（中南林业科技大学土木工程学院， 长沙 410004）

［摘要］通过三榀单层双跨体外预应力混凝土框架结构试验研究，对比分析了中柱失效后体外预应力混凝土框架与非预应力混凝土框架连续倒塌的破坏全过程。研究结果表明：体外预应力混凝土框架的连续倒塌过程分为梁机制与悬链线机制两个阶段，梁机制阶段的倒塌抗力由体外预应力筋的“悬索效应”与框架梁的正截面抗弯承载力共同提供，约为非预应力混凝土框架的1.5～2.6倍； 悬链线机制阶段的倒塌抗力由体外预应力筋和普通钢筋的“悬索效应”共同提供，约为非预应力框架的3.5～6.1倍。体外预应力筋的“反拱”作用将抑制框架压拱机制的形成。直线布筋的框架倒塌极限变形约为非预应力框架的1.5倍； 折线布筋的框架倒塌极限变形与非预应力框架基本一致。结合试验结果与现象对试验模型框架受力过程进行了分析，推导出了基于结构变形的体外预应力混凝土框架倒塌抗力计算公式，计算结果与试验结果吻合良好，可用来预估考虑悬链线作用的体外预应力混凝土框架的倒塌极限抗力。

［关键词］体外预应力混凝土框架； 连续倒塌； 静力试验； 悬链线作用； 预应力

中图分类号：TU398-7文献标识码：A文章编号：1002-848X(2020)23-0077-09

Research on collapse resistance performance of external prestressed concrete frame

FAN Yunlei, WANG Jie, PENG Yifan

(College of Civil Engineering, Central South University of Forestry and Technology, Changsha 410004, China)

Abstract:Through the experimental research on the external prestressed concrete frame structure of three single-story two-span, the failure process of the progressive collapse of the external prestressed concrete frame and the non-prestressed concrete frame after the failure of the middle-column was compared and analyzed. The research results show that the progressive collapse of external prestressed concrete frame is divided into two stages: the beam mechanism stage and the catenary mechanism stage. The collapse resistance with beam mechanism is jointly provided by the “catenary effect” of external prestressing tendons and ultimate moment capacity in normal section of frame beam, which is about 1.5～2.6 times that of the non-prestressed concrete frame. The collapse resistance with catenary mechanism is provided by the "catenary effect" of external prestressing tendons and non-prestressed tendons, which is about 3.5～6.1 times that of non-prestressed frame. The "anti-arch" effect of external prestressing tendons will restrain the formation of compressive arch action. The collapse limit deformation of the frame with linearly arranged tendons is about 1.5 times that of the non-prestressed frame. The collapse limit deformation of the frame with tendons arranged in the broken line is basically the same as that of the non-prestressed frame. Based on the test results and phenomena, the force process of the experimental model frame was analyzed, and the formula of the collapse resistance of external prestressed concrete frame based on the structural deformation was deduced. The calculation results are in good agreement with the experimental results and can be used to predict the ultimate resistance of external prestressed concrete frame considering the role of the catenary action.

Keywords:external prestressed concrete frame; progressive collapse; static test; catenary action; prestressing

*国家自然科学基金青年基金项目（51308556）。

作者简介：范云蕾，博士，副教授，硕士生导师，Email:fanyunlei@163.com。