METHOD STATEMENT FOR TEST PILLING WORK (PREBORING PHC PILE)

METHOD STATEMENT FOR TEST PILLING WORK (PREBORING PHC PILE)_he purpose of this Method Statement is to describe the methodology for structural work of METHOD STATEMENT FOR TEST PILLING WORK (PREBORING PHC PILE) and to details out the steps to be taken in meeting the technical requirements of Van Phong 1 thermal power plant project

Comment Response Sheet (CRS) Project Title Van Phong BOT Thermal Power Plant Project Document Title METHOD STATEMENT FOR TEST PILLING WORK (Pre-boring PHC Pile) Document No Document Type For Approval Returned Status AC Prepared by CRS Issued Date 01 Apr 2020 Engineer YJ Lee VP1-0-L4-C-GEN-10017 VP1-0-L4-C-GEN-10017-B-CRS CRS No No Section/ Page Owner’s Comment Response to Comment Review Date Status O/C * Remarks Page of 15 Comment Response Sheet (CRS) Cover 03/03/2020 (1) Clarification of design calculation for pile class A, B & C (JIS A5373) to be provided 27 Mar 2020: (1)Please add reference of approved calculation for required weld thickness AND test pile calculation 03/03/2020 (2) Quality control of cement grouting- tech specification and welding procedure has to be properly shown including MS 27 Mar 2020: (2) Provide density cement slurry to check at site prior to fill in the borehole Provide estimated volume slurry for each pile and monitor the loss volume if happen 20/03/2020 (1) Design calculation for pile (Calculation for preliminary test pile VP1-0-L4-C-GEN-00020 was submitted and will be clarified separately 03/03/2020 O 01/04/2020 O 03/03/2020 O 01/04/2020 O 20/04/2020 (1) Test pile calculation VP1-0-L4-C-GEN-00020 is add in this MS as an attachment 20/03/2020 (2) Quality control of cement grouting- tech specification is updated in MS (item 10.1 Material and 11.4 Cement Milk Grouting) and welding procedure is updated in MS item 11.6 Pile connection) Closed 20/04/2020 (2) Base on the technical specification of test piling work at item 2.2 Pile construction method, 2.2.1 Preboring with root hardening cement slurry (pile fixed slurry) Cement 600 kg Water 420 L Compressive Strength 200 kg/cm2 Density cement slurry is 1.66 Tolerance : 1.66 +-5% (From 1.58 to 1.74) Volume slurry for pile D600 – 20m: Cement (Ton) Water (lit) Cement milk (m3) 2.4 1.7 2.47 Volume slurry for pile D800 – 20m: Cement (Ton) Water (lit) Cement milk (m3) 3.33 2.33 3.4 Monitor the volume on the mixing machine electric board Page of 15 Comment Response Sheet (CRS) 03/03/2020 (3) Clarification for welding work measuring method (a) Welding quality of work 20/03/2020 (3) DHI have clearance on article 11.6 Pile connection of this MS Rev.B 27 Mar 2020: (3a) No WPS was shown Welding rode is missing information 20/04/2020 a) WPS was attached in this MS at item 11.6.4 Welding rob will be added in the MS at Item 11.6.4 Welding quality to be controlled by Visual inspection, NDT MT test for welding shall be done In accordance with Welding inspection report of ITP 03/03/2020 (b) Checking/ application of anti corrosion for welding joints 20/03/2020 b) Pile Welding joint shall be cover by Slurry Cement 03/03/2020 O 01/04/2020 O closed 03/03/2020 O 01/04/2020 C 03/03/2020 O 01/04/2020 O 27 Mar 2020: (3b) Noted 03/03/2020 (c) Duration of welding joint temperature cooling time prior to pile driving 20/03/2020 c) In order to prevent cracking of welding area, temperature cooling time will be 1minute 27 Mar 2020: (3c) Kindly noted that much different temperature in very short time have no much effect to avoid Reply is not accepted 20/04/2020 3c) In order to prevent cracking of welding area, temperature cooling time will be 10minute 03/03/2020 (d) Estimation of pile length to be incorporate with pile bottom layer soil data & EPC visual inspection records 20/03/2020 (d) Noted, the length of the pile is determined by the boring log and pile bottom layer soil data 27 Mar 2020: (3d) Kindly requested to check the borehole depth, diameter /soil condition before installing the pile in Please describe more information checking bored hole after drilling 20/04/2020 (3d) To check the borehole depth, diameter/soil condition before installing the pile as below: The length of drilling rod longer than the bore hole Checking by mark a red line on the Drilling rod when get the design depth and using hydrometer to check Noted 03/03/2020 O 01/04/2020 O Page of 15 Comment Response Sheet (CRS) Cover Page 03/03/2020 Location of testing pile is not yet stated And location should be chosen in consideration with the use of piles for foundations for example Chimney FDN., Coal conveyor FDN, and others Because soil condition is different from locations 01/04/2020 Closed 03/03/2020 - The purpose of Test Pile should be stated - Number and location of test pile should be stated - Kind of test must be stated 01/04/2020 Closed Page 03/03/2020 Calender date should be written 20/03/2020 PRELIMINARY TEST PILE PLAN PLOT PLAN_ VP10-L4-C-GEN-00021 was submitted and it is attached in this document as Attachment #1 for reference 20/03/2020 The purpose of Test Pile is added in MS - Number and location of test pile : please refer to Attachment #1 VP1-0-L4-C-GEN00021_PRELIMINARY TEST PILE PLAN - Kind of test : refer to item Purpose of Test Pile 20/03/2020 Calendar date is applied on the top of Schedule 03/03/2020 O 01/04/2020 C 03/03/2020 O 01/04/2020 C 03/03/2020 O 01/04/2020 C 03/03/2020 O 01/04/2020 C 03/03/2020 O 01/04/2020 C 03/03/2020 O 01/04/2020 C 01/04/2020 Closed Page 03/03/2020 Capacity of equipment must be stated Mobilization of testing equipment should be stated 01/04/2020 Closed 20/03/2020 Capacity of equipment is added in page in MS (item Mobilize plan of construction heavy equipment) Mobilization of testing equipment in page in MS (item Mobilize plan of construction heavy equipment) 20/03/2020 Page Page 03/03/2020 How much strength is Cement grout ? 01/04/2020 Closed 03/03/2020 Raw material? Not agree, please share the propose mix design if it will effect to the pile bearing calculation The compress strength of Cement Milk is 20Mpa 20/03/2020 Raw material will be submitted separate with MS The propose mix design will be submitted separate with MS 01/04/2020 Closed Page of 15 Comment Response Sheet (CRS) Page 03/03/2020 Material Information said D900? please double check 01/04/2020 Closed Page 03/03/2020 Effective prestress should be stated 01/04/2020 Closed 20/03/2020 Material Information only have kind of Pile (D600 and D800) 20/03/2020 Effective prestress is stated on page (item 10.2 PHC Pile in MS) 03/03/2020 O 01/04/2020 C 03/03/2020 O 01/04/2020 C 03/03/2020 O 01/04/2020 C 03/03/2020 O 01/04/2020 C 03/03/2020 O 01/04/2020 C 03/03/2020 O 01/04/2020 C 03/03/2020 O 01/04/2020 C 20/03/2020 10 Page 03/03/2020 250? Please check It is 300 01/04/2020 Closed 11 12 Page Page 03/03/2020 Concrete ? 01/04/2020 Closed 03/03/2020 How the slime at the bottom of borehole is treated after completion of drilling ? 20/03/2020 It is Concrete and corrected 20/03/2020 The slime at the bottom of borehole will be thrown out of hole by the air compressor after completion of drilling 01/04/2020 Closed 20/03/2020 13 Page 03/03/2020 How much diameter is borehole ? The diameter of borehole will be 10cm larger than Pile 01/04/2020 Closed 14 Page 03/03/2020 This sentence is not clear - How much is bearing capacity of pile? please clarify - Please describe how to use this hammer? 20/03/2020 - The capacity of PHC pile is 6281kN - A pile is fixed to bearing layers by the drop hammer 01/04/2020 Closed Page of 15 Comment Response Sheet (CRS) 15 Page 03/03/2020 Please provide: (i) Pile design calculation report; (ii) Design drawing of PHC Pile; welding joint; (iii) Design length, design load of test piles? (iv) Test piles location drawing? 01/04/2020 Closed 16 Page 03/03/2020 Auger should be in the slurry during injection of grout ? 01/04/2020 Closed 17 18 Page Page 03/03/2020 Borehole should be kept as vertical during drilling 01/04/2020 Closed 03/03/2020 Please explain this step, why need to fill the cement milk after insert PHC pile? 20/03/2020 Attachment documentation: (i) Design calculation for pile (Calculation for preliminary test pile VP1-0-L4-C-GEN-00020 was submitted and will be clarified separately (ii) Design drawing of PHC Pile; Attachment #2 Drawing of PHC-D800 and PHC-D600 (iii) & (iv) VP1-0-L4-C-GEN-00021_PRELIMINARY TEST PILE PLAN was submitted and it is attached in this document as Attachment #1 for reference 20/03/2020 Auger will not be in the slurry during injection of grout 20/03/2020 Borehole will be kept as vertical during drilling by total station or plum line 20/03/2020 Need to fill the cement milk after insert PHC pile if the Cement Slurry deposit after insert pile 01/04/2020 Closed 19 Page 03/03/2020 The hardening time should be decided by trial mix of cement 01/04/2020 Closed 20 Page 03/03/2020 Please explain: (i) How to collect water and cement grout during install the pile? (ii) How to control quality of cement grout to avoid mixing with ground water inside the bore hole? (iii) How to fix top of pile after finish installation? How to check vertical tolerance of pile is acceptable? 01/04/2020 Closed 20/03/2020 The hardening time cement According to mechanical target of Cement PCB40 of Nghi Son using at site 20/03/2020 Please explain: (i) In order to collect water and cement grout during install the pile shall be create a bend hole near the pile to collect Cement Slurry and move to other place (ii) When Cement Milk over flow on the ground, Ground water inside the borehole will be pushed out with gravitation of Cement Milk due to gravitation of Cement Milk heavier than ground water (iii) Using light blow driving pile head until fix to the ground and then using two direct which have been located at the near distance to check vertical of pile head Vertical tolerance of pile will be applied in TCVN 10667 at page 18 item 9.2.8 indicated the vertical tolerance is 1% of pile length are accepted 03/03/2020 O 01/04/2020 C 03/03/2020 O 01/04/2020 C 03/03/2020 O 01/04/2020 C 03/03/2020 O 01/04/2020 C 03/03/2020 O 01/04/2020 C 03/03/2020 O 01/04/2020 C Page of 15 Comment Response Sheet (CRS) 21 Page 03/03/2020 Please supplement: - WPS for welding joint - Welder certificate - Temperature of the joint before second and third layer / or standby time between layer - NDT test for the joint is necessary 20/03/2020 Document supplement: - Welding work and inspection shall be in accordance with the Welding inspection report on ITP for this test piling work - Each layer welding work shall be done continuously without standby and cooling time - NDT- MT test 5% for the joint will be applied to ITP 03/03/2020 O 01/04/2020 C 03/03/2020 O 01/04/2020 C 03/03/2020 O 01/04/2020 C 03/03/2020 O 01/04/2020 O 03/03/2020 O 01/04/2020 C 01/04/2020 Closed 22 Page 03/03/2020 How to hold and fix this bottom pile while welding the upper one? 20/03/2020 The bottom pile will be fixed by wood and checked by level when welding joint with the upper pile 01/04/2020 Closed 23 Page 03/03/2020 Light blow is how much? Is it equal how many tons? How weight of the ram? 01/04/2020 Closed 24 Page 03/03/2020 Please clarify why we use casing in the installing pile 20/03/2020 The Light blow will be used to fix the pile get the required elevation with the weight from 2.5T – 3.7T Light blows is around 10 blows/time for this test piling work The standard of Light blow(hammering height, rebound) for mass piling work shall be decided by this test piling work 20/03/2020 Just using casing in case the soil was been collapsed 20/04/2020 The casing is applied for proper depth to prevent the collapsing of the soft and loose soil/sand layer of the hole 25 Page 03/03/2020 Before setting of counterweight, the area of loading should be well compacted to avoid overload on the ground surface or incident during test 20/03/2020 Noted 01/04/2020 Closed Page of 15 Comment Response Sheet (CRS) 26 27 28 29 30 Page 12 Page 12 Page 12 Page 13 Page 13 03/03/2020 Add more content on testing report: Pile contractor, boring log near the test pile Pile installing equipment Test pile size, length, effective prestress etc Recommend the ultimate load 03/03/2020 Calibration of testing equipment shall be submitted as well 01/04/2020 Closed 03/03/2020 - English please - Not clear, can not read 01/04/2020 Closed 03/03/2020 Please provide: - Load value - Minimum duration for maintain the load value 01/04/2020 Closed 03/03/2020 Lack of 1st cycle application of loads equal to 25, 50, 75, 100% of the pile design load 20/03/2020 03/03/2020 O 01/04/2020 O Noted and modified 20/04/2020 In accordance with form of Laboratory the content on testing report always fully this information Refer to VP1-MS for Pre-boring PHC pile Rev B update 03/03/2020 O 20/03/2020 Calibration of testing equipment shall be submitted as well 01/04/2020 C 20/03/2020 No important in this method, it will be stated in test result 03/03/2020 O 01/04/2020 C 03/03/2020 O 01/04/2020 C 03/03/2020 O 01/04/2020 C 20/03/2020 - Load value is 200% - Duration for maintain of each load value: From hours to hours 20/03/2020 Additional 1st cycle application 01/04/2020 Closed Page of 15 Comment Response Sheet (CRS) 31 Page 13 03/03/2020 According to TCVN 9393-2012: it is recommended testing load should be equal 250-300% design working load 20/03/2020 01/04/2020 Closed VP1 PJT 03/03/2020 O 01/04/2020 C 03/03/2020 O 01/04/2020 C 03/03/2020 O 01/04/2020 C According to the contract “Part III-2 Exibit B1 tech spec section 4.1”, ASTM is also usable standard for In particular, the ASTM related to the test pile is widely used internationally therefore there is no problem in application Furthermore, the applied design capacity of the pile is lower than the allowable pile bearing capacity by calculation, so a sufficient result can be obtained with 32 Page 13 03/03/2020 How much compressive force is 200% of ? 01/04/2020 Closed a 200% test load recommended by ASTM 20/03/2020 The allowable compressive pile bearing capacities are as following and the capacities are based on the calculation report PHC D600 Allowable pile Applied bearing capacity design by calculation capacity 1,570kN(BHO-08) 1,550kN Test load (200%) 3,100kN 2,152kN(BH-45) 33 Page 13 03/03/2020 - For pile head displacements of less than 10 mm, each load increment shall be maintained until the rate of settlement is reducing and is ≤0.1 mm/hour - For pile head displacements of greater than 10 mm, each load increment shall be maintained until the rate of settlement is reducing and is ≤0.2 mm/hour D800 3,728kN(BH-31) 3,300kN 6,600kN 20/03/2020 - For pile head displacements of less than 10 mm, each load increment shall be maintained until the rate of settlement is reducing and is ≤0.1mm/hour - For pile head displacements of greater than 10 mm, each load increment shall be maintained until the rate of settlement is reducing and is ≤0.2 mm/hour 01/04/2020 Closed Page of 15 Comment Response Sheet (CRS) 34 Page 13 03/03/2020 Supplement allowance settlement of each load value 20/03/2020 Allowance settlement of each load value is over 15% D 01/04/2020 Closed 35 37 Page 13 Page 17 03/03/2020 Supplement the Test Result 01/04/2020 Closed 03/03/2020 Please provide - Load value - Duration for maintain of each load value 20/03/2020 Submit Test Result 20/03/2020 - Load value is 200% - Duration for maintain of each load value: From hours to hours 03/03/2020 O 01/04/2020 C 03/03/2020 O 01/04/2020 C 03/03/2020 O 01/04/2020 C 01/04/2020 Closed Page 10 of 15 Calculation for Preliminary Test Pile (PHC) VP1-0-L4-C-GEN-00020 li Qb : length of the pile section in soil layer i-th = ( cN'c + q'γ,p N'q ) Ab = ( 100 x 37.16 + 453.375 x 22.46 ) x 0.503 6,991 kN = Rc,u = Qb + Ra Rc,u γg = γg 6,991 = u ∑fi li 11,897 1.6 = : reliability factor = 4,906 + = = 11,897 kN 7,435 kN 1.6 c) Result based on TCVN 7888:2014 RaL RaS = ( σcu 3.5 - σce ) x A0 = ( 80 3.5 - 8.2 ) x 238447 = x ( σcu 3.5 - σce ) x A0 (Short-term) = x ( 80 3.5 - 8.2 ) x 238447 Ra σcu σce A0 : : : : (Long-term) - - - - - - - - - TCVN 7888-2014 = 4,961 kN = 9,923 kN where, Allowable bearing capacity based on pile material Specified compressive strength of concrete Effective strength of concrete Cross sectional of area of pile = = = 80 N/mm2 8.2 N/mm2 238447 mm2 d) Comparison of the results between TCXD, TCVN 10304 and TCVN 7888 Allowable Axial Capacity = Min.(TCXD, T10304, T7888) = Min.(3728, 7435, 4961) = 3,728 kN 3.2.2 Allowable Pull-Out Capacity a) Result based on TCXD Qa Qs = + W = 5330 + 77.2 = 1,854 kN where, Qs W : : side friction resistance capacity of the pile weight of pile 77.2 kN = W = γpile x L _ REV.B 17 of 31 Calculation for Preliminary Test Pile (PHC) VP1-0-L4-C-GEN-00020 b) Result based on TCVN 10304:2014 Rt,u = γc u ∑ γcf fi li γc γcf Rt,a - 0.8 working rate of the pile in soil = in cohesive soil with consistency index lL < 0.5 Rt,u γg = = 3924.43 1.6 TCVN 10304-2014, 7.2.2.3(11) (= 1.0 ) 2,453 kN = c) Result based on Tensile Stress in PC bar Pt = σpe · Ap = 1,939 kN 798.7 x 2427.8 = where, Pt σpe Ap : : : Max tension by PC bar Effective tensile stress in PC bar Total cross Section AREA of PC bar = = 798.7 N/mm2 2427.8 mm2 d) Comparison of the results between TCXD, TCVN and Tensile Stress in PC bar Allowable Tension Capacity = Min.(TCXD, TCVN, PC bar) = Min.(1854, 2453, 1939) = 1,854 kN 3.2.3 Allowable Horizontal Capacity By using method of Broms(1964), the coefficient and maximum pile bending moment from the design loads will then be calculated Broms, B.B(1964) " Lateral Resistance of Piles in cohesive Soils" Journal of Soil Mechanics and Foundation Engineering, ASCE, Vol 90, SM2, pp27-63 TCXD 205:1998 Appendix G.9 1) Definition of pile type Diameter Short pile Long pile Cohesive soil βL ≤ 2.25 βL > 2.25 Cohesion less soil ηL < 2.0 ηL > 4.0 where, Length(m) = 20.0 m Horizontal displacement = 0.015 m (Design Criteria 2.2) Young modulus of pile = 32,800,000 kN/m2 Moment inertia of pile = 0.0146 m4 KhD 1/4 = ( = 0.60 = 1.68 m ) 4EI , β nh 1/5 = ( = 0.66 ) EI , 300,000 kN/m3 : Coefficient of lateral sub grade reaction(kN/m3 = L : δ : E : I : β η K h _ REV.B 18 of 31 Calculation for Preliminary Test Pile (PHC) VP1-0-L4-C-GEN-00020 Soil Dense sandy gravel Medium dense coarse sand Medium sand Fine or silty, fine sand Stiff clay (wet) Stiff clay (saturated) Medium clay (wet) Medium clay (saturated) Soft clay nh : ks, kcf Remark ks, MN/m3 1400 - 2500 220 - 400 300 MN/m3 1000 - 2000 157 - 300 700 - 1800 110 - 280 80 - 200 500 - 1200 350 - 1400 60 - 220 175 - 700 30 - 110 250 - 900 39 - 140 10 - 80 75 - 500 - 40 10 - 250 Foundation Analysis and Design, Bowles, Table 16.4 Coefficient of soil modulus variation(MN/m3) 60,000 kN/m3 = = 60 MN/m3 refer to the below figure, value of Dense sand ηL = 13.21 > → Long Pile Variation of nh with relative density (Reese, 1975) Fig My rD Kp = 1759.3 26.3 x 0.8^4 x 4.204 = Pult 38.80 rD3Kp = 11 where, r Ø = effective unit weight of soil = Friction angle = (fy - P/A ) X Z My Kp = = = = 26.3 38 kN/m2 1759.3 kN· m Rankine's passive earth pressure coefficient tan2(45+ Ø/2) = 4.204 therefore Pa = 11 rD3Kp = 498.2 Kn _ REV.B 19 of 31 Calculation for Preliminary Test Pile (PHC) VP1-0-L4-C-GEN-00020 Fig Cohesionless soils - Ultimate Lateral Resistance - - - - - - - - - - Broms B.B(1964), Fig 3.3 Elastic Deformation of Pile δ = Q Lp A Ep = 3728 × 20 0.503 × 32800000 = 0.0045 TCXD 205:1998 Appendix E Eq.(E.5) m = 4.52 = = = = 3,728 20 0.503 32,800,000 mm where , δ Q Lp A Ep : : : : : elastic deformation of pile load capacity effected on pile length of pile section area of pile elastic modulus of pile materials kN m m2 kN/m2 3.4 Total Settlement Calculation for Pile(Inc Elastic deformation) s = D 100 + QL AE = 0.8 100 + 3728 × 20 0.503 × 32800000 = 0.0125 TCVN 10304-2014 APP.B (B.1) m = 12.52 mm _ REV.B 20 of 31 Calculation for Preliminary Test Pile (PHC) VP1-0-L4-C-GEN-00020 CALCULATION OF PILE CAPACITY (BH45, 600 DIA, A-TYPE) 4.1 Input Data 1) Location: Waste Water Treatment System for Power Block (TP-04, 05, 06) 2) Based Borehole No : BH-45 3) Material Properties of pile 600 Pile Dia (D) : mm m 0.6 100 Pile Thickness (T) : mm 6.10 Level of Top of Pile (EL.) : m 20.0 Pile Length (L) : m Pile Base Area (Ap) 0.283 : m2 1.88 Pile Perimeter (Φ) : m 4.08 ) Pile Unit Weight (γ : kN/m pile - - - - - - - - - JIS A5373;2010 E-1 Table Minimum Bearing Capacity of Pile Material(Rm) 2,551 : kN (App.B3 Pile Properties) (Refer to the Appendix #2 Properties of Spun Pile) Correction factor for connection : %/EA Number of connection Point EA : 2,423 Minimum Bearing Capacity of Pile Material(Rm) : kN 4) Soil Profile for Bore hole based on S/I Report Stratum 5 5A 6B Description F.G.L.(EL, m) Banking Fill Clayey Sand CLAY W.Clay W.Rock Water level (EL, m) Depth(m) 6.10 -3.50 0.0 ~ 0.0 4.50 ~ 4.5 8.50 ~ 8.5 13.50 ~ 16.50 13.5 ~ Thick SPT N BH Cutting 3.50 4.50 4.00 5.00 3.00 25 31 29 28 50 Pile Head BH-45 N/A Pile End 0.26 _ REV.B 21 of 31 Calculation for Preliminary Test Pile (PHC) VP1-0-L4-C-GEN-00020 4.2 Bearing Capacity of Pile 4.2.1 Allowable Axial Capacity General formula for estimation allowed loading of single pile according to background is : Qa Qu FS = - TCXD 205, Chap 4, (4.1) Extremely limit loading capacity according to background includes components - head strength and boundary condition of pile : Qu = Qs + Qp = Qs + Qp = ∑ ui li fi + 3472.6 = = where, 1966 + 5439 Ap qp - TCXD 205, Chap 4, (4.3) - TCXD 205, APPENDIX B, (B.1) kN Qs : Qp : fs : body friction load bearing capacity of pile load bearing capacity of pile toe - - - - - - - - - - TCXD 205, APPENDIX B, (B.1.3) ca+σh tanØa (ca=0.7c, Øa=0.7Ø) αcu (α=0.3-0.45: for the hard plastic clay, 0.6-0.8: for the plastic clay) - - - - - - - - - - TCXD 205, APPENDIX B, (B.2) Friction load bearing capacity along body of pile Qs = ∑ As f s - Positive friction = 1966 kN For TCXD205 Soil Layer 5A 6B Total Banking Fill Clayey Sand CLAY W.Clay W.Rock Thick Density (m) 3.50 4.50 4.00 5.00 3.00 (kN/m3) 19 19.6 19.2 19.3 26.3 20.00 Friction angle 25 25.5 14.5 15 38 c σ'vp σh Friction (fs) kN/m2 15 8.3 38 40 100 33.25 110.60 193.10 279.75 367.45 19.20 62.99 144.75 207.35 141.23 15.64 23.04 48.75 60.84 129.37 Qs = As fs Negative Friction 102.94 Pile Head 194.93 366.60 571.90 729.62 Pile end 1966 0.00 _ REV.B 22 of 31 Calculation for Preliminary Test Pile (PHC) VP1-0-L4-C-GEN-00020 For TCVN10304 Soil Layer 5A 6B Total Banking Fill Clayey Sand CLAY W.Clay W.Rock Thick Density (m) 3.50 4.50 4.00 5.00 3.00 (kN/m3) 19 19.6 19.2 19.3 26.3 20.00 Friction angle 25 25.5 14.5 15 38 c kN/m2 15 8.3 38 40 100 σ'vp 33.25 44.10 38.40 48.25 39.45 Friction Friction (fs) (fs) Clay 4.50 2.49 11.40 12.00 40.00 Sand 15.50 52.75 49.94 74.96 150.00 Qs = u ∑fi li Negative Friction 102.02 446.29 85.73 112.80 846.00 Pile end Pile Head 1593 0.00 _ REV.B 23 of 31 Calculation for Preliminary Test Pile (PHC) VP1-0-L4-C-GEN-00020 Load bearing capacity of pile toe Ap qp Qp = 0.28 = 12271 = x 3472.6 kN load intensity of ground under pile edge = cNc + σ'vpNq + γdp Nγ qp - TCXD 205, APPENDIX B, (B.4) = 100 x 37.16 + 367.45 x 22.46 + 26.3 x 0.6 x 19.13 = 12271 kN/m2 where, c : the cohesive force of ground, t/m2 σ'vp : effective stress by the vertical direction at the depth of pile edge and weight of ground, t/m2 : load capacity coefficient which depends inside friction of ground by the shape N c , Nq , Nγ of pile implementation Nc Nq 37.16 22.46 19.13 = = = Nγ : volume weight of ground under the depth of pile edge, t/m3 γ a) Result based on TCXD 205 Qa = Qs FSs + Qp FSp = 1966 2.0 + 3472.6 3.0 - = 2140.5 kN → TCXD 205, APPENDIX B, (B.2) 2,141 kN where, FSs FSp : : safety coefficient for the side friction, taken by 1.5-2.0 safety coefficient for supporting capacity under the pile edge, taken by 2.0-3.0 b) Result based on TCVN 10304:2014 Rc,u = qb Ab u ∑fi li + - TCVN 10304, APPENDIX G, (G.1) qb = ( cN'c + q'γ,p N'q ) - TCVN 10304, APPENDIX G, (G.2) fi fi = α cui = ki σ'vz tanδi - TCVN 10304, APPENDIX G, (G.5) TCVN 10304, APPENDIX G, (G.6) where, N' c , N' q : q' γ,p, σ 'vz α c ui ki δi : : : : : : : : Ab u fi the coefficient of bearing capacity of the soil under the pile tip N' c = N' q = 37.16 22.46 the effective pressure the coefficient depending on the soil characteristics on the clay layer the intensity of the undrained strength the coefficient of horizontal prerssure of the soil the friction angle between the soil and pile S/I Report the area of leaning on the pile soil, m2, perimeter of cross-section of the pile body = average resistance strength of the soil layer i-th 1.88 m _ REV.B 24 of 31 Calculation for Preliminary Test Pile (PHC) VP1-0-L4-C-GEN-00020 li Qb : length of the pile section in soil layer i-th = ( cN'c + q'γ,p N'q ) Ab = ( 100 x 37.16 + 367.45 x 22.46 ) x 0.283 3,387 kN = Rc,u = Qb + Ra Rc,u γg = γg 3,387 = u ∑fi li 4,980 1.6 = : reliability factor = 1,593 + = 4,980 kN 3,113 kN = 1.6 c) Result based on TCVN 7888:2014 RaL RaS = ( σcu 3.5 - σce ) x A0 = ( 80 3.5 - 4 ) x 157080 = x ( σcu 3.5 - σce ) x A0 (Short-term) = x ( 80 3.5 - 4 ) x 157080 Ra σcu σce A0 : : : : (Long-term) - - - - - - - - - TCVN 7888-2014 = 3,433 kN = 6,867 kN where, Allowable bearing capacity based on pile material Specified compressive strength of concrete Effective strength of concrete Cross sectional of area of pile = = = 80 N/mm2 4.0 N/mm2 157080 mm2 d) Comparison of the results between TCXD, TCVN 10304 and TCVN 7888 Allowable Axial Capacity = Min.(TCXD, T10304, T7888) = Min.(2141, 3113, 3433) = 2,141 kN 4.2.2 Allowable Pull-Out Capacity a) Result based on TCXD Qa Qs = + W = 1966 + 56.6 = 712 kN where, Qs W : : side friction resistance capacity of the pile weight of pile 56.6 kN = W = γpile x L _ REV.B 25 of 31 Calculation for Preliminary Test Pile (PHC) VP1-0-L4-C-GEN-00020 b) Result based on TCVN 10304:2014 Rt,u = γc u ∑ γcf fi li γc γcf Rt,a - 0.8 working rate of the pile in soil = in cohesive soil with consistency index lL < 0.5 Rt,u γg = = 1274.27 1.6 = TCVN 10304-2014, 7.2.2.3(11) (= 1.0 ) 796 kN c) Result based on Tensile Stress in PC bar Pt = σpe · Ap = 622 kN 872.8 x 712.7 = where, Pt σpe Ap : : : Max tension by PC bar Effective tensile stress in PC bar Total cross section area of PC bar = = 872.8 N/mm2 712.7 mm2 d) Comparison of the results between TCXD, TCVN and Tensile Stress in PC bar Allowable Tension Capacity = Min.(TCXD, TCVN, PC bar) = Min.(712, 796, 622) = 622 kN 4.2.3 Allowable Horizontal Capacity By using method of Broms(1964), the coefficient and maximum pile bending moment from the design loads will then be calculated Broms, B.B(1964) " Lateral Resistance of Piles in cohesive Soils" Journal of Soil Mechanics and Foundation Engineering, ASCE, Vol 90, SM2, pp27-63 TCXD 205:1998 Appendix G.9 1) Definition of pile type Diameter Short pile Long pile Cohesive soil βL ≤ 2.25 βL > 2.25 Cohesion less soil ηL < 2.0 ηL > 4.0 where, Length(m) = 20.0 m Horizontal displacement = 0.015 m (Design Criteria 2.2) Young modulus of pile = 32,800,000 kN/m2 Moment inertia of pile = 0.0051 m4 KhD 1/4 = ( = 1.50 m = 0.67 ) 4EI , β nh 1/5 = 0.68 = ( ) EI , 220,000 kN/m3 : Coefficient of lateral sub grade reaction(kN/m3 = L : δ : E : I : β η K h _ REV.B 26 of 31 Calculation for Preliminary Test Pile (PHC) VP1-0-L4-C-GEN-00020 Soil Dense sandy gravel Medium dense coarse sand Medium sand Fine or silty, fine sand Stiff clay (wet) Stiff clay (saturated) Medium clay (wet) Medium clay (saturated) Soft clay nh : ks, kcf ks, MN/m3 Remark 1400 - 2500 220 - 400 220 MN/m3 1000 - 2000 157 - 300 700 - 1800 110 - 280 500 - 1200 80 - 200 350 - 1400 60 - 220 175 - 700 30 - 110 250 - 900 39 - 140 75 - 500 10 - 80 10 - 250 - 40 Foundation Analysis and Design, Bowles, Table 16.4 Coefficient of soil modulus variation(MN/m3) 25,000 kN/m3 = = 25 MN/m3 refer to the below figure, value of Medium dense coarse sand ηL = 13.67 > → Long Pile Variation of nh with relative density (Reese, 1975) Fig My rD Kp = 857.16 19 x ^4 x 2.464 = Pult 141.30 rD3Kp = 38 where, r Ø = effective unit weight of soil = Friction angle = (fy - P/A ) X Z My Kp = = = = 19 25 kN/m2 857.16 kN· m Rankine's passive earth pressure coefficient tan2(45+ Ø/2) = 2.464 therefore Pa = 38 rD3Kp = 230.6 Kn _ REV.B 27 of 31 Calculation for Preliminary Test Pile (PHC) VP1-0-L4-C-GEN-00020 Fig Cohesionless soils - Ultimate Lateral Resistance - - - - - - - - - - Broms B.B(1964), Fig 4.3 Elastic Deformation of Pile δ = Q Lp A Ep = 2141 × 20 0.283 × 32800000 = 0.0046 TCXD 205:1998 Appendix E Eq.(E.5) m = = = = = 2,141 20 0.283 32,800,000 4.61 mm where , δ Q Lp A Ep : : : : : elastic deformation of pile load capacity effected on pile length of pile section area of pile elastic modulus of pile materials kN m m2 kN/m2 4.4 Total Settlement Calculation for Pile(Inc Elastic deformation) s = D 100 + QL AE = 0.6 100 + 2141 × 20 0.283 × 32800000 = 0.0106 TCVN 10304-2014 APP.B (B.1) m = 10.61 mm _ REV.B 28 of 31 Calculation for Preliminary Test Pile (PHC) VP1-0-L4-C-GEN-00020 APPENDIX #1 : Pile Properties _ REV.B 29 of 31 Calculation for Preliminary Test Pile (PHC) VP1-0-L4-C-GEN-00020 APPENDIX #2 : Standard Specifications of Pre-Stressed Concrete Spun Pile by Manufacturer _ REV.B 30 of 31 Calculation for Preliminary Test Pile (PHC) VP1-0-L4-C-GEN-00020 _ REV.B 31 of 31