中文摘要：

为研究大跨钢管拱桥在船撞作用下的受力机理,以瑞典阿摩尔桥（AlmBridge）船撞垮塌事故为工程背景,船撞力基于AASHTO规范,采用理论公式、三维非线性有限元整体和局部模型,从结构参数和船撞力两方面研究大跨钢管拱桥船撞作用下的连续垮塌过程,并分析关键影响因素。结果表明：阿摩尔桥整体结构宽跨比较小,横向稳定性不足,且缺乏结构冗余度;主拱钢管截面径厚比与临界屈曲应力成反比;船撞作用值和撞击面积也极大影响临界屈曲应力。连续垮塌过程为：船撞作用下钢管截面变形,降低屈曲临界应力;撞击处局部屈服使拱轴压应力增大,至临界应力后局部失稳破坏,导致整体结构垮塌。

英文摘要：

To study the load bearing behavior of the long-span steel tubular arch bridge under the action of ship impact,the collapse incident of the AlmBridge caused by ship impact was taken as the study background.Based on the ship impact forces in the AASHTO specification,the process of the progressive collapse of the long-span steel tubular arch bridge under the action of ship impact was studied from the two aspects of structural parameters and ship impact forces,by the combined use of theoretical formulas and three-dimensional nonlinear finite element models,including both the overall and local models.The key influential factors were analyzed as well.The results of the analysis indicate that the small slenderness of the overall structure of the AlmBridge makes the structure have insufficient transverse stability and short of structural redundancy.The diameter-to-thickness ratio of the steel arch tubes is inversely proportional to the critical values of buckling stress.The critical buckling stress was also immensely influenced by the impact force values and the impact area.The process of progressive collapse exhibits the following salient features.The cross section of the steel tubes deforms under the action of ship impact and the critical buckling stress decreases.The local yielding in the impacted area makes the axial compressive stress of the arch increase,and when the compressive stress reached the threshold stress level,local failure of the structure occurs,which will cause the collapse of the overall structure.