单双柱式桥墩横桥向抗震性能对比分析

Comparative analysis of the seismic performance of single-column and double-column piers in transverse direction

为对比分析单双柱式桥墩横桥向的抗震性能。首先明确了两者的主要差异为墩柱边界约束条件不同以及有无动轴力,然后根据简化计算方法推算出了单双柱式桥墩的弹性阶段性能参数的关系,最后基于有限元模型探讨了动轴力对双柱式桥墩单根墩柱滞回曲线的影响,并对比分析了单双柱式桥墩(双柱式桥墩有效高度为单柱式桥墩2倍)的滞回性能参数以及塑性铰区。结果表明:动轴力的存在使双柱式桥墩中单根墩柱的滞回曲线表现出不对称性,而动轴力对两根墩柱滞回曲线的影响互为消长,致使双柱式桥墩横桥向整体的滞回曲线呈现出对称性;单双柱式桥墩的弹性阶段性能参数关系可通过理论进行推算,在塑性阶段,单双柱式桥墩的滞回性能参数之间成比例关系;然而,单双柱式桥墩的塑性铰区长度以及屈服后截面曲率均存在较大差异。

In order to contrastively analyze the seismic performance of single-column and double-column piers in transverse direction,firstly,boundary constraint condition and dynamic axial force were identified as the main differences between the two types of piers.Then,the relationship between the performance parameters of single-column and double-column piers in elastic stage was deduced according to a simplified calculation method.Finally,based on a finite element model,the influence of dynamic axial force on the hysterstic curve of a single column in a double-column pier was discussed,and the relationship between single-column and double-column piers(effective height is twice as high as single-column pier)in terms of hysteretic performance and plastic hinge area was compared.The results show that the dynamic axial force makes the hysteretic curves of the single column in the double-column pier show asymmetry;however,the influence of dynamic axial force on hysteretic performance of the two columns in the double-column pier offset each other so that the hysteretic curves of the double-column pier in transverse direction show symmetry.The relationship between performance parameters of single-column and double-column piers in elastic stage can be calculated by theory.The hysteretic performance parameters of single-column and double-column piers in plastic stage are proportional.However,there are great differences in the length of plastic hinge and the curvature of section after yield.