ABCDEFGHIJKLMNOPQRSTUVWXYZAAABACAD
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FOUNDATION LOADING
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Christy
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05:43_)30
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12/21/25_)
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ABCDEFGHIJKLMN
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TRAPEZOIDAL SOIL LOADING, ALL EDGES LOADED
16,00' x 16,00' x 2,00'
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The trapezoidal loading calculations are not included
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in the stack calculation set.
Mx
moment about the x-axis or an axis parallel to the
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x-axis, k-ft
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Y-axisMot x
overturning moment about the x-axis, k-ft
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8,0CGY Mrt x
righting moment about the x-axis from loads
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working in the opposite direction of Mot x, k-ft
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2,00
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q 2CGx
center of gravity from the x-axis, ft
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q 1
This is a distance from the x-axis, not a vector.
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MY Width
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ex
eccentricity of all loads including dead and live
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8,0CGX
loads, the slab, and moment due to seismic or
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MX
wind forces geographical center of gravity CGX, ft
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X-axis
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q 3Lengthq 4IXX
moment if inertia about the x-axis or an axis
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parallel to the x-axis, ft4
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Figure 30-1 FOOTING VIEW
q x
soil pressure along the loaded, top, edge, ksf
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row 30
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from x ↑16,00ft
width of slab
from y →16,00ft
length of slab
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IXX ↑5461ft4
rotate about axis parallel to XX
IYY →5461ft4
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CGX ftg ↑8,0ft
from the bottom edge
CGY ftg →8,0ft
from the left edge
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footing plan
load cross hairs
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Locate the Structure CG on the Slab
X0016,0016,0006,48,09,68,08,08,0
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CG PX ↑8,0ft
from the bottom edge
CG PY →8,0ft
from the left edge
Footing Plan
016,0016,0000
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Load Location
8,08,08,06,48,09,6
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h_slab2,00ft
slab depth
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Area256ft2
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weight c76,8k
weight of concrete
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19,0yard3
volume of concrete
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P DL 6,944k
dead loads
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P LL 0,000klive loads
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P DL LL 6,944k
sum of structure DL + LL
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P sum83,744k
sum of structure DL + LL + concrete footing
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q at rest1,309ksf
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Figure 30-2 Footing loaded under entire footing
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bearing area in trapezoidal loading.
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ASD values
ASD values
row 60
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Mot X ↑536,1k-ftMot Y →0,0k-ft
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Mrt DL X 55,6k-ftMrt DL Y 55,6k-ft
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Mrt LL X 0,0Mrt LL Y 0,0
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Mrt slabX 614,4Mrt slabY 614,4
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sum MrtX 670,0sum MrtY 670,0
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row 70
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TRAPEZOIDAL SOIL LOADING, ALL EDGES LOADED -- Continued
16,00' x 16,00' x 2,00'
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aX 1,60ft
(Mrt_X - Mot_X) / p_sum
aY 8,00ft
(Mrt_Y - Mot_Y) / p_sum
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(670,0 - 536,1) /83,744
(670,0 - 0,0) /83,744
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cg X ↑8,00ft
from loaded top edge
cg Y →8,00ft
from loaded right edge
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eX 6,40ftcg X - aX ey0,00ftcg Y - aY
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16,00 from x
16,00 from y
row 80
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8,00 CG Px
8,00 CG Py
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6,40 ex8,00 ax0,00 ey
8,00 ay
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Mot X
Mot Y
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concrete
concrete
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soilsoil
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x-axisy-axis
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Mrt Px
Mrt PY
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8,0 (from x - CGx)
Mrt slabx
8,0 (from y - CGy)
Mrt slabY
row 90
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Figure 30-3 Trapezoidal footing profile
Figure 30-4 Trapezoidal footing profile
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rotating about the x-axis for Mot x.
rotating about the y-axis for Mot y.
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Trapezoidal q in X and Y Directions
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P/A
+ PeXcX /IXX ↑
sum qP/A
+ PeYcY /IYY →
sum q
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q 1 & 20,3270,7851,112ksf0,3270,0000,327ksf
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q 3 & 40,327-0,785-0,458ksf !!!0,3270,0000,327ksf .row 100