FOUNDATION ANALYSIS & DESIGN BASE REACTIONS Based on maximum base reaction 1. Moment M
=
1.058 kN.m
FH
=
0.230 kN
FV
=
156.790 kN
2. Shear 3. Axial
GEOMETRY OF FOUNDATION FV M FH b ht G.L
EL +0.00
Dwater G.W.L
Hpedesal
h hs
φ hpad B LW L
DIMENSION Water Table Depth of water table to ground level Dwater =
N/A 0.00 m
Concrete Height of the top of pedestal to the bottom of pad h = 1.00 m Width of pedestal b
=
0.25 m
Width of inner pedestal b'
=
0.25 m
=
1.50 m
=
0.50 m
ht+hs
Width of pad B Height of pedestal hpedestal
Isolated Foundation
ht+hs
Page 1 of 7
pondasi hotel salemba
Rev : 00
FOUNDATION ANALYSIS & DESIGN above G.L ht
=
0.00 m
below G.L hs
=
0.50
=
0.50 m
Thickness of pad hpad
Soil Angle of frustum φ
=
L
=
1.86 m
B+2*(h-ht-hpad)*tan(φ)
Lw
=
1.86 m
B+2*(h-ht-hpad-Dwater)*tan(φ)
20.00 degree
MATERIALS Specified Yield Strength of Reinforcement fy
=
240 Mpa
for d b
<
13 mm
[ plain bar ]
fy
=
390 Mpa
for d b
>=
13 mm
[ deformed bar ]
Specified Compressive Strength of Concrete fc'
=
18.32 Mpa
K- 225
Unit Weight of Water γwater
=
9.81 kN.m
-3
78.50 kN.m
-3
24.00 kN.m
3 -3
14.72 kN.m
-3
Unit Weight of Steel γsteel
=
Unit Weight of Concrete γconcrt
=
Unit Weight of Soil γsoil
=
OVERTUNING STABILITY Concrete Pad Vpad
=
2 B *hpad 3 1.13 m
=
Boundary Condition (I) : D water <=h s VpadwI
=
2 B *hpad
1.13 m3
=
Boundary Condition (II) : h s
=
2
B *(hs+hpad-Dwater)
=
m3
Vpadw
=
3 1.13 1 13 m
Vpadd
=
Vpad-Vpadw 3 0.00 m
= Pedestal Vpedest
=
[b2*(ht+hs)]-[b'2*(hts+ht)] 3 0.00 m
=
Boundary Condition (I) : D water <=(-h t ) VpedestwI
= =
2
b *(ht+hs) 0.03 m
3
Boundary Condition (II) : (-h t )
= =
Isolated Foundation
2 b *(hs-Dwater)
0.02 m3
Page 2 of 7
pondasi hotel salemba
Rev : 00
FOUNDATION ANALYSIS & DESIGN Vpedestw
=
0.02 m
Vpedestd
=
Vpedest-Vpedestw
= Volume of Concrete Vconcrtd
= =
Vconcrtw
Vconcrt
Weight of Concrete Wconcrt
3
3 -0.02 m
Vpadd+Vpedestd 3 -0.02 m
=
Vpadw+Vpedestw
=
1.14 m
=
Vconcrtd+Vconcrtw
=
3 1.13 m
3
= =
γconcrt*Vconcrtd+(γconcrt-γwater)*Vconcrtw
=
hs/3*(B +B*L+L B*L L )-(b ) (b *hs)
15.78 kN
Soil - 1 Footing Volume of Soil Vsoil
=
2
2
1.39 m
2
3
Boundary Condition (I) : D water <=0 VsoilwI
= =
2 2 2 hs/3*(B +B*L+L )-(b *hs)
1.39 m3
Boundary Condition (II) : 0
=
2 (hs-Dwater)/3*(B +B*LW +LW 2)-Vpedestw
m3
= Vsoilw
=
Vsoild
= =
1.39 m
3
Vsoil-Vsoilw 3 0.00 m
Weight of Soil Wsoil
= =
γsoil*Vsoild+(γsoil-γwater)*Vsoilw
= =
M+FH*h h
= =
((Wconcrt+1/2*Wsoil+FV1)*B/2)/M'
20.44 kN
Moment Forces at Bottom of Pad M'
1.29 kN
Factor of Safety for Overturning SFovertr
Isolated Foundation
106.44
>
Page 3 of 7
1.50
OK !!!
pondasi hotel salemba
Rev : 00
FOUNDATION ANALYSIS & DESIGN SOIL BEARING CAPACITY Loads Total weight of concrete considering the overburden pressure Wtotalc (γconcrt -γsoil)* (Vconcrt-Vpedestal above G.L)+γconcrt*Vpedestal above G.L = = Maximum compression force FV = Total compression p force FV'
10.45 kN 156.79 kN
= =
Wtotalc+FV
= =
M+FH*h
167.24 kN
Moment forces M'
1.29 kN.m
Maximum Soil Pressure qmax
=
2 3 FV'/B +6*M'/B
=
-2 76.62 kN.m
qc
=
2 15 kg.cm
qall
=
Allowable Soil Pressure 98.10 kN.m
at
1.00 m depth
-2
Factor of Safety for Soil Bearing SFsoilbearing
= =
qall/qmax 1.28
>
1.00
OK !!!
1.50
OK !!!
SLIDING CAPACITY Total compression force FVc' FVt'
= =
Wconcrt+2/3*Wsoil+FV
= =
Wconcrt+2/3*Wsoil
186.19 kN
29.40 kN
Lateral force FH
=
0.23 kN
Friction coeficient Φ
=
0 45 0.45
Factor of Safety for Sliding SFsliding
= =
Φ*FVt'/FH 57.53
>
REINFORCEMENT Pad 1.
Punch Shear Factored shear force at section FV'' ϕsh*FVcpsh <= FV''
= =
μf*(Wpedestal+FV) 203.24 kN
Shear strength of concrete (0.5) ϕsh*FVcpsh ϕsh*((1+2/βc)*1/6*fc' *bo*dpad), but not greater than = < ϕsh*FVcpsh
=
ϕsh*(1/3*fc'
(0.5)
*bo*dpad)
1421.10 kN
M ifi d ffactor t for f structure t t d 700 ft or 213 meter t Magnified under μf = 1.30 Strength reduction factor for shear ϕsh = 0.85
Isolated Foundation
Page 4 of 7
pondasi hotel salemba
Rev : 00
FOUNDATION ANALYSIS & DESIGN Ratio of long side to short side b/b βc = =
1.00
Perimeter of critical section 4*(b+dpad) bo = =
2722 mm
Effective depth of section (hpad-ppad-1.5*dbpad) dpad = =
431 mm
Concrete cover ppad =
50 mm
Nominal diameter of bar dbpad =
13 mm
Factor of Safety for Punch Shear SFpshear ϕsh*FVcpsh/FV'' = = 6.99 2.
Critical section for moment is at the face of pedestal 2 Mbot (qbot*B*((B-b)/2) )/2 = =
29.21 kN.m
of reinforcement Specified Spec ed yyield e d strength s e g o e o ce e fy = 390 Mpa Specified compressive strength of concrete fc' = 18.32 Mpa Concrete strength factor β1 =
0.85
Strength reduction factor for flexure ϕflex = 0.90 Minimum reinforcement ratio ρmin 0.7/fy = =
1.79E-03
Balanced reinforcement ratio ρbal 0.85*fc'*β1*600/(fy*(600+fy)) = =
2.06E-02
Maximum reinforcement ratio 0.75∗ρbal ρmax = =
Isolated Foundation
1.54E-02
Page 5 of 7
pondasi hotel salemba
Rev : 00
FOUNDATION ANALYSIS & DESIGN Nominal moment strength Mn Mbot/ϕflex = =
32.46 kN.m 2
Rn
= =
Mn/(B*dpad )
m
= =
fy/(0.85*fc')
1.17E-01
2.50E+01
q reinforcement ratio Required ρreq 1/m*(1-sqrt(1-2*(Rn*m/fy))) = ρreq' Required Area Areq
=
3.00E-04
=
1.79E-03
=
ρreq'*B*dpad
=
1159 mm
<
ρmin
2
Used reinforcement :
D
13
-
175
D
13
-
175
Top reinforcement Required minimum reinforcement Used reinforcement :
PEDESTAL 1.
Shear Compression Maximum compression force FV = 156.79 kN Factored maximum compression force FV''' μf*FV = =
203.83 kN
Factored shear force at section FH''' ϕsh*(Fcsh+Fstr) <= FH'''
Spacing of shear reinforcement 2 π/4*dstr *fy*dpedest*n/Fstr S = = <=
( c'''/ϕ ϕsh-Ftsh) π/4*dstr2*fy*dppedest*n/(F -86 mm
Specified yield strength of reinforcement fy = 240 Mpa Specified compressive strength of concrete fc' = 18.32 Mpa
Isolated Foundation
Page 6 of 7
pondasi hotel salemba
Rev : 00
FOUNDATION ANALYSIS & DESIGN Magnified factor for structure under 700 ft or 213 meter μf = 1.30 Strength reduction factor for shear ϕsh = 0.85 Width of pedestal at the top bt =
