基于支架法施工的独塔斜拉桥施工监控分析

Analysis on Construction Monitoring of Single-Tower Cable-Stayed Bridge Based on Bracing Method Construction

浙江永康南溪大桥为(108+80)m独塔双索面钢箱梁斜拉桥,全宽40 m,主梁采用正交异性板流线型扁平钢箱梁,桥塔整体造型为倒“Y”型。主梁采用支架法施工,斜拉索采用二次张拉方案。为保证施工监控顺利进行,采用有限元软件建立空间模型,对设计计算过程进行复核验证。采用自适应方法对支架法施工斜拉桥进行施工监控,分析不同施工步骤下的斜拉索索力、桥塔偏位、位移变化量、主梁应力等。结果表明:采用初张拉完成落架体系转换施工过程中,主梁受力合理,各监控值均在控制范围内;二次调索完成后,主要构件受力合理,各控制指标均处于安全范围。

The Nanxi Bridge in Yongkang,Zhejiang Province is a(108+80)m single-tower double cable-stayed steel box girder cable-stayed bridge with a full width of 40 m.The main girder adopts orthogonal anisotropic plate streamlined flat steel box girder,and the overall shape of the bridge tower is inverted“Y”.The main girder is constructed by bracing method,and the cable is tensioned twice.In order to ensure smooth construction monitoring,finite element software is used to establish a spatial model and perform a basic review of the design calculation process.The self-adaptation method is used to monitor the construction of the cable-stayed bridge by bracing method,and the cable force,tower deflection,displacement variation and stress of the main beam under different construction steps are analyzed.The results show that:during the construction process of using the initial tensioning to complete the conversion of the drop frame system,the main beam force is reasonable,and the control values are within the control range;after the completion of the second cable adjustment,the main member force is reasonable,and the control indexes are within the safety range.