CCEER-99-11: Axial and Rotational Ductility of Built Up Structural Steel Members

Abstract

Analytical and experimental test programs were carried out to determine the axial and rotational ductility of built-up structural steel members. The experimental program consisted of testing steel tension members with several An/Ag ratios to determine their axial ductilities. The results showed that if An/Ag is less than Fy/Fu a brittle failure mode is expected. The experimental program also consisted of subjecting a built-up bolted steel member to a constant axial force and a cyclic lateral displacement to determine its rotational ductility. The built-up member was infilled with concrete to delay local buckling of the flanges. The member failed due to a net section fracture of the top and bottom plates. The analytical investigation consisted of performing monotonic pushover analyses of the built-up bolted member using the computer program Drain-3DX. The yield surface, load vs displacement curves, and moment vs curvature demand curves were established for the built-up steel section. (by authors)