(北京市设备安装工程公司，北京100039)

［摘要］在扬州体育馆工程中，比赛馆屋架钢结构的安装工程采用脚手架支撑体系，屋架结构完成后为空间结构，因此施工阶段的结构支撑工况与最终结构受力情况不同。为此必须在屋架结构安装完成后，进行受力体系的转换，使屋架结构受力情况与实际受力相同，该文对此卸荷过程进行了介绍。

［关键词］钢结构；大跨度空间管桁架；临时支撑体系；沉降值；预起拱

In the construction of Yangzhou Gymnasium project, scaffold support system is used in the installation of competition stadium roof steel structure. The structure is spatial structure after the installation of roof. The internal force of support during construction is different from the final force. So after the installation of roof, engineers take some unloading techniques to converse the force system, which makes the internal force of the roof match actual situations. In this article, the author introduces the unloading process.