松浦大桥上层桥面板更换施工关键技术

松浦大桥主桥为两联96m+112m公铁两用钢桁架桥,上层为2车道公路,下层为单线铁路,新金山铁路建成后,对该桥进行改造,其中上层设置为双向6车道公路,需将既有12m宽桥面板更换为24.5m宽钢-混组合正交异性桥面板(单块标准段尺寸为8m×24.5m,重约100t)。受桥梁施工区域黄埔江航道、邻近铁路等因素影响,提出"水上提升站+架板机"、"浮吊+架板机"、"全浮吊"3种新桥面板吊装方案,通过比选采用"全浮吊"方案,即新桥面板采用驳船运至现场,在铁路封锁期内单侧航道间断封航,利用桥位上游侧1艘300t浮吊吊装。施工时,通过设置安全作业区(分南、北侧2个施工区域),合理地进行水上交通组织以及4种船舶锚泊布置,采用装配式固定扒杆浮吊四点起吊新桥面板,安全、快速地完成全部新桥面板更换施工。

Key Techniques for Replacing Upper Deck of Songpu Bridge

The main bridge of Songpu Bridge is a rail-cum-road steel truss bridge with two units of 96 m+112 m.The bridge,which originally accommodated two traffic lanes on the upper deck and one railway track on the lower deck,has been renovated to carry 6 traffic lanes on the upper deck after the completion of the new Jinshan Railway.The existing 12 m-wide deck was replaced by the 24.5 m-wide steel-concrete orthotropic steel deck that comprises typical deck panels of 8 m×24.5 m,about 100 tin weight.The navigation channel of Huangpu River and the nearside railways pose restrictions to the deck replacement.To address these issues,three deck erection schemes were put forward,including the scheme of establishing over-water hoisting platform and using deck panel erection gantry,the scheme of combined use of floating crane and deck panel erection gantry and the scheme of using only floating cranes to finish all the deck panels erection.The third scheme was finally chosen via scheme comparison,suggesting that the new deck panels were delivered to the construction site using barges and hoisted and erected by the 300 t-capacity floating crane located on the upstream side of the bridge site,when the railway was closed and the singleside navigation channel was intermittently closed.During the construction,safe operation areas were enclosed,creating two construction areas,a south and a north.The voyage over the water was properly organized and the anchoring places for four types of vessels were properly distributed.The new deck panels were hoisted from four points using the floating crane with scalable fixed booms,and the safe and rapid erection of the new deck panels was realized.