Ultimate Strength of Continuous Composite Beams

Ultimate strength and failure modes of continuous composite beams are studied experimentally and theoretically. The theoretical analysis is based on a stress-strain relationship for steel including elastic, plastic, and strain-hardening regions and a stress-strain relation for concrete including ascending and descending portions. Behavioral studies were conducted for a series of beams in which steel sections, concrete slab thickness, and amounts of longitudinal slab reinforcement are varied. Three two-span continuous composite beams were tested. Theoretical values of ultimate load are in good agreement with test results. Based on experimental and theoretical results, design requirements are proposed for ultimate strength design of continuous composite beams.