【作者】 罗冰；

【导师】 张文献；

【作者基本信息】 东北大学 ， 结构工程， 2009， 硕士

【摘要】 T主梁间湿接桥面板早期破坏后,极易出现纵、横向裂缝,龟裂、渗水、穿孔等病害。早期一些采用英国规范设计的无铺装层的桥梁,由于施工不当等原因,常出现这类病害,处理困难,往往是修补后不久又出现新病害。东莞北大桥运营后,桥面板局部出现了了开裂、渗水甚至穿孔等严重病害。主要源于该桥设计采用的是英国规范BS5400,不设混凝土铺装层；两主梁翼板间采用1.85m现浇混凝土湿接带连成整体。由于混凝土收缩、徐变以及施工质量等因素影响,运营后湿接处产生接缝,且不断开展,造成多处裂缝超标,雨水通过接缝渗入,造成钢筋锈蚀,强度降低,经长期重乍荷载及其冲击作用下,使个别原现浇板穿孔甚至坍落,已危及桥梁使用的安全,应对其进行加固处理。在加厚的混凝土铺装层中掺入钢纤维,布设钢筋网的方法加固桥梁,其方法简单,且可以达到事半功倍之效,这里称之为增铺双钢混凝土桥面补强层加固法。该法非常适宜对东莞北大桥的加固。本文研究了这种加固方式中的有关参数和工艺。利用有限元软件,对该桥分别进行了整体受力和局部受力分析。整体受力分析中,先建立仿真数值模型,分析了原桥和各加固方案的受力状况,求出了各荷载工况下桥梁的应力状态；采用平面横向框架分析法,验算了强度和裂缝宽度,得出了补强层的最佳厚度。桥面板局部受力分析中,将原现浇板与T梁翼缘问存在的微裂缝假定为通缝和铰缝,求出了补强层的配筋率,通过了正截面抗弯承载力验算。由此证明该种加固方式只需剔除严重病害的原现浇桥面板,即可解决原桥现存的各类病害。特别是把微裂缝视为通缝和铰缝的假定,为工程节省了大量资金,缩短了工期。为使补强层与原桥结合紧密,采用锚筋剪力键抵抗层间剪力的办法,并求得了锚筋最佳间距,并且考虑了混凝土收缩、徐变影响。文中还对采用增铺双钢混凝土桥面补强层加固法的施工工艺加以讨论,并在东莞北大桥的加固施工中成功采用。更多还原

【Abstract】 The cast-in-plates between T-beams appeared transverse and longitudinal cracks, leakages and perforations easily. Some bridges were designed by Britian standard without pavement layer. Because of poor constuction, there are above diseases in these bridges. It’s difficult to settle, even if repaired, new diseases will occur again shortly.The bridge deck localized cracks, leakages or even perforations on the operation of Dongguan Northern Bridge. The causes are mainly that the bridge was designed originally on the base of British specification BS5400, so there’s not concrete bridge deck pavement. Moreover, because the concrete shrinkage and creep and construction quality, the wetland joint between the flanges of the prefabricated T.beam has lower quality. On the operation, the cracks propagate continuously, and there are a lot of fracture widths heavy over standard. The rainwater leaks though the crack, result to localized corrosion of steel bars and strength decreases. On the loaded car impact effect, localized cast.in.place plates perforate and even slump. The above are endangering safety of bridge service.The concrete reinforced both by steel bars and SFRC are called additional paving mesh and steel fiber reinforced concrete reinforced layer. Practice proves that the method is effective and easy. It’s applicable to Dongguan Northern Bridge.This paper investigates parameter of the method. Using FEA soft analyzes global and local mechanical.In global mechanical analysis, Original bridge and the three reinforce of different deck thickNess are eablished, and the stress states of all load combinations are analyzed. Then, strength and crack width are checked with the transverse framework of models calculating. The optimal thickNess of mesh and SFRC bridge deck will be given.In local mechanical analysis of bridge deck, the top and bottom joins are assumed to be articulated and propagated throughout the body. The reinforcement ratio of reinforced layer is give. Then the checking meets safety requirement. It’s proved that the heavily damaged cast.in.place plate should be removed. It can settle the above diseases. Especially, the top and bottom joins that assumed to be articulated and propagated throughout the body can save lots of capital, and short construction period.In order to improve the combination of reinforced overlay and the original bridge deck, the anchored steel bars are placed between the two layers. Considering shrinkage tensile stress and shear resistance mechanism between old and new concrete, the optimal anchor bar’s distance has been discussed.Finally, the paper discusses construction technology of the method. The method has been applied to Dongguan Northern Bridge reinforcing construction successfully.更多还原