万墨林  韩继云
    （中国建筑科学研究院 北京 100013）

[提要]  论述了一个大型托换工程设计施工全过程。该工程利用原有条形基础，采用空间闭合框架及组合墙梁结构作为新的传力体，受力合理，克服了新旧结构变形不协调的弊病。施工中采用机械割拆及预应力卸荷措施，保证了力的平稳转换，避免了转换时上部结构出现裂缝。实践表明，该工程使用效果良好。
[关键词]  旧房改造 托梁拆墙  闭合框架 传力途径 预应力卸荷

This paper presents a full process for design and construction by supporting and exchanging procedure to rebuild a large building project. Based on the original strip foundation of primary project, a self-enclosed frame and a combined beam-wall structure were used to form a new force-transmitting system with reasonable bearing capacity, then the uncompatible deformation occurred between the new and existing structures was avoided. In the supporting and exchanging procedure, some measures such as unloading using prestressing method, demolishing primary wall by mechanical cut-off etc. were used to ensure the stable transmission of forces in the process of demolition, the cracking on superstructure are also avioded during the exchange.
Keywords: existing building structure; reconstruction; supporting and exchanging procedure; space selfenclosed frame; force-transmission path; unloading using prestressing