连续钢桁梁-桁拱组合桥节点的局部受力分析

Analysis of Local Forces of Panel Points of a Continuous Steel Truss Beam and Truss Arch Hybrid Bridge

为探讨桁梁-桁拱组合桥节点设计的合理性,建立上海嘉定蕴藻浜大桥梁、板单元相结合的局部计算模型,分析其关键节点受力和桥面板剪力滞效应。分析结果表明:局部模型是正确的;桁架节点板在支座垫板位置边缘有较大的应力集中,建议用加劲加强或改善构造设计;节点板在下弦杆与系梁倒角处出现较大的应力集中,可适当增大倒角的半径;桥面板边跨侧受压、主跨侧受拉,横向应力分布基本相同,纵向应力在横向呈现类似M形的分布,应力在系梁部分最大、向两边逐渐减小,小纵梁和加劲肋对应力变化影响较小。

To study the rationality of panel point design of the continuous steel truss beam and truss arch hybrid bridge,the finite element calculation local models of combined beam element and plate element were created for the Jiading Yunzaobang Bridge in Shanghai.The force conditions of the critical panel points and the deck slab shear lag effect of the bridge were analyzed.The results of the analysis reveal that the local models are correct,the great stress concentration exists in the gusset plates at the edges of the padding plates of the bearings,it is hence proposed that the gusset plates should be stiffened,reinforced or the structural design thereof should be improved.The great stress concentration also occurs in the gusset plates at the rounded corners of the lower chords and tie beams and the radii of the rounded corners should be appropriately increased.The deck slabs on the side span sides are subjected to compression while those on the main span are subjected to tension.The stress distribution in the transverse direction of the deck is basically identical,the longitudinal stress is similar to the M-shape distribution in the transverse direction,the stress in the tie beams is the greatest and it gradually decreases towards the both sides and the influence of either the stringers or stiffening ribs on the variation of the stress is little.