静风荷载作用下大跨度钢拱桥施工稳定性的参数研究

随着钢拱桥跨径的不断增大，钢拱桥在静风荷载作用下的施工稳定性问题已引起了人们的广泛重视。本文以上海在建的主跨550m的中承式钢拱桥为例，采用几何和材科非线性分析法详细分析了大跨度钢拱桥在两个不同施工阶段下的静风稳定性。结果表明，拱肋最初合拢状态是拱桥施工过程中最不利的状态。最后，详细探讨影响大跨度钢拱桥施工过程中静风稳定性的主要参数。

Parametric study on wind-induced stability of long-span steel arch bridges under construction

With the increasing span of steel arch bridges, evaluation of wind-induced instability during construction becomes especially important. This study investigates the wind-induced instability of a long-span steel arch bridge with a 550 m-long central span under construction in Shanghai, China. This will be the longest central span among all arch bridges in the world. Both geometric and material nonlinearities are involved in the analysis. Two different construction stages were chosen for this study, namely construction stages I and II. Construction stage I lasts until the closure of the main arch ribs. Construction stage II lasts until all parts have been completed except the stiffening girder of the main span. Three components of wind loads were assumed to act both on the steel girder and the arch ribs in the analysis, namely the drag force, lift force and pitch moment. The results show that the arch bridge is more susceptible to wind-induced instability at the stage II than at the stage I. The effects of various parameters on the wind-induced instability during construction are also discussed.