长河坝水电站地下厂房顶拱镀锌压型承板施工技术

Construction Technology of Underground Powerhouse Roof Arch Galvanized Profiled Bearing Plate in Changheba Hydropower Station

长河坝水电站地下厂房顶棚为现浇钢筋混凝土叠合结构,由拱板、肋梁、拱梁三部分组成,厂房顶拱具有高差大、跨度大、安全风险大、干扰协调难度大等特点。顶棚施工中,通过计算,确定了在拱梁4 mm厚镀锌压型钢模板底部增加定型槽型钢模板作为主要荷载支撑体系,较好地解决了顶棚施工时施工干扰、承载要求。上部肋梁及板混凝土厚度较薄,入仓强度低、浇筑速度慢,质量控制难度大,通过精心施工,完成了顶棚混凝土浇筑。

The ceiling of underground powerhouse in Changheba Hydropower Station is an on-situ reinforced concrete laminated structure which is consisted of arch plate, rib beam and arch beam. The roof arch of powerhouse has features of large height difference, large span, high security risk and serious cross construction interference. Based on calculation results, the 4 mm-thick galvanized profiled steel slipform for roof arch concrete pouring is supported by external profiled steel template as main load bearing system, which solves the problems of cross construction and load bearing. As thinner thicknesses of rib beam and roof arch concrete, lower concrete transportation intensity and slower pouring speed, the pouring quality of roof arch concrete is difficult to control. Through elaborately implementation, the concrete pouring is completed.