| The purpose of this paper was to find out the mechanical behavior of cold-formed steel roof truss under the load and to apply the results to actual design. Following works were carded out in this paper:the mechanical analysis of the elements of the roof truss;the finite element analysis of the continuous beam;the analysis of the simplified design model of the truss,comparison of the theoretical capacity of the truss calculated by the simplified model with that of finite element analysis to verify the validity of the simplified model.The performance of the truss in the elastic stage is consistent with the theory of structural mechanics.Based on the mechanical analysis of truss elements,the simplified model of truss was put forward,and then simplified design method was obtained to calculate bearing capacity of the truss.The moment on top chord of roof truss was considered to be produced completely by vertical load vector,and can be calculated as the continuous beam under uniform load.Axial force of the chord can be calculated by the pinned truss model.Nonlinear finite element software-ABAQUS was used to analyze the various components.The results of the single-span beam pinned at both ends by ABAQUS was consistent with "Technical code of cold-formed thin-wall steel structures" GB50018-2002.Then beams with different load distribution and different supporting were analyzed to get the calculating factor of the maximum moment,which can be used in the design.With pinned model the axial force was calculated for actual project truss.Then,theoretical bearing capacity was calculated by using the code GB50018-2002.At last,the truss was analyzed by using the finite element model,and the two results were compared,it revealed that the simplified model of the truss can be used in the design safely. |
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