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UNIVERSITY OF TRANSPORT AND COMMUNICATIONS INTERNATIONAL EDUCATION FACULTY DESIGN OF DRIVEN PILE ASSIGNMENT Full name : Nguyen Thien Long ID Student : 172603217 Course : 58 Major : Advanced Training Program Project Supervisor's Report : Assoc Prof.PhD Nguyen Chau Lan Hanoi, November 2020 Foundation design Geotechnical Faculty Category Part I SOIL INVESTIGATION REPORT Contents I Geological structure and characteristic of soil layers II Conclusion and suggestion: I Designing the size of the foundation 1.1 Size and elevation of pier and foundation 1.2 Size and elevation of pile .6 II Design Load 2.1 Weight of column 2.1.1 Height of pier (without pier cap) 2.1.2 Total volume of pier (without pier cap) .8 2.1.3 Volume of pier, which is under water (without pier cap): 2.2 Design loads group corresponding lowest water level 2.2.1 Standard load at longitudinal bridge in service limit state 2.2.2 Designed load at longitudinal bridge in strength limit state III Axial Capacity .10 3.1 Axial bearing capacity of material of pile PR .10 3.2 Bearing resistance of soil QR 11 3.2.1 Frictional Resistance Qs 12 3.2.2 Load carrying capacity of the pile point Qp .14 3.3 Single Pile bearing capacity Ptt 15 IV Pile number and pile distribution in foundation: 15 4.1 Computing Pile number n: 15 4.2 Pile distribution 15 4.2.1 Arranging piles 15 4.2.2 Cap volume: .15 4.3 Loads transfer to cap 15 4.3.1 Loads in service limit state 15 Nguyen Thien Long - 172603217 ATP 58 Foundation design Geotechnical Faculty 4.3.2 Loads in strength limit state 16 V Checking Strength Limit State 16 5.1 Checking single pile axial resistance 16 5.1.2 Checking single pile axial resistance: .18 5.2 Checking the axial bearing capacity of group pile: 18 VI Checking Service Limit State 19 6.1 Determine total consolidation settlement 19 6.2 Checking pile head displacement .21 VII Strength of bars and pile joint 22 7.1 Computing and arranging vertical bar in pile .22 7.1.1 Computing maximum moment of lifting and pitching of pile 22 7.1.2 Caculating the number of reinforce bars needed .23 7.2 Reinforcement of the belt for the pile 24 7.3 Detail of hard pile rod reinforcement 25 7.4 Reinforced wire rod 25 7.5 Steel stake head 25 7.6 Steel hooks 25 VIII Joint construction 25 Nguyen Thien Long - 172603217 ATP 58 Foundation design Geotechnical Faculty Part I SOILS INVESTIGATION REPORT I Geological structure and characteristic of soil layers At Drilled Hole - BH4, drilled to - 40m met layer of soil: ■ Layer 1: Grey-Clayey Silt, liquid state Elevation of the surface: 0.0(m) Bottom elevation: -5.2(m) Water content W = 25.8% Saturated ratio Sr = 85.3% Plastic Index IL= 0.51 ■ Layer 2: Fine sand, grey, very loose Layer occurs in Drilled Hole - BH4 founded under Layer Thickness: 9.0(m) Elevation of the surface: -5.2(m) Bottom elevation: -14.2(m) ■ Layer 3: Green, grey -Clayey Silt, semi-solid state Layer occurs in Drilled Hole - BH4 distributed under layer and layer Thickness: 4.3(m) Elevation of the surface: -14.2(m) Bottom elevation: -18.5(m) Water content W = 20.6% Saturated ratio Sr = 80.9% Plastic Index IL = 0.47 ■ Layer 4: Grey - Fine Sand, semi-dense state Layer occurs in Drilled Hole - BH4, distributed under layer 1, layer and layer Thickness: 21.5(m) Elevation of the surface: -18.5(m) Bottom elevation: -40.0(m) II Conclusion and suggestion: ■ Conclusion: The profile of soil in this area is diverse, complicated and non-uniform Layer & were weak layer because of low SPT index and load capacity, layer had average SPT index, and layer had highest ratio Layer would be appeared settlement when put the foundation in there, ■ Suggestion: Due to this profile, the recommended suggestion is Friction pile- Concrete pile The end of pile should be placed into layer Nguyen Thien Long - 172603217 ATP 58 Foundation design Nguyen Thien Long - 172603217 Geotechnical Faculty ATP 58 Foundation design Geotechnical Faculty Part II Technical design Overall Design I Designing the size of the foundation 1.1 Size and elevation of pier and foundation Elevation of pier In navigable waterway, the elevation of grider’s bottom is calculated as following: Where: o o o o o PTE: Pier top elevation HWL: The highest water level NWE: Navigable water elevation NC: Navigational clearance EGB: Elevation of grider’s bottom So, Choose EGB= 7.3(m) So, Elevation of foundation: o The thickness of foundation(TF): 2(m) o The elevation of foundation’s top(EFT): Choose EFT = -2.5(m) o The elevation of foundation’s bottom(EFB): Elevation of pile: o The thickness of pile cap(TPC): 1(m) o The elevation of pile cap’s top(EPCT): o The elevation of pile cap’s bottom(EPCB): concided with EFB, so EPCB=-4.5(m) 1.2 Size and elevation of pile ❖ Pile tip elevation: -35.50(m) ❖ Shape and size of pile: The cross section of piles is square and the size is 450x450(mm2) ❖ Length of piles: (without the length of pile cap) The slender of pile: Nguyen Thien Long - 172603217 ATP 58 Foundation design Geotechnical Faculty ❖ Total length of precast concrete pile:The pile is divided into segments, each segment is 8m long and spliced by weld II Design Load 2.1 Weight of column 2.1.1 Height of pier (without pier cap) Height of pier(without cap) Htr: Where: o Pier top elevation o Elevation of foundation’s top o Head cap thickness : PTE = 7(m) : EFT = -2.5(m) : HCT = 0.8+ 0.6= 1.4 m 2.1.2 Total volume of pier (without pier cap) Total volume of column Vtr: 2.1.3 Volume of pier, which is under water (without pier cap): Volume of pier column under water surface Vtn: Trong đó: LWL = 3.1(m) : Lowest water level Nguyen Thien Long - 172603217 ATP 58 Foundation design Geotechnical Faculty EFT = -2.5(m) : Elevation of foundation’s top Str : Area of column’s cross section (m2) 2.2 Design loads group corresponding lowest water level Load Unit Service limit state - Vertical dead-load in service limit state at top of pier kN 5000 - Vertical live-load in service limit state at top of pier kN 2500 - Lateral live-load in service limit state at tranverse kN 120 Mo- Momentum of live-load in service limit state KN.m 900 Load factor: Live load : n = 1.75 Dead load: n = 1.25 kN/m3): Unit weight of concrete = 9.81(kN/m3) : Unit weight of water 2.2.1 Standard load at longitudinal bridge in service limit state ■ Standard Axial load at longitudinal bridge: ■ Standard Lateral load at longitudinal bridge: ■ Standard Moment at longitudinal bridge: 2.2.2 Designed load at longitudinal bridge in strength limit state ■ Designed axial load at longitudinal bridge ■ Designed lateral load at longitudinal bridge: ■ Designed moment at longitudinal bridge: Nguyen Thien Long - 172603217 ATP 58 Foundation design Geotechnical Faculty Table of combination of load at top of cap: Load Unit Service Limit State Strength Limit State Vertical Load kN 8659.62 12074.53 Horizontal Load kN 120 210 Moment kN.m 2040 3570 III Axial Capacity 3.1 Axial bearing capacity of material of pile PR ■ Material of pile: - Concrete: f’c = 30 (Mpa) - Reinforced bars: bars Ø 25 f'y = 414 (Mpa) Ast= 510 (mm2) Nguyen Thien Long - 172603217 ATP 58 Foundation design Geotechnical Faculty Where: o f’c: 28-day compressive strength of concrete o Ast: area of cross-section of reinforced steel o f’y: yield strength of steel ■ The factored bearing capacity of a pile: PR Consider that pile bears compressive force only, the resistance force according to material: Where: : Resistance coefficient, = Ag: Gross area of cross-section of pile, Ast: Area of cross-section of reinforced steel, Calculated axial resistance load Nominal axial resistance load Hence: 3.2 Bearing resistance of soil QR With: Where: Qp: Frictional tip resistance load(MPa) qp : Unit frictional tip resistance load(MPa) Qs : Frictional side resistance load(MPa) qs : Unit side resistance load(MPa) Ap: Area of pile’s tip(mm2) As : Area of pile’s side(mm2) :Resistance factor for tip resistance, : Resistance factor for side resistance, Type of soil Clay Nguyen Thien Long - 172603217 0.7 10 ATP 58 Foundation design Geotechnical Faculty Sand Sand 1 0.45 0.45 3.2.1 Frictional Resistance Qs Methodology for calculating: Cohensionless soil(sand): SPT method Cohensive soil(clay): -method Cohensive soil: qs S u Where: Su: Undrained shear strength (Mpa), Su = Cuu : Adhension factor applied for S u according to Tomlinson(1987) designed curve in LRFD specification 2007 Layer Thickness (m) Perimeter (m) Undrained shear strength (MPa) Li 5.2 4.3 U 1.8 1.8 Su 23.4 30.8 Factor 1 Unit frictional side resistance load(MPa ) qs 23.4 30.8 Area of pile’s side (m2) As 9.36 7.74 Frictional side resistance load(kN) 219.024 238.392 ■ Cohensionless soil(sand): and qs = 0.0019 where : As: Side area of pile (mm2) : Corrected SPT blow count (blow/300mm) Correction process for SPT: Using formula: Where: N: Uncorrected SPT blow count(blow/300mm) : Vertical effective stress(MPa) Calculated for : Nguyen Thien Long - 172603217 11 ATP 58 Foundation design Geotechnical Faculty Unit weight of soil (kN/m3) Layer Unit weight of water (kN/m3) 26.6 26.6 9.81 9.81 Specific gravity Void ratio Gs 2.711519 2.711519 e 1.08 0.89 Saturated unit weight (kN/m3) 17.88212 18.6936 Calculated for and : Layer Depth (m) 2 2 4 4 4 4 Db 10.25 13.25 16.25 18 20.45 23.45 26.45 28.45 30.45 32.45 34.45 35.5 Vertical effective stress(MPa) 82.73918 106.9555 131.1719 145.2981 181.6696 208.3204 234.9712 252.7384 270.5056 288.2728 306.0399 315.3677 Uncorrected SPT blow count (blow/300mm) N 12 12 21 21 20 21 21 22 Corrected SPT blow count (blow/300mm) 9.463539 2.896966 4.487023 10.35842 6.307957 8.912622 14.75168 14.23979 13.10733 13.31596 12.89595 13.28916 Calculating Qs: Laye r 2 2 4 Thickness(m ) Perimeter(m ) Li 1.25 3 1.75 1.95 U 1.8 1.8 1.8 1.8 1.8 1.8 Nguyen Thien Long - 172603217 Corrected SPT blow count (blow/300mm ) 9.463539 2.896966 4.487023 10.35842 6.307957 8.912622 12 Unit Area Frictional frictional of side side pile’s resistanc resistance side e load(MPa) (m ) load(kN) qs As 0.0171 17.1 38.475 0.0057 5.7 30.78 0.0095 9.5 51.3 0.0228 22.8 71.82 0.0152 15.2 53.352 0.0228 22.8 123.12 ATP 58 Foundation design 4 4 4 Geotechnical Faculty 2 2 1.05 1.8 1.8 1.8 1.8 1.8 1.8 14.75168 14.23979 13.10733 13.31596 12.89595 13.28916 0.0399 0.0399 0.038 0.0399 0.0399 0.0418 39.9 39.9 38 39.9 39.9 41.8 215.46 143.64 136.8 143.64 143.64 79.002 The total frictional side resistance load: Layer Frictional side resistance load(kN) Coefficient 219.024 192.375 238.392 1038.654 0.7 0.45 0.7 0.45 Total Total frictional side resistance load(kN) 175.2192 115.425 190.7136 623.1924 1104.55 3.2.2 Load carrying capacity of the pile point Qp The pile tip contacted with sand in layer 4, calculated Qp corresponding and Where: Ap: Area of pile tip(mm2) : Corrected SPT blow count(blow/300mm) D: Pile diameter (mm) Db: Depth of penetration (mm) qI: Limiting tip resistance load(MPa) qI = 0.4 for sand Layer Area of pile tip(m2) Corrected SPT blow count (blow/300mm) Ap 0.2025 13.28915868 Limiting tip resistance load (MPa) ql 39.83794 Total frictional tip resistance load(kN) Facto r Calculated frictional tip resistance load(kN) Qp=qp x Ap 806.7184 0.45 484.3898 Soil bearing capacity: Nguyen Thien Long - 172603217 13 ATP 58 Foundation design Geotechnical Faculty 3.3 Single Pile bearing capacity Ptt IV Pile number and pile distribution in foundation: 4.1 Computing Pile number n: Where: N: Designed axial load at longitudinal bridge at strength limited state(kN) Ptt : Single pile bearing capacity (kN) Changing numbers: thus n = 12 4.2 Pile distribution 4.2.1 Arranging piles Piles are arranged in square pattern on plan view, with parameter below: The number of piles: n = 12 The number of pile’s line according to longitudinal direction: n = The spacing between centre of piles responding to longitudinal direction: a = 1400mm The number of pile’s line according to cross section direction: n = The spacing between centre of piles responding to horizontal direction: b = 1400mm The distance from edge of foundation to centre of pile according to longitudinal and horizontal direction: a = b = 500(mm) 4.2.2 Cap volume: With 12 piles, We have overall dimensions of pile cap: Where: a = 2700mm b = 2700mm Cap volume: 4.3 Loads transfer to cap 4.3.1 Loads in service limit state ■ Standard axial load at longitudinal bridge: = Nguyen Thien Long - 172603217 14 ATP 58 Foundation design Geotechnical Faculty ■ Standard lateral load at longitudinal bridge: ■ Standard moment at longitudinal bridge: 4.3.2 Loads in strength limit state ■ Designed axial load at longitudinal bridge: ■ Designed lateral load at longitudinal bridge: ■ Designed moment at longitudinal bridge: Table of loads acting at the bottom of pile cap Loads Unit Service Strength Limit State Limit State Axial load kN 10804.36 14755.45 Lateral load kN 120 210 kN.m 2280 3990 Moment V Checking Strength Limit State 5.1 Checking single pile axial resistance Methodology: Using FB-Pier Final Maximums for all load cases Result Type Value Nguyen Thien Long - 172603217 Load 15 Comb Pile ATP 58 Foundation design Geotechnical Faculty Maximum pile forces Max shear in 0.7589E+01 direction Max shear in kN -0.6228E+00 direction Max moment kN -0.5050E+01 about axis Max moment kN.m -0.4761E+02 about axis Max axial kN.m -0.1363E+04 force Max torsional kN -0.2891E-02 force Max torsional kN.m 0.1294E+00 force kN.m Result Type Value Max axial soil 0.1173E+03 force Max lateral in kN 0.2291E+02 X direction Max lateral in kN 0.6815E+00 Y direction Max torsional kN -0.3003E-02 soil force kN.m 2 10 Load Maximum soil forces Comb Pile 1 10 So, Nmax = 1393(kN) 5.1.2 Checking single pile axial resistance: Using equation: N m a x + ΔN < P t t Where: Nmax: Max axial force ΔN : Own weight of pile (kN) Ptt : Single Pile bearing capacity (kN) We have: Nguyen Thien Long - 172603217 16 ATP 58 Foundation design Geotechnical Faculty So, => Satisfied 5.2 Checking the axial bearing capacity of group pile: Where: Vc: Total compressive load of pile group QR: Axial resistance of pile group : Resistance factor of pile group Qg: Nominal axial resistance of pile group.: Coefficient of resistance of group piles in cohensive, cohensionless soil : Nominal axial resistance of group piles in cohensive, cohensionless soil Using interpolation method, we obtains 5.2.1 Clay soil For calculate Qg, use formula below: Where: X: Width of pile group(m) Y: Length of pile group(m) Z: Depth of pile group(m) : Average undrained shear strength along the depth of penetration of the piles(MPa) : Undrained shear strenth at the base of the group(MPa) Nc: Ratio depends on Z/X With Z/XSatisfied VI Checking Service Limit State 6.1 Determine total consolidation settlement Have: Db = 17(m) Equivalent footing inside and between layer and layer = D b = Nguyen Thien Long - 172603217 18 ATP 58 Foundation design Geotechnical Faculty 11.333(m) Sand soil: Using SPT: In which: and With: : Settlement of pile group (mm) q : Net foundation applied at 2Db/3 This figure is equal to the applied load us the top of group devided by the area of equivalent footing and does not include the weight of piles and soil between the piles (MPa) N0 :Axial load at bottom of cap at service limit state, S : Area of equivalent footing X : Width of the pile group(m) Db : Depth of embedment in the layer that provide support D’ : Efective depth taken as 2Db/3 (mm) : SPT blow count corrected for both the overburden and hammer effeciency effects (blow/300mm) I: Influence factor of the effective group embedment Have: o Compute q: The area of equivalent foundation: So, the force o Determine N160: 13.28916 N160=13.28916 (from the previous table) at the tip of pile o Calculate the settlement: So, the settlement of pile group is 5.619mm 6.2 Checking pile head displacement Methodology: Using FB-PIER Maximum pile head displacements Max displacement 0.3191E-02 M in axial Nguyen Thien Long - 172603217 19 ATP 58 Foundation design Geotechnical Faculty Max displacement 0.5053E-02 M in X Max displacement in Y -0.3953E-06 M 12 Therefore: • In the horizontal direction of the bridge: Δy = 0.3953 x 10-6 m = 0.000395 mm 38mm • In the longitudinal direction of the bridge: Δx= 0.5053 x 10-2 m = 5.053 mm 38mm => Satisfied VII Strength of bars and pile joint 7.1 Computing and arranging vertical bar in pile Total casting length: Lcd = 32 (m) Divined into part, each part is 8m long 7.1.1 Computing maximum moment of lifting and pitching of pile Maximum bending moment Mtt = max (Mmax(1); Mmax(2)) In which: Mmax(1): Pile lifting moment Mmax(2): Pile pitching moment • Pile lifting moment Nguyen Thien Long - 172603217 20 ATP 58 Foundation design Geotechnical Faculty Lifting hook position: a= 0.2 Ld =0.2 x = 1.6 (m) Surcharge pressure : Maximum moment: • Pile hanging moment Nguyen Thien Long - 172603217 21 ATP 58 Foundation design Geotechnical Faculty Lifting hook position b = 0.294Ld = 0.294 x = 2.352 (m) Maximum moment: Thus: Mtt = max (Mmax(1); Mmax(2)) = max (7.94 ; 13.72) = 13.723 (kN.m) 7.1.2 Caculating the number of reinforce bars needed We choose reinforced rebar ASTM A615M include 8Ø 25 have f’c = 30MPa, fy = 414 MPa arrange at the cross-section , calculate same as rectangular section with single reinforcement bar( specifically square cross-section 450x450mm) Essential nominal resistance moment: The height of stress block: Nguyen Thien Long - 172603217 22 ATP 58 Foundation design Geotechnical Faculty Check the elastic condition: Satisfied Calculating for area and arrange of steel Choose reinforced rebar ASTM A615M include 8Ø 25 and total area iis 1530, and the thickness of cover concrete( to centre of steel bar) is 65mm, the effective depth d’=385mm Recalculate height of stress block: Recalculate elastic condition: Satisfied 7.2 Reinforcement of the belt for the pile Because the pile is mainly compressed, it is not necessary to review the strength of the belt reinforcement Therefore, reinforcing steel bars are arranged according to the requirements of structure + The head of each pile is arranged with belt step 50 mm on a length of 1350 mm + Next we arrange with reinforced belt step is 100 mm on a length of 1100mm + The remainder of each pile (middle section of the pile) is arranged with the pile step: 150 mm 7.3 Detail of hard pile rod reinforcement Steel pile nose with a diameter of 40, with a length of 100 mm The protrusion of the pile tip is 50 mm 7.4 Reinforced wire rod At the top of the pile lay a grid of reinforced concrete pile with a diameter of mm, with mesh a = 50 x 50mm The net is arranged to ensure that the concrete pile is not damaged due to local stress during pile driving 7.5 Steel stake head The pile head is coated with a flat steel bar of 10mm thickness for the purpose of protecting the pile head from damage when piling and in addition it is also useful for bonding Nguyen Thien Long - 172603217 23 ATP 58 Foundation design Geotechnical Faculty piles during construction together 7.6 Steel hooks Steel hooks are selected in diameter 22 Because of the rebar in the pile is very redundant so we can always use hooked steel hook for hanging hooks, then we not need to make the third hook to create favorable conditions for construction and piling in yards The distance from the beginning of each pile to each anchor is a = 1.6m = 1600 mm VIII Joint construction We use welded joints to connect the pile back together Joints must ensure that the joint strength is equivalent to or greater than the strength of the pile at the jointed section To connect the piles back together, we use angle steel L-100x100x12 piles into the four corners of the pile and then use the welding line to connect the two piles (for solid piles, square usually use welding joints For round piles, the tube is usually used to connect bolts In addition, to increase safety for joints, we use steel plates 500x100x10mm is dabbed between two angles to increase the length of joints Weld thiclmess =10 mm Nguyen Thien Long - 172603217 24 ATP 58 ...Foundation design Geotechnical Faculty Category Part I SOIL INVESTIGATION REPORT Contents I Geological structure and characteristic of soil layers II Conclusion and suggestion:... Thien Long - 172603217 ATP 58 Foundation design Geotechnical Faculty Part I SOILS INVESTIGATION REPORT I Geological structure and characteristic of soil layers At Drilled Hole - BH4, drilled to