11.67: Cyclic backbone curves for steel wide‐flange columns: A numerical study

Experimental and analytical studies on the cyclic behaviour of deep, slender wide‐flange steel beam‐columns funded by the National Institute of Standards and Technology (NIST) is ongoing at the University of California at San Diego (UCSD). In parallel with full‐scale column tests, numerical simulations of columns under monotonic and cyclic loading conditions were conducted to generate a wide‐ranging database of results. A correlation study using results from the full‐scale tests was conducted to validate the numerical simulation procedure. The simulated columns covered a wide range of cross‐sectional (local) and member (global) slenderness ratios, axial force level, and yield stress. Regression analyses were conducted to construct moment‐rotation responses, ‘backbone curves’, for use in performance‐based evaluations of steel moment frames. The database is divided into three groups based on observed buckling modes. Computational expressions for the key parameters that define the backbone curves are presented.