Ply And Steel - Concrete Composite Box Girder Space Finite Element Analysis

Based on the mechanics of continuous medium, mechanics of thin-walled structure and the finite element analysis, the overall service behavior of skew steel-concrete composite box girders are analyzed. A spacial displacements model for skew composite box girder is built, a skew slab-beam segment element method for skew composite box girder is present, a finite element calculating program for skew composite box girder is compiled, some analysis about primary design parameters are done, and the laws of stiffness and deformation with different parameters such as skew angle, degrees of shear connection and etc are obtained.The main contents are listed as follows:(1) A calculation method of the special displacement model of skew composite box girder is presented. Regard joints of apical plate, soleplate and web plate as rigid, displacements of any point in all plates are 3-dimensions linear displacements. A formulation of transformation between the orthogonal coordinate and the skew coordinate is presented, then taking the skew coordinate to describe displacements of element. In order to obtain displacements of any point in the plane of slab segment, it is assumed that the special displacements of any point in the joint line between slab segments can be described by Hermite interpolation functions and those two displacements in the plane of slab segment are linear in the transverse direction. In order to use Hermite interpolation functions to describe the displacement of any point off the slab plane, a transverse unit-length frame is cut longitudinally form the skew box girder segment.(4) A method is presented for calculating the elastic strain energies of skew box girder element in accordance with deformation in the inner slab plane and the bending off the slab plane, which including the strain energies from flexure, tensile and compressive, torsion etc.On the basis of principle of total potential energy with stationary value and 'set-in-right-position' rule, a finite element method for slab beam segment of skew composite box girder is presented.(5) According to the theory and method presented by this thesis, a finite element analysis program for skew composite box girder, which can be applied to linear statics analysis of orthogonal box girder, unitary material box girder and skew composite box girder, is compiled.(6) By design parameters analysis on some skew composite box girders with different skew angel and degrees of skear connection, which simulated with the skew slab-beam segment element method and analysis program, the laws of deflection, torsion and slippage with different parameters are obtained. It is some reference for design of skew composite box girders.