Footing result

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Isolated footing 84 × 60 × 18 in qa 4 ksf f′c 4,000 psi fy 60 ksi #6 bottom bars d 14.62 in
PASS

All checks pass: bearing, flexure, shear, punching shear, development length, column interface.

Soil bearing, overturning and sliding

PASS
D/C bearing (q max / q net) 0.95
qmax (maximum service pressure)
3.39 ksf
qnet (net allowable pressure)
3.53 ksf
Quantity Value
qmax (maximum pressure, ksf) 3.39
qmin (minimum pressure, ksf) 0.61
qnet (qa less overburden and self-weight, ksf) 3.53
eL (eccentricity from ML, in) 0.00
B/6 (kern limit for eL, in) 10.00
eB (eccentricity from MB, in) 9.71
L/6 (kern limit for eB, in) 14.00
Footing self-weight (kip) 7.88
Soil weight above footing (kip) 8.40
Mresist (resisting moment, kip-ft) 301.96
Moverturn (overturning moment, kip-ft) 56.67
Fresist (friction resistance, kip) 35.00
FSot (overturning factor of safety, minimum 1.5) 5.33
FSslide (sliding factor of safety, minimum 1.5) N/A (no lateral force)
Bearing (qmax ≤ qnet) Satisfied
Kern (e within B/6 and L/6, full contact) Within kern
Overturning (FS ≥ 1.5) Satisfied
Sliding (FS ≥ 1.5) Satisfied
Service loads; friction-only sliding resistance ACI 318-19 §13.2.1 · §13.2.2

Flexure

PASS

L-direction bars (parallel to L)

D/C moment 0.40
φMn (design moment capacity)
141.58 kip-ft
Mu (factored moment at column face)
57.34 kip-ft
Quantity Value
b (design width, in) 60.0
d (effective depth, in) 14.62
As,req (steel required for Mu, in²) 0.88
As,min (minimum steel, in², §13.3.3.2) 1.94
Bars (number of #6 bars) 5
As,prov (steel provided, in²) 2.20
s (center-to-center spacing, in) 13.31
Clear spacing (in, minimum max(db, 1 in), §25.2.1) 12.56
a (stress block depth, in) 0.65
φMn (design moment strength, kip-ft) 141.58
Status PASS

B-direction bars (parallel to B)

D/C moment 0.17
φMn (design moment capacity)
187.82 kip-ft
Mu (factored moment at column face)
33.61 kip-ft
Quantity Value
b (design width, in) 84.0
d (effective depth, in) 13.88
As,req (steel required for Mu, in²) 0.54
As,min (minimum steel, in², §13.3.3.2) 2.72
Bars (number of #6 bars) 7
As,prov (steel provided, in²) 3.08
s (center-to-center spacing, in) 12.88
Clear spacing (in, minimum max(db, 1 in), §25.2.1) 12.12
a (stress block depth, in) 0.65
φMn (design moment strength, kip-ft) 187.82
Status PASS
γs (fraction of short-direction steel in the central band, §13.3.3.3) 0.833
φ = 0.90; critical section at the column face ACI 318-19 §13.2.7.1 · Table 21.2.2 · §25.2.1

One-way shear

PASS

L-direction bars (critical section parallel to B)

D/C shear 0.50
φVc (design shear capacity)
45.24 kip
Vu (factored shear at d from the face)
23.07 kip
Quantity Value
ρw (As,prov / (bw·d)) 0.0025
Vc (concrete shear strength, kip) 60.32
φVc (design shear strength, kip) 45.24
Vu (factored shear, kip) 23.07
Status PASS

B-direction bars (critical section parallel to L)

D/C shear 0.22
φVc (design shear capacity)
61.15 kip
Vu (factored shear at d from the face)
13.54 kip
Quantity Value
ρw (As,prov / (bw·d)) 0.0026
Vc (concrete shear strength, kip) 81.53
φVc (design shear strength, kip) 61.15
Vu (factored shear, kip) 13.54
Status PASS
φ = 0.75; no shear reinforcement ACI 318-19 §13.2.7.2 · Table 22.5.5.1

Punching shear

PASS
D/C punching shear 0.81
φvc (design punching stress capacity, psi)
189.7 psi
vu,max (max eccentric punching stress, psi)
154.7 psi
Quantity Value
davg (average effective depth, in) 14.25
bo (critical perimeter at d/2, in) 76.5
Area inside perimeter (in²) 700
β (long side / short side of column) 1.00
αs (location factor, §22.6.5.3) 30
vc (a) (4λsλ√f′c, psi) 253.0
vc (b) ((2 + 4/β)λsλ√f′c, psi) 379.5
vc (c) ((2 + αsd/bo)λsλ√f′c, psi) 479.9
vc governing (minimum of (a), (b), (c), psi) 253.0
Vc (vc·bo·d, kip) 275.78
φVc (design punching strength, kip) 206.84
Critical perimeter fits in the footing Yes
γv,L (moment transfer fraction, L-axis) 0.000
γv,B (moment transfer fraction, B-axis) 0.368
Jc,L (critical section property, L-axis, in4) 0
Jc,B (critical section property, B-axis, in4) 75,364
cAB,B (centroid to interior face, B-axis, in) 6.99
cCD,B (centroid to free-edge face, B-axis, in) 16.13
vu,conc (Vu/(bod), psi) 79.0
vu,max (total eccentric stress, psi) 154.7
φvc (stress capacity, psi) 189.7
φ = 0.75 ACI 318-19 §22.6.4.1 · Table 22.6.5.2 · §8.4.4.2.3

Development length

PASS

L-direction bars

D/C development length 0.38
Quantity Value
ld (development length, in) 17.1
ld adjusted (reduced for excess steel, minimum 12 in, in) 12.0
lavail (available length beyond the critical section, in) 31.0
cb (cover or half spacing term, in) 3.38
ψt (casting position) 1.00
ψe (coating) 1.00
ψs (bar size) 0.80
ψg (grade) 1.00
Status PASS

B-direction bars

D/C development length 0.63
Quantity Value
ld (development length, in) 17.1
ld adjusted (reduced for excess steel, minimum 12 in, in) 12.0
lavail (available length beyond the critical section, in) 19.0
cb (cover or half spacing term, in) 3.38
ψt (casting position) 1.00
ψe (coating) 1.00
ψs (bar size) 0.80
ψg (grade) 1.00
Status PASS
Straight bars in tension, no hooks ACI 318-19 §13.2.7.1 · Eq. 25.4.2.4a · Table 25.4.2.5

Column to footing interface

PASS
D/C bearing on concrete 0.08
φBn (design bearing strength)
1,131.52 kip
Pu (factored load)
100.00 kip
Quantity Value
A1 (loaded area, in²) 256
A2 (supporting area (frustum base), in²) 2,704
φBn (design bearing strength, kip, §22.8.3.2) 1,131.52
As,dowel,min (minimum dowel area, in², §16.3.4.1) 1.28

Feasible dowel sizes

Sizes whose compression development length fits in the footing depth. A design aid; detailing is the engineer’s responsibility.

Bar Number ldc (in)
#4 7 9.5
#5 5 11.9
#6 3 14.2
φ = 0.65 for bearing ACI 318-19 §22.8.3.2 · §16.3.4.1 · §25.4.9.2

Warnings

A2 assumes a frustum concentric with the column; edge column may have a smaller A2 (22.8.3.2)

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