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Calculate Reinforcement For The Heel Of A Concrete
Cantilever Retaining
Wall: |
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Calculation: |
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Designer/Checker: |
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Input: |
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(Note: All input Metric units are converted to English units
for the equations below and then the output English units are converted back to
Metric) |
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Yield strength of the steel reinforcement, (fy - ksi or kPa) |
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(Use 40 ksi for Grade 40 or 48 ksi for Grade 60) |
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Concrete compressive strength, (f'c- psi or kPa) |
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Thickness of base (h - in or cm) |
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Distance from outside face of concrete to center of steel (Cvr - in or cm) |
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Distance to the soil vertical resultant (Ds - ft or m) |
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Vertical soil resultant on the heel (Rs - kip/ft or N/m) |
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Distance to the vertical concrete resultant (Dc - ft or m) |
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Vertical concrete resultant of the heel (Rc - kip/ft or N/m) |
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Distance to the resultant from soil surcharge load (Dss - ft or m) |
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Vertical resultant from soil surcharge load (Rss - ft or m) |
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Distance to the bearing pressure resultant (Dbp - ft or m) |
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Bearing pressure resultant on the heel (Rbp- kip/ft or N/m) |
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Output: |
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b = 12 in; depth to steel d = h - Cvr; Default is 4.5 inches to center of
bar from outside face. |
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ku = 1 - (1 - (Mu/0.9)/(0.425f'cbd^2))^0.5 |
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Mu/0.9 = 1.9(Rh)(D)(12in/ft)/0.9 |
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As = 0.85(f'c)(ku)(b)(d)/fy |
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Shear capacity, 0.85Vc = 0.85(2)(f'c^0.5)bdv must be greater than shear, Vu
= 1.9V |
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Ratio of stress block depth to effective depth, ku = |
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Area of steel required, As = |
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Shear capacity, 0.85Vc = |
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Shear force at distance d on stem, Vu = |
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Minimum reinforcement ratio, pmin = 200/fy = |
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Maximum reinforcement ratio, pmax = 0.25(0.85f'c/fy)(0.85)(0.003/(0.3 +
fy/29000 ksi)) = |
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Reinforcement ratio, p = As/bd = |
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If pmin < p < pmax then ductility adequate. |
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