考虑桥塔风效应的多塔斜拉桥抖振响应分析

该文以6塔斜拉桥——嘉绍大桥为研究对象,基于ANSYS瞬态动力学分析功能进行了嘉绍大桥风致抖振响应的非线性时域分析,研究了多塔斜拉桥主梁和桥塔在强风作用下的抖振响应特性,并详细考察了自激力和桥塔风效应对主梁和桥塔抖振响应的影响。分析结果表明:1) 主梁与桥塔的风致抖振响应与结构的振动特性联系紧密,其抖振响应由于主梁与桥塔的动力耦合作用呈现出一定的独特性;2) 考虑自激力后主梁竖向抖振响应明显减小,而对主梁横桥向和扭转抖振响应影响相对较小。同时,自激力对桥塔的横桥向抖振响应基本没有影响,但对桥塔的顺桥向抖振响应起到了明显的抑制作用;3) 桥塔风效应对主梁的竖向和扭转抖振响应以及桥塔的顺桥向抖振响应基本没有影响,但会对主梁和桥塔的横桥向抖振响应产生较大影响。

BUFFETING RESPONSE OF MULTI-TOWER CABLE-STAYED BRIDGE CONSIDERING BRIDGE TOWER WIND EFFECTS

With regard to a six-tower cable-stayed bridge- Jiashao Bridge, the nonlinear wind-induced buffeting response of the bridge was analyzed through time domain analysis based on the transient dynamics analysis of ANSYS. The buffeting response characteristics of the main girder and bridge towers under strong wind action were investigated and the influences of wind-excited force and bridge tower wind effect on the main girder and bridge towers were investigated respectively. The analysis results reveal that: 1) The wind-induced buffeting responses of the main girder and bridge towers are closely related with the structural dynamic properties. Due to the dynamic coupling action between the main girder and bridge towers, the structural buffeting responses present certain uniqueness; 2) Due to the effect of wind-excited force, the vertical buffeting response of the main girder becomes obviously smaller, but the transverse and torsional buffeting displacements have little difference. For bridge towers, the wind-excited force has no effect on the transverse buffeting response, but it plays a significant role in reducing the longitudinal buffeting response; 3) The bridge tower wind effect has no effect on the vertical and torsional buffeting displacement of the main girder and the longitudinal buffeting response of bridge towers, but it makes significant difference in the transverse buffeting responses of the main girder and bridge towers.