基于移动模架的铁路40m简支箱梁冬期施工技术研究

以新建蒙华铁路三门峡黄河公铁两用大桥北引桥40 m预应力混凝土简支箱梁施工为背景,介绍了移动模架上混凝土箱梁冬期施工的保温、保湿技术。依据本工程移动模架的具体构造,制定了可供实施的保温、保湿方案,并通过现场埋设的测试元件对混凝土养护期间的温度以及湿度进行实时监测。现场实测结果表明,采用本文提出的保温方案,混凝土箱梁采用移动模架法冬期施工时,40 m预应力简支箱梁体的最低温度为7.6℃,具备规范要求的冬期施工条件。同时,该方案也能保证混凝土浇筑后梁体的质量,可以为今后类似工程提供参考。

Research on Construction Technology of 40 m Railway Simply-supported Box Girder in Winter Based on Movable Formwork

Taking the 40 m prestressed concrete simply-supported box girder of the north approach bridge of Yellow River rail-cum-road bridge of Sanmenxia on the Inner Mongolia- J iangxi railway as the background,the thermal insulation and the moisture retention technologies of concrete box girder construction in winter based on movable formwork frame were introduced in this paper.According to the concrete structure of the movable formwork of this project,a scheme of the thermal insulation and the moisture retention was worked out,and the temperature and humidity during the curing period of concrete were monitored in real time by the test elements embedded in the f ield .The f ield test results show that the concrete box girder is constructed by movable formwork method in winter by adopting the thermal insulation and the moisture retention scheme proposed in this paper.The lowest temperature of 40 m prestressed simply-supported box girder during winter construction is 7.6 ℃,which meets the requirements of the code.At the same time,the scheme can also ensure the quality of the post-cast concrete girder,which can provide reference for similar projects in the future.