九运会体育馆钢屋盖预应力拉索施工技术

Construction Technique for Prestressed Cable-Braces in the Steel Roof of Guangzhou Gymnasium

广州体育馆是新建成的第九届全国运动会用大型室内运动场 .主场馆平面由两个对称的弓形组成 ,纵轴长 16 0m ,横轴长 110m .屋面板全部为透光阳光板 .屋盖为空间钢结构 ,在大跨度钢桁架之间采用了施加预应力的拉索支撑 .与采用型钢支撑相比 ,拉索支撑内无压力、美观 ,而且有利于运动场采光 ,是一种新颖的先进结构 .由于施加预应力 ,后批张拉时会对先行张拉的钢索内力有影响 .屋架安装用支撑的拆除也会对已经张拉完成的钢索内力有影响 .于是选择合理的钢索体系以及如何建立合适的钢索永存拉应力 ,对于本工程的施工既重要又是难点 .

Guangzhou cymnasium is a newly_built large_scale indoor sportground for the Ninth National Games. Its plan consists of two symmetrical bow_shaped plans which have a longitudinal axis of 160 m and a transverse axis of 110 m. All roof_slabs are made of sunlight_slabs through which sunshine can go into the interior of the gymnasium. The roof is a space steel structure in which pre_tensioning cables, as a brace between steel trusses, are used. Compared with a structural_steel shape_brace, such a cable_brace is beautiful, without compression in it and good for sunlight of the gymnasium. So it is a novel and advanced structure. Because a pre_tensioning force is exerted on such a prestressed cable brace, prestress in a previously tensioned cable will be affected by tensioning cable afterwards and also by removing a vertical brace used for erecting a main truss. Therefore, it is an important and difficult problem to find a suitable cable system and to erect necessary permanent values of tension stresses in it. In this paper, techniques about construction and examination of the prestressd cable_braces used in this project are introduced.