满堂支架在四线大桥现浇施工中受力与变形规律研究

Study on the Stress and Deformation Law of Full Space Support Method in the Cast-in-Situ Construction of Four-Lane Bridge

本文基于满堂支架现浇箱梁施工工法,结合有限元模型,对满堂支架在四线大桥现浇施工中受力与变形规律进行研究。梁体支架选择WDJ型碗扣式多功能脚手架,在对其予以局部加密基础上,构建相应箱梁现浇支架模型,将监控参数识别与梁段精准匹配合并,以缩短安装周期。由支架变形监测数据可知,主梁前端纵向变形为34.6 mm,支架前端变形量为29.2 mm,主梁与支架间相对变形约为5.4 mm;究其原因为施工预应力张拉过程中,主梁与支架出现相对滑移现象。支架前端1、2排区域顶部,其摩擦系数介于0.215~0.242之间,接近支架与主梁多层接触所产生的最小值。主梁形态的改变导致支架受力重新分布,致使主梁与下方支撑体系之间产生多层摩擦效应。

Based on the construction method of cast-in-situ box girder of full space support and combined with finite element model,the force and deformation law of full space support method in the construction of four-lane bridge is studied.The beam body bracket adopts WDJ type bowl buckle type multi-functional scaffolding,and after locally encrypting the full space support,the box girder cast-in-place bracket model is formed,and the monitoring parameter identification is accurately matched and merged with the beam segment to shorten the installation period.The deformation monitoring data of the bracket shows that the value of longitudinal deformation at the front end of the main beam is 34.6 mm,the value of the deformation at the front end of the bracket is 29.2 mm,and the relative deformation between the main beam and the bracket is about 5.4 mm.The reason is that there is a relative slippage between the main beam and the support in the prestressed tension stage.The friction coefficient at rows 1 and 2 of the front end of the bracket is 0.215-0.242,which is close to the minimum value generated by multi-layer contact between the bracket and the main beam.The deformation of the main beam will cause the force redistribution of the bracket,and there will be a multi-layer friction effect between the main beam and the support system under the main beam.