Development lengths of non-standard hooked rebar
Development lengths of non-standard hooked rebar
(OP)
We've got a need for hooks of a #5 bar at the edge of a precast bridge plank with a tighter bend radius than a standard hook (to maintain clear cover requirements).
I've been unable to locate any research or recommendation on how this will effect the development length of the bar. Obviously a tighter bend means more crushing of the concrete in the hook and likely a reduction in the development length contribution of the hook; but the question is by how much.
We're not changing the hook by much, going from a 3.75 inch inside diameter bend to a 3.25 inch diameter bend.
I've been unable to locate any research or recommendation on how this will effect the development length of the bar. Obviously a tighter bend means more crushing of the concrete in the hook and likely a reduction in the development length contribution of the hook; but the question is by how much.
We're not changing the hook by much, going from a 3.75 inch inside diameter bend to a 3.25 inch diameter bend.
Professional Engineer (ME, NH, MA) Structural Engineer (IL)
American Concrete Industries
https://www.facebook.com/AmericanConcrete/






RE: Development lengths of non-standard hooked rebar
RE: Development lengths of non-standard hooked rebar
Professional Engineer (ME, NH, MA) Structural Engineer (IL)
American Concrete Industries
https://www.facebook.com/AmericanConcrete/
RE: Development lengths of non-standard hooked rebar
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RE: Development lengths of non-standard hooked rebar
I believe I've found my solution but would still be interested if anyone can dig up research on development length of non-standard hooks.
Our solution we're going to use for this specific project is the project specs reference the CRSI Manual of Standard Practice which allows a ±0.5 inch tolerance on 180° hook diameter, so we're just going to deliberately use up all the bend tolerance for these hooks.
Professional Engineer (ME, NH, MA) Structural Engineer (IL)
American Concrete Industries
https://www.facebook.com/AmericanConcrete/
RE: Development lengths of non-standard hooked rebar
https://www.erico.com/catalog/literature/CP7E-WWEN...
RE: Development lengths of non-standard hooked rebar
To give you an idea, here's a previous project with a less congested cage but similar to what we're trying to work on. For this one we could turn the hooks into the thicker curb area and not have them tilted. For the new panels we have no such curb to fit the hooks into.
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Professional Engineer (ME, NH, MA) Structural Engineer (IL)
American Concrete Industries
https://www.facebook.com/AmericanConcrete/