基于增设刚性纵梁的柔性系杆拱桥力学性能研究

Research on Mechanical Properties of Flexible Bowstring Arch Bridge Based on Addition of Rigid Longitudinal Beam

摘要:

以某柔性系杆拱桥为研究对象，通过增设刚性纵梁，改善柔性系杆拱桥在吊杆断裂时易发生连续倒塌的问题，提升桥梁的安全性。采用MIDAS Civil2021建立全桥有限元模型，对比改造前后桥梁在正常使用状态下的受力特性和自振特性。结果表明，改造方案对吊杆应力有显著改善，尤其在可变作用下，1#吊杆应力减小72.1%；纵梁竖向位移最大减小8.1 mm，纵梁应力最大减小64.2%；拱肋在可变作用下的竖向位移显著降低，拱顶竖向位移最大减小11.5%。改造对桥梁的刚度和振动特性产生了积极影响。该改造方案能显著提升柔性系杆拱桥的安全性和受力性能。

Abstract:

Taking a flexible bowstring arch bridge as the research object, by adding rigid longitudinal beams, the problem that the flexible bowstring arch bridge is prone to progressive collapse when the suspender is broken is improved, and the safety of the bridge is improved. MIDAS Civil 2021 is used to establish the finite element model of the whole bridge to compare the mechanical characteristics and natural vibration characteristics of the bridge before and after the reconstruction under normal use. The results show that the stress of the suspender is significantly improved by the reconstruction scheme, and especially under the variable effect, the stress of 1# suspender is reduced by 72.1%. The maximum vertical displacement of the longitudinal beam is reduced by 8.1mm, and the maximum stress of the longitudinal beam is reduced by 64.2%. The vertical displacement of arch rib under variable action is significantly reduced, and the maximum vertical displacement of arch crown is reduced by 11.5%. The reconstruction has a positive impact on the stiffness and vibration characteristics of the bridge. The reconstruction scheme can significantly improve the safety and mechanical performance of the flexible bowstring arch bridge.