（1 山东建筑大学土木工程学院， 济南 250101；2 山东建筑大学工程鉴定加固研究院， 济南 250013）

［摘要］通过在既有钢筋混凝土框架梁上增设后置腹板柱，改变抽柱托换后框架梁的弯矩分布图，增加弯矩峰值点数，降低框架梁的弯矩峰值； 同时和不设置腹板柱相比，设置腹板柱会大幅度降低托换后框架梁的挠度。通过模型试验，对比了托换前后梁的挠度、应变以及裂缝分布，分析了腹板柱的应力及内力变化，简述了框架柱内力变化规律。结果表明，后置腹板柱托换结构的关键阶段为框架柱抽除阶段，其内力、变形将出现突变，在考虑钢筋混凝土框架结构抗剪、侧向刚度等情况下，该加固方法可以在尽可能不降低净空的情况下实现对既有框架结构的抽柱托换，为框架结构抽柱托换提供一种技术方案。

［关键词］钢筋混凝土； 框架结构； 后置腹板柱； 抽柱托换

中图分类号：TU375文献标识码：A文章编号：1002-848X(2020)06-0039-07

Experimental study on reinforced concrete frame columns underpinned with post-installed web columns

Li Anqi1,2, Zhang Guoqiang2, Zhang Rui1, Su Sili1

（1 School of Civil Engineering, Shandong Jianzhu University, Jinan 250101, China;2 Engineering Research Institute of Appraisal and Strengthening, Shandong Jianzhu University, Jinan 250013, China）

Abstract:By adding post-installed web columns to the existing RC frame beam, the bending moment diagram of the frame beam is changed after the extraction column underpinning, the number of peaks on the bending moment diagram is increased and the maximum peak value of bending moment on the frame beam is reduced. Compared to the frame beam without the web columns, setting the web columns greatly reduces the deflection of the frame beam after the underpinning process. Through model test, the deflection, strain and crack distribution of beams before and after underpinning were compared, the stress and internal force changes of web column were analyzed, and the internal force change rule of frame column was briefly described. The results show that the key stage of post-installed web column underpinning structure is frame column extraction, for its internal force and deformation show sudden change. Considering the shear resistance and lateral stiffness of reinforced concrete frame structure, the reinforcement method can conduct the extraction column underpinning of existing frame structure without reducing the headroom as much as possible, and provides a technical scheme for the extraction column underpinning of the frame structure.

Keywords:reinforced concrete; frame structure; post-installed web column; extraction column underpinning