The Research On The Effective Length Of Compression Web Members In Cold-formed Thin-walled Steel Truss

In recent years, the cold-formed thin-walled steel has been applied widely in the low-rise dwellings and villa abroad with much its advantage,such as light weight,superior performance of carrying force,etc.。Following the rapid development of the light-weight steel structure,the cold-formed thin-walled steel trusses are adopted extensively as residential roof and floor carrying systems。A cold-formed thin-walled steel truss is composed of many members,in order to ensure the stability of this type of structure, the carrying capacity of single compressed member must be analyzed ,which is represented by the concept of member's effective length。Therefore the effective length value directly affect the carrying capability of compressed members,and it is necessary and important to make full use of the material's mechanical property。In current practice of the stability's analysis of cold-formed thin-walled steel trusses,the joints of truss are simplified to ideally pinned connections。Although the adoption of such idealized joint behavior simplifies the analysis and design processes,it by no means represents the actual carrying behavior of the compressed members。The self-drilling screws are usually used as fasteners to connect the members in cold-formed thin-walled steel trusses,this kind of connection is a semi-rigid connection,it usually act as constraints to the compressed members,compared to the model which is connected by ideally pinned ,it increases the carrying capacity of the compressed members,i.e. ,decrease the members'effective lengths。Based on the column deflection curve method (CDC method),the paper analyzed the effect of semi-rigid connection to the effective length of compressed web members in the cold-formed thin-walled steel truss。Considering the effect of effective section and using mutative stiffness members as model,the paper calculated the variety of column curve under the different M ?θcurve。Based on compared the effective length value under only considering initial disfigurement with considering the both initial disfigurement and semi-rigid connection,the suggestion value of effective length factor μin plane of compressed web members in cold-formed thin-walled steel truss were presented。...