Design parameters for vertical bars (concrete wall: ACI 318)
Minimum and Maximum Vertical Bar Diameter
There are no code provisions, but user defined limits can be applied to the minimum and maximum bar diameters - specified in Design Options > Wall > Reinforcement Layout
Minimum and Maximum Vertical Loose Bar Spacing
Limiting minimum horizontal spacing of the vertical bars, sv,lim,min is controlled by the diameters of the 2 adjacent bars and aggregate size1.
sv,lim,min |
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0.5*(dbv,i + dbv,(i + 1)) + cgap |
where
cgap |
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min. clear distance bet. bars | |
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max (1.5*dbv,i , 1.5*dbv,(i+1), 1.33* hagg, 1.5 in.) | US units | |
|
max (1.5*dbv,i , 1.5*dbv,(i+1), 1.33* hagg, 38mm) | metric units | |
where | |||
dbv,i and dbv,(i+1) |
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the diameters of the two adjacent vertical bars | |
hagg |
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aggregate size |
Limiting maximum horizontal spacing of the vertical bars, sv,lim,max is controlled by the wall thickness.
sv,lim,max |
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min (3*hw, 18 in.) | US units |
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min (3*hw, 450mm) | metric units |
You are given control over these values by specifying minimum and maximum spacing limits in Design Options > Wall > Reinforcement Layout.
Minimum and Maximum Reinforcement Area
The code provisions which control the vertical reinforcement area are,
- Limiting minimum ratio of vertical reinforcement area to gross concrete area, rv,lim,min
- Limiting maximum ratio of vertical reinforcement area to gross concrete area, rv,lim,max
The controlling values are:
IF dbv ≤ No. 5 (No. 16) with fy ≥ 60,000 psi (420 MPa) OR WWR ≤ W31 or D31
then ρv,lim,min = 0.0012 else 0.0015 for all other deformed bars
Total minimum area of vertical reinforcement, As,min = ρv,lim,min*Acg
Total maximum area of vertical reinforcement, As,max = ρv,lim,max*Acg = 0.08*Acg
where Acg = Gross area of the concrete wall.
Where 2 layers are specified, this should be distributed equally to each face.
You are given further control over the minimum and maximum reinforcement ratio values via user limits in Design Options > Wall > Reinforcement Layout. These will be used if they are more onerous than the code limits.