DIRECT CALCULATION METHOD OF OVERALL BENDING DEFLECTION FOR COLD-FORMED STEEL FLEXURAL MEMBERS

The effective section method is used for design of cold-formed steel members,in which the effect local buckling on the deflections of members is taken into account in the design codes of most foreign countries.Because the ratio of width to thickness of cold-formed steel members is usually large,besides local buckling,distortional buckling is also occurred during the regular service stage and influences the membersdeflection behavior.It was explored a new method which could be used for calculating the overall bending deflection directly by full sectional properties instead of effective sectional properties.This method could be called direct deflection method(DDM).Based on the existing test results,it was also simulated the tests by the finite element program of ANSYS and the results showed good agreement with the test results.C-section pure bending members with upright,inclined and complex edge stiffeners were selected for finite element parametric analysis.The deflection situations were extracted under every load step for all members.By comparing the scatter pointsdistribution of every curve for different parameters and edge stiffener members,the DDM formulas for upright,inclined and complex edge stiffener members with different thicknesses were established.And the deflection calculation progress was enormously simplified.