Download - Analisis Stabilitas Tiang -EnG
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References:
Coduto, D.P. (1994): Foundation design: principles and
practices
Day, R.W. (2010): Foundation engineering handbook
Hardiyatmo, H.C. (2011): Analisis dan Perancangan
Fondasi, Bagian II
Teng , Wayne C. (1992): Foundation Design
Tomlinson, M.J. (2001): Foundation design and
construction
Deep Foundation
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Topics (from SAP):Kapasitas dukung tiang terhadap gaya lateral
dalam tanah kohesif
a. Ujung tiang bebas (tiang pendek dan tiang panjang)
b. Ujung tiang terjepit (tiang pendek dan tiang panjang)
Defleksi tiang a. Ujung tiang bebas (tiang pendek dan tiang panjang)b. Ujung tiang terjepit (tiang pendek dan tiang panjang)
Analisis stabilitas fondasi tiang
a. Beban tiang
b. Kapasitas dukung tiang
c. Jumlah tiang
d. Susunan tiang
e. Kontrol
Turap
a. Pengertian
b. Tipe struktur turap
c. Tipe turap dari segi bahan
Perancangan turap jenis kantilever
a. Gaya-gaya yang bekerja
b. Panjang turap yang dipancang
c. Dimensi turap dan pemilihan profil turap
Perancangan turap dengan angkur
a. Letak tumpuan angkur
b. Dimensi batang angkur
c. Konstruksi angkur
Fondasi caisson
a. Pengertian dan jenis fondasi caisson
b. Bentuk tampang fondasi sumuran
c. Analisis fondasi sumuran
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Basic principle of Pile Foundation Design
a. Load
• Vertical load (downward/upward)• Lateral load
• Moment
Type of structural load :• Dead load relatively constant over time, including the
weight of the structure itself, and immovable fixtures
• Live load temporary, of short duration, or moving. These
dynamic loads may involve considerations such as impact,momentum, vibration, slosh dynamics of fluids, fatigue, etc.
• Environmental load act as a result of weather, topography
and other natural phenomena (
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Design of Pile Foundation
b. Bearing capacity of the pile
• Dead loadPa : Axial load capacity (downward)
T a : Axial load capacity (upward)
Ha : Lateral load capacity
• Live load / Environmental load
Pas = 1½ PaT as = 1½ T a
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c. Number of pile
Based on dead load
V : Vertical load
Pa : Allowable axial load capacity
n : number of pile
d. Pile arrangement
By trial and error
• Pile distance > minimum distance
• The center of pile group is located at the load resistance point
a P
V n
Design of Pile Foundation
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Example:
An upper structure is made by reinforced concrete, with the
sectional size of 2,0 m x 2,0 m, and 20 m high. Pile foundation isused with the thickness of pile cap = 1,0 m, pile head on the ground
surface. Seismic coefficient = 0,10.
Allowable bearing capacity of the pile (based on soil characteristic)
• Pa = 400 kN/pile dead load
• T a = 100 kN/pile dead load
• Ha = 10 kN/pile dead load
Unit volume weight of concrete ( concrete) = 25 kN/m3
Design the pile foundation.
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Solution:
a. Considering dead load
Construction weight, P1 = 222025 = 2000 kN
Assumed Pile-cap weight, P2 = 250 kN
Total vertical weight, V = P1 + P2 = 2250 kN
Number of pile use 6 piles
The seismic load may act to every direction, therefore
symmetrical piles is considered.If pile-cap is square use 8 piles.
6,54002250
a P V n
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Control of the pile-cap weight
Pile-cap weight
= 331 m325kN/m3 = 225 kN
P1 = 2000 kN
Pile-cap load = 225 kNV total = 2225 kN
p (=287,12 kN) < Pa (= 400 kN)
The foundation can be used
kN128,278
8
2225
n
V p
P1=2000 kN
O
0,5
O
0,5
0,5 0,5
1,0
1,0
1,0
1,0 1,0
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b. Control by the seismic load
Seismic load is calculated as the weight of upper structure,
working on the center weight of the structure.
Upper structure weight:
= 2225 kN = 2000 kN
Seismic load (H):
= 0,12000 = 200 kN
(center weight is working at 10 m
above the ground surface)
20 m
1 m
P2
P1
H
10 m
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Conclusion:
• Due to dead load OK
• Control by seismic load NOT OK
• Increase the pile distance (moment arm)
Pile-cap weigth
= 3,53,5125 = 306,25 kNV = 2000 + 306,25 = 2306,25 kN
H = 200 kN
M = 2200 kN m
x 2 = 3(-1,25)2 + 3(+1,25)2 = 9,375 m2
0,5
O
0,5
0,5 0,5
1,25
1,25
1,25 1,25
IIIIII
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Dead load
< Pa (= 400 kN)
Seismic load
< 1,5 Pa (downward)
< 1,5 T a (upward)
Conclusion :
The pile foundation arrangement can be applied to support dead
load and seismic load
kN28,288
8
25,2306
n
V p
kN615,581
375,9
25,12200
8
25,2306III)(columnmaks
p
kN052,5
375,9
25,12200
8
25,2306I)(columnmin
p
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Control by the lateral load due to earthquake
Without inclined pile : Ht = H
For each pile : > Ha= 10 kN
The use of inclined pile is considered
Inclined pile of number: 2, 5, 4, 7
Pile inclination 1 : m = 1 : 4
kN258
200 n
H h t t
0,5
O
0,5
0,5 0,5
1,25
1,25
1,25 1,25
1 2 3
4 5
6 7 8
1
4
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Col I : ( )
( )
< 1,5 T a OK
Col II : (no inclined piles)
( )
Col III : ( )
( )
< 1,5 Pa OK
kN052,5614 P P V
kN263,14
052,544
m
V
H
kN43,41 244 mm
V P
kN28872 n
V V V
kN14555 n
V H
kN581853 P V P
kN5991 255 mn
V P
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Lateral load
= 200 + (-1,263 – 145,404) = 53,333 kN
< Ha= 10 kN
Conclusion: the group pile arrangement could support the horizontalload.
NOTE:Seismic load may work to every direction, therefore the inclined
pile is designed symmetrical to both X and Y axes.
it H H h
kN667,68333,53
n H h t t