梯形截面箱梁横向弯矩研究

RESEARCH ON TRANSVERSE BENDING MOMENT OF BOX GIRDER WITH TRAPEZOIDAL CROSS SECTION

考虑偏心荷载作用下畸变对箱梁横向弯矩的影响,对梯形截面箱梁横向弯矩的计算进行了研究。畸变翘曲系数表征了顶板、底板面内力矩分布的情况,其大小和箱梁截面尺寸相关。通过对箱梁畸变翘曲系数的推导,分析荷载的分布模式对箱梁横向弯矩值的影响,以及箱梁横向弯矩沿桥梁纵向的分布情况。研究表明:箱梁横向弯矩计算要考虑畸变的影响,所给出的箱梁畸变翘曲系数计算式能够提高横向弯矩计算的精度;横向弯矩采用有限元计算时,宜采用均布荷载,横向弯矩沿桥梁纵向的分布,其值在梁端和跨中差异较大。

Considering the influence of distortion under eccentric load on the transverse bending moment of box girder,the calculation of transverse bending moment of box girder with trapezoidal section was studied. The distortion warping coefficient of the box girder was deduced. The distortion warping coefficient was used to characterize the distribution of the moment in the top slab and the bottom slab. The value was related to the cross-section size of the box girder. The influence of load distribution mode on the transverse bending moment value of box girder was analyzed. The distribution of transverse bending moment of box girder along the longitudinal direction of the bridge was analyzed. The results showed that the calculation of transverse bending moment of box girder should take into account the influence of distortion. The calculation formula of box girder distortion warping coefficient could improve the accuracy of lateral bending moment calculation. When the transverse bending moment was calculated by finite element,uniform load should be adopted. The distribution of the transverse bending moment along the longitudinal direction of the bridge had a large difference between the beam end and the middle span.