Research On Intensity Of Steel Box Girder Under Combined Bending And Torsion

All kinds of plates have been welded to produce the steel box girder includingupper plates, bottom plates, flange, stiff and many others. In terms of architecture,box girder has smaller section so that it can provide more space for people and it isconvenient to erect pipe and for wires to pass through. On the other hand, in terms ofmechanical properties, it has good bending stiffness and torsional stiffness. Becauseof its good features of architecture and mechanical properties, box girder is gettingwidely used in the modern architectural engineering.The object this thesis mainly worked on is simply supported box girders undercombined bending and torsion. Due to the excellent mechanical performance of thebox girder, its stability can be well guaranteed in practical engineering. So this thesisconcentrated on the intensity of it. Steel box grider has the deformation of bending,torsion, distortion and local bending. In order to prevent the box grider frompremature failure, diaphragms should be set in it to weaken the latter twodeformations. This thesis can be divided into theoretical analysis and ANSYSsimulation. In the theoretical analysis, the bending performance and the torsionperformance were studied separately at first. But the precise solution can hardly begot by combining those two efforts. Then ANSYS simulation was carried on on thebasis of theoretical analysis. In the use of ANSYS, material nonlinearity, the largedeformation effect and the initial defects factors that exist in practical engineeringwere considered.In the study of intensity, this thesis counted in the influence of span, eccentricity,height-thickness ratio, width-thickness ratio. Then the change pattern of the intensityhas been got when those factors change.At last, this thesis ended up with the bending intensity formula and relationshipformula of intensity considering those factors. They can be used in practicalengineering and be considered when the code is revised.