| In this paper, three different high cross-ratio model is established,andanalyze the shape of the truss cold-formed steel portal frame structure as awhole.through observation of the finite element analysis results truss failure ischaracterized by: the beam-column connection tuck lever and connected to thebeam chord node, connected to the ridge beam and girder truss apparentbuckling, local stress concentration is very obvious and the force is verycomplex, is beyond the material yield strength. The beams of the vertical webmember only small stress, are to reach their yield strength.Based on above, many factors affect the bearing capacity of performanceon the chord and web thickness, chord and web section type, the level of steelrigid frame beam slope varying parameter analysis. The results show that the barthickness, the form of a rod cross-section, steel level, the slope of the framebeam truss cold-formed steel portal frame ultimate bearing capacity has agreater impact. In addition, the frame of the lateral displacement analysis ofvariable vertical load, studies have shown that changes in vertical load affect the frame lateral deformation, lateral deformation significantly increased with theincrease of vertical load.Secondly, the three sets of model to consider the elastic analysis, plasticanalysis, the second-order inelastic analysis of defective second-order inelasticanalysis, the conclusion that with defective second-order inelastic analysis ismore accurate understanding of the structure of the ultimate bearing capacity. Inaddition, the chord of the two back-to-back C-shaped steel double-limb model isbuilt, nonlinear analysis has been the ultimate bearing capacity of the truss in theform of cold-formed steel portal frame.Finally, referencing above research achievements, current design codes ordocuments, simplified design method of truss cold-formed steel portal framesystem and recommendation is promoted. |
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