敞开式钢桁架桥设计及整体稳定参数分析

Design of Open-truss Steel Bridge and Parametric Analysis of Overall Stability

摘要:

敞开式桁架桥行车视野较好，整体造型较为美观，但上弦杆易发生面外失稳，其稳定问题为设计的关键因素。结合工程实例，采用有限元方法对长虹路钢桁架桥进行计算分析，结果表明该桥的刚度、强度、稳定、抗疲劳等均满足规范要求。为探讨敞开式钢桁架整体稳定的影响参数，对该桥构件尺寸及斜交角进行调整，通过调整各杆件刚度建立对照模型，发现上弦杆、腹杆等构件的横向刚度影响较大；通过与非敞开式桁架对比分析，验证敞开式桁架桥的技术可行性。

Abstract:

Open truss bridge offers a good view for vehicles and has a relatively beautiful overall shape, but the top chords are prone to out-of-plane instability, and its stability is the key factor of design. Combined with the engineering examples, the finite element method is used to calculate and analyze a steel truss bridge on Changhong Road. The result shows that the stiffness, strength, stability and fatigue resistance of the bridge all meet the code requirements. To explore the parameters influencing the overall stability of open-steel trusses, the component dimensions and skew angles of the bridge should be adjusted. By adjusting the stiffness of individual members to establish the contrast model, it is found that the lateral stiffness of components such as the top chords and web members has a significant influence. Through the comparative analysis on the non-open truss bridges, the technical feasibility of open-truss bridges is validated.