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.