Composite steel construction has been recognized as one of the most economical systems available for constructing building floors. This presentation focuses on design requirements for composite steel joists as outlined within the Steel Joist Institute's recently published "Second Edition, Standard Specifications for Composite Steel Joists, Weight Tables and Bridging tables, Code of Standard Practice".
Installation of welded shear studs through the steel deck to the top chord of a CJ-Series Joist allows the concrete slab to act compositely, resulting in significant reductions in steel joist weight along with reducing overall floor deflections.
CJ-Series Composite Joists, now utilized in thousands of buildings across the United States, provide shallow floor systems capable of spanning greater distances than other alternate floor systems. Shallow floor heights result in reduced building cladding costs and increase the potential floor rental space for multi-story buildings. Floor-to-floor heights can be reduced with mechanical ductwork and piping running through the open webs. Specifically designed panel configurations are possible so that web openings can accommodate larger HVAC ducts.
Results from prior full scale testing of composite joists conducted by Nucor Corporation are discussed. This research closely examined the behavior of the CJ-Series joist chords, web members, concrete slab, and welded shear connectors.
Conference attendees will develop an understanding of how CJ-Series joists are cambered and how different methods of concrete placement affect the levelness of the finished floor slab. Plenty of examples are provided, covering shear stud sizing and spacing, camber and deflection issues, vibration, and construction concerns. Several actual building projects are shown and discussed