［摘要］托换梁受力性能及其荷载传递方式是既有砖混结构改造设计中的一个重要问题，但现行规范对此内容尚不明确。结合实际工程，利用有限元分析软件对托换梁在承重墙体拆除过程中的受力性能进行分析，并对实际结构进行全过程监测。结合有限元分析和监测结果，讨论了托换梁上部墙体的荷载传递方式。结果表明，托换梁的受力特性取决于上下结构相互变形的协调，托换梁与上部墙体形成了墙梁，而托换梁可仅考虑其自重和本层楼盖的恒、活荷载。
［关键词］砖混结构； 加固改造； 托换梁； 承重墙拆除； 有限元法； FBG监测
中图分类号：TU362.2文献标识码：A文章编号：1002-848X(2011)10-0135-04
Study on mechanical performance and load transfer mechanism of a underpinning beam  in brick-concrete structure
Shao Jianwen1, Gan Gang1， He Yong2， Mao Jianghong2（1 Architectural Design and Research Institute, Zhejiang University, Hangzhou 310027, China；2 Institute of Structural Engineering, Zhejiang University, Hangzhou 310058, China)
Abstract:The mechanical performance of the underpinning beam and its load transfer mechanism are significant but indefinite in current codes. Based on an actual project, the mechanical properties of underpinning beams were analyzed during the removal process of the bearing walls by FEM, and the real structural mechanical monitoring was also done by Fiber Bragg Grating (FBG) sensor. Through comparing the results of FEM and structural monitoring, the load transfer mechanism of the underpinning beam was discussed. The results show that the mechanical properties of the underpinning beam are mainly depending on the compatible state of deformation, and the load of the underpinning beam comes mainly from the dead and live load just one layer upon it.
Keywords:brick-concrete structure;  strengthening and modification; underpinning beam; bearing wall removal; finite element method; FBG monitoring
作者简介：邵剑文，博士，工程师，一级注册结构工程师，Email：shaojw@gmail.com。
参考文献
［1］施楚贤. 砌体结构理论与设计［M］. 北京: 中国建筑工业出版社, 1992
［2］ 浙江大学西溪校区东一教学楼改造工程质量检测鉴定报告［R］. 杭州：浙江省建设工程质量检验站有限公司,2009
［3］ GB50010—2010混凝土结构设计规范［S］. 北京：中国建筑工业出版社，2011.
［4］ GB50003—2001砌体结构设计规范［S］.北京：中国建筑工业出版社，2001.