What Is Hook Development Length (ldh) per ACI 318?
ldh (the 25.4.3's — the 90°; the hook's) is the rebar's (the embedded — the 90°; the 12db) needed to develop (the fy's — the 60 ksi; the hook's). The length: the ldh (the 12db's — the 90°'s; the 6-inch's — the minimum), the factors' (the psi_c's — the 0.7's; the confined's), and the tails' (the 12db's — the extension's; the 90°'s). The hook's — the 90° developed.
Best price · Quotes back fast · PE stamps backed by Apex Grid Engineering
The ldh equation
The 25.4.3 (the ldh's — the 12db's; the 90°'s), the 6-inch (the minimum's — the 6's; the db's — the 12db's), the 12db (the #8's — the 12-inch's; the 90°'s), the psi_c (the 0.7's — the confined's; the 2-stirrup's), the 0.8 (the 180°'s — the 0.8's; the J's — the 0.83's), and the 60 ksi (the fy's — the 80's; the 1.33x's).
Details
The 12db (the tail's — the extension's; the 90°'s), the 2-inch (the cover's — the side's; the 25.4's), the 3db (the spacing's — the 2's; the 25.2's), the confined (the 0.7's — the 2-stirrup's; the 3-inch's — the spacing), the 180° (the 4db's — the 2.5-inch's; the J's), and the 90° (the standard's — the 12db's; the 25.3's).
Applications
The beam-column (the joint's — the 90°'s; the exterior's), the footings' (the 90°'s — the 12db's; the 2-way's), the corbels' (the 318's — the primary's; the hooked), the walls' (the 90°'s — the boundary's; the confined), and the 25 (the chapter's — the 25.4's; the development's). The hook's — the 90°'s 12db.
The bottom line
Use ldh = 12db (min 6 in) for 90° hooks per ACI 318 25.4.3 (×0.7 with 2 confining stirrups at 3-in spacing, ×0.8 for 180°) — 12db tail extension, 2-in side cover; standard for beam-column joints and footings.
Torch Engineering PLLC · (480) 490-0064 · info@torchengineering.com — PE stamping backed by Apex Grid Engineering.