域受力最大处设置预制UHPC壳。首先，针对预制UHPC和后浇普通混凝土接合面开展抗剪性能试验和理论研究，提出全过程抗剪承载力-滑移理论模型。然后，开展预制UHPC壳局部增强预制构件连接的理论分析和抗震性能试验，研究受力机理，掌握构件连接的滞回特性，确定关键参数，提出构件连接的力学计算理论模型。最后，通过数值模拟手段研究该整体结构的地震响应规律，形成结构设计方法。本项目创新装配式混凝土框架结构形式，实现预制技术与UHPC的优势互补，推动我国装配式混凝土框架的提升和发展，同时形成UHPC与普通混凝土组合结构力学理论模型，补充当前的研究不足。

装配式混凝土框架结构在构件连接区域易发生局部破坏，大大影响结构性能，阻碍其发展；超高性能混凝土（UHPC）由于其自身特点，难以在建筑结构中大量应用。为突破上述问题的制约，提出并研究一种预制UHPC壳局部增强装配式混凝土框架结构，该结构在连接区域受力最大处设置预制UHPC壳。主要研究内容和结果包括：1）开展了22个不同形式的UHPC和普通混凝土接合面试件的抗剪性能试验研究，提出了气泡膜结合面全过程抗剪承载力-滑移模型；2）开展了环形预制UHPC壳局部增强预制混凝土柱脚连接低周反复试验，试验加载了包括对比试件在内的6个足尺试件，并进行有限元分析研究，掌握了该形式柱脚连接的抗震性能；3）开展了6个足尺小型预制UHPC壳局部增强装配式梁柱连接试件的低周反复试验加载，结合有限元分析研究，优化了构造形式，掌握了新型梁柱连接的抗震性能；4）根据截面分析和构件变形分解计算方法，研究环形预制UHPC壳局部增强预制混凝土柱脚和U形预制UHPC壳梁端局部增强的预制构件梁柱连接的骨架曲线模型，并结合刚度关系，形成了恢复力模型，以此形成了相关结构设计方法和建议。研究成果可望应用于装配式混凝土框架结构中，进一步提高结构性能，便于震后修复，促进装配式混凝土的提升和发展。