南京大胜关长江大桥三主桁钢正交异性板整体桥面结构受力特性的试验研究

Experiments on the mechanical characteristic of the integral steel orthotropic bridge deck with three main trusses of Nanjing Dashengguan Yangtze River Bridge

南京大胜关长江大桥采用三主桁多横梁体系钢正交异性板整体桥面结构,结构受力状态复杂。设计制作了一个1∶6的6节间钢桁梁节段模型,研究了实桥受力状态的模拟方法,完成了多种工况下的模拟实桥正、负弯矩区受力状态的加载试验;考察了桥面荷载在3片主桁之间的横向分配,"第一系统"作用下整体桥面的应力分布。结果表明,试验实测结果与实桥的理论分析结果较吻合,说明本文的试验方法可较好地反映实桥整体桥面结构的受力状态;桥面荷载在3片主桁之间的分配是不均匀的,对称桥面荷载在3片主桁之间的分配比例为1.0∶2.0∶1.0,偏载时为1.0∶1.0∶0.0;"第一系统"作用下钢桥面板顺桥向应力沿横桥向分布较均匀,3片主桁挠度较接近,说明三主桁整体桥面结构受力状态合理,整体性好。该研究成果验证了南京大胜关长江大桥的设计计算理论和计算方法的正确性,为该桥的设计提供可参考依据,同时也为整体桥面结构的进一步研究和应用提供了技术储备。

Multi-transvers girder integral steel orthotropic bridge deck with three main trusses was adopted in Najing Dashengguan Yangtze River Bridge （NDB）. The stress condition of the structure is quite complicated. A steel truss segment model with 6 panels was designed and constructed with a scale of 1 ： 6. Methods of simulating the stress condition of the real bridge was studied, loading experiments of simulating the stress condition of the sagging and hogging moment segment of the real bridge were accomplished with multi - load cases; the transverse distribution of the deck load among the three main truss and the stress distribution of the integral bridge deck with the action of ＂the first system＂ were well investigated. Results show that the test values of the segment model are well coincided with theoretical values of the real bridge, which demonstrated that the stress condition of the real bridge deck can be well simulated by the experiment methods proposed in the paper; the distribution of the deck load among the three main trusses is asym-metrical, the distribution ratio is 1.0： 2.0： 1.0 under symmetrical deck load, and 1.0 ： 1.0 ： 0.0 under asymmetrical deck load; with the action of ＂the first system＂, the transverse distribution of the stress of the bridge deck in direction along bridge is quite even, and the deflection of the three main trusses is quite close, which illustrated the integral bridge deck with three main tresses in reasonable in stress condition, and is good in the integration. The research results demonstrated the correctness of the design theory and calculation methods of NDB ; provide reference and basis for the design of the bridge, and provide technical accumulation for further research and application of integral bridge deck structure.