先浇盖板法在钢筋混凝土拱桥施工中的应用

Application of“Pouring-First Cover Plate Method”in the Construction of Reinforced Concrete Arch Bridge

本文以西成客运专线木河中桥施工为例,介绍一种新型的拱圈节段施工方法——先浇盖板法。钢筋混凝土拱桥施工拱圈通常分层分段浇筑,块段处于曲率较大的曲面上。拱圈合龙前,块体会因自重和模板曲率沿模板产生极大下滑力,加之块段之间有较为密集的钢筋连接,使得端头模板的支撑、拆装和凿毛变得极为费力甚至无法进行。“先浇盖板法”是一种“先弱后强”的方法,先行施工结构简易、易拆或免拆的模板支撑,利用弱支撑施作小体积混凝土盖板作为模板,再以此混凝土盖板作为具有极大承载力的模板,使后续混凝土浇筑更为安全,极大程度减少了块段模板拆除时间。

The paper takes the construction of the middle bridge of Xi’an-Chengdu High-Speed Railway across Mu River as an example,and introduces a new method of constructing arch ring segment—“pouring-first cover-plate method”.The technology of layered and segmented integral pouring is used widely in constructing arch ring segment of reinforced concrete arch bridge,in this way,the segments will be placed on the surfaces with large curvature.Before the arch rings are connected together,a great down-slide strength which is created between the segments and the template due to the large gravity of the segments and the large curvature of the template,along with the dense connection of steel bars between the segments,makes it is very hard even cannot be conducted for the head of the templates to support,dismount and rough.From gentle to tough,“pouring-first cover-plate method”supports that the segments with a simple structure which is easy to or do not need to be dismounted should be made at first,which can be a gentle support,with which small concrete cover plates are made then as templates which possess a huge bearing capacity.This new method can ensure the following pouring of concrete much safer,and greatly save the time of dismounting the segments.