薄壁箱梁的挠曲扭转有限元分析

FLEXURAL TORSIONAL FINITE ELEMENT ANALYSIS OF THIN WALLED BOX GIRDERS

本文根据薄壁杆件的约束扭转理论和有限元方法,推导了薄壁箱梁的约束扭转刚度矩阵.将此刚度矩阵与一般实体杆件的单元刚度矩阵相组合,并注意到薄壁箱梁截面形心和扭心的差别后导出了建立在形心坐标系下的新的薄壁箱梁弯扭组合刚度矩阵,以便工程应用.此外,对薄壁箱梁非节点载荷的处理方法进行了简要说明.最后用本文推导的新的刚度矩阵分析了某一具有非对称断面的两跨薄壁箱形连续梁.

In this paper, the restrained torsional stiffness matrix of thin-walled box girders is derived by means of the restrained torsional theory of thin-walled members and the finite element method. Combining this stiffness matrix with the ordinary stiffness matrix for beam element and in consideration of the difference between the centroid and the torsion center of thin-walled cross sections,a new element stiffness matrix for the torsion-bending coupled analysis of thin-walled box girders is developed, which is in the centroid coordinate system and is convenient for the engineering use. The method for treating thin-walled box girder with loads not acting on nodes in structural analysis is elucidated. Lastly, a numerical example of a two span continuous box girder with unsyin-metric thin-walled section analyzed by the suggested stiffness matrix is presented.