长悬臂混凝土箱梁翼缘板动力放大系数计算分析

Dynamic amplification coefficient of cantilever concrete box girder flanges plate

《公路桥涵设计通用规范》中规定对于局部荷载加载以及箱梁翼缘板上的动力冲击系数可采用0.3。然而随着翼缘板长度的增加,翼缘板内不仅存在负弯矩,而且存在正弯矩,规范对于箱梁翼缘板的动力冲击系数的规定已经不再适用。以有限元为基础,应用大型有限元ANSYS软件建立有限元模型,考虑路面不平度、翼缘板长度、翼缘板坡度以及横向预应力等参数的影响,分别对翼缘板内负弯矩和正弯矩的动力放大系数进行计算分析。结果表明:正弯矩的动力放大系数远大于负弯矩的动力放大系数,因此很有必要对翼缘板内正负弯矩动力放大系数分别进行计算以满足翼缘板内正负弯矩的配筋要求。

It is stipulated in the General Specifications for Design of Highway Bridges and Culverts that the dynamic impact coefficient on local load and flange plate of box girder can be 0.3.However,with the increase of flange plate length,there are not only negative bending moment but positive bending moment in the flange plate.The regulation of dynamic impact coefficient of box girder flange plate is no longer applicable.On the basis of finite element,the finite element model was established by using large finite element software ANSYS.Considering the influence of road roughness,flange length,flange slope and transverse prestress,the dynamic amplification coefficients of negative bending moment and positive bending moment in flange plate were calculated and analyzed respectively.The results show that the dynamic amplification coefficient of the positive moment is much larger than the negative moment,so it is necessary to calculate the dynamic amplification coefficient of the positive and negative moments in the flange plate separately to meet the requirements of reinforcement.