| In this article,the specimen is composed of three C-shaped steels and one U-shaped steel.Then,the axially and eccentrically compressed behavior of cold-formed thin-walled quadruple-limb built-up triple-box section column was researched by experiment and finite element analysis.The ultimate bearing capacity of the built-up column was calculated by the Chinese standard Technical code of cold-formed thin-wall steel structures(hereinafter referred to as GB50018-2002)and North American Specification for the Design of Cold-formed Steel Structural Members(hereinafter referred to as AISI2007).Then suggested calculation methods of the axial and eccentric bearing capacity for this built-up column in the specification GB50018-2002 were proposed.First,axially and eccentrically compressed experiments on 15 cold-formed thin-walled quadruple-limb built-up triple-box section columns with different slenderness ratios were carried out.The specimen design,test set-up,test procedure and failure modes,as well as the analysis of test results were introduced and compared in detail.Second,the finite element software ABAQUS was used to simulate the experiment.The finite element model was established based on actual size and initial defects of specimens,then the finite element analysis results were compared with experiment.There was a good agreement between them,so that they can verify each other greatly.On the basis of the correct finite element model,the parameter analyses including slenderness ratios,web highness-to-thickness ratio,screw spacing,eccentric direction and eccentricity were conducted.The results show that the ultimate bearing capacity of specimen decreases with the increase of slenderness ratio and web highness-to-thickness ratio.The screw spacing has little impact on the bearing capacity of the specimen,while the eccentric direction and eccentricity have great influence on the bearing capacity and failure modes of the specimen.Finally,the ultimate bearing capacity of cold-formed thin-walled quadruple-limb built-up triple-box section specimens are calculated through the Chinese standard GB50018-2002 and AISI2007.Then calculated results are compared with test results as well as finite element analysis results.After that,suggested calculation methods suitable for axially and eccentrically compressed cold-formed thin-walled quadruple-limb built-up triple-box section specimens are proposed based on the calculation methods of the Chinese standard. |
