为了开展大型钢结构桥梁损伤模拟研究,基于相似理论,按照厚度与几何尺寸不同比例的畸变缩尺,针对九江长江大桥主桥三联拱桥部分开展大缩尺比的静动力模型试验研究。在验证模型结构有效性与可靠性的基础上,通过各类构件的不同损伤模拟研究结构的动力特性变化。研究结果表明:基于畸变相似比例设计的大跨度钢桁架拱桥大比例缩尺模型能很好地满足模型与实型之间的静动力相似关系;结构损伤与结构刚度变化之间存在高度非线性关系,同类构件的不同损伤之间不存在叠加关系;次要构件损伤虽可能在某阶特定振型中贡献相对较大,但其对结构整体刚度和频率影响不明显。
In order to study the damage simulation for large steel bridges, with distorted scale for thickness and other dimensions of structural components, the similarity theory was employed to perform static and dynamic large-scaled model test for the three-span arch of main part of Jiujiang Yangtze River Bridge. Based on verifying reliability and effectiveness of the model, different kinds of damages were intentionally produced on all kinds of structural members to study the dynamic properties of the structure. The results show that good similarity relations for both static and dynamic properties of long-span steel arch bridges can be reached according to the model design with distorted scales for both the model and actual bridge. The relationship between structural damage and stiffness is highly nonlinear, and no damage can be superimposed even for the same kind of structural components. Secondary component damage is insignificant for both structural stiffness and frequencies, even if they may show some contribution to a mode shape of certain order.