Continuity Analysis Of Honeycomb Steel Beams Considering Shear Effects

The castellated steel beam has the advantages of large bending rigidity,high bearing capacity,reasonable section form,and significant economic benefits.However,compared with the solid web beam,the castellated steel beam has a larger shear deformation,which obviously affects the stress and deformation of the beam.This paper proposes a new homogenized method for theoretical calculations of the beam,considering the large shear deformation.In this paper,the research work on the internal force,deformation and elastic stiffness of castellated steel beam covers the following aspects:(1)The fabrication method and research status of castellated steel beam are introduced.This paper summarizes and analyzes the theoretical calculation and analysis methods of castellated steel beam,and points out that the above methods are not applicable to the calculation of castellated steel beam with large span.(2)For a common castellated steel beam,the continuous distribution coefficients of shear stiffness,bending stiffness and axial stiffness of the web post of four different openings of castellated steel beams with horizontal oval holes,circular holes,regular hexagonal holes and general hexagonal holes are obtained based on the equivalence of displacement and rotation angle of unit cell.The influencing factors of each continuous distribution coefficient are analyzed,and the suggested values of each factor in these coefficients are given,respectively.(3)Using the above-mentioned continuous distribution coefficient,the castellated steel beam is homogenized to a solid web beam.According to the different stress characteristics between the castellated steel beam and the sandwich beam,and based on the theory of linear elasticity with small deformation,the basic balance governing equation of castellated steel beam is derived in the two cases where the back bending point is in the middle and the back bending point is not in the middle.(4)The basic equilibrium equations of the castellated steel beams with the bending point in the middle and the bending point not in the middle are solved respectively,and the result of FEM,and the outcome of existing theory shows that the theoretical formula in this paper takes into account the large shear deformation of castellated steel beams.Thereby,the solution in this paper is more accurate than the existing theory.In order to avoid an excessive shear deformation,the factors,affecting the bending stiffness reduction coefficient and the shear deformation ratio of the beam,are analyzed to acquire the value ranges,including the unit cell spacing to beam span ratio,the web post height to its width ratio,and the beam span to its height ratio under two different conditions.