Research On Cold-formed Thin-walled Steel Semi-rigid Beam-to-column Connections Of Gable Frames

In recent years, cold-formed thin-walled steel gable framing system caused the extensive concern of engineering and academic circles of home and abroad. Owing to the lagging of research, the internal research achievements is still inadequate in to be used to lay down the design code (specification) and guide design of engineering at present, so the project of this system is still lack in our country. In order to enrich and perfect the exisiting theory research achievements, and promoting the application of cold-formed thin-walled steel gable framing system in our country, this paper use the method of nonlinear finite element analysis, the capability of cold-formed thin-walled steel beam-to-column semi-rigid connections have bean done; Combines current national and abroad research achievements, propose the design methods and suggestions of the cold-formed thin-walled steel beam-to-column semi-rigid connection.This paper designs a series of "cold-formed thin-walled steel beam-to-column connections "based on summing up the research of cold-formed thin-walled steel connections at home and abroad, and through the finite element analyses of the beam-to-column connections, the further studying is going on which analyzes the influence of the member's plate thickness, the quantity of high-strengh bolt, the distance of high-strengh bolt to the rigidity of connections and the stress of the plate, and the modes of failure. The research indicates that all the curves of the M—θhave a liner and a nonliner stage. The most important influence to connections are the member's plate thickness and the distance of the high-strengh bolt. The most of the connections have three failure modes, mode I: bearing failure in gusset plate around bolt hole; mode II :lateral torsional buckling of gusset plate; mode III: flexural failure of connected cold-formed steel section.Through the M—θcurves from the finite element analysis, this paper proposes the multinomial mode of cold-formed thin-walled steel beam-to-column semi-rigid connections. This mode is in keeping with the result of the finite element analysis, and the form is simple.Using the initial connection stiffness which from the finite element analysis, the effect of joint flexibility on the gable frames is analyzed. Furthermore, its rule and some advance on considering the joint flexibility in practical design are put forward.