独塔斜拉桥悬臂拼装施工的线形控制研究

针对斜拉桥悬臂拼装的线形控制问题,文章建立了斜拉桥结构有限元模型,基于零初始和切线初始位移法,分析悬拼钢梁段在不同施工临时荷载作用下的结构安装线形和制造线形,利用几何方法确立梁段安装夹角与制造夹角的关系。结果表明,梁体安装线形和制造线形虽存在本质上的区别,但又具备固有的内在联系。桥梁的安装线形随着施工临时荷载的不同而改变,但制造线形不会发生改变,梁段的制造夹角与其在施工中的安装夹角相等,在悬拼安装施工梁段时,按制造夹角进行拼装,施工过程中的安装线形、安装夹角以及设计成桥状态将会得到保证。桥梁结构的制造线形是无应力线形,在保证结构单元无应力状态量一定时,成桥线形和内力状态是唯一的,同时梁段的制造线形也可利用一次落架法进行求解。

This paper is to investigate the alignment control of the cantilever erection of cable-stayed bridge. A finite element model of a real bridge is established to analyze the installation alignment and fabrication alignment of the cantilevered steel girder segments under the action of different temporary construction loads based on the zero initial displacement method and tangent initial displacement method. The relationship between the installation angles and fabrication angles of the girder segments is analyzed via the geometric method. The results indicate that there are internal connections between the installation alignment and fabrication alignment though they are essentially different. The installation alignment of the bridge changes with the changing of temporary construction loads, but the fabrication alignment does not change. The fabrication angles of the girder segments are equal to the corresponding installation angles during the construction process, which means that the installation alignment, installation angles and designed bridge state can be guaranteed when the girder segments are assembled according to the fabrication angles during the cantilever installation. When the unstressed state amount of the structural element is ensured to be constant, the bridge alignment and the force state will be unique as the fabrication alignment of the bridge structure is unstressed alignment, and the fabrication alignment of the girder segments can be solved by the one-drop frame method.