Moment Curvature Analysis of wide-flange steel columns with local buckling dominant mode of failure

Abstract

One of the key information that can provide an insight into the seismic behaviour of structural elements is their force-displacement curve. Such a curve can be obtained based on a moment-curvature analysis and using an equivalent plastic hinge length. Plastic hinge analysis method was utilised for determining the force-displacement curve of wide flange steel columns as part of moment resisting frames. The accuracy of available equivalent plastic hinge length relations for determining the displacement capacity of steel columns was assessed by comparing the analytical results with experimental tests of a database of 33 columns. Kolwankar et al. (2020) method was used to determine the compressive stress-strain curve of steel material. The results showed that these relations are not able to estimate the displacement capacity of steel columns with reasonable accuracy. Therefore, an expression for determining the equivalent plastic hinge length of wide flange steel columns is developed based on a numerical parametric study. The numerical parametric study was conducted by means of a validated finite elements (FE) modelling procedure in software Abaqus. According to the numerical results, the web and flange slenderness ratios and the column axial load intensity affect the behaviour of the columns in terms of their ultimate mode of failure, ultimate strength, and drift capacity. Using the proposed plastic hinge length relation, it is possible to estimate the drift capacity of steel columns with dominant local buckling mode of failure with reasonable accuracy.