Research On The Strength And DSM Design Of Cold-formed Steel Plain Channel Axial Compression Column

The design methods of cold-formed steel are effective section method and direct strength method?DSM?.Current American codes give the scope of application of the direct strength method for members with various cross-sections,but do not include cold-formed steel plain channel,that is to say,the current direct strength method can not be directly used to calculate the strength of plain channel members.In recent years,scholars at home and abroad have not studied the applicability of the direct strength method for strength of cold-formed steel plain channel under axial compression.Nowadays,DSM has been more and more welcomed by scholars and engineers all over the world,and has a broad space for development.Therefore,it is imperative to further study the direct strength method.Based on this,this paper takes thin-walled steel plain channel members under axial compression as the research object,and conducts experimental and theoretical analysis on their local buckling,local-global related buckling,overall buckling performance and ultimate bearing capacity.The specific work is as follows:?1?cold-formed steel plain channel properties test and axial compression test.?2?Two batches of test specimens were simulated and analyzed by Abaqus software,and the accuracy of the finite element model was verified.On this basis,the parametric analysis of the strength of plain channel members under axial compression is carried out.The influence of web height-thickness ratio,flange width-thickness ratio and section thickness on the strength of cold-formed steel plain channel axially compressed short columns and the influence of initial geometric defects and section width-height ratio on the strength of cold-formed steel plain channel axially compressed medium-long columns and long columns are found out.?3?Solving local buckling stress is the key to calculate strength of cold-formed steel columns by direct strength method.In this paper,the generalized beam method for calculating the local buckling critical load of section P_crlrl is introduced and expounded in detail.Based on the original formula of direct strength method,the formula of direct strength method for plain channel members is revised.?4?Two batches of test results,the results of other scholars and the simulation results of finite element analysis components are compared with the existing direct strength method formula and the calculation results of the revised formula.The validity of the revised direct strength method formula is verified and the design method available for engineering design is obtained.