高速铁路矮塔斜拉桥墩塔梁固结段局部应力分析与验证

Analysis and Verification of Local Stress on Pier-Tower-Girder Fixed Segment of High-Speed Railway Low-pylon Cable-stayed Bridge

局部分析是桥梁设计中常采用的重要手段,也是设计中不可或缺的重要环节,利用实体有限元模型能反应出结构细部的受力状况,对考察结构重要部位的真实应力状态、结构设计配筋有着指导性作用。为了解高速铁路矮塔斜拉桥墩塔梁固结段的真实应力状态及验证局部分析中边界条件表达的准确性,以京沈客运专线(115+95)m双线无砟轨道预应力混凝土矮塔斜拉桥为工程背景,利用Ansys有限元建立细化的空间实体有限元模型,并对局部模型的边界条件模拟的正确性进行验证,分析表明,墩塔梁固结段进人洞角点处应力集中,应适当加强配筋,其余部位应力均满足要求,通过验证局部模型的内力传递及支反力,确保实体模型应力结果的准确性,保证结构安全。最后总结出了铁路桥梁中不失一般性的局部分析方法,从而对其他结构局部分析具有借鉴意义。

Local analysis is an important method often used in bridge design and also an indispensable part of the design. The solid finite element model is used to reflect in detail the local stress of structures, playing a guiding role in investigating real stress state of important structures and in the design of reinforcement. In order to investigate real stress state of the pier-tower-girder fixed segment of the prestressed concrete low-pylon cable-stayed bridge and verify the accuracy of local boundary condition analysis, a refined space solid finite element model is established and the accuracy of local boundary condition analysis is verified with reference to a （115＋95）m unballasted double line prestressed concrete low-pylon cable-stayed bridge on Beijing-Shenyang dedicated passenger line. The analysis shows that the pier-tower-girder fixed segment experiences a stress concentration at the hole, where reinforcement should be strengthened appropriately, and the stress on the remaining parts meets the requirement. The accuracy of resulted stress is guaranteed by validation of the local model＇s internal force transmission and support reactions, and structural safety is ensured. Finally, a typical local analysis method is concluded, which may provide some references for other local stress analysis.