朔黄铁路高窝中桥4h天窗点内换梁施工技术

Beam Replacement for Gaowo Middle Bridge on Shuozhou-Huanghua Railway in 4-Hour Window Time

朔黄铁路高窝中桥为3孔10 m低高度钢筋混凝土双线桥,中孔上跨高窝公路。上行线(重车方向)中孔由2片分片式板梁组成,每片梁重25.5 t、高70 cm、宽192 cm。上行线中孔碳纤维加固过的梁体腹板及上翼缘再次出现多条裂缝,已严重危及行车安全,急需更换改造。朔黄铁路运输繁忙,鉴于待换桥梁跨度小、数量少,为实现4 h的维修天窗点内换梁,采用台车法施工。新梁采用预应力混凝土整体式板梁,梁重53.3 t、高70 cm、宽390 cm。新支座为高130 mm、带上下钢板的球型支座。换梁施工中通过分析天窗点内作业用时、精简维修天窗点内作业量、对支座垫石预处理并配合破裂试验、加强架梁精度控制等措施,有效减少了封锁点内的作业时间、提高了工作效率,顺利实现了4 h天窗点内对旧梁的更换。

The Gaowo Middle Bridge on Shuozhou-Huanghua Railway is a low-depth reinforced concrete beam bridge comprising three spans of 10 m.The bridge accommodates two rail tracks,with the central span crossing the Gaowo Highway.The upline(heavy train line)central span consisted of two plate beams each weighing 25.5 t and measuring 70 cm deep and 192 cm wide.Although strengthened with carbon fibers,the soffit and upper flange on the upline still bore multiple cracks that could develop to be threats of riding safety,and a replacement plan was proposed.Since the bridge had small span length,the replacement of the beams was not demanding,it was decided to use trolleys for beam replacement in a 4-hour window time,aiming to reduce the disruption to the busy Shuozhou-Huanghua Railway.The new beams are prestressed concrete integral plate beams each weighing 53.3 t and measuring 70 cm deep and 390 cm wide.Bearings were replaced by the 130 mm-high spherical bearing with top and base steel plates.The time needed for replacement was analyzed and engineering quantity was calculated and reduced to the most rational level.The bearing padstones were treated ahead of installation and breaking test was conducted.The installation accuracy of the beams was strictly controlled.By implementing the aforementioned measures,the time consumed was reduced,working efficiency was improved,and the replacement construction was finished in the 4-hour window time.