20m大跨预应力空心板先张法施工技术

Pre-tensioned Construction Technology of Large-span Prestressed Hollow Slab with 20m Span

邢威高速公路在K31＋300～K51＋150的主线跨线桥上部结构为20m跨大型预应力空心板。介绍预应力空心板先张法、集中预制施工工艺。研究预应力钢筋张拉采用的单张整放方式以及砂箱四次放张工艺。同时阐述空心板外模采用大块钢模、内模采用抽拉式钢模及胶囊芯模、采用人字桅杆配合卷扬机架设的安装方法。实践证明，该方法施工机械简单、施工速度快、经济效果明显。

Large-span prestressed hollow slab is adopted in the upper part of main flyover with K31 ＋ 300 - K51 ＋ 150 in Xingtai-Weihai Highway. The pre-tensioned method and centralized pre-fabrieation in the factory are introduced in this paper. Besides, one end of tension with whole putting and four-time tension of the flask are studied. The technologies of hollow slabs are outlined such as large outer steel fonnwork, extraetion-tension inner steel formwork and inner capsule-core formwork, installation of hoist with biped mast. The results show that its method is available with simple machine, fast construction and good economic benefit.