Concrete Development Length for Hook
Concrete Development Length for Hook
(OP)
Hello,
I have a job where I have a one-way-slab (8" deep) that needs to be supported by a 6" wide concrete arch beam. My top slab reinforcement is #4 bars at 12" o.c. Is there a way to obtain the reinforcement development in a 6" wide member or is there a type of connection that would be considered acceptable. ACI says that the absolute minimum development length for a hook is 8 bar diameters or 6". This also made me start thinking about all of the 8" wide concrete walls on condos I see here in Florida. 8" really does not provide enough depth for a reasonable development either. Is there something I am missing here? Any thoughts would be appreciated.
I have a job where I have a one-way-slab (8" deep) that needs to be supported by a 6" wide concrete arch beam. My top slab reinforcement is #4 bars at 12" o.c. Is there a way to obtain the reinforcement development in a 6" wide member or is there a type of connection that would be considered acceptable. ACI says that the absolute minimum development length for a hook is 8 bar diameters or 6". This also made me start thinking about all of the 8" wide concrete walls on condos I see here in Florida. 8" really does not provide enough depth for a reasonable development either. Is there something I am missing here? Any thoughts would be appreciated.






RE: Concrete Development Length for Hook
RE: Concrete Development Length for Hook
You can increase the width of the arch, change the support condition to one in which the slab bears on the beam instead of frames into the beam, or change your reinforcing so that you do not need to develop the bars.
RE: Concrete Development Length for Hook
DaveAtkins
RE: Concrete Development Length for Hook
For example, I know the standard tilt-up concrete wall has dowels that connect the walls to the slab at 1'-0" on center or some such spacing. But some tilt walls I have seen are only 6" thick so you can't get the std hook development length. The dowels (example #4 bars) are bent up into the wall then extend up into the wall further 18 or 24". So I am not sure if ACI allows you to treat the hooked part of the dowel as if it were the same as a straight bar being developed in tension, therefore giving the full development of the hooked dowels.
RE: Concrete Development Length for Hook
I'm not sure what the development length for a #4 is, but the development length for a #8 is only 7.25in. I would guess a #4 is significantly less and will possibly work in your situation.
RE: Concrete Development Length for Hook