SECTION 31 08 13 – STATIC PILE LOAD TESTING PART 1 - GENERAL 1.01 A. B. C. D. E.

F. 1.02 A.

B.

1.03 A. B.

SUMMARY: This Section covers the requirements for load testing of piles under static axial compression, static axial tension, and static lateral modes of loading. The number of static pile load tests for each mode of loading shall be as defined in the applicable Foundation Piling Section. The Design Capacity, Maximum Anticipated Test Load, and Ultimate Capacity for each mode of loading shall be as defined in the applicable Foundation Piling Section. Pile load testing shall be performed from a working elevation within 1 foot of the anticipated final design pile cutoff elevation. Select compression piles, as specified in the applicable Foundation Piling Section, shall be instrumented with Geokon Model 4911 “sister bar” strain gauges embedded along the length of the piles to assess the distribution of skin friction and end bearing contributions. Select compression piles, as specified in the applicable Foundation Piling Section, shall be instrumented with a single full-length tell-tale to assess the tip movement of the pile. REFERENCE STANDARDS: General: 1. Standards listed by reference, including revisions by issuing authority, form a part of this Section to extent indicated. Standards listed are identified by issuing authority, authority abbreviation, designation number, title or other designation established by issuing authority. Standards subsequently referenced herein are referred to by issuing authority abbreviation and standard designation. 2. Where specifications and reference documents conflict, the Contractor shall make the final determination of applicable document. 3. Unless otherwise noted, the latest revision of the following reference standards shall apply to this Section. Applicable Standards: 1. ASTM International (ASTM): a. D1143/D1143M – Test Methods for Deep Foundations Under Static Axial Compressive Load. b. D3689 – Test Methods for Deep Foundations Under Static Axial Tensile Load. c. D3966/D3966M – Test Methods for Deep Foundations Under Lateral Load. SUBMITTALS: Submit as specified in DIVISION 01. Design and Pre-Construction Submittals: 1. Provide the following submittals two weeks prior to commencing load testing: a. Details of load test arrangements (plan, location, and elevation). b. Drawings and calculations for member reaction frame beams, connections, stiffeners and piles; signed and sealed by Subcontractor's Professional Engineer. c. Electrical load cell calibration curves. d. Hydraulic jack calibration curves. e. Methods for performing load test. f. Embedment length of reaction piles with calculations proving adequate capacity for load test requirements. g. Reaction pile pretension sequence (if applicable).

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Dial gauges; minimum 4 around load test pile head for axial loading, and minimum 2 around load test pile head for lateral loading. i. Calibration data for each strain gauge (as applicable). j. Readout box for strain gauges (as applicable). k. Junction box to be used in conjunction with vibrating wire strain gauges and readout box assembly (as applicable). l. Datalogger for collection of strain gauge measurements (as applicable). m. Tell-tale details (as applicable). n. Swivel plate. o. Thermometer. p. Piano wire/mirror/engineer’s scale setup. (a) Portable gas generator, fuel, and operator for continuous power to equipment (if required for electronic readout). q. Weatherized enclosure for protection of all materials and equipment from the elements, if required. r. Sandbags and/or grading to divert water, if required. s. Schedule of load testing. 2. The calibration testing shall have been performed by an independent testing laboratory and tests shall have been performed within 6 months of the date submitted. Contractor will approve or reject the calibration data within five working days after receipt of the data. Testing cannot commence until Contractor has approved the calibration data. Construction and Closeout Submittals: 1. Submit test pile installation records within 24 hours of the completion of installation, including all information required for production piles. 2. Submit load test data within 48 hours of the completion of static pile load testing operations; consisting of dial gauge readings for all test and reaction piles, scale/mirror/piano wire readings, survey data, strain gauge records (if applicable), hydraulic jack pressure data and load cell data.

PART 2 - PRODUCTS 2.01 A. B. 2.02 A. B. C.

D.

TEST PILES: Test piles and reaction piles shall be installed in accordance with procedures and material requirements for production piles. The diameter/width and depth of load test piles shall be equal to the proposed production pile dimensions, unless noted otherwise by the Contractor. STRAIN GAUGE INSTRUMENTATION Where specified in the applicable Foundation Piling Section, select compression piles shall be instrumented with Geokon Model 4911 “sister bar” strain gauges. The quantity and depth of strain gauges shall be as defined in the applicable Foundation Piling Section. Provide a readout box for strain gauges, capable of converting frequency reading directly into strain units by means of an internal microprocessor, with a 5-digit LCD display, such as Geokon Model GK-403 terminal box or equal. Provide a junction box to be used in conjunction with vibrating wire strain gauges and readout box assembly, allowing for connection of multiple strain gauges to the readout box simultaneously.

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SECTION 31 08 13 – STATIC PILE LOAD TESTING: continued E.

2.03 A.

2.04 A.

B. C. D. E.

F. G. H. 2.05 A.

B. C. D.

Provide a datalogger (Geokon Model 8002-16 or equal) for the purpose of collecting strain measurements during the grout curing process of each test pile and during the static axial compression and static axial tension load tests. Each datalogger shall be housed in a weather proof enclosure and shall be capable of accommodating the quantity of strain gauges indicated for each test pile. Dataloggers shall be capable of collecting and storing strain gauge data at designated intervals using battery power. Datalogger shall have the ability to connect to a computer via a USB interface cable to download collected data and to observe data in real-time during static load tests. TELL-TALE INSTRUMENTATION If required in the applicable Foundation Piling Section, select compression piles shall be instrumented with a tell-tale extending to the tip of the pile. The tell-tales shall be located adjacent to the center bar and shall be of sufficient stiffness to prevent bending over the length of the pile. Subcontractor shall be responsible for developing final details regarding tell-tale configuration to be approved by Contractor. EQUIPMENT: All equipment necessary for the pile load test; such as load cell, hydraulic jacks, dial gauges, strain gauges (as applicable), tell-tale, swivel plate, thermometer, piano wire, mirror, engineer’s scale, surveyor’s level, etc., shall be furnished and operated by Subcontractor. The equipment shall conform to the requirements of ASTM D1143/D1143M, D3689, and D3966/3966M for the respective mode(s) of loading. The apparatus for applying and measuring axial loads shall be capable of safely applying at least 120% of the maximum anticipated test load. The apparatus for applying and measuring lateral loads shall be capable of safely applying at least 125% of the maximum anticipated test load. Provide adequate back-up equipment to complete all load testing operations. Loads shall be applied to the pile accurately and concentrically by means of certified, calibrated hydraulic jacks, pressure regulating devices and tanks, hand jacks, or other approved equipment so that there will be a constant load maintained under increasing pile deflection. Using hydraulic jack pressure gauges or transducers as sole means to control applied loads in lieu of an in-line load cell will not be permitted. Ground line for the load testing operations shall be established as the elevation which coincides to the appropriate production pile cutoff elevation. The equipment for lateral load testing shall be capable of supporting and applying the test load within 3 inches of the ground line. REACTION FRAME: Subcontractor shall provide all necessary equipment, materials and labor to provide and install the test pile reaction systems. The reaction frames and all associated members shall be designed by Subcontractor’s Engineer and shall be capable of safely loading the pile to three (3) times the Design Load or the Maximum Anticipated Test Load (whichever is greater). Structures and reaction beams for the load tests shall be constructed in accordance with specifications and approved shop drawings. Test arrangement shall be designed so that loads are applied to the pile accurately and concentrically. Load test reaction pile layout shall consist of the following: 1. Piles shall be uniformly and evenly spaced with respect to both axes of the test pile centerlines. The number of required reaction piles shall be determined based upon 31 08 13 - 3

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F.

G.

H.

2.06 A.

B. C.

D. E. F.

G.

specified ultimate test pile and allowable reaction pile capacity values, and as required by Subcontractor’s Professional Engineer. Reaction piles may need to be installed deeper than test piles to provide sufficient reaction capacity to the applied test pile load. 2. Placement of all reaction piles in a single line will not be permitted for axial loading. Subcontractor shall use a minimum of four reaction piles for the axial loading modes, and two reaction piles for the lateral loading mode. 3. If Subcontractor plans to pretension the reaction piles, detailed procedures of the pretension loading sequence shall be submitted to the Contractor. 4. Satisfy minimum spacing specified in ASTM D1143/1143M, D3689, and D3966/3966M for the applicable mode of loading as required to avoid overlapping of pile stresses. 5. Height of test and reaction piles above ground surface shall be minimized for axial loading modes to limit unsupported height of piles under axial loading. Soil confinement around pile at time of testing shall coincide with final grade for pile cap base, taking into account proposed pile cutoff elevations. Alternate methods of dead weight reaction system consisting of a tank to be filled with water or dead weight reaction system may be used for axial compression mode, as designed by Subcontractors Professional Engineer, and as approved by Contractor. All reaction components, including but not limited to, steel reinforcement, lock off nuts, welds, wide flanges, and other load test system equipment shall be designed, fabricated, and constructed by Subcontractor to adequately support or maintain ultimate load test capacities as specified. Design the structures and test apparatus to safely carry the test loads during all stages of loading and unloading in a manner that will adequately support the imposed loads and prevent movement perpendicular to the direction of loading. The load platform shall be supported by piles, cribbing, or other approved means designed so as to prevent excessive deflection and to preclude differential movement, tilting, or eccentric loading. Where specified, shown on Contract drawings, or as required by Subcontractor’s Professional Engineer, brace the jack/load cell assembly to prevent lateral movement of the pile(s) and buckling or loss of jack/load cell assembly. Limit height of exposure at test pile to minimize movement perpendicular to the direction of loading. The system of bracing shall not restrain deflection of the pile due to imposed test load. PILE MOVEMENT MONITORING EQUIPMENT Subcontractor shall install reference beams and dial gauges as the primary means to measure test pile movement. Dial gauges shall have a precision of one thousandth (0.001) of an inch and shall provide for a travel of three (3) inches. A minimum of four dial gauges shall be installed at 90-degree intervals around the test piles subjected to axial loading. Two (2) dial gauges shall be installed on the lateral load test pile; one horizontally at or near the ground line (coinciding with the point of load application), and one horizontally at 12 inches above the first. A minimum of one dial gauge shall be installed at each reaction pile. One dial gauge shall be installed to measure tell-tale movement, if applicable. Reference beams may be made from wood, angle steel, or pipe that is stiff in consistency. Only one location of each reference beam shall be fixed, with all other portions being surface supported and free floating to permit elongation or contraction of reference beams without affecting dial readings. Subcontractor shall install a scale/mirror/piano wire setup supported with an additional independent set of reference beams, isolated from the main reference beams, as a secondary 31 08 13 - 4

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SECTION 31 08 13 – STATIC PILE LOAD TESTING: continued means to measure test pile movement. In lieu of the scale/mirror/piano wire setup, Subcontractor may elect to utilize a surveyor’s level instrument tied to an independent reference scale approved by the Contractor as the secondary means of measuring test pile movement. PART 3 - EXECUTION 3.01 A. B.

C.

D.

E. F.

G.

H. I. J.

PILE LOAD TEST: For all pile types, test pile loading shall not commence until a minimum of 7 days after completion of test pile installation activities. In addition to the requirement listed above, load testing operations for concrete-filled or grouted pile types shall not commence until the test pile concrete and/or grout achieves the required design strength, as specified in the applicable Foundation Piling Section. Perform grout compression tests on the day that the piles are load tested. Results of laboratory cube breaks (fc’ and E) shall be submitted to Contractor prior to commencement of load testing program. Perform static pile load tests at the location shown on the drawings, or where approved by Contractor. The load testing shall be performed prior to the start of production pile installation. The scheduling of load testing shall be as approved by Contractor. Unless otherwise specified in the applicable Foundation Piling Section, the Subcontractor shall perform load testing at non-production pile locations to be abandoned upon completion of the load test program. Subcontractor shall provide qualified personnel to set up and operate all equipment required for the load testing. For lateral load testing, the hydraulic jack shall be fully supported by a dug out cradle in the ground surface or by other bracing to prevent the jack from slipping out during loading. The cradle shall be sufficient to allow placement of the saddle, bearing plates, hydraulic jack, and dial gauges. The jack shall be positioned with its ram moving horizontally at a location somewhere between the ground line and a point 3 inches above or below the ground line. Protect benchmarks, reference marks, test piles, reference beams, dial gauges, jacks, compensators and pressure tanks with canopy, canvas or other protective system from the sun. In addition, provide a portable shelter to shield the survey level instrument from sun, rain, and wind, and provide necessary lighting to conduct the load test during the hours of darkness. Provisions shall also be made to prevent inundation of the load test area as a result of precipitation, runoff, etc. Mound soil, provide sandbags or other grading around edges of the test pile location and divert all water encountered. The load test shall only be performed in the presence of Contractor. Provide personnel to operate load test equipment throughout all required tests. Loading Sequence: 1. Axial compression load tests shall be performed in accordance with the procedures outlined in Part 8.1.2 of ASTM D1143, Procedure A – Quick Test (with the following modifications): a. Except as modified herein, the static axial compression pile load testing shall be performed in general accordance with the latest revision of ASTM D1143/1143M. In the event of conflicting provisions between ASTM D1143/1143M, the provisions of this Section shall govern. b. Loading sequence shall be applied in increments of 5% of the maximum anticipated test load. Add load increments until reaching a failure load but do not exceed the safe structural capacity of the pile or loading apparatus. During each load interval, 31 08 13 - 5

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3.

keep the load constant for a time interval of 10 minutes, using the same time interval for all loading increments throughout the test. The time interval for the maximum test load shall be held for 60 minutes to assess creep behavior. c. Remove the load in five equal decrements, keeping the load constant for a time interval of 10 minutes, using the same time interval for all unloading decrements. The time interval for the final zero load shall be held for 60 minutes to assess rebound behavior. d. Record test readings for 10-minute load increments at 1, 5 and 10 minutes. Record test readings for the 60-minute load hold at 1, 5, 10, 15, 20, 40, and 60 minutes. Record test readings for 10-minute load decrements at 1, 5, and 10 minutes. e. If pile failure occurs prior to reaching the maximum anticipated test load, continue jacking the pile until the total axial movement equals 15% of the pile butt diameter or width. f. If excessive tilting of the pile reaction system is observed, cease testing and remove the load. Re-align system and re-start testing. Axial tension load tests shall be performed in accordance with the procedures outlined in Part 8.1.2, Procedure A – Quick Test of ASTM D3689 (with the following modifications): a. Except as modified herein, the static axial tension pile load testing shall be performed in general accordance with the latest revision of ASTM D3689. In the event of conflicting provisions between ASTM D3689, the provisions of this Section shall govern. b. Loading sequence shall be applied in increments of 5% of the maximum anticipated test load. Add load increments until reaching a failure load but do not exceed the safe structural capacity of the pile or loading apparatus. During each load interval, keep the load constant for a time interval of 10 minutes, using the same time interval for all loading increments throughout the test. The time interval for the maximum test load shall be held for 60 minutes to assess creep behavior. c. Remove the load in five equal decrements, keeping the load constant for a time interval of 10 minutes, using the same time interval for all unloading decrements. The time interval for the final zero load shall be held for 60 minutes to assess rebound behavior. d. Record test readings for 5-minute load increments at 1, 5 and 10 minutes. Record test readings for the 60-minute load hold at 1, 5, 10, 15, 20, 40, and 60 minutes. Record test readings for 10-minute load decrements at 1, 5, and 10 minutes. e. If pile failure occurs prior to reaching the anticipated failure load, continue jacking the pile until the total axial movement equals 15% of the pile butt diameter or width. f. If excessive tilting of the pile reaction system is observed, cease testing and remove the load. Re-align system and re-start testing. Lateral load tests shall be performed in accordance with the procedures outlined in Section 8.1.2 of ASTM D3966/3966M, Procedure A – Standard Loading (with the following modifications): a. Except as modified herein, the static lateral pile load testing shall be performed in general accordance with the latest revision of ASTM D3966/3966M. In the event of conflicting provisions between ASTM D3966,/3966M the provisions of this Section shall govern. b. Loading sequence shall be applied in increments of 10% of the maximum anticipated test load. Add load increments until reaching a failure load but do not 31 08 13 - 6

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K. L.

M.

exceed the safe structural capacity of the pile or loading apparatus. During each load interval, keep the load constant for a time interval of 10 minutes, using the same time interval for all loading increments throughout the test. The time interval for the maximum test load shall be held for 60 minutes to assess creep behavior. c. Remove the load in four equal decrements, keeping the load constant for a time interval of 10 minutes, using the same time interval for all unloading decrements. The time interval for the final zero load shall be held for 60 minutes to assess rebound behavior. d. Record test readings for 10-minute load increments at 1, 5 and 10 minutes. Record test readings for the 60-minute load hold at 1, 5, 10, 15, 20, 40, and 60 minutes. Record test readings for 10-minute load decrements at 1, 5, and 10 minutes. e. If excessive pile movement (i.e. failure) occurs prior to reaching the maximum anticipated test load, continue jacking the pile until the total lateral movement equals the maximum value as defined in the applicable Foundation Piling Section. f. If excessive tilting of the pile reaction system is observed, cease testing and remove the load. Subcontractor’s personnel shall perform optical survey and dial gauge readings of test and reaction piles throughout all required tests. Evaluation of static pile load test data for determination of the ultimate pile capacity values and final production pile dimensions shall be in accordance with the requirements of the applicable Foundation Piling Section. Cut off all non-production test and reaction piles to be abandoned to a depth below prevailing ground surface of at least 3 feet. Subcontractor, prior to abandoning piles in-place, shall determine and record the location of all test and reaction piles relative to reference marks at the site.

END OF SECTION 31 08 13

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