Standard 90-degree and 180-degree hook geometries for reinforcing bars feature bend diameters, extension lengths, and development lengths indexed by bar size from number 3 through number 18. Uncoated bars embedded in normal-weight concrete require a two-and-a-half-inch minimum concrete cover all around. Hook development lengths vary according to concrete compressive strengths of 3000 psi, 4000 psi, and 5000 psi or greater, with a multiplier applied for lightweight concrete. Reinforcement partially embedded in concrete must not be field bent.
90° D BAR SIZE D (BEND Ø) 90° BEND #3 #4 #5 #6 #7 #8 #9 #10 #11 11 1/2" NOTES: 1.db = BAR DIAMETER. 2.UNCOATED BARS. 3.NORMAL WEIGHT CONCRETE. 4.MULTIPLY HOOK DEVELOPMENT LENGTH BY 1.33 FOR LIGHTWEIGHT CONCRETE. 5.DO NOT FIELD BEND REINFORCEMENT PARTALLY EMBEDDED IN CONCRETE. f'c=3000psi f'c=4000psi f'c≥5000psi E (HOOK EXTENSION) Ldh (HOOK DEVELOPMENT LENGTH) E=12db ALL AROUND 2 1/2" MIN. STD. HOOK Ldh 10 1/4" 9 1/2" 6" 5 1/4" 4 1/2" 3 3/4" 3" 2 1/4" 17" 15 1/2" 14" 12" 10 1/2" 9" 7 1/2" 6" 4 1/2" 22" 18" 16" 14" 8" 19" 12" 6" 17" 14" 11" 7" 6" 20" 17 16" 15" 14" 12" 10" 9" 12" 10" 9" 8" 6" 6" #14 #18 22 3/4" 17" 27 1/2" 20 1/2" 50" 43" 39" 38" 33” 29" 180° BEND 6" 3 1/2" 2 1/2" 5 1/2" 5" 4" 3" 2 1/2" 2 1/2" 9 1/2" 7" 180° D E = 4db ≥ 2 1/2"
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