for Highway Construction Page 352 of 71 5 SECTION 505 – PILING
505.01 Description.
Provide and drive piles, including test piles.
505.02 Materials.
Provide materials as specified in: Concrete ...................................................................................................................................... 502 Steel H -Piles ............................................................................................................................ 708.08 Steel Shell Piles ....................................................................................................................... 708.30 Timber Piles ............................................................................................................................. 710.05
505.03 Construction Requirements.
A.General. Provid e pile type and size as shown on the bridge plans. Drive test piles with the same pile driving hammer make, model, and size as will be used for production pile driving. Do not drive test piles with a vibratory hammer, unless specified in the contract or as directed. Notify the Engineer at least 7 calendar days before driving each test pile. The Engineer will require up to 2 business days after receiving each test pile record (ITD 0970) and corresponding signed and sealed CAPW AP Analysis Report to evaluate each test pile result, and provide the production pile driving criteria and revised estimated pile length. Drive test piles as shown in the bridge plans or as directed. If the required bearing capacity is not achieved when the test pile is driven as shown in the bridge plans, continue driving the test pile until the required bearing capacity has been achieved as determined by the Engineer. Complete the foundation excavation before driving piles . Drive production piles as shown in the bridge plans or as directed. If the required highest pile tip elevations or minimum penetrations cannot be achieved using a hammer with higher energy, then removing and replacing the pile, driving an adjacent pile, or predrilling may be required. Pile restriking may be required if the pile does not have the design capacity at the end of initial driving. Restrike piles for 4 inches of penetration or as di rected, with the hammer that has been warmed up by applying at least 20 blows to another pile or to a timber mat placed on the ground. Provide a suitable light for shell pile inspection. Piles must achieve the required pi le driving criteria through 2 consecutive, 1- foot or 1 -inch penetration intervals.
B.Helmet Assembly. Use a helmet assembly with a suitable hammer cushion for driving piles. Fit the helmet assembly closely to the pile tops. Provide a helmet assembly design that has been proven satisfactory and is properly sized for driving the piles. for Highway Construction Page 353 of 71 5 C. Hammer Cushion. Remove the hammer cushion from the helmet and inspect in the Engineer’s presence before beginning pile driving at each structure or after each 100 hours of pile driving. If there is any damage to the cushion or a hammer cushion thickness reduction of 25 percent or more of the original thickness, replace the hammer cushion before continuing the pile driving.
D.Pile Tips and Cutting Shoes . Fit the piles with pile tip protectors or cutting shoes as specified or as directed. Carefully shape the pile toe to provide uniform, even bearing on the tip or shoe. Use AWS certified welders to install pile tips or shoes in accord ance wi th the manufacturer’s written instructions.
E.Steam, Air, Diesel, or Hydraulic Hammers. Provide steam, air, diesel, or hydraulic hammers as specified. Submit the hammer type and hammer operation specifications for review at least 15 calendar days before pile d riving begins. Operate pile driving hammers in accordance with the manufacturer’s written instructions. Ensure the hammer operator’s manual is available onsite during pile driving. Operate and maintain air/steam hammers within the manufacturer’s spec ified ranges. Equip the plant and equipment with accurate pressure gauges that are easily accessible by the Engineer. For closed- end (double acting) diesel hammers, provide a bounce chamber pressure gauge near the ground level that can be easily read by the Engineer. For hydraulic hammers, provide a power plant with sufficient capacity to maintain at the hammer, under working conditions, the volume and pressure specified by the manufacturer. Equip the plant and equipment with accurate pressure gauges that are easily accessible to the Engineer. Provide hydraulic hammers with at least 3 hydraulic control settings that ensure predictable energy or equivalent ram stroke. The maximum stroke for concrete piles is 2 feet. The hydraulic hammer stroke must be able to be set at 0.5- foot increments up to the maximum stroke. Supply hammer instrumentation with an electronic read out and control unit that allows the Engineer to monitor, and the operator to read and adjust the hydraulic hammer energy or equivalent ram stroke. When pressure measuring equipment is required to determine hydraulic hammer energy, calibrate the pressure measuring equipment before use in accordance with the hammer manufacturer’s written requirements. Provide an acceptable written record of the calibration before beginning pile driving. If the Contractor is unfamiliar with hydraulic hammer operation, a manufacturer’s representative must be onsite for the first driven piles to ensure that the equipment is operated proper ly.
F.Vibratory Hammers. If specified or approved, use vibratory hammers to drive production piles at the beginning of the driving, but finish the pile driving with impact hammers so the pile bearing capacities can be determined. The Engineer will determine the penetration depth for piles driven by vibratory hammers.
G.Pile Bearing Capacity . To confirm the pile capacity during driving, the Engineer will develop the pile- driving criteria as the required blow count per foot or inch of pile penetration using a wave equation analysis. The Engineer will use the following pile driving dynamic formula to determine the pile capacity when a wave equation analysis is unavailable. R u = 1.75 [E 0.5(log(10N i))] - 100 for Highway Construction Page 354 of 71 5 Where: Ru = ultimate pile capacity (kips) E = W x H, hammer energy (foot -pounds) at the field observed ram stroke, that equals field ram stroke H (feet) multiplied by ram weight W (pounds) Ni = number of hammer blows per inch of pile penetration The required number of hammer blows per foot of driving (N f) for pile to achieve the ultimate pile capacity can be determined as follows: Nf = 1.2 (10A) Where: A = 𝑅𝑅𝑅𝑅+100 1.75√𝐸𝐸 Use of the pile driving dynamic formula instead of pile- driving criteria developed using a wave equation analysis will normally require piles to be driven to a higher capacity. The Engineer will obtain the revised ultimate pile capacity from the bridge designer of record when the pile driving dynamic formula is used.
H.Splicing.
1.Timber Piles. Do not splice timber piles .
2.Steel Piles . Weld pile splices (including prefabricated splicers), pile tips, pile anchors, and other welded attachments to steel piles according to AWS D1.1. All welds must be performed by a welder certified by AWS in the AWS qualified weld procedure and weld position. Provide a Certified Welding Inspector (CWI) holding QC1 Certification as defined in AWS D1.1 for ultrasonic testing . Provide a Certified Welding Inspector (CWI) holding QC1 C ertification or ASNT Central Certification Program (ACCP) Level II certification as defined in AWS D1.1 , or an ICC Certified Structural Welding Special Inspector level S2 (must possess both S2P and S2C) for visual testing. Provide a third- party weld inspection report after welding is complete.
a.Splices . Splice shell piles and H piles conforming to Joint B -U4a or B -U4a-GF (Single -Bevel Groove Weld) in AWS D1.1 Figure 5.1. Weld back -up rings or plates with a full penetration groove weld. Joint B -U3b or B -U3-GF (Double V -Groove Weld) in AWS D1.1 Figure 5.1 may be substitute d for Joint B -U4a or B -U4a-GF for H piles. Provide access holes at web ends according to AWS D1.1 Section 5.17.
1.Do not make more than 2 field splices on any individual pile before driving.
2.The minimum pile section length for pile splicing is 10 feet.
3.Prefabricated splicers can be used as specified in the bridge plans.
b.Inspection. Visually inspect all shell pile and H pile welds. Ultrasonic test 25% of weld s for shell piles with O.D. greater than 18” per construction phase or stage . Include visual inspection and ultrasonic test results in the third party inspection report. Visual weld inspections must be performed and signed off by a Welding Inspector possessing an ASNT Central Certification Program (ACCP) Level II certification or AWS QC1 Certification as defined in AWS D1.1 Section 8, or an ICC Certified Structural Welding Special Inspector level S2 (must possess both S2P and S2C) . Ultrasonic tests must be performed and signed off by a Welding Inspector possessing QC1 Certification as defined in AWS D1.1 Section 8. In the event of 1 failing ultrasonic weld for Highway Construction Page 355 of 71 5 test, increase the testing frequency to 100% of welds until 4 consecutive ultrasonic weld tests pass. Reduce ultrasonic testing frequency back to 25% of welds after 4 consecutive ultrasonic weld tests pass following 1 failing ultrasonic test. Remove and replace failing welds at no additional expense to the Department .
c.Acceptance . Following completion of all welding, the Contractor must submit a third- party inspection report to the Engineer stating that the welding under the Contract was performed according to AWS D1.1. The report must include a Welding Procedure Specifications review, a welder certifications review, and a report on all weld inspections.
I.Followers . Use followers only when approved.
J.Loading Tests. Determine pile capacities by static loading tests when required. Perform these tests in accordance with ASTM D1143.
K.Pile Dynamic Tests. Perform pile dynamic tests on test piles in accordance with ASTM D4945, when required.
L.Pile Storage and Handling. Store and handle piles so as to avoid damaging the piles. Take special care to avoid breaking the surface of treated timber piles .
M.Cutting Piles . For steel piles, neatly cut the piles on a horizontal plane at the cutoff elevation(s) shown in the bridge plans after the piles have been driven to the required capacity, inspected, and accepted.
N.Concreting. Completely fill shell piles with concrete after the cutoff has been removed, unless otherwise shown in the bridge plans. Before placing concrete in shell piles, remove debris and water from inside the pile. Do not place concrete in shell piles until all piles within a pier or abutment have been driven to the required capacity.
O.Alignment, Location, and Orientation. Drive piles with a variation of plumbness of not more than ¼ inch per foot from the vertical or from the batter shown in the bridge plans. Drive piles for elevated pier caps so the pile cap may be placed without inducing excessive stresses in the piles as determined by the Engineer. The Engineer will determine excessive stressed based on loading conditions, pile type, and unsupported length. Ensure pile locations at cut off are within 6 inches (2 inches for elevated pier caps) of plan location. Ensure the distance to the as -driven centroid (the distance from any edge of concrete of the footing or abutment to the as -driven centroid) of the pile group is within 5 percent of the distance to the plan centroid location of the pile group (the distance from any edge of concrete of the footing or abutment to the plan centroid). Ensure H -pile orientation is within 15 degrees of that shown in the bridge plans. If the location or alignment tolerances specified in this paragraph are exceeded, and if in the Engineer’s judgment corrective measures are necessary, design and construct suitable measures at no additional cost or time to the Department. for Highway Construction Page 356 of 71 5 P. Heaved Piles. Check pile heave immediately after completing installation and periodically thereafter until the Engineer determines checking is no longer required. Take level readings referenced to a fixed datum immediately after the pile has been dr iven to the required capacity and again after all piles within a 15 -foot radius have been driven. Redrive piles that have heaved vertically more than ¼ inch to the required pile capacity, at no additional cost to the Department.
Q.Installation Sequence. Start driving individual piles in pile groups from the center of the group and proceed outwards in both directions or start at an outside row and proceed progressively across the group.
R.Defective Piles. Do not subject piles to excessive and undue abuse that may result in pile damage. Correct piles that have been damaged during driving, driven out of plan location or driven below the pile cutoff elevation at no additional cost to the Department. Make corrections to the damaged or out of position piles by one of the following methods and as approved:
1.Remove and replace the pile with a new pile and, if necessary, a longer pile.
2.Drive a new pile adjacent to the defective pile, at a minimum 1 -foot separation from the defective pile or as directed.
3.Splice or build up the pile or widen a sufficient portion of the footing (including redesign of steel reinforcement , if necessary) to properly embed the pile. Other corrective methods may also be used if approved.
S.Driving Pile Next To Concrete Less Than 28 Days Old. Do not drive piles closer to green concrete than the distance determined from the following formula: D = C x E 0.5 Where: D = distance (foot) E = rated energy of pile driving hammer (foot -pounds) C = coefficient shown in Table 505.03-1 based on the number of days of curing time Table 505.03 -1 – Curing Time Coefficient Curing Time (days) Coefficient C Curing Time (days) Coefficient C 1 0.34 6 0.12 2 0.23 7-9 0.11 3 0.18 10-13 0.10 4 0.15 14-20 0.09 5 0.13 21-28 0.08 for Highway Construction Page 357 of 71 5 505.04 Method of Measurement. The Engineer will measure acceptably completed work as follows:
1.Provide and drive piles and test piles will be by the foot of pile below the cutoff elevation not including the pile shoe or tip.
2.Pile shoes or tips and pile splices will be by the each.
505.05 Basis of Payment .
The Department will pay for accepted quantities at the contract unit prices as follows: Pay Item Pay Unit Provide & Drive Timber Piles .................................................................. FT Provide & Drive Steel Shell Piles ____ O.D. ........................................... FT Provide & Drive Steel H- Piles ____ x ____ ............................................ FT Provide & Drive Test Piles ...................................................................... FT Provide & Install Pile Shoes or Tips ........................................................ Each Splice Steel Pile Before Driving .............................................................. Each Splice Steel Pile During Driving .............................................................. Each For splice steel pile before driving, the Department will pay for 1 splice per pile if the pile length(s ) shown are longer than 60 feet. For splice steel pile during driving, the Department will pay up to 2 splices per pile if the plan pile length is less than 100 feet and up to 3 splices per pile if the plan pile length is longer than 100 feet. For pile cutoffs, which are not permanently incorporated into the work, the Department will pay 100 percent of the prorated purchase cost as shown on the seller’s invoice, including freight charges and sales or use taxes. Pile cutoff pay lengths will be the difference between the pile top elevation after pile driving is completed and the pile cutoff elevation in the plans. Leftover piles that are not cutoffs and not permanently incorporated into the work, will not be paid for and will become the Contractor’s property. Pile-driving criteria developed by wave equation analyses, steel reinforcement, and concrete for steel shell piles are incidental. The cost to drive pile shoes or tips is incidental. for Highway Construction Page 358 of 71 5 SECTION 506 – PRESTRESSING CONCRETE
506.01 Descri ption.
Provide, place, and tension prestressing steel in precas t or cast -in-place concrete. Prestressing includes the providing and installation of appurtenant items necessary for the particular prestressing system to be used, including ducts , anchorage assemblies, and grout used for pressure grouting ducts. For cast -in-place prestressed concrete, the term “member” means the concrete that is to be prestressed. Perform prestress ing using pre- tensioning or post -tensioning methods, unless the plans show only pre- tensioning details. If the plans show only pre- tensioning details, the Contractor may use a post -tensioning system only if complete modification details are approved.
506.02 Materials.
Provide prestressing reinforcement that meets 708.05. The Engineer will reject members with failing strand or steel. Grout and Mortar .......................................................................................................................... 705
506.03 Construction Requirements.
A.General. Submit complete shop drawings detailing the method, materials, and equipment proposed for use in the prestressing operations, including additions or rearrangement of reinforcing steel or prestress rei nforcing strands. Outline the method and sequence of stressing and include complete specifications and details of the prestressing steel and anchoring devices, working stresses, anchoring stresses, types of ducts , and other data pertaining to the prestressing operation, including the proposed arrangement of the prestressing steel in the members, pressure grouting materials, and equipment. Submit elongation calculations based on the sequence of stressing. Do not cast members to be prestressed before shop detail drawings are approved. Submit as -built shop drawings. Precast, prestressed concrete manufacturing plants are required to be certified by the Prestressed Concrete Institute plant certification program, in category B2 (prestressed miscellaneous bridge products), B3 (prestressed straight strand bridge members), or B4 (prestressed draped strand bridge members), corresponding to the products specified. Submit proof of current certification to the E ngineer before beginning production. For the fabrication of precast and prestressed members, use the provisions in the current edition, at the time of bid opening, Manual for Quality Control for Plants and Production of P recast, Prestressed Concrete Products published by the Prestressed Concrete Institute with the following exceptions:
1.The contract specifications govern where there are conflicts.
2.If a wire in a pre- tensioning strand fails, the Engineer will reject.
3.If a wire in a post -tensioning tendon fails, the Engineer may reject. Retain a professional engineer, who is experienced in post -tensioning operations and registered in at least 1 state of the United States. The Contractor’s professional engineer is to be in charge of post -tensioning
Source: Idaho Standard Specifications for Highway Construction, 2023 Edition. Pages 388–393 of 768.