大跨径拱桥钢箱主梁顶推滑移施工技术

Incremental Launching and Sliding Techniques for Steel Box Main Girder of Long-Span Complicated Arch Bridge

盘锦辽东湾新区连岛中桥主桥为主拱跨径200m的系杆拱桥与连续梁的组合体系,主梁为钢箱梁。因运输距离远、路况复杂,在工厂将钢箱梁划分为19个节段,每节段分2个分段预制,现场将分段拼装成节段后,从中间向两侧依次顶推滑移施工。在距桥梁中线两侧5m、16m处共布置4条滑移胎架,胎架基础采用132根Φ630mm×10mm钢管桩基础,胎架立柱采用Φ630mm×10mm的钢管(与钢管桩焊接),在立柱顶沿纵向设置连续滑移轨道梁,轨道梁上安装43kg/m轨道,轨道处设置水平导向轮,增加了钢箱梁滑移时整体稳定性,故未设置横向分配梁。采用2台300t履带吊机吊装钢箱梁节段至滑移胎架上,在最外侧2条轨道上布置顶推系统(2台100t千斤顶),交替进行两侧钢箱梁节段顶推滑移施工,已就位的梁段焊接的同时,其它梁段继续顶推。

The main bridge of the Island-Linking Center Bridge in the Liaodong Bay New Dis-trict in Panjin is a combined system of tied arch bridge and continuous girder, and the main arch spans 200 m. The main girder adopts steel box girder. Due to the long transportation distance and complicated road conditions,the steel box girder was divided into 19 sections in the factory and each section was fabricated in two subsections. During the installation, the subsections were as-sembled first to form main girder sections which were in turn incrementally launched and slid from the center of the span towards the two ends. Four sliding jigs were prepared at the locations that were respectively 5 m and 16 m away from and distributed at the two sides of the bridge central line. The foundation of the jig is formed of 132 , φ630 mm×10 mm steel pipe piles. The columns of the jig are the steel tubes of φ630 mm×10 mm （welded with the steel tube piles）. At the tops of the columns, continuous track beams were installed along the longitudinal direction, on which the tracks of 43 kg/m were installed at the location of the track, horizontal guiding wheels were in-stalled to enhance the overall stability of the structure during the sliding of the steel box girder. Hence, no transverse distribution beams were added. Two crawler cranes with a capacity of 300 t each were used to lift and install the steel box girder sections to the sliding jigs. On the two outer tracks, the incremental launching system （two crawler cranes with a capacity of 100 t each） was placed to alternatively carry out the pushing and sliding of the steel box girder sections on both sides. As the girder sections already built were being welded, the launching of the remaining girder sections continued.