PRESTEDGE RETIEF DRESNER WIJNBERG (PTY) LTD CONSULTING PORT AND COASTAL ENGINEERS PROJECT 1096 Matola TCM - FEL 3 DATE 6/6/2022 SHEET # 01 ISSUED BY SIGNED DATE SECTION DESIGN WGD DRAWING REF. 1096/00/5040 and 1096/00/5100 CHECKED SAH MODEL REF. NA APPROVED PES CALC # 1096|Socket Ø 1016 Piles|001 Rev 00 CALC FILE RE X:\PRDW Projects\Current\Mozambique (1096) Matola TCM FEL 3\Working\Engineers\WGD\4. Calculations MODEL FILE R Group Effects Must be considered for a centre to centre spacing less than 4 diameters between pile shafts for axial load Design of rock sockets for tubular steel piles Check 1. Axial loading (Compression and Tension) Check 2. Lateral Loading Input Calculation Note Design of rock sockets to LRFD using FHWA, 2010 - Drilled Shafts: Construction procedures and LRFD design methods In accordance with extracts from Tomlinson Lateral checks conducted using Lpile v 6.0 from Ensoft Pile Group Ø 1016 x 18wt Piles Critical Pile D4 (Comp) & D3 (Lat) Position (in x) All 1016mm Piles Rock Level -19 m MSL Critical Load Combination Raked (Y/N) N Tubular Steel Pile Outside Diameter D ### m See sk Wall Thickness t ### m Level at top of pile z1 1.70 m MSL Sea bed level z2 ### m MSL Raking angle a 0.24 RAD Rock Socket Socket Length Ls 6.50 m Socket outside diameter Ds 0.90 m Penetration depth Pd 3.00 m Steel Elastic Modulus Steel Es ### MPa Steel yield Strength Fy 350 MPa Unit weight of steel g ste 77 Concrete Elastic Modulus Concrete Ec ### MPa Concrete Strength fc 45 MPa Unit weight of reinforced concrete γ con 25 Rock Rock UCS (average over socket) 2.00 MPa RQD (average over socket) RQD 60.0% Unit weight of rock y roc 20 Loading Working Ultimate Axial Compression (Reactions for Prokon Model) PDE 2238 3003 Axial Tension (Reactions from Prokon Model) TDE 1 1 Momets load cases included under the lateral load checks Socket Sizing - Ø 1016 x 18wt Piles X:\PRDW Projects\Current\Mozambique (1096) Matola TCM FEL 3\Working\Engineers\DJP\2. Design\Prokon Models\Phase 4A - 4B loading\Final Rakers\1096 - 4A Berth 4B Loads - 2012-03-21 - API Rev01.A03 Calculation Description → Initial sizing of pile (Ø governed by casing Ø length governed by loading and geo resistance - ULS case and SLS case → Use Initial sizing from Check 1. Calculate RC pile axial load bending moment inte (use Lpile), factor interaction curves by LRFD structural resistance factors, calcu lateral resistance using LPile input LRFD factored loads factored again by the geot resistance factor and check that pile response does not exceed the factored interac allowable bending moment for associated vertical loads. ULS case and SLS case Spreadsheet Notation Governing Code Reference Pile Reference Member Dimensions Material Properties kN/m³ kN/m³ quc kN/m³
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PRESTEDGE RETIEF DRESNER WIJNBERG (PTY) LTD
CONSULTING PORT AND COASTAL ENGINEERS
PROJECT 1096 Matola TCM - FEL 3 DATE 4/7/2023 SHEET # 01 of 01
ISSUED BY SIGNED DATE SECTION
DESIGN WGD DRAWING REF. 1096/00/5040 and 1096/00/5100
CHECKED SAH MODEL REF. NA
APPROVED PES CALC # 1096|Socket Ø 1016 Piles|001 Rev 00
Group Effects Must be considered for a centre to centre spacing less than 4 diameters between pile shafts for axial loads and 5 diameters for lateral loads
Design of rock sockets for tubular steel piles
Check 1. Axial loading (Compression and Tension)
Check 2. Lateral Loading
Input Calculation Note
Design of rock sockets to LRFD using FHWA, 2010 - Drilled Shafts: Construction procedures and LRFD design methods
In accordance with extracts from Tomlinson
Lateral checks conducted using Lpile v 6.0 from Ensoft
Pile Reference Pile Group Ø 1016 x 18wt Piles
Critical Pile D4 (Comp) & D3 (Lat)
Position (in x) All 1016mm Piles
Rock Level -18.5 m MSLCritical Load Combination
Raked (Y/N) N
Tubular Steel Pile
Outside Diameter D 1.0160 m See sketch below
Wall Thickness t 0.0180 m
Level at top of pile z1 1.70 m MSL
Sea bed level z2 -18.50 m MSL
Raking angle a 0.24 RAD
Rock Socket
Socket Length Ls 6.50 m
Socket outside diameter Ds 0.90 m
Penetration depth Pd 3.00 m
Steel
Elastic Modulus Steel Es 210000 MPa
Steel yield Strength Fy 350 MPa
Unit weight of steel g steel 77
Concrete
Elastic Modulus Concrete Ec 20000 MPa
Concrete Strength fc 45 MPa
Unit weight of reinforced concrete γ concrete 25
Rock
Rock UCS (average over socket) 2.00 MPa
RQD (average over socket) RQD 60.0%
Unit weight of rock y rock 20
Loading
Working Ultimate
Axial Compression (Reactions for Prokon Model) PDE 2238 3003 kN
Axial Tension (Reactions from Prokon Model) TDE 1 1 kN
Momets load cases included under the lateral load checks
→ Initial sizing of pile (Ø governed by casing Ø length governed by loading and geotechical axial resistance - ULS case and SLS case
→ Use Initial sizing from Check 1. Calculate RC pile axial load bending moment interaction curves (use Lpile), factor interaction curves by LRFD structural resistance factors, calculate geotechnical lateral resistance using LPile input LRFD factored loads factored again by the geotechnical lateral resistance factor and check that pile response does not exceed the factored interaction curves allowable bending moment for associated vertical loads. ULS case and SLS case
Spreadsheet Notation
Governing Code Reference
Member Dimensions
Material Properties
kN/m³
kN/m³
quc
kN/m³
I13
YH: FHWA, 2010, pg 14-2 to 3
F42
YH: Can't change, otherwise you need to read off new values from settlement curves
F46
YH: Not applicable since we considering verticle piles
F59
YH: Can't change
F63
YH: If Changed, then reduction factors need to be calculated manually in the spreadsheet
F64
YH: Changing this value requires you to change to change the mass factor manually in the sheet.
Design Checks
Rock Socket Design Checks Criteria Reference Results
Axial Compression
Rock Socket Shaft Friction 0.94 OK
Settlement under axial loading 3.82 mm
Axial Tension
Rock Socket Pull Out Resistance 0.00 OK
Rock Socket Shaft Friction 0.00 OK
Rock Socket Design Checks Criteria Reference Results
Lateral Loading
Casing Factored Moment Resistance OK OK
Socket Factored Moment Resistance OK OK
Deflection at ULS 0.0036 OK
Typical Section
Condition Status
ρ < 25mm
Condition Status
ρ < 10% shaft Ø
Steel tubular pile - length varies
Pile Cap - Pile Concrete ConnectionLconpp | Lconsk
Penetration depth (2-3m) (Pd)
Rock socket - length varies (Ls)
Rock socket
Socket- Pile Concrete ConnectionLconpp | Lconsk
Insitu concrete
Insitu concrete
Precast pile cap
Rock level
D
t
z1
z2
Ds
PRESTEDGE RETIEF DRESNER WIJNBERG (PTY) LTD
CONSULTING PORT AND COASTAL ENGINEERS
PROJECT 1096 Matola TCM - Phase 4 - FEL 3 DATE 4/7/2023 SHEET # 01 of 01
ISSUED BY SIGNED DATE SECTION Socket Sizing - Ø 1016 x 18wt Piles
DESIGN WGD DRAWING REF. 1096/00/5040 and 1096/00/5100
CHECKED SAH MODEL REF. NA
APPROVED PES CALC # 1096|Socket Ø 1016 Piles|001 Rev 00
Ignore end bearing - DLP report (Mozal, 99) Stated that as the nature of the intermittent or alternating sequence of very weakly cemented sands and very soft rock sandstone will result in a high degree of uncertainty regarding the base resistance of these piles
- For Ø Ds =
(Use API LRFD factored ulimate loads from Prokon model)
Axial Compression Settlement
Pile head settlement will be caused by the compression of the rock socket only.
Settlement Settlement of pile head where load is only carried by rock socket skin friction
Settlement ρ =
Ip = 0.18 See below
L/B = 7.2
R = Ec/Ed
Ec = 20000 MPa
Deformation modulus Ed = Section 5.5 Tomlinson
Mr = 150 See below
= 150 x 0.32 x 2
= 96 MPa
R = 208
(Tomlinson, 1994)
(Tomlinson, 1994)
F = 0.82 See below
D/B = 3.3 Assume 3m pentration of casing
(D = recess)
Factor F
(Tomlinson, 1994)
® Criterium Pile Head Settlement ρ =
= 0.82 x 2238 x 0.18 / ( 0.9 x 96 )
= 3.8 mm
F x PDE(working) x Ip/(Ds x Ed)
Mr x j x quc
Elastic settlement influence factors for
rock sockets skin friction on piles
Values for Mr Section 5.5
Reduction factors for calculation of settlement of
recessed sockets
Socket assumed recessed - pile casing pentrates +- 3m into
rock
F x PDE(working) x Ip/(Ds x Ed)
The Ultimate Axial Tensile Capacity of The Substructure is The Lesser Value of the 'Pull out Resistance' and 'Axial Tension' Pull Out Resistence
Ultimate pull out resistance - Based on pull out cone
- Tomlinson 1994
- LRFD design factors from FWHA, 2010
Ultimate pull out resistance resistance weight rock pull out cone
Ignore weight contribution of soft silty clay overlaying rock
Node Max Axial LC X-Moment Z-Moment Node Min Axial LC Max X-Moment Max Z-Moment Node Max X Moment LC Max Axial Max Z-Moment Node Min X Moment LC Max Axial Max Z-Moment Node Max Z Moment LC Max Axial Max X-Moment Node Min Z Moment LC Max Axial Max X-Moment
Node Max Axial LC X-Moment Z-Moment Node Min Axial LC Max X-Moment Max Z-Moment Node Max X Moment LC Max Axial Max Z-Moment Node Min X Moment LC Max Axial Max Z-Moment Node Max Z Moment LC Max Axial Max X-Moment Node Min Z Moment LC Max Axial Max X-Moment
Base on Geotechnical Laboratory and Site Investigation.ULTIMATE LIMIT STATE
The ultimate bearing capacity for rock sockets are only dependant on skin friction. Therefore the the fundamental Equation is:
The above equation is based on the following site specific soil/rock properties that need to be measured:*Rock Quality Designation*Rock Unconfined Compressive Strength*Mass factor
**α is determine from the graph below utilizing the field test result for the quc
Based on the number of test results collected for the above material properties, their respective skin friction can be determined
Hence the allowable pile settlement is set by the engineer and is project specific, settlements are generally limited between 10mm to 25mm at pile head
Example: (same as in spreadsheet)
The settlement (ρ) for piles with rock sockets can be determined from the following equation established by Pells and Turner
F is a reduction factor to account for the pile
recess
Standard calculation method
RQD (assumed) % 602
Therefore, based on equation 1 Fs = 895.7 MpaUltimate bearing capacity Qu = 5822kN
Refer to example 4.7 of tomlinson's; a rock socket design in weak mudstone has been undertaken. Tomlinsons assumes that both shaft friction and base bearing are activated.He utilizes a factor of safety of 3 for the Ultimate bearing resistance Qu. Shaft resistance is more than twice the working load and end bearing is 0.9 times the working load
Base on Geotechnical Laboratory and Site Investigation.
The ultimate bearing capacity for rock sockets are only dependant on skin friction. Therefore the the fundamental Equation is:
eqn 1
The above equation is based on the following site specific soil/rock properties that need to be measured:
Based on the number of test results collected for the above material properties, their respective skin friction can be determined
Then the determine the charateristic resistance (Rsk) using the appropriate correlcation factors according to number of tests completed
is determine from the graph below utilizing the field test result for the Mass factor (j) based on the elastic modulus of the rock
B167
YH: Note the skin friction should be determined for each test pit and corresponding data.
Design Approach 1: Combination 2(Design Resistance set by partial factor set R4 according to piling type)
(Design Actions set by partial factor set A2)
Design Action (Fd) = G*1.0 + Q*1.3
R4 without explicit verificationBored CFA
2 21.6 1.62 22 2
Design Resistance (Rd) = Rsk/ϒs
Overal Design Safety Factor (Г) = Rd/Fd
Hence the allowable pile settlement is set by the engineer and is project specific, settlements are generally limited between 10mm to 25mm at pile head
for piles with rock sockets can be determined from the following equation established by Pells and Turner
Design Combination 22347.5
2238
0.953355
Refer to example 4.7 of tomlinson's; a rock socket design in weak mudstone has been undertaken. Tomlinsons assumes that both shaft friction and base bearing are activated.He utilizes a factor of safety of 3 for the Ultimate bearing resistance Qu. Shaft resistance is more than twice the working load and end bearing is 0.9 times the working load
Overal Design Factor (Г) = Rd/Fd
CONFORMING ROCK SOCKET DESIGN TO EUROCODE 7
Design Approach 1: Combination 2(Design Resistance set by partial factor set R4 according to piling type)