THE 3-D FINITE ELEMENT ANALYSIS METHOD OF BOX GIRDERS WITH COARSE MESH

To resolve the universal contradiction between the computation accuracy and the computation efficiency in present analysis methods of box girders, the 3-D finite element analysis method of box girders with coarse mesh is proposed. Considering the deformation characters of box girders, two 8-node hexahedral hybrid stress elements with the name of 8N21β and 8N21βc are developed. The construction of the two elements is based on the modified Hellinger-Reissner variation principle with unconforming displacement functions. The 8N21β element is constructed in Cartesian coordinates and can be used for the 3-D finite element analysis of straight box girders, and the 8N21βc element is constructed in cylindrical coordinates and can be used for the 3-D finite element analysis of curved box girders. The numerical examples indicate that the two elements can yield good results under coarse mesh in the 3-D finite element analysis of box girders, and the computation efficiency can be much improved.