Study On Torsional Behavior Of Steel Octagon-web Beam

The steel octagon-web beam(SOWB)is a new type of open web steel bridge developed on the basis of steel ring-web beam.SOWB is composed of top and bottom plates with orthogonal stiffening ribs,regular octagonal web units and end members assembled by high-strength bolts.In this paper,by means of experimental research,finite element calculation and theoretical analysis,the constrained torsion elastic analysis of SOWB is carried out.A large number of parameter analysis of the constrained torsion of SOWB is carried out,and the improvement measures are proposeed.The specific work of this paper includes the following:1.The experimental research on constrained torsional elasticity of SOWB is carried out.The stress distribution of the deck and web under elastic deformation is studied,and the torsional moment of inertia of the main girder is calculated according to the measured deflection.2.The FEA software ABAQUS is used to establish three-dimensional finite element model of shell.The mechanical properties of torsion resistance of SOWB are studied,including the stress distribution rule of deck and web and the overall Mises stress distribution rule of the girder.Compare the experimental data and the FEA results to verify the finite FEA model.3.The SOWB is treated as a homogeneous steel plate by using the shear stiffness equivalent principle and strain energy equivalent principle respectively.Based on the Umansky’s second theory,the calculation formula for restrained torsion of SOWB are derived.4.The framework of parameter analysis model based on softwares of Dassault Systèmes is established.Then it is applied to the example of constrained torsional parameter analysis of SOWB.The important parameters of the structure are selected to study the influence of the parameters on the torsion resistance of the main girder,and the improvement measures are pointed out.5.Based on parameter analysis,the theoretical calculation results are compared with the FEA results.The law of effect of constrained torsion varying with parameters is analyzed.The equivalent plate thickness formula is simplified.Finally,the importance of the parametric analysis model framework for structural parametric design and analysis and its relationship with BIM are pointed out.