复杂海域条件下大跨悬索桥钢箱梁安装关键技术

浙江秀山大桥主桥为主跨926 m的双塔三跨连续钢箱梁悬索桥,全桥加劲梁共分89个安装节段,标准节段吊装重量212.6 t,最大吊装重量247.1 t。桥址处地理环境复杂、海洋环境恶劣,钢箱梁安装难度大。根据现场实际情况,钢箱梁中跨由跨中向桥塔方向对称吊装,两岸边跨由锚碇向桥塔方向对称吊装,先合龙中跨再合龙边跨。施工过程中,运梁船采用自航驳船动力定位+辅助钢丝绳定位;中跨和秀山岸边跨的一般梁段采用船舶运输+缆载吊机安装;官山岸边跨梁段采用移梁轨道存梁,然后采用液压同步提升系统安装;秀山岸边跨锚碇无索区梁段采用浮吊+轨道牵引纵移到位;桥塔无索区梁段采用缆载吊机+液压同步提升系统起吊荡移方式安装;边跨侧合龙段安装时,需对合龙口两侧梁段进行纵向牵引。

Key Installation Techniques for Steel Box Girders of Long-Span Suspension Bridge in Complex Marine Environment

The main bridge of Xiushan Bridge is a two-tower,three-span steel box girder suspension bridge with a main span of 926 m.The stiffening girder was divided into 89 assembly segments,with standard lifting weight of 212.6 t and maximum lifting weight of 247.1 t.The complex geological condition and harsh marine environment pose great challenges for the installation of the steel box girders.The steel box girders in the central span were hoisted and installed from the midspan towards the towers,and the steel box girders in the side spans were erected from the anchorages towards the towers,with the closure of the central span ahead of the side spans.During the construction,the barges transporting steel box girders were positioned by the combined application of self-propelled barge dynamic positioning and auxiliary steel ropes.The standard girder segments in the central span and the Xiushan-bank side span were transported by barges and erected by main cable supported cranes.The girders in the Guanshan-bank side span were stored on the girder delivery rails and installed by the hydraulic synchronous lifting system.In the Xiushan-side anchorage zone with no hangers,the girders were lifted by floating crane and longitudinally dragged along the rails into position.The girders in the tower zone with no hangers were lifted by the combined utilization of main cable supported crane and hydraulic synchronous lifting system and swung into position.The girders at the closure gap of the side spans were longitudinally dragged before the installation of the closure segments.