（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］针对砌体结构房屋加固改造中拆墙托换的问题，提出了一种新型的托换结构体系。首先对拟拆墙体上部采用外包角钢加固形成钢-砌体组合托梁，然后对上层墙体采用钢筋网聚合物砂浆面层进行加固，组合托梁与加固后的上层墙体形成组合墙梁结构，形成托换结构体系。通过对4个试件的试验研究得到：该托换结构的受力机理与砌体墙梁结构相同，可简化为拱结构，加固后的上层墙体通过拱作用将荷载向两端支座传递，角钢和钢筋网水平钢筋为拉杆，减小了组合托梁的内力，提高了构件的承载力。托梁端部和上层墙体端部均设置构造柱，保证了上层墙体内钢筋网水平钢筋的锚固，避免了托梁支座处砌体局压破坏。原墙体内是否有圈梁和角钢大小对托换结构的承载力有一定影响。该托换体系墙体最终产生斜压破坏，墙体的抗剪承载力可按照砌体墙梁墙体抗剪计算公式计算，但计算结果偏保守。

［关键词］加固改造； 托换结构； 钢-砌体组合梁； 墙梁； 托梁

中图分类号：TU398.9文献标识码：A文章编号：1002-848X(2020)06-0046-05

Study on application of steel-masonry composite wall beam structure in transformation underpinning of masonry structure buildings

Zhang Yuming1,2， Guo Donghui1， Fang Xiaopeng1， Zhao Kaozhong1,2

(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:A new underpinning structural system was proposed for removing walls for underpinning in the reinforcement and transformation of masonry structure buildings. Firstly, the top part of the wall which would be moved was strengthened with external angle steels to form steel-masonry composite underpinning beams, and then the upper wall was strengthened with steel wire web-polymer mortar layer. The composite underpinning beam and the strengthened upper wall made up a composite wall beam structure, forming the underpinning structural system. The static test of four specimens was carried out. The test results show the mechanism of the underpinning structure  is the same as the wall beam in masonry structures and  can be simplified as arch structure. The strengthened upper wall transfers the load to the two supports by arch effect. The angle steels and the horizontal reinforcements are tensile bars to reduce the internal force of the composite underpinning beam and improve the bearing capacity of the member. The structural columns which are arranged at the end of the underpinning beam and the upper wall provide a good anchor for the horizontal reinforcements of the upper wall and can avoid the local pressure damage at the two supports of underpinning beam.The size of ring beam and angel steel in the wall has a certain influence on the bearing of the underpinning structure.  The final failure mode is the diagonal-compression failure. The shear bearing capacity of the wall in this new style wall beam can be calculated in accordance with wall beam of masonry structures, but the calculation result is conservative.

Keywords:reinforcement and transformation; underpinning structure; steel-masonry composite beam;wall beam; underpinning beam

*国家重点研发计划项目（2017YFC0702900）。

作者简介：张玉明，博士，副教授，硕士生导师，一级注册结构工程师，Email：13808920620@163.com。