下承式钢桁组合梁桥纵梁不同施工次序下横梁受力分析

公路下承式钢桁组合梁桥多采用纵横梁桥面系,若采用常规施工方案,桥面系横梁会产生相当大的面外弯矩,对结构受力不利。文章结合工程实例,分析该弯矩产生的主要原因,并对比分析了4种不同的纵梁施工次序下横梁的受力状态,结果表明：改变纵梁的连接时机,将会改变横梁面外弯矩,若再在预制桥面板上施加压重,则还可以减少或消除2期恒载甚至活载对横梁的面外影响,改善横梁的受力状态,研究结果可为同类设计结构提供参考。

Stress Analysis for Transverse Beam under Different Construction Order of Longitudinal Beam of Through Steel Truss Composite Bridge

The bridge deck system with longitudinal and transverse beams is widely used in the through steel truss composite bridges on highway. With conventional construction method, considerable out-of-plane bending will developed on transverse beam of bridge deck system, which is harmful to structure. Combining with engineering examples, the mechanical state of transverse beam was contrasted and analyzed with four different construction orders of longitudinal beam. Results indicate that the out-ofplane moment of the transverse beam can be greatly reduced by changing the order of longitudinal beam. By press ballast weight on prefabricated bridge deck, the out-of-plane moment of transverse beam under second dead loading and live loading can be further reduced or even eliminated. These methods can improved the mechanical state of transverse beam and results could provide reference for the similar structure design.