Reinforcement requirements for openings in concrete slabs and walls distinguish between penetrations that interrupt existing rebar and those that do not. For single openings interrupting reinforcement up to 400mm (1'-4") maximum, existing bars are hooked on all four sides with 15Mx1400 (4'-7") long diagonal bars at the mid-depth, plus replacement reinforcement on each side equal to two-thirds of the cut rebar. Non-interrupting single openings up to 400mm (1'-4") maximum require minimum 15M reinforcement on each face around the opening with diagonal bars. Grouped openings up to 300mm (12") diameter require 10M top and bottom extra reinforcement on each side of electrical ducts and sleeves, maintaining a minimum spacing of three times the diameter of the larger sleeve. Openings in slabs closer than 1800mm (7'-10") to columns or walls must be reviewed by the engineer prior to casting.
TYP. 600 (2' - 0") TYP. 600 (2' - 0") 10M TOP & BOT EXTRA EACH SIDE OF ELECTRICAL DUCTS AND SLEEVES TYPICAL MIN 15M EACH FACE EDGE AROUND OPENINGS OPENING 400mm (1' - 4") MAX 15Mx1400 (4' - 7") LONG DIAG MID TYP. 600 (2' - 0") TYP. 600 (2' - 0") OPENING 300mm (12") DIA MAX LARGER SLEEVE 3 x DIAMETER OF (4") 100 SINGLE OPENING WITHOUT INTERRUPTING SLAB OR WALL REINFORCEMENT GROUPED OPENINGS WITHOUT INTERRUPTING SLAB OR WALL REINFORCEMENT 15Mx1400 (4' - 7") LONG DIAG MID EXISTING REINFORCEMENT, HOOK BOTTOM AND TOP REINFORCEMENT THAT INTERFERES WITH THE OPENING (TYP ALL 4 SIDES OF OPENING) OPENING 400mm (1' - 4") MAX TYP. TENSION SPLICE PROVIDE 15M REINFORCEMENT ON EACH SIDE OF OPENING EQUIVALENT TO 2/3 OF THE REINFORCEMENT CUT BY THE OPENING (ROUNDED UP TO THE NEAREST WHOLE NUMBER) SINGLE OPENING INTERRUPTING SLAB OR WALL REINFORCEMENT OPENINGS IN SLAB CLOSER THAN 1800mm (7' - 10") TO COLUMN OR WALLS TO BE REVIEWED. IDENTIFY SUCH OPENINGS TO THE ENGINEER FOR INSTRUCTION PRIOR TO CASTING. MIN
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