大跨度两铰钢拱桥面内稳定分析

STUDY ON IN-PLANE STABILITY OF LONG-SPAN TWO-HINGED STEEL ARCH BRIDGES

几何非线性及稳定问题是大跨度钢拱桥设计中的重要课题之一。本文应用弹塑性大变形计算方法 ,通过对两座大跨度两铰钢拱桥的面内非线性分析 ,讨论了结构稳定计算中加载方法的影响以及材料屈服与结构失稳间的关系 ,结果表明 ,加载顺序对承载力计算结果的影响十分小 ,按 μ (恒载 +活载 )比例加载法推定的极限荷载与再现结构初始状态的逐次加载法所得到的结果基本一致 ;加劲梁的早期屈服增加拱肋的负担 ,对钢拱桥的失稳具有显著的影响 ;

This paper presents the ultimate behavior and load carrying capacity of long-span two-hinged arch bridges under in-plane loading. Two arch bridge models with the continuous stiffening girder were employed and the elasto-plastic finite displacement analysis was carried out. In this study, the effect of loading condition upon the load carrying capacity of long-spans arch bridges is discussed. Two loading conditions, (1)μ(Dead load + Live load), and (2) Dead load + Live load +μ(Dead load + Live load), are considered. It is found that the load carrying capacity is almost the same under the two loading conditions. From this result, the elasto-plastic buckling stability of long-span arch bridges under in-plane loading is investigated using loading condition (1). The numerical results show that the arch bridges become instability when the initial yielding of the stiffening girder occurs. It is also found that the ultimate behavior and load carrying capacity of arch bridges is improved if adopting higher yield point steel for the stiffening girder.