SECTION 502 – LOAD BEARING PILES
502.01 Description
This Section describes the requirements for furnishing and installing concrete, steel, and timber piles.
502.02 Materials
502.02.01 Materials
Provide materials as specified: Concrete ................................ ................................ ................................ ................................ ...................... 903.03 Structural Precast Concrete ................................ ................................ ................................ ........................... 904.03 Prestressed Concrete ................................ ................................ ................................ ................................ .... 904.04 Reinforcement Steel ................................ ................................ ................................ ................................ ...... 905.01 Steel Castings for H-Pile Tips (Medium Strength) ................................ ................................ ......................... 906.02 Steel Piles ................................ ................................ ................................ ................................ ..................... 906.02 Coal Tar Epoxy Paint ................................ ................................ ................................ ............................... 912.01.03 Round Timber Piling ................................ ................................ ................................ ................................ ..... 915.02 Timber Treatment ................................ ................................ ................................ ................................ ......... 915.05
502.02.02 Equipment
Provide equipment as specified: Impact Hammers ................................ ................................ ................................ ................................ ......... 1004.01 Vibratory Hammers................................ ................................ ................................ ................................ ..... 1004.02 Leads and Followers ................................ ................................ ................................ ................................ ... 1004.03
502.03 Construction
502.03.01 Furnishing Pile Driving Equipment
Perform a wave equation analysis program (WEAP) for each pile type and hammer combination. Ensure that the number of required hammer blows at the nominal pile resistance indicated by the WEAP analysis is between 3 and 10 blows per inch. Also ensure that the compressive and tensile pile stresses are within the allowable limits. Submit 4 copies of the WEAP analysis, signed and sealed by a Professional Engineer, and 4 copies of the NJDOT Pile and Driving Equipment Data Form to the Department for approval 30 days before delivery of the equipment to the Project Limits. Submit a separate WEAP analysis and NJDOT Pile and Driving Equip ment Data Form for each pile type and hammer combination.
502.03.02 Prebored Hole
When preboring holes for round piles, use an auger with a diameter that is between 2 inches smaller than the average nominal diameter of piles. When preboring holes for steel H -piles, use an auger with a diameter that is 4 to 6 inches smaller than the nominal diagonal dimension of the piles. Backfill the void between the piles and the prebored holes with granular material.
502.03.03 Driving Piles
A.Wave Equation Analysis Program (WEAP). When Dynamic Pile Load Tests will not be performed, the RE will determine the nominal bearing resistance of the pile, the anticipated number of hammer blows per inch, and the anticipated compressive and tensile pile stresses at the required nominal pile resistance using the wave equation analysis.
B.Methods of Driving. Do not drive piles in embankments until the embankment work, including placement, compaction, and removal of surcharge has been completed. Do not drive piles within 200 feet of concrete that is being placed or has been placed within the previous 24 hours unless approved by the RE. When driving piles in groups, start from the center of the group and proceed outward in both directions, or start from the end of the group and proceed to the opposite end of the group. When using followers in driving, drive 1 long pile in each group of 10 without a follower as a test pile to determine the average bearing resistance of the group. Do not install precast and prestressed concrete piles for at least 21 days after fabrication. If at any point precast and prestressed concrete piles are cured at 40 °F or below, the RE may require additional curing time before the installation of the piles. Additionally, do not install precast and prestressed concrete piles in seawater, brackish water, or sulfate soils for at least 30 days after fabrication. The Contractor may use vibratory pile drivers, with the approval of the RE, to advance steel bearing pil es. Obtain RE approval before jetting piles. The RE will require use of an impact pile driver for at least the final 10 feet of penetration. Drive piles as follows:
1.Accuracy of Driving. Ensure that piles are driven within 1/4 inch per foot from the vertical or batter. Ensure that the driven piles are within 6 inches of the specified position. Ensure that piles for trestle bents are driven within 1/2 inch per foot from the vertical or batter. Ensure that the driven trestle bent piles are within 2 inches of the specified position. The RE will prohibit excessive manipulation of the piles to force them into proper position.
2.Penetration. At least 10 days before beginning the work, submit a plan to the RE for approval for the types of piles, including those whose tip elevation is noted, for jetting, blasting, or the use of spuds and other work necessary to obtain the penetration required.
3.Rock Bearing Piles. Drive steel H-piles or other steel piles that are intended to bear on rock to the refusal necessary to penetrate the rock sufficiently to provide uniform and adequate bearing. The pile is considered as reaching refusal when a penetration of not less than 5 blows per 1/4 inch has been achieved.
C.Test Piles. The RE will determine the length of the test pile. Excavate the ground at each footing location to the elevation of the bottom of the footing before the pile is driven. Drive the test piles with the same type of equipment that will be used for driving production piles. Drive the test piles at the designated locations to the specified bearing resistance or hammer blow count, and tip elevation. Perform the following tests when shown on the Plans:
1.Static Pile Load Test. Obtain the services of a professional testing laboratory, or Professional Engineer with satisfactory pile load test experience, to conduct the load test, to record data, and to provide reports of the test results to the RE. Determine the top elevation of the test piles immediately after driving and again just before static load testing to check for heave. Redrive or jack piles that heave more than 1/4 inch relative to the original elevation prior to testing. Allow a t least 3 days to pass between the driving of any anchor piles or the load test pile and the commencement of the load test. If pipe walls are not of adequate strength to sustain the static test loading when empty, place the required reinforcement and concrete before loading. Do not apply loads for static load tests for cast -in-place concrete piles until the concrete in the test pile has set at least 7 days. Refer to the Special Provisions to determine the total static test load to be applied to piles. Perform static load tests according to ASTM D 1143, using the quick load test method for individual piles, except perform the test to plunging failure or the capacity of the loading system. Provide testing equipment and measuring systems according to ASTM D 1143, except ensure that the loading system is capable of applying 150 percent of the nominal pile resistance or 1,000 tons, whichever is less. At least 20 days before beginning the work, submit detailed plans of the proposed loading apparatus, prepared by a Professional Engineer, to the RE for approval. Construct the apparatus to allow the various increments of the load to be placed gradually without causing vibration to the test pile. When the approved method requires the use of anchor piles that will be used as production piles, drive anchor piles of the same type and diameter as the production piles in the location of the production piles when feasible. Remove the loads after the completion of the tests. The RE may allow the test piles to become part of the structure if approved. If any pile is found unsatisfactory for use in the structure, the RE will direct removal of the pile or cutoff of the pile below the ground line or footing. Upon completion of each test, submit to the RE for approval 4 copie s of the static load test records/reports signed and sealed by a Professional Engineer.
2.Dynamic Pile Load Tests. At least 30 days before beginning the work, submit verification to the RE that the components of the apparatus for obtaining dynamic measurements and the apparatus for recording, reducing, and displaying data have been calibrated by the equipment manufacturer within the past 12 months. Submit the name, qualifications, and previous experience of the person performing the dynamic pile load tests to the RE for approval. Perform dynamic testing according to ASTM D 4945. Take dynamic measurements while driving the piles specified as dynamic load test piles. Using pile analyzer instruments, determine the nominal resistance of the pile. Monitor the stresses in the pile during driving operations to ensure that the pile is not damaged by excessive compressive or tensile stresses. Monitor the driving of test piles during the f ull length of driving and during restriking. Drive piles to the depth at which the dynamic equipment indicates that the required nominal bearing resistance has been achieved and to the required tip elevation. If needed to maintain acceptable stresses in the piles, modify the driving method. If the dynamic test equipment measurements indicate non -axial driving, immediately realign the driving system. If restrike is specified in the Special Provisions or directed by the RE, wait a minimum of 24 hours and t hen reattach the instruments before restriking the dynamic load test pile. Warm up the hammer by applying at least 20 blows to another pile before restriking. Terminate the restrike when the nominal resistance of the pile is reached, when the amount of penetration reaches 6 inches, or when the total number of hammer blows reaches 50, whichever occurs first. If the established hammer blow count is not attained on restrike, the RE may direct the Contractor to drive a portion of or all of the remaining test pile length and repeat the restrike procedure. After restrike, the RE will determine whether additional pile penetration and testing is required. The RE may require splicing of a test pile driven to plan grade that does not meet the required hammer blow count. Drive the spliced pile until the required bearing is obtained. Within 48 hours of the completion of each test, submit 4 copies of the pile dynamic monitoring report to the RE. Include the Pile Dynamic Analyzer (PDA) test results, the Case Pile Wave Analysis Program (CAPWAP) results, and an interpretation of the data that is signed and sealed by a Professional Engineer.
D.Production Pile Lengths. When test piles or load tests are specified, the RE will use the data obtained in conjunction with other available geotechnical information to determine the lengths of production piles to be furnished. The RE will not prepare the order list for any portion of the foundation until the required test data has been completed. The Contractor may increase the length of the production piles to be furnished to provide fresh heading or to suit the Contractor’s method. Complete test piles before driving any production piles unless approved by the RE.
E.Cutoffs and Cappings. Ensure that the tops of foundation piles are embedded in the concrete footing at least 12 inches. At locations where tremie concrete is used, ensure the piles project at least 12 inches above the top of the tremie concrete. Ensure that the length of pile cutoff is sufficient to allow the removal of all injured material. Ensure that the distance between the edge of a pile to the nearest edge of the footing is at least 9 inches. When the cutoff elevation for a precast concrete pile is below the elevation of the bottom of the cap, build up the pile from the butt of the pile to the elevation of the bottom of the cap with a reinforced concrete extension. Cut off piles at right angles to the axis of the pile at the designated elevation. Make the cuts in clean, straight lines.
F.Painting Steel Piles and Pipe Shells. When steel piles or pipe shells in the completed structure extend above the original ground line or finished ground surface, protect the piles or pipe with coal tar epoxy paint as specified in
511.03.01 C. Ensure the coating extends from an elevation 3 feet below the bed of waterbody or finished ground
surface to the top of the exposed steel.
G.Defective Piles. Ensure that the pile driving procedure does not subject the piles to excessive and undue abuse, producing crushing and spalling of the concrete, injurious splitting, splintering and brooming of the wood, or deformation of the steel. Correct damaged or defective piles using one of the following methods:
1.Withdraw the pile and replace it with a new and, if necessary, longer pile.
2.Drive a second pile adjacent to the defective pile. Remove the defective pile to at least 24 inches below cutoff elevation, and fill the hole with sand if it is a cast-in-place pile.
3.Splice, build up the pile, or extend a sufficient portion of the footing to properly embed the pile. Redrive piles that heave by more than 1/4 inch as a result of the driving of adjacent piles or any other cause. If a pile cannot be driven as specified due to an obstruction, the RE will determine when adequate penetration has been achieved.
502.03.04 Splices
Use full length steel piles, pip es, shells, precast concrete piles, and prestressed concrete piles. Do not splice partial pile lengths to achieve the production pile length unless directed. At least 10 days before beginning the work, submit the method of splicing, splice location for each pile, and name of certified welder to the RE for approval. Do not splice timber piles. RE reserves the right for weld verification testing if the integrity of the welding is in question.
502.03.05 Pile Shoe
Attach pile shoes as shown on the Plans.
502.04 Measurement and Payment
The Department will measure and make payment for Items as follows: Item Pay Unit FURNISHING EQUIPMENT FOR DRIVING PILES LUMP SUM PREBORED HOLE LINEAR FOOT TEST PILE, FURNISHED LINEAR FOOT TEST PILE, DRIVEN LINEAR FOOT STATIC PILE LOAD TEST UNIT DYNAMIC PILE LOAD TEST UNIT CAST-IN-PLACE CONCRETE PILE, FURNISHED, ___" DIAMETER LINEAR FOOT CAST-IN-PLACE CONCRETE PILE, DRIVEN, ___" DIAMETER LINEAR FOOT PRECAST CONCRETE PILE, FURNISHED, ___ X ___" LINEAR FOOT PRECAST CONCRETE PILE, DRIVEN, ___ X ___ " LINEAR FOOT PRESTRESSED CONCRETE PILE, FURNISHED, ___ X ___" LINEAR FOOT PRESTRESSED CONCRETE PILE, DRIVEN, ___ X ___" LINEAR FOOT PRESTRESSED CONCRETE PILE, FURNISHED, ___" DIAMETER LINEAR FOOT PRESTRESSED CONCRETE PILE, DRIVEN, ___" DIAMETER LINEAR FOOT STEEL H-PILE, FURNISHED, HP ___ X ___ LINEAR FOOT STEEL H-PILE, DRIVEN, HP ___ X ___ LINEAR FOOT TIMBER PILE, FURNISHED, ___" DIAMETER LINEAR FOOT TIMBER PILE, DRIVEN, ___" DIAMETER LINEAR FOOT SPLICE (___) UNIT PILE SHOE UNIT The Department will pay 75 percent of the lump sum price bid for FURNISHING EQUIPMENT FOR DRIVING PILES when the equipment necessary for driving piles is furnished and driving of test piles has started on an individual structure basis. The Department will pay the remaining 25 percent when the work of driving piles is completed on an individual structure basis. The Department will measure prebored holes that are specified or directed by the RE by the linear foot from the bottom of the foundation excavation elevation to the bottom of the hole elevation. The Department will make payment for the length of pile furnished based on the RE’s order list. The Department will not make payment for the additional length of furnished pile to provide fresh heading, to drive through water, or to meet the Contractor’s driving method. If the required penetration for any pil e is greater than the length in the order list, the Department will include, for measurement in furnished piles, the additional length directed by the RE. The Department will measure the length of piles driven by total length of linear foot installed and accepted, from the pile tip to the pile cutoff elevation, excluding the pile shoe. The Department will not include static pile load tests under piles driven. The Department will make payment for static pile load tests under STATIC PILE LOAD TEST. The Department will not include dynamic pile load tests under piles driven. The Department will make payment for dynamic pile load tests under DYNAMIC PILE LOAD TEST . The Department will not make separate payment for dynamic pile load tests and CAPWAP analysis performed on piles that require restriking. The Department will include restriking and a CAPWAP analysis of a dynamic pile load test in the DYNAMIC PILE LOAD TEST. When dynamic pile load tests (Dynamic or PDA Monitoring) are used, the Department will not make payment for installation of test piles until recorded data is submitted to the RE. The Department will make payment for splices within the pile order length if the order length is greater than 80 feet under SPLICE (___). The Department will not make p ayment for splices in piles that are less than or equal to 80 feet unless directed by the RE.
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Source: Standard Specifications for Road and Bridge Construction, 2019 (rev. 2022-12-21) Edition. Pages 247–251 of 651. View official source ↗