Abstract
It has long been criticized that the popularly used cold-formed box-section columns in building frames have not sufficient ductility in the local buckling behavior to resist a severe earthquake, because the steel material consumes its ample plastic strain capacity with a rise of yield ratio during the cold-forming process. However, recent development in steel manufacturing processes has established hot-rolled box-columns, in that process cold working is eliminated. Experimental investigation showed that the ductility of stub-columns governed by local buckling is larger in hot-rolled columns than in cold-rolled columns in a range of small width-to-thickness ratios, and consequently it was demonstrated by numerical analyses that hot-rolled columns provide larger plastic deformability under bending moment than cold-rolled columns in the range of small B/t ratios.
