3. GROUP: 03
GROUP MEMBERS
GROUP MEMBERS
3
SL# NAME ID
01 NOOR E JANNAT 13106166
02 NUR AHMED ZUBAIR SHATU 13206064
03 MINTU MIAH 13206095
04 MD. ABDUL ALIM 13206097
05 MD. MAHADI NAWAZ 13206109
06 S. M. MEHEDI HASAN 13206112
07 MD. SHAMIM REZA 13206010
08 PIAS ROY CHOWDHURY 13306089
09 MD. OSMAN GONI 13306120
10 ATIQUR RAHMAN 13306127
11 MOTIUR RAHMAN 13306008
7. Sheet piling is an earth retention and excavation
support technique that retains soil,
using sheet sections with interlocking edges. Sheet
piles are installed in sequence to design depth
along the planned excavation perimeter or seawall
alignment.
Sheet pile is act as a temporary supportive wall that
been driven into a slope or excavation to support
the soft soils collapse from higher ground to lower
ground.
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8. Use of sheet piles
* Retaining walls
* Bridge abutments
* Tunnels
* Pumping station
* Water treatment plants
* Basements
* Underground car parks
* Port facilities
* Locks and dams
* Waterfront structures
* Piled foundations
* Excavations and trenches
* Cofferdams
* Ground water diversion
* Barrier for ground water
treatment systems
* Containment walls
* Flood protection
* Coastal protection
* Tunnel cut and cover
* Bulkheads and seawalls
* Weir walls
* Slope stabilization
* Landfill
9. ADVANTAGES
1. Provides high resistance to driving stresses.
2. Light weight.
3. Can be reused on several projects.
4. Long service life above or below water with modest
protection.
5. Easy to adapt the pile length by either welding or
bolting.
6. Joints are less apt to deform during driving
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10. DISADVANTAGES
1. Sections can rarely be used as part of the
permanent structure.
2. Installation of sheet piles is difficult in soils with
boulders or cobbles. In such cases, the desired wall
depths may not be reached.
3. Excavation shapes are dictated by the sheet pile
section and interlocking elements.
4. Sheet pile driving may cause neighborhood
disturbance.
5. Settlements in adjacent properties may take place
due to installation vibrations
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11. TYPES OF SHEET PILE
Several types of sheet piles are commonly used in
construction
a) Wooden sheet piles
b) Precast concrete sheet piles
c) Steel sheet piles
d) Aluminum sheet piles
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13. Construction method
Sheet pile may be divided into two basic categories.
1. Cantilever
2. Anchored
Construction methods generally can be divided into
two categories.
a) Backfilled structure
b) Dredged structure
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14. CONSTRUCTION METHODS
Sequence for backfilled structure:
step 1: Dredged the situ soil in front and back of
the proposed structure.
step 2: Drive the sheet piles
Step 3: Backfill up to the level of the anchor and
place the anchor system.
Step 4: Backfill up to the top of the wall
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15. CONSTRUCTION METHODS
Sequence for dredged structure
Step 1: Drive the sheet piles
Step 2: Backfill up to the level of the anchor and
place the anchor system.
Step 3: Backfill up to the top of the wall
Step 4: Dredged the front side of the wall
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17. Design of sheet pile in cohesive soil
Calculating active earth pressure
Calculation of active earth pressure above excavation is
the same as that of cantilever sheet pile in cohesive soil.
The free-standing height of soil is d = 2C/
The lateral earth pressure at bottom of excavation, pa =
h – 2C, where is unit weight of soil. The resultant force
Ha=pa*h/2
18. Design of sheet pile in cohesive soil
Calculating passive earth pressure
For cohesive soil, friction angle, = 0, Ka = Kp = 1.
The earth pressure below excavation,
p1= p-a= 2C-(h-2C) = 4C-h
Assume the embedded depth is D, the resultant
force below bottom of excavation is
HBCDF = p1*D
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19. Design of sheet pile in cohesive soil
Derive equation for D from Mo = 0
Mo = Ha1*y1 – HBCDF* y3 = 0
Where
y1 = 2(h-d)/3-(b-d)
y3 = h-b+D/2
The equation can be determined with a trial and
error process.
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20. Design of sheet pile in cohesive soil
Determination of anchor force:
1. Determine anchor force T from Fx = 0
2. Fx = Ha1– HBCDF-T = 0
3. T = Ha1+ Ha2– HCEF
Design size of sheet pile:
1. Maximum moment locates at a distance y below T
where shear stress equals to zero.
2. T- Ka (y+b-d)2/2=0
3. Solve for y, we have, y = -b+d+2*T/( Ka)
4. The maximum moment is
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21. 5. Mmax = T y - Ka (y+b-d)3/6
6. The required section modulus is S = Mmax / Fb
7. The sheet pile section is selected based on section
modulus
Design of tie rod and soldier beam
Design of tie rod and soldier beam is the same as
that of anchored sheet pile in cohesion less soil
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Design of sheet pile in cohesive soil
22. Design procedure
1) Calculate free standing height, d = 2C/
2) Calculate pa=(h-d)
3) Calculate Ha=pa*h/2
4) Calculate p1=4C-h,
5) Assume a value of D, and calculate HBCDF =
p1*D
6) Calculate R= Ha*y1 – HBCDF* y3.
7) Where
8) y1 = 2(h-d)/3-(b-d)
9) y3 = h-b+D/2
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23. Design procedure
10. If R is not close to zero, assume a new D, repeat
steps 5 and 6
11. The design length of sheet pile is L=h+D*FS,
FS=1.2 to 1.4.
12. Calculate anchored force T = Ha – HBCDF
13. Calculate y = -b+d+2*T/
14. Calculate Mmax = T y - (y+b-d)3/6
15. Calculate required section modulus S= Mmax/Fb.
Select sheet pile section.
16. Design tie rod
17. Design soldier beam. 23
24. Design anchored sheet pile in cohesionless soil.
Given:
Depth of excavation, h = 10 ft
Unit weight of soil, g = 115 lb/ft3
Internal friction angle, f = 30 degree
Allowable design stress of sheet pile = 32 ksi
Yield strength of soldier beam, Fy = 36 ksi
Location of tie rod at 2 ft below ground surface spacing, s
= 12 ft
Requirement: Design length of an anchored sheet pile,
select sheet pile section, and design tie rod
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25. SOLUTION
Design length of sheet pile:
Calculate lateral earth pressure coefficients:
Ka = tan (45-/2) = 0.333
Kp = tan (45-/2) = 3
The lateral earth pressure at bottom of excavation is
pa = Ka h = 0.333*115*10 = 383.33 psf
The active lateral force above excavation
Ha1 = pa*h/2 = 383.33*10/2 = 1917 lb/ft
The depth a = pa / (Kp-Ka) = 383.3 / [115*(3-0.333)] =1.25 ft
The corresponding lateral force
Ha2 = pa*a/2 = 383.33*1.25/2 = 238.6 lb/ft
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26. Assume Y = 2.85 ft
HCEF = (Kp-Ka) Y2/3 = 115*(3-0.333)*2.852/3 =
830.3 lb/ft
y1 = (2h/3-b) = (2*10/3-2)=4.67 ft
y2 = (h+a/3-b) = (10+1.25/3-2)=8.42 ft
y3 = (h+a+2Y/3) = (10+1.25+2*2.85/3) = 13.15 ft
R = Ha1*y1 + Ha2* y2 – HCEF* y3 =
1917*4.67+238.6*8.42-830.3*13.15 = 42.5 lb
R closes to zero, D = 2.85+1.25 = 4.1 ft
Length of sheet pile, L = 10 + 1.2* 4.1 = 14.9 ft
=>Use 15 ft 26
27. Calculate anchor force,
T = Ha1+ Ha2– HCEF = 1917+238.6-830.3 = 1326 lb/ft
Calculate location of maximum moment,
y = -b+2*T/( Ka) = -2 ft + 2*1326/(115*0.333) = 6.32 ft
Mmax = T y - Ka (y+b)3/6 = 1326*6.32 –
115*0.333*(6.32+2)3/6 = 4.7 kip-ft/ft
The required section modulus S= Mmax/Fb = 4.7*12/32 = 1.8
in3/ft
Use PS28, S = 1.9 in3/ft
Design tie rod, the required cross section area,
A = T s / (0.6*Fy) = 1.326*12/(0.6*36) = 0.442 in2.
Use1@ ¾” diameter tie rod, A = 0.442 in2.
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