梁格法在四线大跨连续刚构桥上的应用

Application of Grillage Method in Four-line Long-span Continuous Rigid Frame Bridge

以安家山河连续刚构桥为研究,文章采用专业有限元软件Midas建立了单梁与梁格模型,研究对比梁格模型与单梁模型的支座反力、内力、变形、应力、自振特性等内容,确认了所建的梁格模型准确无误。在此基础上对比梁格模型中各片纵梁的内力分配,得出了以下结论:(1)合理的梁格划分可以高效的获得更加细致的结果,梁格法获得的正应力与单梁模型是吻合的,而剪应力、主应力结果差值较大,为获得特殊位置局部应力时应采用更加精细的有限元分析方法;(2)梁格法可以获得多室箱型截面横向的弯矩分配,并依据弯矩分配,四线连续刚构铁路桥在运营时,一侧双线行车的情况下为最不利状态;(3)支座位置对连续刚构桥支座反力分布的影响明显,该连续刚构桥,支座最优位置为正对腹板中心线处。通过在梁格模型上改变支座间距,对比不同间距下支座反力,找出了支座布置的最优位置。

Taking Anjiashan river continuous rigid frame bridge as background, in this paper, the bearing reaction , in- ternal force, deformation, stress, natural vibration characteristics etc. of ied and compared by using the professional finite element software Midas, grillage model and single beam model are stud- and the grillage model founded in this paper is confirmed accurate. On this basis, a conclusion is obtained from the internal force distribution of each longitudinal beam： （1） Reasonable beam meshing can obtain more detailed results efficiently, and normal stress got from grillage method is consistent with the stress from single beam model, while shear stress and primary stress are not. More sophisti- cated finite element analysis should be used to obtain local stress for the special position. （2） Grillage analysis method can get bending moment distribution of box cross-section, and find out the moment distribution of box beam under the worst status-double line driving on the same side during the operation of four-line continuous rigid frame railway bridge. （3） The support position has great effects on support reaction distribution, and where directly facing the web centerline is the best support position for in this kind of bridge. Finally, the optimal support position is found out by changing dis- tance between supports on beam grillage model and comparing the reaction under different distance.