大跨径曲线连续刚构桥冲击系数影响因素

Study on Factors Influencing Impact Coefficient of Long-span Continuous Rigid Frame Bridge

针对大跨径曲线连续刚构桥的结构特点,以白土北江特大桥主桥为例,研究不同曲率半径对大跨径连续刚构桥冲击系数的影响。建立不同曲率半径的连续刚构桥有限元模型,利用车桥耦合振动方程得出响应峰值的相应变化规律。研究表明,在曲率半径较小时,结构最不利截面冲击系数变化较大。随着曲率半径的增大,控制截面挠度、弯矩和扭矩冲击系数都呈减小趋势,但当曲率半径为250m,冲击系数值较大;墩顶截面弯矩冲击系数变化幅度较小,但扭矩冲击随曲率半径增大而增大。

In this paper,taking Beijiang Special Large Bridge of Baitu as an example,the effect of curvature radius on the impact coefficient of long span continuous rigid frame bridge has been studied. The rule of peak value variation has been summarized by means of the dynamic equation of vehicle- bridge coupling system on the basis of different curvature radius of the element models. The results have shown that the smaller the radius is,the larger the impact coefficient of the structure will be. With the increasing of the radius,the deflection,bending moment and torque impact coefficient will decrease. While the radius reaches 250 m,the impact coefficient will become larger,the impact of the bending moment will become smaller,but the impulsive torque coefficient will increase with the increased radius of curvature.