The Effect Of Stiffener To The Stability Of I-steel Beams

Welded I-beams are widely used in the industrial and civil construction.In order to make full use of the material properties,the beam web is high and thin.For ensuring the local stability,we always lay some transverse stiffeners on the web,and also lay some longitudinal stiffeners sometimes.The overall stability is achieved by reducing the torsional and warping in the beams,but the vertical-horizontal stiffeners is little useful to reduce torsional and warping.So in the paper,we present cross stiffener and channel stiffener which were effectively in constraining the torsional and warping.The《Code for Design of Steel structures》only gives the relevant provisions of the vertical-horizontal stiffeners,has not yet given the relevant provisions to calculate the bearing capacity of the beam stiffened by channel stiffener and cross stiffener.Since the beam that with stiffeners has not been studied and the design method is not available, therefore affect the security evaluation of the components.The main objective of this thesis is to study the effect to stability of steel beams when the design parameters of the cross stiffeners and channel stiffeners changes.In the paper,the large-scale finite element program ANSYS11.0 is applied to carry out the finite element nonlinear analysis of the beams which were set up by the channel stiffener and cross stiffener.In the analysis,initial geometric imperfections as well as the residual stress and other factors were taken into account.The formula was introduced to calculate the bearing capacity of the beam stiffened by the channel stiffener which was derived by Carsten M.Plum and others in 1993.We use the finite element program ANSYS11.0 to build model to contrast the calculating result,and Verify the correctness of the formula.Based on the numerous parametric analysis,the paper modify the overall stability coefficientsφb in《Code for Design of Steel structures》and proposed the overall stability coefficientsφs of the channel stiffeners andφ_c,φ_cs of the cross stiffeners.It also gives out a simplify formula for calculating the stability bearing capacity of the beam stiffened by stiffener,which can provide the reference for designing staff.