中塔对大跨度三塔连跨悬索桥抖振性能的影响
Influence of Mid-tower on Buffeting Performance of a Long-Span Triple-Tower Suspension Bridge with Continuous Span

为探讨中塔对大跨度三塔连跨悬索桥抖振性能的影响，以世界第一大跨度三塔连跨悬索桥——泰州大桥为研究对象，通过基于有限元的结构非线性时域分析，研究了中塔型式和中塔纵向刚度对大跨度三塔连跨悬索桥风致抖振响应的影响。实测模态参数与计算模态参数的对比验证了所建立有限元模型的准确性。研究结果表明：相比人型中塔，A型中塔可显著降低主梁扭转抖振位移并削弱竖向与横向位移响应；主梁侧向抖振位移几乎不受中塔纵向刚度的影响，增加中塔纵向刚度可以一定程度上抑制主梁竖向及扭转抖振位移响应；中塔纵向刚度变化对边塔平动抖振位移影响微弱，在一定范围内增加中塔纵向刚度可以显著降低中塔顺桥向平动和扭转抖振位移，同时在略微增加边塔扭转抖振位移的前提下可以一定程度上抑制中塔横桥向平动抖振位移。
In order to investigate the influence of a mid-tower on the buffeting performance of a long-span triple-tower suspension bridge with continuous span, the first triple-tower suspension bridge in the world, the Taizhou Bridge, is taken as the research object. The influences of the type and longitudinal stiffness of a mid-tower on wind-induced buffeting responses of the long-span triple-tower suspension bridge with continuous span are studied using structural nonlinear time-domain analysis accompanied by a finite element model. The comparison between calculated and measured modal parameters of the Taizhou Bridge validates the accuracy of the established finite element model. The results show that an A-type mid-tower can significantly decrease the torsional buffeting displacements of the main girder with slightly suppressed vertical and lateral displacements when compared to a herringbone type mid-tower. Increasing the longitudinal stiffness of the mid-tower can decrease the vertical and torsional buffeting displacements of the main girder to some extent, while hardly affecting the lateral displacements. Variation in the longitudinal stiffness of the mid-tower has feeble influence on the translational buffeting displacements of the side tower. The torsional displacement and displacement along the bridge deck are prominently decreased with the increment of longitudinal stiffness of the mid-tower with limits. Meanwhile, increased longitudinal stiffness of the mid-tower will slightly augment the torsional buffeting displacement of the side tower, and can positively suppress lateral buffeting displacement of the mid-tower to some extent.