Abstract: A bridging system (50) for steel joists (56) comprises fasteners (52) secured to the chords (54) of the steels joists (56) by welding. Bridging members (60) comprise the lengths of angle iron having fastener receiving holes (62) formed therein at equally spaced intervals. Selected fastener receiving holes (62) of the bridging members (60) are engaged with the fasteners (52), and the bridging members (60) are mechanically retained in engagement with the fasteners (52). The fasteners (52) may comprise steel dowels, in which case the bridging members (60) are retained by retaining rings (74), or threaded members, in which case the bridging members (60) are retained by nuts (76) threadedly engaged with the fasteners (52).