Analytical Study of FRC-Encased Steel Joist Composite Beams

Abstract

An analytical study was conducted to investigate the behavior of fiber-reinforced concrete (FRC)-encased steel joist composite beams under monotonic loading. This new and innovative composite system eliminates the need for shear connectors between the steel joists and surrounding concrete as well as the need for conventional longitudinal and transverse reinforcement, all of which are quite labor intensive. All connections in the system are steel-to-steel. Therefore, the system can be used with cast-in-place or precast construction. Simplified analytical methods are suggested in this paper to calculate the flexural and shear strength of this new type of composite member for analysis and design purposes. The study indicates that the presence of steel joists as well as steel fibers can adequately inhibit the chances of brittle shear failure, thus forcing the system to have a flexural mode of failure. The proposed composite structural system has great potential for use under monotonic and wind loading.