DESIGN
Project
OF
I S O LAT E D
SLOPED
NATIONAL ENTERPRISE
User
AAM
Date
21-Oct-16
Footing Identifier =
Time
F1
Safe Bearing Capacity of Soil =
Depth of Founding Level below Ground
30
T/m2
(Df) =
Weight Density of Soil & Backfill together
1.8
T/m3
Load Factor for Limit State Method
(LF) =
1.5
Factor
Concrete Grade
(Fck) =
20
N/mm2
Steel Grade
(fy) =
415
N/mm2
Column Dimensions: E_W
Column Dimensions: N_S
Offset from face of column
Crack width
(L1) =
(B1) =
=
=
0.23
0.65
50
0.3
m Width
m Width
mm
m
LOAD CASES
Case
Load (T)
P
I
II
III
IV
V
VI
VII
VIII
DL + LL
DL + LL
DL + LL
DL + LL
DL + LL
DL + LL
DL + LL
DL + LL
120
Moments (T.M)
MZ( @Z )
MX( @X )
M_E-W
M_N-S
0
Soil over
Stress
Factor
1
1
1
1
1
1
1
1
Trial Footing Size
Length - L
Width - B
1.93
2.35
M E_W
M N_S
if (P > Pp) then 'Revise Footing Size'
Depth of Footing at Centre
Eff. Cover to Bott. Reinf. d'
L/B
AREA
1.22
4.5355
Section Modulus
Z_NS
Z_EW
680
70
1.8
1.5
mm
mm
m2
m3
m3
Depth of Footing at Edge
de=D-d'=
Distances from CL of to a) Column Face, b) De from & its Distance from Edge,
Perimeter & Punching Area for Shear ECT,.
For Moment
For punching shear
L1 (E-W)
L (E-W)
B1 (N-S)
B (N-S)
Lpu=(L1+De)
Bpu=(B1+De)
0.23
1.93
0.65
2.35
0.84
1.26
E-W
0.115
0.85
0.725
0.24
Xf
Lf
Xd
Ld
N-S
0.325
0.85
0.935
0.24
perimeter
4.2
Area of footing @ critical section for one way shear
E-W
(((0.23+2*610/1000)+1.93)/2*(344-200)/1000)+((200-70)/1000*1.93)
N-S
(((0.65+2*610/1000)+2.35)/2*(344-200)/1000)+((200-70)/1000*2.35)
E-W
J=
0.35
0.27
C=
0.42
M_E-W
Shear due to Moment =
1.525
2.14366413
Overburden Pressure
Df - D =
0.00
IF (foundation depth-D) is <= 0, then this component is 0
*Volume of concrete x 2.5 + (Total volume of excavation i.e. L x B x D - volume of concrete) x 1.8
OB Load(Ptot)
1.25
Eb = {M_E-W} / (P + Pob)
OB Press(Pob)
0.276
El = {M_N-S} / (P + Pob)
R = 0.138 or 0.15 * fck
R=
0.138
p-max=Ptot*(1+6*Eb/B+6*El/L)
p-min=Ptot*(1-6*Eb/B-6*El/L)
20
P-edge=Ptot*(1+6*Eb/B)
P-face=Ptot*(1+12*Eb/B^2*X
P-d =Ptot*(1+12*Eb/B^2*Xd
M-face = Lf^2*{P-edge/3+P-fa
V-De = Ld*{(P-edge+P-d)*0.5
Punching shear stress =
((A-Ap)*(Ptot-Pob)) /
(P.Perimeter*De)+((M_E-W*a*c_E-W) /
(0.85J_E-W))+((M_N-S*a*c_N-S) /
Case
(0.85*J_N-S))
I
I
III
IV
V
VI
VII
VIII
Ptot
(P+Pob)/A
26.73
M-(E-W)/
M/Z
M-(N-S)/
M/Z
p-max
t/m2
p-min
t/m2
0.00
0.00
26.73
26.73
Err:504
26.73
26.73
Err:504
Limit state
De = SqRt((Mu / K Fck) * b)
De (cm)=
P-edge
t/m2
26.73
Permissible Punching Shear Stress
Ks = (0.5 + c)
c = L / B
c = 0.25 * Sqrt(Fck)
Ks =
c =
= Ks * c
0.85
111.80
=
t/m2
R = Mu / b * de2 - N/mm2
Pt (Req) = 0.5*Fck/Fy{[1-(1-4.6*Mu/B*de^2)/Fck]^0.5}*b*de
Pt (Req)
Min = 0.12%
Ast - Reinforcement to be required = Pt (req) * A * d
Ast - Reinforcement Provided
Pt (Provided) @ Efffective depth d from face of column
=0.85*sqrt(0.8*Fck)*(sqrt(1+5*)-1)/6*
Allowable Shear Stress (t/m2)
=0.8 * Fck / 6.89 * pt
Actual Shear stress (t/m2)
8.12
for E_W
Bearing pressure = Pu/bD in t/m2
for N_S
1.20
1.80
4535500
149500
Permissible bearing pressure = 0.45 fck (sqrt(A1/A2))
A1 = (min of (Lf x Bf or ( b + 4Df )x ( D + 4 Df )
A2 = b x D
where sqrt(A1/A2) should not be greater than 2
Footing Size
Pedestal Dimensions: E_W =
Pedestal Dimensions: N_S =
Length - L: E_W =
Width - B: N_S =
Depth =
Column face
Footing Edge
Ast =
8.19
0.23
0.65
1.93
2.35
680
200
m
m
m
m
mm
Bottom Reinf.
Quantities
Footing
1 Excavation
2 PCC
3 RCC
4 Formwork
5 Reinforcement
Total reinforcement per cft =
Pedestal
1.95
0.59
1.79
1.7
54
m3
m3
m3
m2
Kgs
1 Concrete
2 Formwork
54
1.79
35.314
AT E D
SLOPED
FOOTING
BY
LIMIT
S TAT E
METHOD
Comments: EXECUTION
13:24
0.85
Ld
De
Z-Axis
BP/2
0.24
+
-
Case I
No Tension
Lf =
X - Axis
P-face
P-face
0.85
B pu =
B 1 = 0.65
B =
2.35
1.26
L1 =0.23
Ld
Lf
+
-
Xf = 0.12
Xd =0.725
Lf
Actual /
Allowable
P -fa ce
P -fa ce
Pd
Pd
P e d ge
(P-max
- Pob)
26.46
(0.28)
(0.28)
(0.28)
(0.28)
(0.28)
(0.28)
(0.28)
93.54
For SBC
Fdn Size OK
Punching Shear
Stress (EW)
Stress (NS)
Depth OK
Depth OK
Depth OK
Depth (bending)
Bearing pressure
Depth OK
OK
epth of Footing at Edge
610
mm
1.93 m
200
93.54
(actual /
allowable
allowable)
30.00
0.88
30.00
30.00
30.00
30.00
30.00
30.00
30.00
0.88
Case I
No Tension
Case II
Tension Allowed
L1 (E-W)=
B1 (N-S)=
d eff= 610
mm
Dcentre= 680
D (for one way shear)
For punching shear
Pedge
Ld
P e d ge
0.88
L=
Pd
Lpu = 0.84
+
+
D_os=344 For E-W
area, Ap
Dmin= 200
D_os=344 For N-S
L (E-W)=
1.93 m
&
1.06
=
0.49 m2
(Area of trapaezoid)
0.61 m2
(Area of trapaezoid)
E-W
N-S
0.45
0.49
0.63
N-S
1-(1/(1+2/3*SQRT(Lpu/Bpu)))
J=
[2*(De*Lpu^3)/12]+[2*(Lpu*De^3)/12]+
[De*(Bpu*Lpu^2/2))]
1-(1/(1+2/3*SQRT(Bpu/Lpu)))
C= Lpu/2
Bpu/2
[2*(De*Lpu^3)/12]+[2*(Lpu*De^3)/12
M_N-S
1.08
(0.85*J_E-W)
M=
concrete) x 1.8
2.76
WITH NO TENSION
P-edge=Ptot*(1+6*El/L)
P-face=Ptot*(1+12*El/L^2*Xf)
P-d =Ptot*(1+12*El/L^2*Xd)
-edge=Ptot*(1+6*Eb/B)
-face=Ptot*(1+12*Eb/B^2*Xf)
-d =Ptot*(1+12*Eb/B^2*Xd)
-face = Lf^2*{P-edge/3+P-face/6-Pob/2}L TM
-De = Ld*{(P-edge+P-d)*0.5-Pob}L T/m
P-face
t/m2
26.73
FOR - M_E-W only
P-d
M-face
t/m2
tm
26.73
22.46
22.5
33.7
22.79
FOR - M_N-S only
V@De
t
Punch.sh
strs t/m2
14.92
14.92
22.38
49.15
49.15
73.72
Depth OK
P-edge
t/m2
26.73
P-face
t/m2
26.73
95.46
Depth OK
0.39
0.109
0.12
1720
1414
0.29
38.03
34.76
Depth OK
OK
Summary
Long Side
(E_W)
Kgs
22
Nos.
18
Pedestal
0.855007
m3
m2
Dia
10
Spacing
135
Short Side
(N_S)
Kgs
32
P-face
0.24
Ld
Pedge
Case I
No Tension
Case II
Tension Allowed
0.23 m
0.65 m
d eff/2= 305
D (for Punching shear)
D_ps=536 For E-W
Case II
Tension Allowed
P-face
Pd
Case I
No Tension
P-face
Pd
Lf
P-face
Pedge
D_ps=536 For N-S
B (N-S) =
2.35 m
Column offset+2xEffective depth
D_os
Footing base dimension
D min
N-S
+2/3*SQRT(Bpu/Lpu)))
e*Lpu^3)/12]+[2*(Lpu*De^3)/12]+ [(De*Lpu*Bpu^2)/2)]
(0.85*J_N-S)
FOR - M_N-S only
P-d
t/m2
26.73
M-face
tm
18.45
18.45
27.67
22.79
V@De
t
12.26
12.26
18.38
0.39
0.109
0.12
1413
1728
0.28
.
37.90
34.76
Depth OK
Nos.
22
Dia
10
Spacing
90
