Abstract: A composite floor system comprises a system of joists, where each of the joists has a top chord, a bottom chord and a web, including tension and compression members in the space between the top chord and the bottom chord and secured to the top and bottom chords, and the top chord of the joist having a substantially cruciate or cross-shaped cross section about a longitudinal axis of the upper chord.

Abstract: The composite floor system of the present invention comprises a plurality of joists at least partially embedded in the concrete slab of the floor system. In the most preferred embodiments of the present invention, each of the joists is formed from a single piece of cold rolled sheet metal and, in at least one orientation, exhibits a substantially “Z-shaped” or “C-shaped” cross section along a longitudinal axis. In addition, for certain applications, a novel mounting bracket may be affixed to each end of the joists to provide for an underslung installation.