横系梁对超高墩大跨连续刚构双幅桥抗震性能的影响分析

Influence of Cross Tie Beam on Anti-Seismic Performance of Long-Span Continuous Rigid-Frame Double-Deck Bridge with Very High Piers

为研究横系梁对超高墩大跨连续刚构双幅桥抗震性能的影响,以云南山区某超高墩大跨连续刚构双幅桥为例,考虑桩土相互作用,采用MIDAS Civil软件建立桥梁结构模型,改变横系梁的位置、截面尺寸及数量,计算桥梁结构的地震响应并进行对比分析。结果表明:增设横系梁可以较好地改善超高墩大跨连续刚构双幅桥的横向抗震性能;在整体墩与双肢薄壁墩分界处设置横系梁对提高结构抗震性能效果最佳,其中横系梁同桥墩刚度比在0.40~0.67内,对改善结构抗震性能最有利;根据桥墩的高度适当增加横系梁数量对结构抗震有利,在该桥双肢薄壁墩顶部和整体墩与双肢薄壁墩分界处设置2道横系梁效果较好。

To study the influence of cross tie beam on the anti seismic performance of the long-span continuous rigid frame bridge with double decks and with very high piers, a long-span continuous rigid frame bridge of this type in the mountainous region in Yunnan Province was cited as an example. The MIDAS Civil software was used to establish the model of the bridge structure, taking into consideration of the pile soil interaction. The seismic responses of the bridge structure were calculated and contrastively analyzed, accounting the effect of different location, cross section dimension and amount of the cross tie beam. The results show that adding cross tie beams can better improve the transverse seismic performance of the long-span continuous rigid frame double-deck bridge with very high piers. To install the cross tie beam in the interface of the monolithic pier and the double leg thin walled piers can achieve the optimum effect. When the stiffness ratio of cross tie beam to pier is within the range of 0.40-0.67, the seismic performance of the structure can get most favorable improvement. To increase the number of cross tie beams according to the pier height is favorable to the seismic performance of the structure. For this bridge, 2 cross tie beams are installed on the top of the double leg thin walled piers and the interface of the monolithic pier and the double-leg thin-walled pier, which is proved able to bring good effect.