斜交刚构扭转效应分析及非对称预应力应用  

Analysis of Torsional Effect of Oblique Rigid Frame and Application of Asymmetric Prestressing

作　　者：梅晨星 MEI Chenxing(China Railway Shanghai Design Institute Group Corporation Limited,Nanjing,Jiangsu 210009,China)

机构地区：[1]中铁上海设计院集团有限公司,江苏南京210009

出　　处：《黑龙江交通科技》2025年第2期72-75,81,共5页Communications Science and Technology Heilongjiang

摘　　要：针对新建江苏南沿江城际铁路金坛站同步实施连镇铁路南延工程I类变更设计预应力混凝土斜交连续刚构桥主跨大、墩梁斜交及受力复杂的特点,依据主梁空间受力效应理论,分别采用有限元单梁建模方法和梁格建模方法,研究了梁体扭转的有效模拟方式,并给出了针对荷载作用下梁体因扭转产生左右角点不对称应力的情况,在箱梁内布置不对称预应力钢束的方式抵消应力差的新方法,研究表明:(1)主梁横桥向位移是由刚臂墩横桥向压力分布不均衡造成的自身变形,在单梁模型中,横桥向位移峰值为0.06 mm,采用梁格法建模其峰值增加至0.17 mm,采用梁格法建模更符合工程实际。(2)主梁在预应力钢束对称布置时,刚臂墩内侧底缘会出现拉应力,采用不对称的钢束布置,可消除因扭转效应产生的截面横桥向应力差,使主梁整体受力更佳。According to the category I change design in which the southward extension project of the Lianzhen Railway is constructed simultaneously with the newly-built Jintan Station of Jiangsu south along the Yangtze River intercity railway,a kind of oblique PC continuous rigid frame bridge is taken as an example because of its large main span,oblique intersection between the pier and the beam,as well as complex stress conditions.Based on the theory of the spatial force effect of the main girder,In this paper,the finite element single-beam modeling method and the grillage modeling method are respectively adopted to study the effective simulation mode of the beam torsion,and a new method is given for the situation that the beam body generates asymmetric stress at the left and right corner points due to torsion under the action of the load,that is,to offset the stress difference by arranging asymmetric prestressed steel strands in the box girder.The results show that:(1)The transverse displacement of the main beam is its own deformation caused by the unbalanced distribution of the transverse pressure of the rigid arm pier.In the single-beam model,the peak value of the transverse displacement of the bridge is 0.06 mm,and the peak value increases to 0.17 mm when the beam grid method is used for modeling,which is more in line with the engineering practice.(2)When the main beam is symmetrically arranged with prestressed steel bundles,tensile stress will occur at the inner bottom edge of the pier of the rigid arm.The asymmetric steel bundle arrangement can eliminate the cross section and bridge stress difference caused by the torsion effect,so that the overall force of the main beam is better.

关 键 词：斜交连续刚构 扭转 非对称预应力钢束 箱梁 

分 类 号：U24[交通运输工程—道路与铁道工程]