沁伊黄河大桥主梁施工方案研究

Construction Scheme of the Main Girder of Qinyi Yellow River Bridge

沁伊黄河大桥主桥采用85m+25×100m钢混组合梁,主梁采用整体槽型箱组合截面,主梁总高4.8m,桥面总宽16.56m。为了减少对河道的施工干扰,经综合比选,主桥施工时不在水中设置临时墩,采用无支墩顶推法施工。主梁采用多点自平衡分联顶推工艺,标准步距0.35m。钢主梁顶推到位后,分别对中支点和边支点设置20cm和25cm的预抬升,再按“皮尔格”法进行混凝土桥面板架设。计算结果表明,顶推过程中主梁各关键部位受力及稳定性均满足要求。

85m+25×100m steel-concrete composite beams with an integral groove box composite section are adopted in the main bridge of Qinyi Yellow River Bridge.The total height of the main girder is 48m,and the total width of the bridge deck is 1656m.In order to reduce construction interference on the river channel,after comprehensive comparison,temporary piers are not set in the water during construction of the main bridge,and the unsupported pier top pushing method is adopted for construction.The main girder adopts a multi-point self balancing top pushing process and a segmented top pushing process,with a standard step distance of 035m.After the steel main girder is pushed into place,pre-lift values of 20cm and 25cm are set for the middle and edge support points respectively,and then the concrete bridge deck is erected using Pilger method.The calculation results indicate that the stress and stability of each key part of the main girder in top pushing process meet the requirements.