Postbuckling and Hysteresis Models of Open‐Web Girders

Abstract

The paper presents analytical studies of hysteretic behavior of open‐web girders with angle web members. The partial inelasticity of the member cross section is traced using finite segment formulation with stress‐strain control. A member is divided into a number of segments and, for each segment, the cross section is divided into many small elements, which allows the inelastic deformation of the member to be modeled. Therefore, member stiffness is established for various inelastic deformation stages. The eccentricities and initial imperfections of web members are considered in the analysis. Good agreement between experimental and present analytical results was found for individual angle member. Based on analytical results of open‐web girders, a typical girder's hysteresis model is then generated. The nonlinear bending stiffness matrix of a girder is determined according to the rules for this model. The hysteresis model and the stiffness matrix can be incorporated easily into existing computer programs for seismic analysis of steel buildings.