Abstract: A composite slab and joist assembly includes a joist, at least one deck panel on the joist, slab reinforcement above the joist and dock panel, and a slab of concrete formed on the deck panel and joist such that the slab encloses the slab reinforcement and a top portion of the joist. The joist includes a bottom chord, a top chord, and a web affixed therebetween. The top chord has first and second structural angles. The first structural angle has in cross-section a horizontally-extending leg and an upwardly-extending leg meeting at a corner. The second structural angle has in cross-section a horizontally-extending leg and a downwardly-extending leg meeting at a corner. The upper portion of the web is joined to the second structural angle against the downwardly-extending leg.