This is a technical architectural drawing document containing two detailed construction specifications for structural steel work.
Detail 2 presents a typical roof opening frame and mechanical unit support system. The drawing specifies steel joist configurations using L6x4x3/8 and L3x3x3/8 angles for spans ranging from 7'-1" to 11'-0", with supporting members constructed from L3x3x3/8x0'-4" angles welded to support members. The detail includes specifications for roof opening frames to be installed before the steel deck is in place, with all exposed surfaces requiring welding typical for roof opening frames installed after the deck is positioned.
Detail 3 provides bracing specifications for steel joists with point loads. This detail includes RTU (Roof Top Unit) angle frame point load locations on top of chords, with double-angle bracing (2x2x2x1/8" configurations) at specified locations. A critical note indicates that when point loads exceed 50 pounds and the joist manufacturer has designed the joist for full concentrated load capacity, angles must be in place prior to load application. The contractor is required to coordinate all superimposed loads with the joist manufacturer and engineer before applying any load to ensure proper structural integrity and load distribution.
