基于新型电涡流轴向阻尼器的大跨度悬索桥纵向减震参数分析

Analysis on Longitudinal Damping Parameters of Long-span Suspension Bridge based on a Novel Axial Eddy Current Damper

针对新型电涡流轴向阻尼器不同阻尼系数及最大阻尼力组合,以即将建设的张官高速洞庭溪沅水特大桥为背景,通过非线性时程分析方法,得到了大跨度悬索桥索塔和加劲梁的关键地震响应。在此基础上,通过定义性能指标函数,得到了最优阻尼参数。结果表明:由于官庄侧索塔下塔柱高度大于张家界侧,官庄侧索塔刚度较小,设置阻尼器后官庄侧塔底弯矩、塔底剪力及塔顶位移的降低值均明显小于张家界侧,但两侧梁端位移的降低值相差不大;阻尼器的设置对塔底弯矩、塔底剪力、塔顶位移影响相对较小,但对梁端纵向位移的影响很大,在参数变化范围内,梁端纵向位移最大可以降低到原来的30%左右;阻尼系数或者最大阻尼力越大,则响应越小,但随着最大阻尼力的继续增大,响应的变化量越来越小,此时应根据阻尼器的造价综合考虑选取最优阻尼参数。

Aiming at different damping coefficients and maximum damping force combinations of a novel axial eddy current damper, taking the Dongtingxi Yuanshui Bridge of Zhangjiajie-Guanzhuang Expressway as the background, the key seismic responses of cable tower and stiffening beam are compared and analyzed by using nonlinear time history analysis method. On this basis, the optimal damping parameters are obtained by defining the performance index function. The results show that, because the height of the lower tower column of the cable tower at Guanzhuang side is greater than that at Zhangjiajie side, the stiffness of Guanzhuang side tower is smaller, the reduction values of the tower bottom bending moment, the tower bottom shear force and the tower top displacement at Guanzhuang side are obviously less than that at Zhangjiajie side, but the reduction values of the beam end displacement at both sides are not different. Setting damper has minor effect on the bending moment at the bottom of the tower, the shear force at the bottom of the tower and the displacement at the top of the tower, but has a great impact on the longitudinal displacement at the beam end. Within the range of parameters, the maximum longitudinal displacement at the beam end can be reduced to about 30% of the original. The larger the damping coefficient or maximum damping force, the smaller the response. However, with the continuous increase of the maximum damping force, the smaller the change of the response. At this time, the optimal damping parameters should be selected according to the cost of the damper.