铁路自复位桥墩地震动最不利输入方向研究

Critical angle of earthquake input for self-centering bridge piers of railways

摘要:

为探究地震动输入角度对铁路自复位桥墩地震反应的影响,以一座简支梁桥为工程背景,建立空间自复位桥墩地震反应分析模型,并对模型进行验证。选择22组强震记录作为地震动输入,以屈服面函数Ψ作为判别最不利输入角度的标准,从0°开始顺时针旋转,每次增加5°,进行铁路自复位桥墩地震反应分析。结果表明:145°输入时,Ψ值最大,145°为桥墩最不利输入角度;在最不利方向下桥墩的地震反应大于顺桥向和横桥向。自复位桥墩设计时若不考虑地震动最不利输入方向,则偏于不安全。

Abstract:

To investigate the influence of ground motion input angles on the seismic response of railway self-centering piers, a seismic response analysis model for spatial self-centering bridge piers was established and validated using a simply supported beam bridge as the case study. A total of 22 sets of strong motion records were selected as seismic inputs. The yield surface function Ψ was used to determine the critical input angle. Starting from an initial angle of 0°, the seismic response of the railway self-resetting pier was examined by rotating clockwise, increasing the angle by 5° increments each time. The results show that the value of Ψ was maximized at an input angle of 145°, designating this as the critical input angle for the pier. The seismic response in this critical direction surpassed those observed in the longitudinal and transverse directions. Designs that ignore the critical angle of ground motion in the design of self-centering bridge piers may be unsafe.