calcnote ACI 318-19
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Beam result

12 × 24 in 3-#8 f′c 4,000 psi fy 60 ksi d 21.62 in
PASS

Flexure and shear D/C ratios ≤ 1.00 and code limits satisfied.

Flexure check

PASS
D/C moment 0.70
φMn (design moment capacity)
212.05 kip-ft
Mu (factored moment demand)
150.00 kip-ft
Quantity Value
As (tension steel area, in²) 2.37
ρ (reinforcement ratio As / (b·d)) 0.0091
a (equivalent stress block depth, in) 3.49
c (neutral axis depth, in) 4.10
β1 (stress block factor, §22.2.2.4.3) 0.850
εt (net tensile strain) 0.01282
εty (yield strain fy / Es) 0.00207
φ (strength reduction factor, §21.2.2) 0.90
Mn (nominal moment strength, kip-ft) 235.61
φMn (design moment strength, kip-ft) 212.05
As,min (minimum steel area, in², §9.6.1.2) 0.86
As,req (steel area required for Mu, in²) 1.63
Minimum steel check (As ≥ As,min) Satisfied
Whitney stress block, singly reinforced ACI 318-19 §22.2 · §9.3.3.1 · §21.2.2

Shear check

PASS
D/C shear 0.58
φVn (design shear capacity)
51.38 kip
Vu (factored shear demand)
30.00 kip
Quantity Value
Vc (concrete shear strength, kip) 32.82
Vs (stirrup shear strength, kip) 35.68
fyt (stirrup yield strength used, ksi) 60
Av (stirrup area, all legs, in²) 0.22
Av/s (provided, in²/in) 0.0275
Av,min/s (minimum, in²/in, §9.6.3.3) 0.0100
Av,req/s (required for Vu, in²/in) 0.0055
smax (maximum stirrup spacing, in, §9.7.6.2.2) 10.8
Vs,max (section limit 8√f′c·b·d, kip) 131.30
Controlling equation (Vc) Table 22.5.5.1(a)
φ = 0.75 for shear ACI 318-19 §22.5 · §9.6.3 · §9.7.6.2
Input summary (values as entered)
b (in)12
h (in)24
Clear cover (in)1.5
Effective depth d (in, computed)21.62
Tension bars3-#8, 1 layer
f′c (psi)4,000
fy (ksi)60
λ (lightweight factor)1
Mu (kip-ft)150
Vu (kip)30
Stirrups#3, 2 legs @ 8 in

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