504Load Testing of Bearing Piles

504.1 Description

This Work consists of static a xial compressive load tests (pile load test), static axial tensile load tests (pile pullout tests), and high strain dynami c measurements (dynamic measurements) of piles for the purpose of determining ultimate bearing capacity and pile pullout capacity. For driven piles, dynamic measurements determine driving stress es, pile integrity, and hammer efficiency. For cast-in-place concrete piles (drilled s hafts), dynamic measurements verify pile integrity.

504.1.1 Contractor’s Responsibilities

504.1.1 1 Dynamic Measurements

The Contractor shall provide labor, Equipment, and Materials ne cessary to drill the dynamic test piles holes and fo r mounting transducers. The Con tractor shall provide the analysis Equipment power supply. Where dynamic measurements are to be made on cast-in-place pile s, the Contractor shall provide a gravity drop hammer and pile cushioning. The C ontractor shall excavate around the pile, cut the permanent casing, drill holes in the t est pile(s) and provide impacts on cast-in-place dynamic test piles as required. If a Pile Dynamic Test Consultant Testing is required as design ated on the Plans, the consultant’s qualifications and Equipment must meet the require ments of this Section and Section 504.3, “Construction Requirements.” Pile Dynamic Consu ltant Equipment must meet the requirements of Section 504.3.1.5, “Pile Driving Analyzer.” The Contractor shall perform field Pile Dynamic Testing with an experienced technician or En gineer having at least two (2) years of experience with Pile D ynamic Testing methods. The Con tractor shall use a licensed Professional Engineer having at least three (3) years of experi ence in Pile Dynamic Testing performed to interpret the recorded measurements and generate r eports. At the option of the State Geotechnical Engineer, Department pe rsonnel may perform the Pile Dynamic Testing.

504.1.1 2 Pile Load and Pile Pullout Tests

The Contractor shall provide everything necessary to perform pi le load or pile pullout tests. The Contractor shall record load measurement and pile m ovement readings, and produce a report(s) showing the load displacement curve(s).

504.1.2 Department’s Responsibilities

504.1.2 1 Dynamic Measurements

If Pile Dynamic Testing performed by the Department is required , as designated on the Plans, the Department will provide the Equipment to perform dyn amic measurements and the Department will provide personnel to take the dynamic measureme nts.

504.1.2 2 Pile Load and Pile Pullout Tests

The Contract will specify the anchor pile requirements. The De partment will provide Section 504: Load Testing Of Bearing Piles Page 293 personnel to observe and monitor the Contractor’s test apparatu s, test methods, and data collection.

504.1.3 Pile Testing Mobilization

The Contractor shall mobilize testing Equipment as needed and a s designated by the Contract or authorized by the State Geotechnical Engineer. The Contractor shall mobilize testing Equipment only after receipt of written authorization.

504.2 Materials

504.2.1 Submittals

504.2.1 1 Load Test Frame

The Contractor shall submit the proposed load test frame and an chorage method, details, and design computations 30 Days before the start of pile load t ests and pile pullout tests. The Contractor shall use a professional Engineer licensed in New Me xico to prepare and seal the proposed loading apparatus detail Plans.

504.2.1 2 Certificates of Calibration

The Contractor shall submit a calibration certificate and a cal ibration chart relating pressure to load for the load pressure gauge(s) from a certifie d Laboratory before use. The Contractor shall calibrate each jack and its gauge as a unit. The Contractor shall submit a calibration certificate for load cell(s). The Contractor shall calibrate gauges and cells within six

504.2.1 3 Pile and Equipment Data Form

The Contractor shall submit a Pile and Driving Equipment Data Form as required in Section 501.2.3.1, “Pile Driving Equipment Submittals,” when pr oposing a gravity drop hammer for dynamic measurements of cast-in-place piles.

504.3 Construction Requirements

504.3.1 Equipment

504.3.1 1 Equipment for Dynamic Testing

504.3.1 1.1 Power Supply

The Contractor shall provide dynamic test Equipment electric po wer that supplies 10 A, 115 V, 55 Hz to 60 Hz, AC only. If a field generator is used a s the power source, the Contractor shall provide functioning voltage and frequency leve l monitoring meters.

504.3.1 1.2 Gauge Mounting Equipment

The Contractor shall provide a power drill, bits, taps, and exp andable masonry anchor studs to drill holes in the dynamic test p iles for bolting tran sducers to the piles. The Contractor shall provide a six (6) lb rubber mallet hammer when dynamic te sting is specified on precast concrete piles.

504.3.1 1.3 Personnel Lift

Section 504: Load Testing Of Bearing Piles Page 294 To assist with the installation of instruments for testing, the Contractor shall provide a hydraulic, telescoping arm personnel lift. The Contractor shal l provide a personnel lift with adequate length to reach the top of the pile while the pile is located in the leads. The Contractor may use an alternative to a personnel lift in ac cordance with Section

504.3.4 1.2, “Preparation for Testing.”

504.3.1 1.4 Gravity Drop Hammer

The Contractor shall provide a gravity drop hammer and pile cus hion when cast-in-place piles dynamic testing is specified. The Contractor shall provi de the minimum hammer ram weight and free fall height and c ushion thickness specified in the Contract. The Contractor shall equip gravity hammers wit h guides to ensure concentric dr ive head impact. If approved by the State Geotechnical Engineer, the Contractor may use a diesel hammer with the minimum required ram weight and impact energy. The Contractor shall cut- off the fuel flow.

504.3.1 1.5 Pile Driving Analyzer

The Contractor shall perform the Pile Dynamic Testing using a P ile Driving Analyzer® (PDA) system (Model 8G or PAX) or equivalent. The Dynamic Test ing Consultant shall furnish all Equipment necessary for the Pile Dynamic Testing such as se nsors, cables or wireless transmitters, etc. The Equipment s hall conform to the requirem ents of ASTM D-4945.

504.3.2 Equipment for Pile Load Test

The Contractor shall provide te sting Equipment and measuring sy stems in accordance with ASTM D 1143, except as modified within these Specification s.

504.3.2 1 Load System

The Contractor shall provide a load system capable of applying 250% of the required ultimate pile capacity. The Contractor shall provide a load te st frame design compatible with the anchor pile requirements in accordance with Section 504.3.4 .2.1, “Test Pile and Anchor Pile Requirements.” The Contractor shall construct the apparatus so that it is poss ible to place load increments gradually without cau sing test pile or load test fra me vibration.

504.3.2 2 Load Application System

The Contractor shall use hydraulic jacks to apply the load. Wh en using multiple jacks, fit each jack with a pressure gauge in addition to the master hydra ulic pressure gauge. The Contractor shall use jacks from the same manufacturer with the same rated capacity. The Contractor shall connect jacks to a common manifold with pressu re supplied by one (1) hydraulic pump.

504.3.2 3 Load Measuring System

The Contractor shall provide a dual load measuring system (gaug e and load cell) to verify the test pile load. The Contractor shall calibrate the load ce ll and mount it between the load frame and the pile head to confirm the load recorded from the p ressure gauge.

504.3.2 4 Settlement Measuring System

The Contractor shall use a dual settlement measuring system. T he Contractor shall provide two (2) dial gauges bea ring on the reference beams at o pposite sides of the pile, below the test plate. The Contractor shall support the referen ce beams outside of pile-soil movement influences. The Contractor shall provide two (2) line ar variable differentiating transformers, with remote digital read-outs bearing on referenc e beams on opposite sides of the pile.

504.3.3 Equipment for Pile Pullout Test

The Contractor shall use testing Equipment and measuring system s in accordance with Section 504.3.2, “Equipment for Pile Load Test,” except as modi fied within these Specifications. 504.3.3.1 Load System The Contractor shall provide a load system capable of applying 200% of the required ultimate pile pullout capacity.

504.3.3 2 Reaction System

It is permissible to use suitabl e cribbing or other bearing pla tes for reaction points instead of anchor piles. The Contractor shall use cribbing or bearing plates of sufficient size and stiffness to limit undesirable reaction frame movement.

504.3.4 Testing Requirements

504.3.4 1 Pre-Construction Wave Equation Analysis

The State Geotechnical Engineer or Dynamic Testing Consultant s hall use the submitted information required in Section 501.2.3.1, “Pile Driving Submit tals” to perform wave equation analyses and shall prepare a summary report of the wave equatio n results. The wave equation analysis (using GRLWEAPTM software by Pile Dynamics, I nc. or equivalent) shall be used to assess the ability of the proposed driving system to in stall the pile to the required capacity and desired penetration depth within the allowable dri ving stresses. Approval of the proposed driving system by the Engineer shall b e based upon the wave equation analyses indicating that the proposed driving system m eeting the requirements of Section 501.3.1.4, “Approval of Driving System.” A Preliminary Wave Equation Analysis Acceptance Chart shall be developed and submitted to the Project Manager a minimum of seven (7) Days be fore commencing pile driving. The Contractor shall submit the Preliminary Wave Equa tion Analysis Acceptance Chart meeting the template requirements as provided by the NMDO T Geotechnical Section.

504.3.4 1.1 Dynamic Pile Testing Requirements

The Contractor shall perform dynamic testing during the pile dr iving as described in the Contract as “Dynamic Test Piles.” The State Geotechnical Engin eer may decide to designate additional piles shown in the Contract as dynamic test piles.

504.3.4 1.1.1 Notification to Proceed

The Contractor shall notify the Project Manager at least 21 Day s before commencing dynamic test pile testing. The Contractor shall confirm the te sting schedule with the Project Section 504: Load Testing Of Bearing Piles Page 296 Manager three (3) Days before the testing date. The Contractor shall notify the Project Manager promptly of any changes in the schedule. The Contracto r shall test dynamic test piles before any other piles are driven or installed. The Cont ractor shall drive production piles no deeper than the estimated or minimum penetration elevation a s applicable before receiving the field Acceptance criteria.

504.3.4 1.2 Preparation for Testing

The Contractor shall prepare dy namic test piles as follows: 1. Drilling for Mounting Transducers. Drill holes for mounting the transducers. Bolt the instruments near the head of the pile at the location and using a bolt pattern designated by the State Geotechnical Engineer. Drilling requirements for each test pile include the following: 1.1. Steel pipe piles: Seven (7) holes drilled with a 7/32 inc h diameter bit, tapped to accommodate ¼ in bolts; 1.2. Steel HP piles: Five (5) holes drilled with a 5/16 inch d iameter bit through the web; 1.3. Precast concrete or cast-in-place concrete piles: 7 ¼ inc h x 1 ½ inch holes with ¼ inch expandable anchor studs set in the holes to accommo date ¼ inch bolts; 2. Wave Speed Measurements. When precast concrete p iles are specified as dynamic test piles, place the pile horizontally on wooden sleep ers so that it is not in contact with the ground or with other piling. The State Geotec hnical Engineer will take wave speed measurements for the Pile Driving Analyzer (PDA ) by hitting the pile with a six (6) lb rubber mallet hammer. The Department will not require wave speed measurements for ste el piles; and 3. Transducer Installation. Install the instruments while the pile is in the leads using a man-lift raised to the top of the pile. As an alternative to the man-lift requirement, the State Geotec hnical Engineer may install the instruments after the pile is driven to a tip eleva tion of ten (10) ft above the Plan tip elevation.

504.3.4 1.3 Procedure for Testing Driven Piles

The following are the procedures for testing driven piles for e ither Department or Consultant Pile Dynamic Testing: 1. Drive the test pile in accordance with Section 501.3.5, “Pil e Driving Operations,” while the State Geotechnical E ngineer monitors the dynamic meas urements; 2. Monitor the test pile stresses that result from the driving to ensure that the compressive or tensile stresses do not exceed the allowable dri ving stresses as defined in Table 501.3.1.4:1, “Wave Equation Analysis Allowable Driving Stress.” If the monitored pile stresses exce ed these criteria, stop driving . Perform necessary modifications to the driving operat ion to ensure that pile dama ge does not occur; 3. Monitor the test pile stresses on individual gauges to deter mine if non-axial driving is indicated. If the pile bends bey ond Acceptable allowances, sto p driving and realign the driving system; 4. If the Contract specifies an estimated penetration elevation , drive the first dynamic test pile until the required ultimate capacity or the estimated penetration elevation is achieved; If the Contract specifies a minimum penetration elevation, driv e the first dynamic Section 504: Load Testing Of Bearing Piles Page 297 test pile to that elevation; If the test pile does not achieve the required ultimate capacit y at the estimated or minimum penetration elevation, splice the test pile with additi onal length of pile. Remove and relocate the instruments to the spliced section. Pr oceed with driving until the ultimate driving capacity is achieved; and 5. Forty-eight hours after the initial drive, restrike each tes t pile previously driven with the dynamic measuring Equipment installed. The State Geotechni cal Engineer may allow shorter wait periods depending on soil and test condition s. Alternatively, the Contract may require longer wait periods, multiple restrike int ervals, or both on a given test pile. Use a “warm” hammer that has previously drive n at least one (1) pile, other than the test pile(s), to restrike the test pile(s) . The maximum total number of hammer blows for the restrike is 40.

504.3.4 1.4 Procedure for Testing Cast-in-Place Piles

The following are the procedures for testing cast-in-place pile s: 1. When the Contractor casts the dynamic test pile(s), the Insp ector will make three (3) test cylinders of concrete or grout for each test pile in accor dance with AASHTO T 23M. Provide concrete that will achieve a compressive strength at se ven (7) Days of 3,000 psi; 2. After seven (7) Days, weigh the three (3) concrete test cyli nders and report the average unit weight to the State Geotechnical Engineer. Test one (1) concrete cylinder at seven (7) Days. If the compr essive strength is at least 3,000 psi, test the other two (2) cylinders. Report the average of the three (3) breaks to the State Geotechnical Engineer. Perform the dynamic test on the test pile the same Day that the cylinders are broken; 3. If the first test cylinder breaks at less than 3,000 psi, re port the result to the State Geotechnical Engineer. The State Geotechnical Engineer may dec ide either to have the last two (2) cylinders tested the same Day or to wait up to a maximum of 14 additional Days before breaking the last two (2) cylinders. The Day the last two

504.3.4 1.5 Case Pile Wave Analysis

NMDOT Geotechnical Section per sonnel or approved Pile Dynamic T esting Consultant will perform the Case Pile Wave Analysis as designated on the P lans or determined by the NMDOT State Geotechnical Engineer. Signal matching analysis (by CAPWAP® software, available from P ile Dynamics, Inc. or equivalent) of the dynamic pile testing data shall be performed on data obtained from the end of initial driving and the beginning of restrike of specified P ile Dynamic Test piles. CAPWAP analysis should be performed by an Engineer who meets the minim um requirements outlined in Section 504.1.1.1, “Dynamic Measurements” and is capable of returning analysis within one

504.3.4 2 Pile Load and Pile Pullout Testing Requirements

504.3.4 2.1 Test Pile and Anchor Pile Requirements

1. Driven Piles. The Contractor shall apply the load to a production pile driven in the final Plan location, unless otherwise specified in the Contract , and apply the test frame against anchor (tension) piles; The Contractor shall use production piles driven in final Plan locations for the anchor piles unless the layout of the test frame reaction points is fi xed and inconsistent with the production pile layout or unless an alternative pile type i s required to develop adequate pullout resistance. The Project Manager will decide i f anchor piles that are not final production piles may be cut-off below final grade or pulled after the testing is completed; and 2. Cast-in-Place Piles. The Contractor shall apply the load to a production pile located in the final Plan location, unless otherwise shown in t he Contract. The Contractor shall use either driv en piles or cast-in-place piles as anchor piles. The Contractor shall not use anchor p iles as final production piles . The Contractor shall provide cast-in-place anchor pile s with reinforcement capable o f carrying the pile tension force.

504.3.4 2.2 Commencement of Load Test

Unless otherwise specified in the Contract, the Contractor shal l wait a minimum of 24 h between driving or installing anchor piles or the test pile and commencing with the pile load or pile pullout test. When testing pipe piles filled with concrete or cast-in-place c oncrete piles, the Contractor shall begin load tests after the concrete has attained a compre ssive strength of 2,500 psi.

504.3.4 2.3 Load Testing Procedures

The Contractor shall conduct pile load tests and pile pullout t ests in accordance with the following requirements: 1. Perform the Quick Load Test Method for Individual Piles in accordance with ASTM D 1143, but take the load test to the first of either fail ure of the test pile or capacity of the load system; Section 504: Load Testing Of Bearing Piles Page 299 2. Test pile failure is defined as total vertical pile movement equal to the greater of either five percent (5%) of the pile diameter or two (2) inches ; 3. If failure occurs, remove the test load in four (4) approxim ately equal amounts with a five (5) minute interval between removals; 4. For pile load tests where pile s are 24 inch or less in diame ter or width, the ultimate capacity is the load that produces a settlement of the pile hea d in accordance with the following equation: ( 1 ) Where, is the settlement at the ultimate pile capacity in inches is the pile diameter or width in inches is the elastic deformati on of pile length in inches Use the following equation for piles with diameters or widths g reater than 24 inches: ( 2 ) Where, is the settlement at the ultimate pile capacity in inches is the pile diameter or width in inches is the elastic deformati on of pile length in inches 5. For pile pullout tests, the State Geotechnical Engineer will de termine when the ultimate pile capacity is attained.

504.3.4 3 Completion of Dynamic Testing of Driven Piles

After completing the dynamic test pile(s) at a Substructure ele ment, the Contractor shall prepare the pile(s) for any specified pile load or pile pullout test(s). If no load testing is required as determined in Section 501.3.6 , “Pile Acceptance” the Final Wave Equation Analysis Acc eptance Charts based on results of the Pile Dynamic Testing should be submitted to t he Project Manager within thirt y six (36) hours after completion of PDA testing and C APWAP analyses at the applicable Bridge or Structure element. The Dynamic Testing Consultant shall prepare a written report o f the Pile Dynamic Testing results within seven (7) Days of completion of all dyna mic test piles specified. This report shall include the results of static load test(s) (if per formed) and shall contain a discussion of the pile capacity obtained from the dynamic and s tatic testing. The report shall also discuss hammer and driving system performance, driving str ess levels, and pile integrity. The Contractor shall drive production piles no deeper than the estimated or minimum penetration elevation before receiv ing the field Acceptance cri teria. The Contractor shall record the average hammer stroke and pile set after driving of each pile to determine pile Acceptance once the driving crit eria is established. After rec eiving the field Acceptance criteria, the Contractor shall dr ive piles until attaining the required ultimate capacity.

504.3.4 4 Completion of Dynamic Testing of Cast-in-Place Piles ) 008.0 15.0( D S Sf 

Sf D S 30DS Sf Sf D S The Contractor shall base the required production pile tip elev ation on the dynamic testing and load testing results if specified. The State Geote chnical Engineer will require up to 36 h after completion of the last test pile to provide the pile tip elevation. Unless the State Geotechnical Engineer directs otherwise, the C ontractor shall place no other piles until receiving the production pile tip elevation.

504.3.4 5 Completion of Load Testing

After completing the specified load test(s) to the Project Mana ger’s satisfaction, the Contractor shall dismantle the test apparatus and Equipment and remove from the site. The Contractor shall use the load test results to determine the ult imate pile capacity Acceptance criteria of driven piles as e stablished under Section 501.3.6, “Pile Acceptance,” and to confirm ultimate pile capacities deter mined by dynamic pile tests. Pulled anchor piles of the same type as the production piles ma y be reused as production piles if not rejected by the Project Manager due to damage as c overed in Section 501.3.6.3, “Damaged Pile Limitations.” For cast-in-place piles, the Contractor shall use the load test results to determine the pile penetration requirements if no subsequent dynamic testing is sp ecified. The State Geotechnical Engineer will require up to 36 h after c ompletion of the last test pile to provide the pile tip elevation. The Contractor shall re-drive production piles used as anchor p iles in accordance with Section 501.3.6, “Pile Acceptance.”

504.4 Method of Measurement

The Department will measure the actual number of pile tests ad ministered and approved. Pile testing mobilization will be measured as a Lump sum unit.

504.5 Basis of Payment

Pay Item Pay Unit Pile Testing Mobilization Lump Sum Pile Load Test Each Pile Pullout Test Each Pile Dynamic Test Department Testing Each Case Pile Wave Analysis Test Department Testing Each Pile Dynamic Test Consultant Testing Each Case Pile Wave Analysis Test Consultant Testing Each

504.5.1 Work Included in Payment

The following Work will be considered as included in the paymen t for the main item(s) and will not be measured or paid for separately: 1. Non-production anchor and test piles which will not remain i n use as part of the permanent Structure. Section 505: Pile Integrity Testing Page 301