高速铁路连续梁柔性拱桥拱梁结合部受力分析

Local Stress Analysis for Arch-girder Binding Site of Long Span Continuous Beam-flexible Arch Composite Bridge on a High Speed Railway

研究目的:连续梁拱组合体系桥拱肋与主梁固结,依靠主梁内配置的预应力束来平衡拱的水平推力,拱脚是拱梁组合桥的关键部位,其受力性能对全桥承载能力和跨越能力至关重要;拱脚为钢管混凝土拱肋向混凝土主梁的过渡段,局部构造非常复杂,为了给拱脚节点处的构造设计提供理论依据和合理方案,有必要在桥梁整体分析的基础上,建立拱梁结合部精细化有限元计算模型,精确分析其受力状态和传力机理。研究结论:(1)拱梁结合部主梁和拱脚混凝土、拱肋钢管和拱肋内灌注混凝土等构件应力均在规范给定的限值内,结构安全可靠;(2)拱梁结合部应力集中区域主要分布在0号和1号节段连接截面,该处拱脚和主梁均存在较大的主压应力;拱脚与主梁间宜采用圆弧过渡等平滑连接构造,以减小应力集中,使混凝土受力更为均匀;(3)应确保拱肋与主梁、拱肋与拱脚混凝土之间共同作用良好,并保证拱梁结合部位受力的整体性;(4)本研究结果可供大跨度连续梁拱桥的设计和施工参考。

Research purposes: The arch rib is consolidated with the main girder,and the prestressed steel bundles arranged in the main girder is used to balance the horizontal thrust of the arch for the bridge combinated of prestressed concrete continuous beam and steel tube arch. The arch-girder binding site is the key part of the arch-girder composite bridge,and its mechanical properties is very important for the carrying and spanning capacity of the bridge;it is also the transition section of the steel tubular arch rib filled by concrete to the concrete main girder. The local structure is very complicated. In order to provide theoretical basis and reasonable scheme for the structural design of the arch-girder binding,it is necessary that a refined finite element calculation model of the arch-girder binding site is established on the basis of the overall analysis of the structure,and the stress state and force transmission mechanism are analyzed accurately.Research conclusions:(1) The stresses of the main girder and arch concrete,arch rib steel pipe and concrete poured into the arch rib at the arch-girder binding site are within the limits given by the specification,and the structure is safe and reliable.(2) The stress concentration area at the arch-girder binding site is mainly distributed in the connection sections of 0# and 1# segments where there is a large principal compressive stress at the arch and the main girder,and smooth connection structures such as arc should be used between the arch and the main girder to reduce stress concentration.(3) The connection performance between the arch ribs and the main girder,the arch ribs and the arch concrete should be ensured,and the mechanical integrity of the arch-girder binding site should be guaranteed.(4) The research results can be referenced in the design and construction of long span continuous beam-arch bridges.