特大跨越江悬索桥龙卷风致静力响应

Tornado-Induced Static Structural Response of Suspension Bridges Spanning Across Large River

摘要:

基于大跨度桥梁主梁龙卷风荷载物理识别结果，开展大跨径悬索桥龙卷风致响应的计算分析，将其与常规风荷载下的风致响应进行对比，探讨桥梁抗龙卷风设计时，用常规风荷载模式进行结构龙卷风响应等效的可能性。结果表明，与常规风荷载不同，龙卷风荷载具有局部影响性且升力作用相对明显。涡流比、龙卷风相对距离以及加载点桥轴向位置都对悬索桥的龙卷风致结构响应有所影响，不同类型的响应随上述3个参数的变化规律不尽相同。常规风致响应与龙卷风致响应本身具有不同的特性，两者在数值上的表现也有较大不同，两者的荷载等效方法有待研究。

关键词:龙卷风;风荷载;悬索桥;响应分析

Abstract:

Based on the previous tornado-induced wind load identification results of long-span bridges， the calculation and analysis of the tornado-induced responses of a long-span suspension bridge were conducted， and the tornado-induced responses were further compared with the synoptic wind-induced responses to discuss the possibility of using synoptic wind load in tornado-resistant design of bridges. The results show that， the influence of tornado load is local， and the lift force is relatively significant， which differs from that of the synoptic wind load. The tornado-induced structural responses of the suspension bridge can be influenced by parameters such as the swirl ratio， relative distance of the tornado， and the axial position of the loading points， whose impacts vary with different types of structural responses. Synoptic wind-induced responses differ both qualitatively and quantitatively from tornado-induced responses， leading to unresolved issues regarding load equivalence between the two.

Key words:tornado;wind load;suspension bridge;response analysis