A square or rectangular opening in a steel beam or girder web is reinforced with stiffener plates welded to each side of the web. The plates measure one-half the flange width by the web thickness, with fillet welds applied typically. The opening corners feature a radius equal to twice the beam web thickness with a five-eighths inch minimum. Opening dimensions and locations are coordinated with mechanical drawings, restricting penetrations to the middle third span of the beam unless otherwise noted. Flange and stiffener plates are omitted for openings three inches by three inches and smaller.
DETAIL AT SQUARE OR RECTANGULAR OPENING WHERE INDICATED ON DRAWINGS NOTE: FLANGE & STIFF. PLATE NOT REQ'D. FOR 3"x3" AND SMALLER OPENINGS. PLATES 1/2 FLANGE WIDTH x WEB THICK. EACH SIDE OF BEAM TYPICAL. RADIUS = 2 x BEAM WEB THICKNESS, 5/8" MIN., @ CORNERS OF OPENING D 1' - 0" 0.87 x FLANGE WIDTH (B/4 MINIMUM) 1' - 0" HOLES SHALL BE LOCATED WITHIN THE MID 1/3 SPAN OF THE BEAM OR GIRDER U.N.O. DIMENSION "B" VARIES SEE MECH. DWG. (3 D/4 MAX.) MIN. D/3 MAX. D/3 MIN. D/3 1/4 1/4 TYP.
Members view this detail in full resolution, download the CAD files (SVG, PDF), and can adapt it in the built-in CAD editor — export DXF, DWG, or PDF.
Start membership