旧桥拓宽中拼接方式对旧桥受力状态的影响分析

针对斜桥拓宽时新桥与旧桥跨径不协调情况,结合沪宁高速公路上一座箱型桥梁,应用空间有限元方法,分析了横向采用钢板连接和铰缝连接时,拼接前后汽车荷载作用下旧桥挠度、应力的变化、旧桥悬臂端挠度及悬臂根部应力状态以及横向拼接结构的受力情况。通过分析认为铰缝连接比钢板连接能提供更大的连接刚度,且拼接使活载作用下桥梁变形及纵向应力减小,但使横向受力不利;而错孔拼宽使旧桥整体受力变得有利,但接缝处受力较大。

Analysis of the Influence of Connecting Method on Old Bridge Performance in Widening Bridge

Aiming at the inharmony of spans between new and old bridge in widening skew bridge,the paper takes a box bridge on Hu-Ning expressway as an example using three-dimension finite element analysis methods to consider the influence of connecting methods.The performance includes deflection,stress variation,deflection at cantilever end,and stress at cantilever root of old bridge and the force state of the joint structure are analyzed before and after widened by two connecting modes.It shows that connect by concrete then by steel plane cause high joint stiffness.While the cross direction stress becomes disadvantage after widening,the deflection of old bridge under car loads and longitudinal stress are reduced.The staggered spans widening makes the old bridge stress in better condition but the joint part bears more force.