邻近既有线悬臂梁冬季施工保温措施研究

Study on Thermal Insulation Measures for Cantilever Beam Construction in Winter Near Existing Railway

陇漳高速公路渭河特大桥第三联采用41.4 m+70 m+41.4 m连续刚构跨越陇海铁路,采用转体法施工。上部结构采用悬浇法施工,由于梁体平行于铁路施工距离较近,施工过程存在较多限制及不便,安全风险高,且冬季施工传统保温措施要求高、难度大。为保证悬臂梁冬季施工质量及陇海线运营安全,对大量试验数据进行综合分析,提出梁体采用蒸汽养生及阻燃聚氨酯泡沫涂层的保温措施可以达到预期效果,既施工方便,又降低安全风险。本文以具体工程实例进行论述,为冬季施工提供参考。

The third joint of the Weihe River Bridge of Longxi-Zhangxian Expressway is constructed by 41.4 m+70 m+41.4 m continuous rigid frame across the Lanzhou-Lianyungang Railway,with the rotating construction method,and the superstructure is constructed by the cantilever casting method.As the construction distance of the beam body parallel to the railway is relatively close,there are many restrictions and inconveniences in the construction process,and the safety risk is high,and the traditional thermal insulation measures for winter construction are high and difficult.In order to ensure the quality of cantilever beam construction in winter and the operation safety of Lanzhou-Lianyungang Railway,a large number of test data are comprehensively analyzed,and it is proposed that the insulation measures of steam curing and flame retardant polyurethane foam coating can achieve the expected effect,which is convenient for construction and reduces the safety risk.In this paper,the concrete engineering examples are discussed to provide a reference for winter construction.