Tie spacing for slab reinforcement
Tie spacing for slab reinforcement
(OP)
What is the requirement of tie spacing for slab reinforcement? Is there any code specifies minimum or maximum spacing requirements?
Thanks
Thanks
When was the last time you drove down the highway without seeing a commercial truck hauling goods?
Download nowINTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS Come Join Us!Are you an
Engineering professional? Join Eng-Tips Forums!
*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail. Posting GuidelinesJobs |
Tie spacing for slab reinforcement
|
RE: Tie spacing for slab reinforcement
RE: Tie spacing for slab reinforcement
RE: Tie spacing for slab reinforcement
RE: Tie spacing for slab reinforcement
ACI318-08 Cl.11.4.6.1 says 'A minimum area of shear reinforcement Av,min shall be provided in all reinforced concrete flexural members (prestressed and nonprestressed) where Vu exceed 0.5*φ*Vc'. (Vu=Shear force; Vc=Shear capacity of the concrete)
Very similarly, AS3600-09 Cl.8.2.5 says 'Where V*<=0.5*φ*Vc, no shear reinforcement is required, except where the overall depth of the beams exceeds 750mm. (V*=Shear force; Vc=Shear capacity of concrete).
Typically the beam shear or one-way shear in a slab is very low and peaks in regions around the supports which will have thickenings to satisfy punching shear requirements. You can read a recent thread about one-way shear and two-way shear in a recent thread thread507-268971: One Way Shear.
Close ties are provided in torsion strips as punching shear reinforcement. Personally, I have never seen this done and I have read some literature explaining why this reinforcement can be in-effective against punching shear.
Only once have I seen shear reinforcement detailed in a slab for one-way shear at the face of a column. It was for a transfer slab and my opinion was that the shear reinforcement was not necessary.
RE: Tie spacing for slab reinforcement
Thanks
RE: Tie spacing for slab reinforcement
RE: Tie spacing for slab reinforcement
Frequency of tying is dependent on bar size and support locations. If the mat is placed on carrier (bury) bars, which are supported on chairs, then ties can be very infrequent.
As a rule, tying every 4th or 5th intersection is a good place to start. Stagger ties on a diagonal. Ties on #5 bars spaced at 12" might be 4 feet apart, which is usually fine.
John Turner CSP PE
CRSI Greater Southwestern Regional Manager
RE: Tie spacing for slab reinforcement
RE: Tie spacing for slab reinforcement
RE: Tie spacing for slab reinforcement