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Course InstructorMd. Hishamur Rahman
Faculty, Department Of Civil Engineering, IUBAT
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GROUP: 03
GROUP MEMBERSGROUP MEMBERSSL#
NAME ID
01 NOOR E JANNAT 1310616602 NUR AHMED ZUBAIR SHATU 1320606403 MINTU MIAH 1320609504 MD. ABDUL ALIM 1320609705 MD. MAHADI NAWAZ 1320610906 S. M. MEHEDI HASAN 1320611207 MD. SHAMIM REZA 1320601008 PIAS ROY CHOWDHURY 1330608909 MD. OSMAN GONI 1330612010 ATIQUR RAHMAN 1330612711 MOTIUR RAHMAN 13306008
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SHEET PILE
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PRESENTATION OUTLINE1. Introduction2. Use of sheet piles3. Advantages4. Disadvantages5. Types of sheet piles6. Construction methods7. Design of sheet pile in cohesive soil
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SHEET PILE
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IntroductionSheet 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.
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
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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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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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TYPES OF SHEET PILE Several types of sheet piles are commonly
used in construction
a) Wooden sheet pilesb) Precast concrete sheet pilesc) Steel sheet pilesd) Aluminum sheet piles
12Various types of wooden and concrete sheet piles
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Construction method
Sheet pile may be divided into two basic categories.
1. Cantilever2. Anchored
Construction methods generally can be divided into two categories.
a) Backfilled structureb) Dredged structure
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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 pilesStep 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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CONSTRUCTION METHODS
Sequence for dredged structureStep 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 wallStep 4: Dredged the front side of the wall
DESIGN OF SHEET PILE IN COHESIVE SOIL
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
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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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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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Design of sheet pile in cohesive soil
Determination of anchor force:1. Determine anchor force T from Fx = 0 2. Fx = Ha1– HBCDF-T = 03. T = Ha1+ Ha2– HCEF
Design size of sheet pile:4. Maximum moment locates at a distance y
below T where shear stress equals to zero.5. T- Ka (y+b-d)2/2=06. Solve for y, we have, y = -b+d+2*T/( Ka)7. The maximum moment is
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5. Mmax = T y - Ka (y+b-d)3/66. 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
Design of sheet pile in cohesive soil
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Design procedure1) 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) Where8) y1 = 2(h-d)/3-(b-d)9) y3 = h-b+D/2
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Design procedure10. If R is not close to zero, assume a new D,
repeat steps 5 and 611. 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.
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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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SOLUTIONDesign 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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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 ftLength of sheet pile, L = 10 + 1.2* 4.1 = 14.9 ft =>Use 15 ft
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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/ftThe required section modulus S= Mmax/Fb = 4.7*12/32 = 1.8 in3/ft Use PS28, S = 1.9 in3/ftDesign 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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