Method Statement of load Test for Steel Tubular Load Test Trial Piles Rev.3

Transcription

1

2 Doc. No.: PMBP-MBEC-MS-SZ001 Rev. No.: Third Issue Date: Method Statement of load Test for Steel Tubular Load Test Trial Piles Rev LSC Revised Issue LYF MYG YBJ LSC Revised Issue LYF MYG YBJ LSC Revised Issue LYF MYG YBJ Revision Date Prepared by Description Checked by Approved by Project Approved STATUS DEFINITION (latest revision): 3 Total no. of pages (incl Att): 69

3 Contents 1 WORK CONTENTS AND PURPOSE 3 2 TEST CRITERION 3 3 PDA TEST OF DRIVEN STEEL TUBULAR PILES PREPARATORY WORK BEFORE TESTING THE TECHNICAL REQUIREMENTS OF PDA TEST AXIAL BEARING CAPACITY ESTIMATION AND PILE INTEGRITY COMMENTS PDA REPORT 8 4 TRIAL PILE AXIAL STATIC LOAD TEST TRIAL PILE NUMBERS AND THE MAX LOADS VALUE STEEL TRIAL PILE PARAMETERS STEEL TRIAL PILE INSTRUMENTATION ARRANGEMENT STATIC LOAD TEST METHOD STATIC LOAD TEST REPORT CONTENTS OF THE STEEL TUBULAR TRIAL PILE 24 5.TRIAL PILE REPORT 25 APPENDIX: 27 APPENDIX A: SCHEMATIC OF MOUNTING HOLES FOR PDA TRANSDUCERS INSTALLATION 28 APPENDIX B: SCHEMATIC OF THE DISPLACEMENT WIRES AND STRAIN GAUGES INSTALLATION 29 APPENDIX C: CALIBRATION CERTIFICATES OF PDA TRANSDUCERS 32 APPENDIX D: ANCHOR LENGTH DETERMINATION FOR ANCHOR PILES Project: Padma Multipurpose Bridge Project (PMBP) Date: Doc. No. : PMBP-MBEC-MS-SZ001 Page: 1 of 69

4 36 APPENDIX E: APPROVAL STATUS METHOD STATEMENT OF LOAD TEST FOR STEEL TRIAL PILE R2 错误! 未定义书签 APPENDIX F: REPLYING TO CONSULTANT COMMENTS ON THE MBEC RESPONSES 40 APPENDIX G: CONSULTANT REMARKS ON THE MBEC RESPONSES FOR LOAD TEST METHOD OF STEEL TUBULAR TRIAL PILES-REV APPENDIX H: RESPONSES TO COMMENTS FOR METHOD STATEMENT OF LOAD TEST FOR STEEL TRIAL PILE R1 57 Project: Padma Multipurpose Bridge Project (PMBP) Date: Doc. No. : PMBP-MBEC-MS-SZ001 Page: 2 of 69

5 1 Work Contents and Purpose According to the design drawings of PADMA Multipurpose Bridge Project, the steel tubular trial load test piles shall be carried out. The main fieldwork included as follows: (1) Contents (a) PDA tests on steel trial piles. (b) Static pile loading tests on steel trial piles. (2) Purpose (a) PDA tests shall be carried out to estimate the capacity of the piles. (b)pda tests shall be carried out on the pile after driving installation to designed depth to ensure integrity. (c)trial pile load test shall be carried out to determine the ultimate skin friction of the steel piles, the ultimate end bearing resistance and the bearing capacity of the trial piles. When driving the steel tubular pile, acceleration sensors and strain sensors shall be installed to carry out pile driver analyzer (PDA) using CAPWAP to monitor the pile after driving installation to designed depth to estimate the capacity of the pile and to ensure integrity. Pile loading test shall be carried out as per the specifications in Section 7 and taken to failure with a reaction force not less than 40MN to determine the ultimate skin friction values and ultimate end bearing. 2 Test Criterion (1) The drawings of PADMA Multipurpose Bridge Project in Bangladesh. (2) The technical Specification in Section 7 of PADMA Multipurpose Bridge Project. (3) The Drawings of trial piles construction of PADMA Bridge, MBEC. (4) ASTM D PDA Test of Driven Steel Tubular Piles According to the drawings and technical specification in section 7 of PADMA Bridge, high-strain dynamic testing (PDA testing) shall be carried out on the steel tubular trial piles during installation and after driving to designed depth to ensure the integrity and to estimate pile capacity. Project: Padma Multipurpose Bridge Project (PMBP) Date: Doc. No. : PMBP-MBEC-MS-SZ001 Page: 3 of 69

6 3.1 Preparatory Work before Testing Apparatus Pile Driver Analyzer, PAX type, manufactured by PDI Company, shall be used for PDA tests at the time of driving of steel tubular trial piles. The system includes principal machine, signals acquisition and transmission equipment, two strain transducers and two acceleration transducers, cable or wireless equivalent, etc (See Fig 3.1) Transducers installation Fig 3.1 Apparatus of PDA According to the Specification in Section 7, PDA tests shall be carried out in conformance to the requirement of ASTM D To avoid irregular stress concentrations at the top of the pile, locate transducers a distance of 4.5m from the top of pile as illustrated in Appendix 1. Align transducers with their sensitive direction parallel to the long axis of the pile. Transducers shall be symmetrically opposed and equidistant from the pile centroid in a plane perpendicular to the pile axis. For each impact event, the raw or processed signals from the transducers shall be displayed during data acquisition or replay as a function of time, such as on a digital graphics display on the PDA principle machine. Four transducers shall be securely attached on opposite sides of the pile. Two of these transducers are strain gauges and two are accelerometers (Certificates of Calibration have been listed in Appendix). For transducers installation, remove any unsound or deleterious material from the pile surface, which is smooth, and no appearance defect or abrupt change of cross-section etc, and firmly attach two of each of type of transducer at a measurement location of pre-drilled holes using bolts. The pre-drilled holes at a measurement location for transducers installed and field installation as illustrated in Fig 3.2. Project: Padma Multipurpose Bridge Project (PMBP) Date: Doc. No. : PMBP-MBEC-MS-SZ001 Page: 4 of 69

7 Fig 3.2 Schematic of transducers installation During the installation of driven steel tubular piles, the cable or wireless equivalent shall be protected to avoid being damaged. 3.2 The Technical Requirements of PDA Test (1)Testing values of relative parameters 1 Section area refers to the section where the transducers installation; 2 The pile length refers to the distance between the locations of transducers installation to the bottom of the pile. 3 The strain wave velocity of the pile shaft should be set as 5123m/s; 4 The density of steel pile should be set as 77.3 kn 3 ; m 5 Elastic modulus of the pile shaft shall be determined by Where 2 E C E = elastic modulus of the pile shaft ( kpa ) c = velocity of one dimensional longitudinal strain wave of the pile shaft ( m / s ) = mass density of the material of the pile shaft ( 3 t / m ) Project: Padma Multipurpose Bridge Project (PMBP) Date: Doc. No. : PMBP-MBEC-MS-SZ001 Page: 5 of 69

8 6 PDI company calibration coefficient shall be used as the transducers parameters of PDA tests. (2)Field test shall meet the requirements below 1Before testing, transducers, wires, and connector shall be checked for open circuits, short circuits before test. Normal state of the test system shall be confirmed according to the calibration method inside of it, and parameters shall be set according to 3.3 (1). 2 Effective hammering signal of each pile shall be comprehensively determined by the maximum dynamic displacement and the maximum velocity of the pile top, the maximum compressive stress of the pile shaft, hammering energies, penetrations, signal quality, seriousness of defects and developing trend of these defects. (3)Selection of testing signal shall follow the regulations below 1)For selection of signal when measuring the capacity, hammerings with higher energy is preferred. 2)The signals are not allowed for analysis and calculation in case of the following situations after hammering: (a) The end of the force curve cannot come to zero because of severely plastic deformations of the location transducers installation. (b) The amplitude one side gets as high as 1 time of the amplitude at the other side or more caused by eccentricity of hammering. (c) Test data of the four channels are incomplete. (4)Determination of wave speed The overall wave speed observed during a high-strain event shall be estimated as follows: Divided two times the length of pile below transducers by the observed time between start of the impact (for example, initial sharp rise of the signal) and the start of the tensile reflection (for example, later relative velocity increase) to obtain the wave speed. Schematic as follows: Project: Padma Multipurpose Bridge Project (PMBP) Date: Doc. No. : PMBP-MBEC-MS-SZ001 Page: 6 of 69

9 In general, the wave speed of structural steel piles can be assumed as 5123 m s. 3.3 Axial Bearing Capacity Estimation and Pile Integrity Comments Estimation of Bearing capacity There are two analysis methods for the determination of single pile bearing capacity by PDA test, CASE method and CAPWAP method. 1) Methodology of CASE method (1) The vertical compressive capacities of single piles can be determined by case method by R C L 2L 1 J Ft Z V t 1 J F t Z V t C C 1 c 1 c (2) The integrity coefficient β can be determined by F t1 Z V t1 2Rx F t x Z V t x F t Z V t F t Z V t 1 1 x x 2) Curve-fitting method (CAPWAP 2006) (1) Select one measured curve as the calculated curve. Usually, choose the velocity curve as the calculated wave. (2) Set the parameters of piles and soil according to the geological date. (3) Do fitting analysis using another measured curve, which is force curve usually. (4) Compare the measured curve with calculated curve and then calculate it repeatedly until the fitted curve is similar to the measured curve. Then the parameters of piles and soil are similar to actual parameters. (5) Output result The ultimate bearing capacity of trial piles shall be calculated by the software Pile Driving Project: Padma Multipurpose Bridge Project (PMBP) Date: Doc. No. : PMBP-MBEC-MS-SZ001 Page: 7 of 69

10 Analyzer and CAPWAP The result obtained from CAPWAP 2006 shall be the bearing capacity of the trial piles PDA test Comments on the Integrity The degree and location of a pile shaft defect should be observed and pay attention to the expanding or closed conditions of the defect during continuous hammering. 1Fitting parameters for fitting analysis shall be in a reasonable range. 2Prolonged part of the time span for curve fitting shall not be less than 20 ms after t 2L c 1. 3The selected value for maximum elastic displacement of soil in each element shall not exceed the maximum calculated displacement of the corresponding pile element. By means of PDA tests, piles integrity shall be determined according to the specified in the PDA-W Manual of Operation as shown in the table 3.1 below. Table 3.1 Pile integrity categories judgment BETA Value Description 100% Uniform Pile 80 to 99% Slight Damage 60 to 80% Damage <60% Pile Broken (generally pile is then rejected) 3.4 PDA Report The report of the PDA testing shall include the following information: (a) General -Date and time of driving, -Project identification, -Project location, -Test location, -Employer, Engineer, Contractor, -Designation and location of the nearest boring and/or cone penetration test with reference to location of the test pile and vertical control datum. Project: Padma Multipurpose Bridge Project (PMBP) Date: Doc. No. : PMBP-MBEC-MS-SZ001 Page: 8 of 69

11 -Log of nearest test boring and/or cone penetration test -Horizontal control datum, -Vertical control (elevation) datum, -The coordinates and the elevations at the test location, -River water level and tide records (even if the location is not inundated), -Level of the surface of the sand inside the pile at any given time while installing the pile. and especially at the time of splicing or hammer change and completion of driving, -Details and specifications of the instruments installed along with their calibration curves and calibration certificates, (b) Pile Installation Equipment -Plant used to drive the piles, -Make, model, type, size, and recent service history of hammer, -Weight of hammer and ram, -Stroke of ram -Rated energy of hammer, -Rated capacity of compressor, -Type, dimensions and stiffness values of capblock and pile cushion (no capblock and pile cushion for the hydraulic hammer) -Weight and dimensions of drive cap and follower (no follower for the hydraulic hammer) -Type, size, length, weight and stress transmitting area of mandrel -Detailed specifications of any special arrangement for applying impact force. (c) Test Piles -Identification and location of the pile tested -Number, weight and length of the test pile -Working load of pile (no working load for trial piles) -Type of pile, -Test pile material including basic specifications, -Tip and butt dimensions of pile, -Wall thickness of test pile, Project: Padma Multipurpose Bridge Project (PMBP) Date: Doc. No. : PMBP-MBEC-MS-SZ001 Page: 9 of 69

12 -Description of test pile tip reinforcement or protection, -Description of special coating used, -Test pile (mandrel) weight as driven, -Concrete cube strengths of plug when pile tested, -Rake of pile, -Orientation of pile rake, -Final elevation of test pile buttes referenced to fixed datum. (d) Pile Installation -Date installed, -Volume of concrete or grout placed in pile, -Grout pressure used, -Description of pre-excavation or jetting depth, pressure, duration, -Operation pressure for all hammers, -Description of special installation procedures used, such as piles cased off, -Type and location of pile splices, -Driving records, -Final penetration resistance, -Stroke of ram during final driving and/or blows/minute of hammer, -Penetration for last two series of 5 blows with the hammer, -Penetration resistance during re-strike, -When capblock replaced (indicate on log), (no capblock for the hydraulic hammer) -When pile cushion replaced (indicate on log), (no pile cushion for the hydraulic hammer) -Cause and duration of interruptions in pile installation,. -and Any unusual occurrence during installation, (e) PDA Testing - Detailed description of all components of the apparatus for obtaining dynamic measurements and apparatus for recording, reducing, and displaying data. -Date tested, -Test pile identification, Project: Padma Multipurpose Bridge Project (PMBP) Date: Doc. No. : PMBP-MBEC-MS-SZ001 Page: 10 of 69

13 -The modulus of elasticity, density, and wave speed of test pile, and how determined, -Sequence in pile driving test carried out, such as End of Initial Driving, Beginning of re-strike, - Length of pile embedded and length below apparatus for obtaining dynamic measurements during driving, -Penetration resistance during dynamic testing, -The range, average and standard deviation of the measurements of maximum and minimum compression force and the maximum computed tension force, -The range, average and standard deviation of the impact velocity data, The range, average and standard deviation of the measurements of maximum acceleration, -The range, average and standard deviation of the measurements of final penetration of the pile, -The range, average and standard deviation of the maximum and final energy data, -Which one-dimensional wave theory used for the analysis of the pile driving, -The variables entered into the wave theory, such as damping, quake and resistance, -The computed soil resistance acting on the pile at the time of testing, both end bearing and skin friction and how to be computed, -Comments on the integrity of the pile. 4 Trial Pile Axial Static Load Test 4.1 Trial Pile Numbers and the max Loads Value According to the drawings and technical specification in section 7, there are provisions for 4 test locations and at least 2 such piles shall be tested at each test location. The test locations and pile installation details are shown in the Drawings. The trial piles for driven steel tubular piles load tests taken to failure shall be carried to determine the ultimate skin friction of the steel piles and the ultimate end bearing resistance. The trial piles should be constructed identical to the working pile. The test length of the trial piles shall be 30m in length, and the section of pile that is above the dense sand layer of the test section shall be sleeved to eliminate skin friction contributions from the upper soils layers. In addition, there are also provisions for 2 test locations with 1 pile (30m length section) for each location to Project: Padma Multipurpose Bridge Project (PMBP) Date: Doc. No. : PMBP-MBEC-MS-SZ001 Page: 11 of 69

14 be tested after skin grouting. Thus a total of at least 10 steel driven piles shall be tested. The testing piles shall be taken to failure with a reaction force of not less than 40MN. 4.2 Steel Trial Pile Parameters According to the steel tubular trial pile parameters shown in the drawings, trial pile static load tests shall be carried out. Strain gauges shall be arranged in the scope of testing section. The trial pile parameters as shown in the table 4.1 below. Table m Diameter Steel trial pile Schedule and parameters Trial pile location Trial pile No. Pile diameter (m) Skin grouting (N/Y) Pile toe (mpwd) Testing section (Refer to DWG. BR1865)(mPWD) Level A Level B Max. test load(mn) TD1 TD2 TD3 TD4 TD1A 1.5 N TD1B 1.5 N TD1C 1.5 Y TD2A 1.5 N TD2B 1.5 N TD3A 1.5 N TD3B 1.5 N TD3C 1.5 Y TD4A 1.5 N TD4B 1.5 N Steel Trial Pile Instrumentation Arrangement According to the requirements of drawings and technical Specification, The axial force of trial piles shall be measured during the trial pile static load test (taken to failure). By means of destructive static load test, the ultimate bearing capacity of single pile, the ultimate skin friction values and ultimate end bearing shall be determined Arranged principle of instrumentations On the basis of the requirement of the Specification, the ultimate skin friction values and the estimation of the end bearing capacity of the pile shall be submitted in the report. According to the distribution and levels of the soils, the strain gauges shall be arranged to the reinforcement cage at the interfaces of different soils and within the scope of soils. In the scope of concrete plug, there is reinforcement cage in concrete, so the instrumentation shall be arranged in concrete and attached to the rebar firmly; Due to the absence of Project: Padma Multipurpose Bridge Project (PMBP) Date: Doc. No. : PMBP-MBEC-MS-SZ001 Page: 12 of 69

15 reinforcement cage in the scope of soil plug, can only arranged the strain gauges on the steel pile wall. During test, the variation of strain gauges shall be measured to calculate the parameters of the ultimate skin friction values and ultimate end bearing Strain gauges layout design According to the Specification and the geological data around the pile, the strain gauges sections and levels along the steel trial pile shaft should be arranged as shown in table 4.2 to 4.4. Table 4.2 Strain gauges No. of each section and levels along the shaft-1 Suitable Pile No. TD1A TD1C, TD3A TD4A No. of layers (mpwd)layout In Arranged on Steel level 1 concrete pile Remarks Sleeve Casing Pile Toe Notes: 1:The layout levels arranged according to the geological data, are temporary levels. The actual levels for each trial pile shall be adjusted according to the soils levels after the GI information. The same back with this. Table 4.3 Strain gauges No. of each section and levels along the shaft-2 Suitable Pile No. No. of layers (mpwd)layout level 1 TD1B TD3B TD3C TD2B TD4B In concrete Arranged on Steel pile Remarks Sleeve Casing Project: Padma Multipurpose Bridge Project (PMBP) Date: Doc. No. : PMBP-MBEC-MS-SZ001 Page: 13 of 69

16 Pile Toe Table 4.4 Strain gauges No. of each section and levels along the shaft-3 Suitable Pile No. No. of layers (mpwd)layout level 1 In concrete TD2A Arranged on Steel pile Remarks Sleeve Casing Pile Toe Strain gauges installation 1)Installation of Strain gauges mounted on the steel pile wall Steel tubular trial piles shall be processed by subsections, during fabrication, strain gauges Project: Padma Multipurpose Bridge Project (PMBP) Date: Doc. No. : PMBP-MBEC-MS-SZ001 Page: 14 of 69

17 near the pile end shall be mounted on the steel pipe wall. On the processed steel pipe pile, four steel angles shall be welded from pile end up to pile top. Steel angles shall be welded on the outside of the steel pipe pile. After the joint of upper and lower section, steel angles shall be welded. The strain gauges, arranged according to the GI information, shall be mounted in the steel angles. The levels of the strain gauges as shown in table 4.2 to 4.4. After installation, the cables of the strain gauges should be prolong to the top of the pile through the steel angles. From the location of the gauges, valid measures shall be adopted to fix the gauges cables. The cables shall be firmly hung on the pile section, and drawn to the pile top along the steel angles. The steel angles shall be arranged considering the structures of centering rollers and skin grouting pipes. According to the drawings Steel Tubular Trial Piles for Load Test of PMB-MB-1101 to 1103, there are 5 rows centering rollers for the all trial piles, and there are 5 rows grout slots for the trial piles with skin grouting pipes shall be arranged symmetrically on the outer wall of them, the layout of steel angles shall be staggered arrangement unsymmetrical with the centering rollers. For the trial piles with skin grouting pipes, the steel angles shall be staggered arrangement in the gap between the centering rollers and skin grouting pipe. To ensure welding quality,four steel angles plane position should be symmetrical as far as possible. The relative plane position of the steel angles and steel pile, centering rollers and pile skin grouting pipes shall be shown in figure 4.1. (a) Pile section with skin grouting pipes (b) Pile section without skin grouting pipes Fig 4.1 Relative Plane Position of the Steel angles Project: Padma Multipurpose Bridge Project (PMBP) Date: Doc. No. : PMBP-MBEC-MS-SZ001 Page: 15 of 69

18 2) Protection of Steel angles for strain gauges arranged on the trial pile shaft The strain gauges in the scope of soil plug arranged on the trial pile shaft shall be protected by steel angles welded with the trial pile shaft firmly. The schematic of steel angles have been indicated as follows: Fig 4.2 Protection of Steel angles for strain gauges 3) Installation of Strain gauges mounted in concrete plug In the section of concrete plug, 4 strain gauges shall be symmetrically attached to the rebars Project: Padma Multipurpose Bridge Project (PMBP) Date: Doc. No. : PMBP-MBEC-MS-SZ001 Page: 16 of 69

19 in plane section. The Cables of the gauges should be tied to the reinforcement bars, and led to the pile top working platform through hole on the steel pipe pile. The strain gauges and cables must be protected during the transport, hoisting, construction process of the steel tubular pile and reinforcement cage. Make sure not to damage the strain gauges and cables. The strain gauges embedded levels indicated in Appendix Static Load Test Method According to the drawing of No. BR1118, PADMA Main Bridge, the maximum test load of the steel tubular piles in Table 1-Trial pile schedule is 30MN, and the testing piles shall be taken to failure with a reaction force not less than 40MN. The intervals between the pile sinking finished and pile static load test start is no less than 7 days Test method and principle Pile top relative displacement, pile skin friction shall be generated under static axial compressive load. With the increase of pile top load, pile elastic (plastic) displacements produced. By means of measurements of the pile top test load and corresponding displacements, test results may also provide information used to assess the distribution of side resistance along the pile shaft, the amount of ending developed at the pile toe, and the long-term load-deflection(q~s) behavior, etc. And then, the bearing capacity of the pile shall be determined. The apparatus for applying compressive loads to a test pile shall include the reaction beam system, loading device(pump and hydraulic pressure jacks) and anchor piles, trial pile top settlement measurement system, anchor pile top extension measurement system. According to the requirements of drawings and technical Specification, the load tests shall be taken to failure with a reaction force not less than 40MN, or to the maximum test loads stated in Drawings. The maximum test load is big, construction term is limited, and the pile location is in the water. The design of anchor pile and reaction beam system is specially designed to meet the demand of load test. The reaction system is made up of anchor pile and loading reaction beam system. Reaction beam system mainly includes the columns, cross arm, tie rod and distributive girder, as well Project: Padma Multipurpose Bridge Project (PMBP) Date: Doc. No. : PMBP-MBEC-MS-SZ001 Page: 17 of 69

20 as the test pile and anchor pile transmission force structures. After completion of the steel tubular trial pile and anchor piles construction, transmission force structures and reaction beam system shall be assembled. After the resting phase between the pile and soil meets the test requirements, static load tests shall be carried out Test equipment and data acquisition equipment (1) Loading and load measurement system By means of the kN hydraulic jacks in parallel, placed on the trial pile top, and electric oil pump provides loading force for the vertical compressive tests of steel tubular trial piles. Using precision pressure gauge shows the oil pressure. Pile top load values shall be calculated by jack rate curves and the oil pressure gauges reading. The full-scale value of the pressure gauge is 0~100MPa, accuracy of 0.4 grade, shockproof precision. The nominal range of the pressure gauge is satisfied with the needs of the jack load capacity. Schematic of vertical compressive test of anchor piles trial pile indicated in Fig 4.3. (a)vertical view Project: Padma Multipurpose Bridge Project (PMBP) Date: Doc. No. : PMBP-MBEC-MS-SZ001 Page: 18 of 69

21 (b)lane arrangement of trial pile and anchor piles Fig 4.3 Schematic of vertical compressive test of anchor piles and trial pile Appendix 7.1.3, (a) of technical Specification Section 7, required that the anchor piles or other anchorages shall be installed. The centre of each anchor pile shall be at least 2 m or three times the pile diameter, whichever is greater, from the centre of the pile to be tested and from the centre of any adjacent pile.). Actually, the space between anchor piles and trial pile is not less than 4.5m (3 times of the trial pile diameter), and it meets the needs of technical Specification. (2) Displacement Acquisition Equipment According to the technical Specification, during the static load test, the settlements of trial pile head shall be monitored by four displacement transducers, which accuracy is 0.025mm. In order to meet the requirement of load test and data precision, the static load tests of this project intends to use the RSM-JC Ⅲ Static load test instrument. The system can automatically collect data, automatic recording, and can meet the requirement of the technical Specification. Data collection devices as shown in Fig 4.4. Project: Padma Multipurpose Bridge Project (PMBP) Date: Doc. No. : PMBP-MBEC-MS-SZ001 Page: 19 of 69

22 Fig 4.4 Data acquisition Equipment Loading and unloading procedures Tests load shall be applied and removed in four stages. Test producers, such as loading and unloading sequence, holding time etc shall be as stipulated in Specification and design drawings. According to the requirements of Appendix 7.1 of technical Specification, the division of loading and unloading stages and scheduled load values for steel tubular piles vertical compressive tests shall be as shown in Table 4.5. The next load shall be applied when the relatively stable standards of the load and corresponding displacements reached. Stage Ⅰ Ⅱ Ⅲ Table 4.5 Load Schedule of Steel Tubular Trial Pile Vertical Compression Test Test load/max load 12.5% 25% 0 Applied in increments of 12.5% of the max. test load 50% Removed in decrements, of 25% of the max. test load 0 Applied in increments of 12.5% of the max test load 100% the max. test load Holding time(displacement relative stable standard) Rate of settlement is less than 0.1mm/20min After rate of settlement is less than 0.1mm/1hour, maintained for 24 hours 0.1mm/20min After rate of settlement is less than 0.1mm/1hour, maintained for 72 hours Rate of settlement is less than 0.1mm/20min After rate of settlement is less than 0.1mm/1hour, maintained for 72 hours Displacement collection interval 20 min Project: Padma Multipurpose Bridge Project (PMBP) Date: Doc. No. : PMBP-MBEC-MS-SZ001 Page: 20 of 69

23 Ⅳ Removed in decrements, of 25% of the max. test load % Applied in increments, of 12.5% of the max. test load and Taken to failure Removed in decrements, of 25% of max applied load Rate of settlement is less than 0.1mm/20min Rate of settlement is less than 0.1mm/20min, continue testing until the settlement exceeds 10% of the pile diameter Rate of settlement is less than 0.1mm/20min 0 Notes: max test load of every trial pile is shown in table Reference beam installation and displacement observation (1) Reference supports and reference beam layout According to the requirements of layout steel tubular trial piles and anchor piles, and the Appendix (e) of the technical Specification of PADMA bridge, i.e., the reference frame shall be set up on supports (reference piles). Reference piles shall be located at least 2m or three times the pile diameter, whichever is greater, from the test pile center and anchor pile center. Before loading test, two reference supports shall be located at the side of trial piles along the direction of diameter, as shown in Fig 4.5. Reference beams shall be supported independent of the loading system, with supports firmly embedded in the ground at a clear distance from the test pile of at least 3 times diameter of the anchor piles and reference supports but not less than 4.5m. It is satisfied with the requirements of the Specification. A distribution beam shall be installed at the top of the support piles. According to the test requirement, two reference beams, which should be placed on the distribution beam, shall be installed on both sides of the trial pile. The displacement transducers for monitoring the pile top settlements shall be placed on the reference beams. And vice-reference beam shall be installed to monitor the top displacements of the nearest four anchor piles at the end time of each step load level during the loading test. Reference beams shall have adequate strength, stiffness, and cross bracing to support the test instrumentation and minimize vibrations that may degrade measurement of the pile Project: Padma Multipurpose Bridge Project (PMBP) Date: Doc. No. : PMBP-MBEC-MS-SZ001 Page: 21 of 69

24 movement. One end of each beam shall be free to move laterally as the beam length changes with temperature variations. Supports for reference beams shall be isolated from moving water and wave action. Provide a tarp or shelter to prevent direct sunlight and precipitation from affecting the measuring and reference systems. Schematic of reference supports and reference beams as shown in Fig 4.5. Fig 4.5 Schematic of reference supports and reference beams (2) The four deflectometers, which matched with static load equipment, being used for settlement observation during loading tests, shall be arranged near the pile top cross-section symmetrically. Test pile settlement measurement plan shall be set below the top of the pile 200mm. The measuring point should be firmly fixed on pile shaft. Displacement collection intervals of loading and unloading, holding time, displacement relative stable standards for each stage as described in aforesaid table 4.5. (3)In the process of compression test, the settlement of the trial pile shall be measured at Project: Padma Multipurpose Bridge Project (PMBP) Date: Doc. No. : PMBP-MBEC-MS-SZ001 Page: 22 of 69

25 predetermined intervals, at the same time, should pay attention to the uplift displacements of anchor piles. According to the relative position of the test pile and anchor piles, four anchor piles which are most close to the test trial pile shall be chosen as the observation targets. The uplift displacements of anchor piles shall be monitored at the end of each level load, when the trial pile settlement reached stabilized. Dial indicator shall be used for the uplift displacements measured of selected anchor piles. The system of measurements for trial pile settlement and anchor piles displacement shall be shown in Fig 4.5. (4)The level of the reference beam shall be checked at regular intervals agreed by the Engineer during the test Extensometer of pile shaft displacement According to the requirements of the drawings of BR1865~1866, the extensometer for the displacement of selected pile section shall be arranged during construction, and the extensometer displacement shall be collected during static load test. Displacement wire shall be installed as extensometer to monitor the pile shaft displacement at the platform near pile top. Two test sections shall be installed in pile shaft in the scope of (-55.0~-85.0 mpwd) or (-85.0~ mpwd), one is located at the bottom of the steel pile concrete plug section, another is located at the bottom of the sleeve casing section, i.e. level A. Two groups of the displacements measurement devices shall be installed in the pile shaft symmetrically. Take the average displacement of the two groups of the same level as the test section displacement values. Displacement of steel wires shall be embedded in the pile as shown in Appendix 2. Displacement test devices (wires and protected tubes) shall be attached to the reinforcement cage firmly at the predetermined level, and the displacement wires and tubes shall be extended to the pile top. Displacement observation points shall be arranged near the pile top and reference beam. Pile shaft displacements shall be monitored at the end of each level load, when the trial pile settlement reached stabilized Calculation of related parameters During the vertical compressive load test stage, the changes of strain gauges shall be Project: Padma Multipurpose Bridge Project (PMBP) Date: Doc. No. : PMBP-MBEC-MS-SZ001 Page: 23 of 69

26 measured by means of special instruments at the end of each load level. The axial forces of pile shaft shall be calculated on the basis of strain gauges test values. According to the pile axial force of all test sections, the ultimate skin friction values and the ultimate end bearing values shall be calculated. 4.5 Static Load Test Report Contents of the Steel Tubular Trial Pile The following shall be included in the test report: -The coordinates and the elevations at the test location. -As built detailed drawing of the trial piles installed and tested. -Trial pile test number. -Number, weight and length of the pile. -Static test loading arrangement details and drawings. -The loads applied to the nearest 0.05t. -The settlement/heave of the pile head to the nearest 0.05 mm at hourly intervals and under each increment and decrement of loading. -The exact times at which increments were applied and decrements removed. -The levels of the reference beam, to the nearest millimeter. -The ground conditions at the location of the pile. -The results from the in-situ and laboratory test results. -Pile installation methodology including plant and equipment used. -Details of the test pile configuration including instrumentation, where the piles are instrumented. -Details of instrumentation, when piles are instrumented. -Determination of the elastic modulus of the pile from the testing of concrete core samples. - Description of the static load test, details of the jacks, loading sequence and unload-loading sequences, pile head settlement. -Presentation of the load and stress distribution plots with depth along the pile for the various loads, as the load is increased and decreased. -Detailed analysis of the fully instrumented pile load tests and the estimation of the Project: Padma Multipurpose Bridge Project (PMBP) Date: Doc. No. : PMBP-MBEC-MS-SZ001 Page: 24 of 69

27 ultimate skin friction values along the pile shaft at 2m pile segments, and the estimation of the end bearing capacity of the pile in the case of the Trial Pile load tests. -Detailed analyses of the pile load test result (Pile settlement versus load curve data) and the estimation of the pile capacity using a suite of methods as agreed with the Engineer and the establishment of the pile capacity and the applicable overall factors of safety of the pile for the various load cases. -Conclusions and the recommendations including the ultimate skin friction and end bearing capacities of the test piles. 5.Trial Pile Report The report shall present the analyses of the pile driving records and the capacity of the pile as installed. -The coordinates and the elevations at the test location -The ground investigation data (borehole logs, CPT logs, in-situ test data and laboratory test data) (shall be submitted before construction of the trial pile) -Details and specifications of the instruments installed along with their calibration curves and calibration certificates -Plant used to drive the piles -Pile driving records Date and time of driving Trial Pile test number Number, weight and length of the pile Weight and drop of the hammer Number of blows per meter over the whole depth of penetration Number of blows per 250 mm over the last 5.5m of penetration, Number of blows per 50mm over the last 500mm. (can t be obtained directly and will be calculated as per driving record) River water level and tide records (even if the location is not inundated) Level of the surface of the sand inside the pile at any given time while installing the Project: Padma Multipurpose Bridge Project (PMBP) Date: Doc. No. : PMBP-MBEC-MS-SZ001 Page: 25 of 69

28 pile; and especially at the time of splicing or hammer change and completion of driving, Submit the Pile Driver Analyzer report prepared using the data gathered from the attached instrumentation during pile driving, which shall include the data and the results of the analyses using the appropriate software used (CAPWAP, GRLWEAP etc.,) and the predicted pile capacity of the as-driven pile at final set of founding elevation Any other information which the Engineer may require. -records of pressure grouting for preloading (grout mix details, grout pressures, grout volumes, and time taken for grouting), pressure reached and locations -Details of the PDA test carried out and the capacity predicted -Detailed drawings showing the instrumentation layouts and the type of instrumentation installed -details of tremie concreting for the concrete plug of the pile -Concrete cube test results ( necessary for bored pile and unnecessary for steel tubular pile ) -Concrete Elastic Modulus determination tests on concrete cores recovered from the installed pile ( necessary for bored pile and unnecessary for steel tubular pile ) -Static test loading arrangement details and drawings -Description of the static load test, instrument monitoring data, details of the jacks, loading sequence and unload-loading sequences, pile head settlement -Reduction and processing of monitoring data -Presentation of the load and stress distribution plots with depth along the pile for the various loads, as the load is increased and decreased and the final loads and stresses at failure -End bearing pressures at various loads and the end bearing at failure -Conclusions and the recommended ultimate skin friction and end bearing pressures for the pile, and correlation with the soil parameters to determine the and values, and any other parameters Project: Padma Multipurpose Bridge Project (PMBP) Date: Doc. No. : PMBP-MBEC-MS-SZ001 Page: 26 of 69

29 Appendix: Project: Padma Multipurpose Bridge Project (PMBP) Date: Doc. No. : PMBP-MBEC-MS-SZ001 Page: 27 of 69

30 Appendix A: Schematic of mounting holes for PDA transducers installation Steel trial pile 75mm 1-1 φ mm±1 Cable supports B The steel trial pile top(before incision) B' C 75 A Detail 38±0.5 A Note: 1 All dimensions are in mm in addition to be specified; 2 The line form the center of B to B' is parral to the pile shaft; Cable supports Project: Padma Multipurpose Bridge Project (PMBP) Date: Doc. No. : PMBP-MBEC-MS-SZ001 Page: 28 of 69

31 Appendix B: Schematic of the displacement wires and strain gauges installation Appendix B.1: Schematic 1 of the displacement of the steel wires and strain gauges installation(td1a TD1C TD3A TD4A) Extensometer Project: Padma Multipurpose Bridge Project (PMBP) Date: Doc. No. : PMBP-MBEC-MS-SZ001 Page: 29 of 69

32 Appendix B.2: Schematic 2 of the displacement of the steel wires and strain gauges installation(td1b TD3B TD3C TD2B TD4B) Extensometer Project: Padma Multipurpose Bridge Project (PMBP) Date: Doc. No. : PMBP-MBEC-MS-SZ001 Page: 30 of 69

33 Appendix B.3: Schematic 3 of the displacement of the steel wires and strain gauges installation(td2a) Extensometer Project: Padma Multipurpose Bridge Project (PMBP) Date: Doc. No. : PMBP-MBEC-MS-SZ001 Page: 31 of 69

34 Appendix C: Calibration Certificates of PDA transducers Project: Padma Multipurpose Bridge Project (PMBP) Date: Doc. No. : PMBP-MBEC-MS-SZ001 Page: 32 of 69

35 Project: Padma Multipurpose Bridge Project (PMBP) Date: Doc. No. : PMBP-MBEC-MS-SZ001 Page: 33 of 69

36 Project: Padma Multipurpose Bridge Project (PMBP) Date: Doc. No. : PMBP-MBEC-MS-SZ001 Page: 34 of 69

37 Project: Padma Multipurpose Bridge Project (PMBP) Date: Doc. No. : PMBP-MBEC-MS-SZ001 Page: 35 of 69

38 Appendix D: Anchor length determination for anchor piles A diameter of 1.5m steel pile piles will be used as the anchor piles. Its self-weight is 220kN. The required pull-out resistance for single pile will be calculated: T= /16-220=3030KN (unbalance factor is considered as 1.3). The GI information at test pile location as shown below: TD1 B unit 1a unit 2a&b unit 2c unit 2d unit 2d unit 2e The anchor piles shall be embedded from m (river bed level) to -33.3m (pile toe), that is to say, the anchor length of anchor piles is 30.0m. Taking into account the safe factor 1.5, the actual pull-out resistance of single anchor pile is P=0.4U f i l i =0.4x x1.5x(4.5x68+7.5x x80)=3333kn>3030kn It is satisfied with the designed load requirement. Project: Padma Multipurpose Bridge Project (PMBP) Date: Doc. No. : PMBP-MBEC-MS-SZ001 Page: 36 of 69

39 Approval Status on the Method Statement for Load Test of Steel Tubular Load Test Trial Piles-Rev.1 (Submitted with Ref: MBEC-PMBP/CSC-25/ Dated 14 March 2015) No. Engineer s Inquiry MBEC s Responses According to the methodology mentioned in last MBEC s Response Steel Trial Pile Load Test R1. The further basic PDA theories have been listed as follows: Approval Status PDA Test is a fast, reliable and effective method of evaluation foundation bearing capacity. PDA Test encompasses Dynamic Pile Monitoring and Dynamic Load Testing. Both are covered by ASTM D The methodology is accepted, However it is required to prepare the technical manual for more efficient confirmation at site Pile Driving Monitoring is based on the Case Method of pile testing, and it consist of performing real time evaluation of Case Method capacity, energy transfer, driving stresses and pile integrity. Dynamic Load Testing involves combining field measurements obtained with a high strain dynamic testing system such as the PDA with wave-equation based analytical procedures performed with a signal matching program such as CAPWAP. Dynamic Load Testing predicts soil behavior including staticload capacity, soil resistance distribution, pile soil load transfer characteristics, soil damping and quake value, and pile load versus movement plote (e.g. a simulated static load test). Pile Driving Monitoring, also called Dynamic Pile Monitoring, helps achieve a safe and economical driven pile installation. During the installation of production piles, it helps check that driving happens in accordance with the established criterion and gives information on soil resistance at the time of monitoring and on driving system performance. Dynamic Monitoring with a Pile Driving Analyzer (PDA) dynamic testing system also calculates driving stress, helping reduce the risk of pile damage. Approved When a hammer or drop weight impacts the top of a foundation, a compressive stress wave travels down its shaft as a speed c, which is a function of the elastic modulus E at a speed c, which is a function of the elastic modulus E and mass density. The impact induces a force F and a particle velocity v at the top of the foundation.

40 Accelerometer and strain transducers attached to it obtain data that is converted to velocity and force readings. The force is computed by multiplying the measured signals from a pier of strain transducers attached near the top of the pile by the pile area and modules. The velocity measurement is obtained by integrating signals from a pair of accelerometers also attached near the top of the pile. Strain transducers and accelerometers transmit data to a high strain dynamic testing system such as the Pile Driving Analyzer (PDA), for signal processing and results. Data obtained during Pile Driving Monitoring may be used to estimate bearing capacity driving with CASE, or after data collection with CAPWAP. As long as the wave travels in one direction, force and velocity are proportional: F = Zv, Where: Z = EA/c is the pile impedance E is the pile material modulus of elasticity A is the cross sectional area sectional area of the pile c is the material wave speed at which the wave front travels. Soil resistance forces along the shaft and at the toe cause wave reflections that travel and are felt at the top of the foundation. The times at which these reflections arrive at the pile top are related to their location along the shaft. The measured force and velocity near the pile top thus provide necessary and sufficient information to estimate soil resistance and its distribution. CAPWAP (CASE Pile Wave Analysis Program) is a software program that estimates total bearing capacity of a pile or shaft, as well as resistance distribution along the shaft and at the toe. The program takes as input the force and velocity data obtained with a Pile Driving Analyzer (PDA) system. It is essential to post-process PDA data with CAPWAP for at least one foundation elements per job. CAPWAP completes the Dynamic load Testing procedure and simulates a Static Load Test. Dynamic Load Testing predicts soil behavior including staticload capacity, soil resistance distribution, pile soil load transfer characteristics, soil damping and quake values, and pile load versus movement (e.g. a simulated static load test). PDA Test can also be used to evaluate the integrity of the pile foundation. PDA Test can also be used to evaluate the integrity of the pile foundation.

41 7 If the protection angle for the cable shall be installed outside the steel tubular piles, it will potentially increase driving resistance and disturb pile skin friction. So please review and clarify again these problems described above. According to the PDA theories, the pile integrity and pile capacity will be calculated automatically by the software CASE and CAPWYP of American PDI Company. We explained the reason why the steel angles are installed outside the steel tubular piles. Further explanation please refers to the Attachment. Just as engineer s remarks, we understand that the protection angle for the cable have been installed outside the steel tubular piles, the potential influence on slightly increasing driving resistance and slightly disturbing pile skin friction is probably existing. Numerical calculation has been attempted to carry on the influence analysis. Because of the complexity of geotechnical engineering, the imprecision of simulation and the difficulty of calculation astringency, it is very difficult to achieve a certain quantity index to estimate the potentially minor influence. However, unit skin friction can be achieved from the static load test despite size of surface area of test pile. The unit skin friction shall equal to that the difference of axial force obtained from corresponding instruments of the two adjacent test sections divided by the surface area including steel angle. After static loading test we will compare the skin friction values derived from static load test with GI data and analyze the potential disturbance of unit skin friction due to the steel angle. Approved with Conditions The resulting load test data (unit skin friction, end bearing capacity, etc.) is required to be interpreted for checking design of working piles (3m dia. and 60mm wall thickness). As per your proposal, the Contractor shall compare the unit skin friction values derived from static load tests with GI data and analyze the potential disturbance of unit skin friction due to the steel angles. Your comparison and analyzed results shall be included in the final report of pile load tests.

42

43

44

45

46 Attachment Reasons for Steel Angles Installed on Outer Surface of Load Test Pile For soil plug section, the strain gauges will be attached on the surface of the steel tubular pile and then covered by steel angle which will be welded on the surface of test pile. The strain gauge cables will be extended from the bottom gauges up to the top of test pile and the steel angle (steel angle short piece) for strain cables protection shall also be installed from the bottom to the top of test pile. Due to very long steel tubular trial piles, the Steel piles have to been divided into three or four sections. At the splicing joint, the steel angles are discontinuous and inserting angles will be post-installed during installing the load test piles. If the steel angles welded on the inside surface of the load test piles (refer to figures A), it will be very difficult to extend the strain gauges cables up to the top of the pile. When the steel pile splicing completed, workers will have to go inside the test pile and down to the level of the splicing joint to assist for drawing out strain gauge cables from the lower section and extend the cables to the upper section, which is very unsafe and shall be prohibited. Moreover, inserting angles at the joints is extremely difficult to install as welding cannot be conducted inside such a small and confined space. Figure A Secondly, after driving test pile to the designed depth, soil excavation and cleaning inside the pile will become much more inconvenient due to the presence of these welded steel angles inside the pile.

47 Attachment The following sketches illustrate the details procedures for fixing & installation of strain gauge cables and strain gauge cables when the steel angles welded outside the test piles, which is easier to install the gauge cables. Step 1

48 Attachment Step 2 Step 3

49 Consultant Remarks on the MBEC Responses for Method Statement for Load Test of Steel Tubular Load Test Trial Piles-Rev. 1 SL. No. 1 2 Engineer s Inquiry MBEC s Responses Remarks 1)Work Contents and Purpose You have not included the purpose in this provision. Please include the purpose of the tests more in detail, e.g. Trial pile load test shall be carried out to determine the ultimate skin friction of the steel piles and the ultimate and bearing resistance when installed in the ense granular materials. 3) PDA Test of Driven Steel Tubular Piles According to Technical Specification (Volume 03) Section 7, Clause No. Work contents and Purpose have been modified in the document No. of PMBP-MBEC-MS-SZ001 (revised issue R2). (1) Contents (a) PDA tests on steel trial piles. (b) Static pile loading tests on steel trial piles. (2) Purpose (a) PDA tests shall be carried out to estimate the capacity of the piles. (b)pda tests shall be carried out on the pile after driving installation to designed depth to ensure integrity. (c)trial pile load test shall be carried out to determine the ultimate skin friction of the steel piles, the ultimate end bearing resistance and the bearing capacity of the trial piles. First, Pile driving monitoring shall be carried out on the steel tubular trial piles during driving installation. PDA testing shall be carried out after driving installation to designed depth to ensure the integrity and estimate Accepted Accepted

50 (1) (f)/(h)-(iii)/(j), PDA test shall be carried out on the pile after driving installation to designed depth to ensure integrity. However, you have described to carry the test during installation. Tests are to be done after installation as well. Please specify clearly all the sequences of pile driving works and different types of test Transducers Installation (a) What numbers of transducers to be used? According to ASTM D4945 Clause 5.2.1, a minimum of two of these devices shall be securely attached on opposite sides of the pile. Please specify the numbers of devices accordingly. (b) Fig 3.2 Schematic of transducers installation (Photograph) is not clear for understanding. Please provide detailed sketches/line diagrams for alignment of transducers for better understanding. trial piles capacity. At last load test shall be carried out after concrete plug has been cast. (a) Four transducers shall be securely attached on opposite sides of the pile. Two of these transducers are strain gauges and two are accelerometers. (b) In order to indicate the transducers installation clearly, The similar pictures have been updated in the document No. PMBP-MBEC-MS-SZ001 (revised issue R2). Accepted

51 Technical requirements of PDA test (a) You have not specified anything regarding calibration. Equipment need to be calibration before using, or provide valid calibration certificates if already calibrated. (b) According to technical specification section 7 clause 7.11 (8) (b) more detail of installation, monitoring, data analysis is needed i.e. detail method statement. Please provide the details as required. 3.3 Axial bearing capacity determination and pile integrity comments (a) Please include more details of the following items: ⅰ) What is the procedure for selection of signal? ⅱ) How to determine the average wave velocity? (b) Please include the detailed procedure for determination of bearing capacity. (a) The Certificates of Calibration have been provided in Appendix 3 in the document No. of PMBP-MBEC- MS-SZ001 (revised issue R2). (b) The installation of PDA transducers is shown in Appendix 1 in the document No. PMBP-MBEC-MS- SZ001. According to technical specification section 7, clause 7.11 (8) (b), Determination of Strain Wave Speed, the explanation for the determination of wave speed has been listed in the below item ⅱ). (a) ⅰ) Selection of testing signal shall follow the regulations below 1)For selection of signal when measuring the capacity, hammerings with higher energy is preferred. 2)The signals are not allowed for analysis and calculation in case of the following situations after hammering: (1) The end of the force curve cannot come to zero because of severely plastic deformations of the location transducers installation. (2) The amplitude one side gets as high as 1 time of the amplitude at the other side or more caused by Accepted The methodology is accepted, However, it is required to prepare the technical manual for more efficient confirmation at site.

52 eccentricity of hammering. (3) Test data of the four channels are incomplete. ⅱ) The overall wave speed observed during a highstrain event shall be estimated as follows: Divided two times the length of pile below transducers by the observed time between start of the impact (for example, initial sharp rise of the signal) and the start of the tensile reflection (for example, later relative velocity increase) to obtain the wave speed. Schematic as follows: In general, the wave speed of structural steel piles can be assumed as 5123m s. (b) There are two analysis methods for the determination of bearing capacity by PDA test, CASE method and curve-fitting method. 1) Methodology of CASE method (1) The vertical compressive capacities of single piles can be determined by case method by (2) The integrity coefficient β can be determined by 2) Curve-fitting method (CAPWAP 2006) (1) Select one measured curve as the calculated curve. Usually, choose the velocity curve as the calculated wave.

53 PDA Report Your have not included all the information as required by the Technical Specification Clause no (9) (a). Please specify all information which are included in the clause indicated above Strain Gauges installation You have indicated that steel angles shall be welded from pile end to pile top. However, in design drawing DRG No. 1C-01-BR-1865/1866, there is no provision to attach the steel angle. Moreover, you have indicated that (2) Set the parameters of piles and soil according to the geological date. (3) Do fitting analysis using another measured curve, which is force curve usually. (4) Compare the measured curve with calculated curve and then calculate it repeatedly until the fitted curve is similar to the measured curve. Then the parameters of piles and soil are similar to actual parameters. (5) Output result The ultimate bearing capacity of trial piles shall be calculated by the software Pile Driving Analyzer and CAPWAP The result obtained from CAPWAP 2006 shall be the bearing capacity of the trial piles PDA test. The information included in the Technical Specification Clause no (9) has been listed in 3.4 PDA Report, in the document No. PMBP-MBEC-MS- SZ001 (revised issue R2). According to the requirement, the base of the trial piles shall be partially plugged with a length of soil column of 1⅔ times the diameter of the pile, the reinforcement cage cannot be installed to the pile toe, so the instruments (strain gauges in the scope of soil plug) can only be arranged on the surface of pile, the strain gauges cables shall be pull to the pile top platform. Accepted If the protection angle for the cable shall be installed outside the steel tubular piles, it will potentially increase driving resistance and disturb pile skin friction. So please review and

54 strain gauges will be attached to the outer surface of pile and in the angles, which is not as per the design drawings. As per the design drawings, all instruments are to be attached in inner wall of piles. You have referred to drawings Steel Tubular Trial Piles for Load Test. However, these drawings are not available in the detailed design drawings or any of your submissions. Please clarify about angles, locations of strain gages, and also information the referred drawings. The purpose of installing the instruments is to measure the stress of pile during load test, and then we can get the end bearing capacity and the pile shaft resistance. The measured stress from the inner and outer pile shaft is equivalent. After driving installation to designed depth, the soil column in inner pile shall be cleared to the predetermined elevation. If the strain gauges (in the scope of soil (plug), cables and steel angles are arranged on the inner wall of pile shaft, the drilling machine for dredging soil inside the steel tubular pile shall be unable to handled due to the protection angle for the cable. So the strain gauges (in the scope of soil plug), cables and steel angles can only be arranged on the outer wall of pile shaft. In order to avoid the strain gauges and cables being damaged during driving installation, using steel angles to protect strain gauges and cables is necessary from pile toe to pile top. Please kindly noted that Notes-4 The trial pile test arrangement shown in this drawing is indicative only. The contractor shall submit to the engineer 60 days before installation of the trail pile. Detailed method statement including detailed drawings showing how he propose to carry out the trial pile tests for the engineer s approval on DRG No. 1C- 01-BR-1865/1866. The referred to drawings PMB MB 1101 to 1103 Steel Tubular Trial Piles for Load Test were submitted to clarify again these problems described above.

55 Test Method and Principle According to the requirements of drawings and Technical Specification section 7, clause 7.10 (1), the load test shall be taken to failure with a reaction force not less than 40MN. However, you have written According to the requirements of drawings and technical specification, the load tests shall be taken to failure, or the maximum test load of trial piles reaches 40MN, which is not according to the specification. Please specify them as per the specification CSC via letter (MBEC PMBP/CSC 25/ ) on January 8,2015. The locations of strain gages are shown in table 4.2 to 4.4 and Appendix 2 in the document No. PMBP-MBEC-MS-SZ001. According to the requirements of drawings and technical Specification, the load tests shall be taken to failure, or the maximum test load of trial piles reaches 40MN is stated in Method Statement for Load Test of Steel Tubular Trial Piles based on the following points. (a) As described in the technical Specification Appendix 7.1.4, (a), Trial piles shall be tested to failure, or to the maximum test loads stated in Drawings. (b) Meanwhile, as stated in design drawing notes 1 of DRG No. 1C-01-BR1118, The testing piles shall be taken to failure with a reaction force of not less than 40MN and the max. Test load listed in Table 1-Trial pile schedule. Please refer to the Ref.: MAUN-2115-MBEC prepared by AECOM on 25 July 2014, Item 8 states that The 40MN is the minimum required reaction force for pile load test set up (such as kentledge, reaction piles, etc.), which is stated in the drawing note. There may be two cases in static loading test of trial piles, one is the max. load applied on the pile top is Accepted

56 Test equipment and data acquisition equipment You have not included the length of the anchor piles and the detail calculations to determine the required length of the anchor piles. Please specify the length for anchor piles and the detailed calculation for the determination of length. 4.5 Static load test report contents of the steel tubular trial pile You have not included all the points to be included in this reports as required by the Technical Specification Section 7 Appendix 7.1 Clause no Please specify all points that are required as per the specification. Appendix and others 1. Length of soil plug at toe of pile not indicated, but as per Technical Specification Section 7, Clause 7.10 smaller than 40MN, the pile test has be taken to failure; another is when the max. Load applied on the trial pile top reaches 40MN, the test pile has not lost bearing capacity, then the loading shall be terminated, which was confirmed by AECOM. The anchor pile length and calculations are attached in the document No. PMBP-MBEC-MS-SZ001 (revised issue R2). The contents of Appendix have been listed in the document No. PMBP-MBEC-MS-SZ001 (revised issue R2), as a minimum, the contents mentioned shall be included in the static load test report. Length of soil plug is indicated in the attachment 2 of the document ((revised issue R2) and in the shop drawing Steel Tubular Trial Piles for Load Test (PMB- Accepted Accepted Accepted

57 2 (1) (a) After installing the pile to the required test depth as described by the construction method 1⅔ times the diameter of the pile, along the pile shaft from the pile toe as shown on the Drawings. Please specify the thickness of soil plug and how to obtain this thickness 2. As per design drawing DRG No. 1C-01-BR-1865/1866, all instruments are to be attached in inner wall of pile. Please specify your drawings and methodology accordingly. MB ) Submitted to CSC via letter (MBEC- PMBP/CSC-25/ ) on January 8,2015. This method statement for load testing follows the shop drawing. The thickness will be obtained by measuring the depth during drilling and air-lifting the soil inside the steel tubular pile. The details refer to the document Method Statement for Construction of Steel Tubular Load Test Trial Pile (PMBP-MBEC-MS-SZ002) submitted on 8 January 2015 via our letter Ref. MBEC-PMBP/CSC-25/ According to the requirements of technical Specification Section 7, Clause No (1), (a), the base of the pile shall be partially plugged with a length of soil column of 1 ⅔ times the diameter of the pile along the pile shaft from the pile toe and (b), For these particular test piles, a concrete plug shall be constructed with tremie along the shaft from the top of the soil plug to the top of the pile to accommodate the installation of instrumentations for monitoring of pile stress under pile load testing as described in the Drawings, the soils in the steel tubular pile shall be cleared out, so the strain gauges in the scope of soil plug shall be arranged on the outer wall, the strain gauges in the scope of concrete plug shall be attached on the rebars. Same as item No. 7 of the Main Comments

58 3 3. You need to submit the detailed trial pile load test reports as per Technical Specification Section 7, Clause No (1) (t) including all details indicated in that clause. Please include this provision in your methodology. The reason of bottom instruments attached in outer wall of pile is stated on above item 7. Please kindly noted that Notes-4 The trial pile test arrangement shown in this drawing is indicative only. The contractor shall submit to the engineer 60 days before installation of the trail pile. Detailed method statement including detailed drawings showing how he propose to carry out the trial pile tests for the engineer s approval on DRG No. 1C- 01-BR-1865/1866. According to the requirements of Clause No (1) (t), the Technical Specification Section 7, trial pile report shall be submitted to the engineer for approval. The contents of the report are listed in the document No. PMBP-MBEC-MS-SZ001 (revised issue R2). Accepted

59 中铁大桥局股份有限公司孟加拉帕德玛大桥项目部 PADMA MULTIPURPOSE BRIDGE PROJECT OFFICE CHINA MAJOR BRIDGE ENGINEERING CO., LTD.(MBEC) Our Ref: MBEC-PMBP/CSC-25/ Date: 21 February 2015 To: Mr. Lee Myung Geun Project Manager CSC Services for Main Bridge & RTW, Korean Expressway Co. and Associates House #13/A, Road #83, Gulshan-2, Dhaka-1212, Bangladesh (Dhaka) Service Area-1, Mawa Site, Munshiganj (Site) Attn.: Mr. Robert Aves Deputy Project Manager (Main Bridge) Project Title: Subject: Padma Multipurpose Bridge Project - Main Bridge (ICB No.: PMB/MB/01) Responses to CSC Comments for Method Statement of Load Test for Steel Tubular Load Test Trial Piles-R1 Dear Sir, Reference is made to the above captioned subject and your dated on February 12, 2015 regarding the Comment on the Method Statement for Load Test for Steel Tubular Load Test Trial Pile, we are pleased to submit herewith the response to CSC Comments for Method Statement of Load Test for Steel Tubular Load Test Trial Piles(Rev.1) which is enclosed herewith for your kind reference. We kindly look forward to your approval on our method statement as soon as practicable. Thank you Yours faithfully, Mr. Liu Jianhua Project Manager Padma Multipurpose Bridge Project China Major Bridge Engineering Co., Ltd.(MBEC) Attachment1: Enclosure: Responses to CSC Comments for Method Statement of Load Test for Steel Tubular Load Test Trial Piles-Rev.1 Attachment2: Method Statement of Load Test for Steel Tubular Load Test Trial Piles-Rev.2 Copy to: 1. Project Director, Padma Multipurpose Bridge Project, Setu Bhaban, Banani, Dhaka Project Manager and Executive Engineer (Bridge), Service Area-1, Mawa, Munshiganj 3. Office Copy Address: House No.454, Lane No.08, DOHS Baridhara, Dhaka, Bangladesh, Zip Code: 1229 Tel.: padmabridge@163.com Website: