厦漳跨海大桥南汊主桥施工控制方法

Construction Control Method for South Main Bridge of Xiazhang Sea-Crossing Bridge

依据无应力状态控制理论,以厦漳跨海大桥南汊主桥施工为背景,研究结合梁斜拉桥标准梁段施工、边跨合龙施工、中跨合龙施工控制方法。施工中斜拉索分两次张拉,桥面板湿接缝滞后1个梁段浇筑;施工过程中以主纵梁安装、浇筑湿接缝和斜拉索第二次张拉3个阶段为重点控制工序。通过采取悬臂端压重、调整合龙口附近的斜拉索索力、对边跨支架区梁段刚性转动和竖向顶升等控制措施,使边跨合龙状态满足顺接合龙的要求。中跨采用长圆孔工具拼接板为辅的自然降温法合龙方法;根据观测结果确定夜间最大温差,计算合龙间距的变化量,进而确定工具拼接板长圆孔的尺寸及合龙梁段的实际长度。

Based on the unstressed state control theory and against the background of the con- struction of the south main bridge of Xiazhang Sea-Crossing Bridge, the construction control meth- ods for the erection of the standard girder sections, side span closure construction and middle span closure construction of composite girder cable-stayed bridges were studied. During the construction process, the stay cables were tensioned for two times, the wet joints in the bridge deck were cast one section lagging behind the girder section casting. The installation of the main longitudinal beams, the casting of the wet joints and the second tensioning of the stay cables were the three key control processes. In order to make the closure condition of the side spans meet the requirements of smooth closure, the control measures of placing counterweights on the cantilevers, adjusting the forces of the stay cables near the closure gaps, and making rigid rotation and vertical jacking-up for the girder sections in the scaffolding region of the side spans were taken. For the middle span, the natural cooling closure method assisted by the tool splice plates with long round holes was adopt- ed. The maximum temperature differences during the night were determined according to the measured data, and then the variation of the closure spacing was calculated, as a result, the di- mension of the long round holes on the tool splice plates and the actual length of the closure sec- tions were determined.