钢箱桁架拱桥V型墩受力分析与优化设计

桥梁V墩结构形式特殊且受力情况复杂，是桥梁建设中的重要部位，为研究其力学性能，以某钢箱桁架拱桥为背景，首先通过Midas全桥模型求解出最不利荷载工况下V构的边界条件，分析了ABAQUS局部模型的受力情况，随后以V构失高与墩座高度比、内外肢腿倾角比为参数，揭示了参数变化时V墩最大应力变化规律，最后结合分析所得，对V构进行优化设计。研究表明：在承载能力极限状态下，墩座底部和外侧肢腿下缘产生了较大的拉应力；随着两种参数的增大，肢腿与墩座最大主拉应力呈现相反的变化趋势，而最大主压应力均趋于降低，这主要是由于力臂长度、桥墩整体柔度改变对主应力产生影响；结合参数分析所得，以主拉应力减小为优化目标，采用合适的结构布置形式后，主要受拉部位主拉应力明显减小，且小于允许值，安全储备得到提高。

Analysis on stress and optimal design of V-shaped pier of steel box truss arch bridge

To study the mechanical properties of V-shaped pier which is the key position during the bridge construction and has a special shape and complicated load condition, a certain steel box truss arch bridge was taken as the background. Firstly, the boundary conditions of the V-shaped pier under the most adverse load conditions were solved by the full bridge model in Midas, and analyzed the local stress conditions by ABAQUS. Then, it revealed the maximum stress variation rule with the parameters changing based on the ratio of vector height, ration of pier base height and ratio of angle between V-pier. Finally, combined with the analysis results, the optimal design of the V-shaped pier is carried out. The results show that the bottom of the pier base and the lower edge of the outer leg produce a large tensile stress under the ultimate bearing capacity. With the increase of the two parameters, the maximum principal tensile stress of the legs and the pier base presents a contradictory trend, while the maximum principal compressive stress tends to decrease, which is mainly due to the influence of the length of the moment arm and the overall flexibility of the pier on the principal stress. Combined with the results of parameter analysis, taking the reduction of the main tensile stress as the optimization objective, the main tensile stress of the main tensile position is significantly reduced and less than the allowable value, and the safety is improved after adopting the appropriate structure layout.