7-11 Section 705. Foundation Piling
705.01. Descripti on This work consists of providing and driving timber piles, cast -in-place (CIP) concrete piles, and steel piles . The following definitions apply to this work: CIP. In this section, the abbreviation for cast -in-place. Manufacturer . The company that manufactures the pile driving equipment including hammers and appurtenances. 705.02. Materials Provide materials in accordance with the following sections : Concrete, Grade 4000 ........................................................................ 1004 Granular Material, Class II .................................................................... 902 Steel Reinforcement ............................................................................. 905 Foundation Piles ................................................................................... 906 Water ..................................................................................................... 911 Treated Timber Piles ............................................................................. 912 Pile Points and End Plates .................................................................... 906 Pile Protection ....................................................................................... 906 Provide new or used steel piles, consisting of the rolled structural steel shapes meeting yield strengths shown on the plans or the Engineer ’s authorization. Used steel piles must be in good condition meeting the approv al of the Engineer . Provide new steel shells for watertight CIP concrete piles. Provide end plates for CIP concrete piles. Provide steel reinforcement meeting the yield strength shown on the plans. Provide full -length treated timber piles. Provide Concrete, Grade 4000 for CIP concrete piles. Provide natural aggregate and with no greater than 2.50 % absorption as specified in ASTM C127 for structure concrete. Do not use slag aggregate. 705.03. Construction
A.Piling
1.Storage and Handling of Piles . Store piles off the ground with cribbing to prevent bending or distorting the piles. Store and handle piles to prevent dirt, water, or other deleterious material from entering steel shells for CIP concrete piles. Handle timber piles in accordance with subsection 709.03. MDOT Standard Specifications for Construction Section 705
7-12 2. Equipment . Size pile driving equipment to drive production and test
piles without damage in accordance with this subsection. Do not use driving equipment that damages the piling. Submit a description of pile driving equipment and a completed MDOT Form 1956 LRFD [Load and Resistance Factor Design] Pile and Driving Equipment Data to the Engineer for review and approval at least 14 calendar days before beginning pile driving. Pile driving equipment includes a pile driving hammer, hammer cushion, helmet, pile c ushion, and other appurtenances . The Engineer will evaluate the proposed driving system using the dynamic formula, wave equation analysis, or both. The Engineer will use the required number of hammer blows per inch and the pile driving stresses over the entire driving process to evaluate the pile driving equipment. Select pile driving equipment that installs piles at a rate of 2 to 10 blows per inch at the required nominal pile driving resistance for every method of pile resistance certification. For prelim inary hammer selection purposes, the minimum and maximum hammer energy may be estimated as follows: 𝐸𝐸𝑑𝑑≥0.082 (𝑅𝑅𝑛𝑛𝑑𝑑𝑛𝑛+100 )2 Formula 705-1 𝐸𝐸𝑑𝑑≤0.193 (𝑅𝑅𝑛𝑛𝑑𝑑𝑛𝑛+100 )2 Formula 705-2 Where: 𝑅𝑅𝑛𝑛𝑑𝑑𝑛𝑛 = Nominal pile driving resistance measured during pile driving in kips 𝐸𝐸𝑑𝑑 = Energy developed by the hammer per blow in foot-pounds For pile stresses determined by wave equation analysis, do not exceed the maximum pile driving stresses specified in Table 705-1 for the entire driving operation. Table 705- 1: Maximum Pile Driving Stress Pile Material Maximum Pile Driving Stress Steel 90% of the yield strength Timber 3.1 ksi (F co = 0.9) MDOT Standard Specifications for Construction Section 705
7-13 The Engineer will predict pile stresses for vertical piles using wave
equation analysis based on the hammer efficiencies specified in Table 705-2. Table 705- 2: Hammer Efficiencies Hammer Type Efficiency Single acting air 67% Double acting air 50% Diesel 80% Hydraulic or diesel with built-in energy m easurement 95% Drop 25–40% The Engineer will notify the Contractor of acceptance or rejection of the driving system within 7 calendar days of receiving MDOT Form 1956 LRFD Pile and Driving Equipment Data. If the Engineer rejects the driving system, modify or replace the proposed methods or equipment at no additional cost to the Department. Use the approved system during pile driving operations . Submit revised pile driving equipment data to the Engineer for review and acceptance before changing the driving system . The Engineer will notify the Contractor of acceptance or rejection of the driving system changes within 7 calendar days of the Engineer ’s receipt of the requested change. The Department will not grant an extension of time for time required for submission, review, and approval of a revised driving system. The Engineer ’s approval of pile driving equipment does not relieve the Contractor of the responsibility to drive piles without damage to the required nominal pile driving resistance and the minimum pile penetration elevation shown on the plans. Use air, diesel, or hydr aulic hammers to drive piles.
a.Air Impact Hammers . Operate air hammers within the manufacturer ’s specified ranges . Provide the Engineer with the hammer specifications to determine the energy developed by the hammer with each blow . Use striking parts that weigh at least 2.75 kips and at least one-third the combined weight of pile and helmet. Provide the power plant and equipment for air hammers with a capacity capable of maintaining, under working conditions, the air volume and pressure at the hammer, as specified by the MDOT Standard Specifications for Construction Section 705
7-14 manufacturer . Equip the power plant and equipment with accurate
pressure gauges that are easily accessible to the Engineer. Connect the compressor to the hammer with a hose of at least the minimum size recommended by the manufacturer. The Engineer will evaluate hammer performance at the end of driving by measuring blows per min ute and comparing with the manufacturer ’s recommendations . Measure the blow rate using an automatic measuring device.
b.Diesel Impact Hammers. For open- end, single- acting hammers, provide the Engineer with a chart from the hammer manufacturer equating stroke and blows per minute. The Engineer will determine the average hammer stroke at the end of drive from the blow rate in blows per minute or by using an automatic measuring device to determine average hammer stroke. Equip open-end diesel hammers with rings or other device on the ram to allow the Engineer to visually determine hammer stroke during pile driving operations. Equip closed-end, double-acting hammers with a bounce chamber pressure gauge that is mounted near ground level and easily accessible to the Engineer . Provide a correlation chart of bounce chamber pressure and potential energy . The Engineer will determine the average hammer stroke at the end of drive from bounce chamber pressure.
c.Hydraulic Impact Hammers . Operate hydraulic hammers within the manufacturer ’s specified ranges . Provide a power plant for hydraulic hammers with a capacity capable of maintaining the hydraulic volume and pressure specified by the manufacturer . Equip the power plant with pressure gauges that are easily accessible to the Engineer. Equip hydraulic hammers with an energy readout device. Provide wave equation analysis to the Engineer indicating the nominal pile driving resistance of the pile. The Engineer will use the wave equation analysis to determine the capability of the hammer . Do not use Formula 705- 1 through Formula 705- 5 for calculating the nominal pile driving resistance.
d.Drop Impact Hammers . Drop impact hammers may be used to drive timber piles if allowed by the contract. Do not use drop hammers for piles where the required nominal pile driving resistance exceeds 200 kips. If the contract allows drop hammers, use a ram that weighs at least 2 kips with a height of MDOT Standard Specifications for Construction Section 705
7-15 drop no greater than 12 feet. Do not use a ram weight less than
the combined weight of t he helmet and the pile. Equip drop hammers with hammer guides and a helmet to ensure concentric impact.
e.Non-Impact Hammers. Do not use non-impact hammers, including vibratory hammers, or driving aids, followers, or prebored holes unless approved by the Engineer in writing or stated in the contract.
3.Additional Equipment or Methods . If using a hammer specified in subsection 705.03.A.2 does not obtain the minimum pile penetration elevation, provide a hammer of greater energy or, if approved by the Engineer, us e supplemental methods such as preboring. The Engineer will conduct additional wave equation analyses for the new hammers to assess pre -driving pile stresses in accordance with subsection 705.03.A.2.
B.Driving Appurtenances
1.Hammer Cushion . Equip impact pile driving equipment with a hammer cushion to prevent damage to the hammer or pile except drop hammers and hammers designed for use without hammer cushions. Provide hammer cushions fabricated from durable manufactured materials that retain uniform properties during driving. Do not use wood, wire rope, or asbestos hammer cushions . Place a striker plate on the hammer cushion to ensure uniform compression of the cushion material. Remove the hammer cushion from the helmet and inspect in the presence of the Engineer before beginning pile driving at each structure or after each 100 hours of pile driving, whichever is less . Replace the hammer cushion if the thickness is reduced more than 25% of the original thickness before continuing driving.
2.Helmet . Fit piles with a helmet to distribute the hammer blow uniformly and concentrically to the pile top. The helmet surface contacting the pile must be planed, smooth, and parallel with the hammer base and pile top. Guide the helmet with leads . Do not allow the helmet to swing freely . Fit the helmet to the pile top to maintain the hammer and pile in concentric alignment. For timber piles, do not allow the least inside horizontal dimension of the helmet or hammer base to exceed the pile top diameter by more than 2 inches . Trim the pile top to fit the helmet if the timber pile MDOT Standard Specifications for Construction Section 705
7-16 diameter exceeds the least helmet or hammer base horizontal
dimension. Do not trim the pile top below the cutoff elevation.
3.Pile Cushion . If CIP concrete piles require redriving after concrete placement and curing inside steel shells, protect pile tops with a pile cushion. Proportion the pile cushion to distribute the blow of the hammer throughout the cross -section of the pile.
4.Lead s. Use pile driving leads that align the pile and hammer in positions throughout the driving operation. Use leads constructed to allow free movement of the hammer and maintain hammer and pile alignment to ensure concentric impact . Use leads designed to all ow alignment of battered piles if required. Do not allow the driven pile section to extend above leads. Provide fixed or swinging type leads . Fit swinging leads with a pile gate at the bottom of the leads . Use leads embedded in the ground or constrain the pile in a structural frame to maintain alignment . Provide leads with a length that eliminates the need for a follower.
5.Followers . Use followers only if the Engineer approves in writing or required by the contract . If the Engineer does not perform a wave equation analysis, use a follower with impedance from 50 to 200 % of the pile impedance. Maintain the follower and pile in alignment during driving. Drive the first pile and every tenth pile full length without a follower to ensure that pile penetration develops the required nominal pile driving resistance. Use a follower constructed of material and dimensions to allow pile driving to the penetration depth determined by driving the full-length piles . Verify the final position and alignment of the first two piles in each substructure unit, installed with followers meet ing location tolerances specified in subsection 705.03.C.2.e, before installing additional piles.
6.Spuds . Do not use spuds instead of preboring.
C.Driving Methods .
1.Preparation for Driving . Before driving, cut pile tops square with the axis of the pile. Use collars, bands, or other devices to protect timber piles against splitting and brooming. Construct lifting holes as detailed in the contract . Do not drive piles within a radius of 25 feet of newly placed concrete until the concrete attains at least 70% of its required minimum 28-day flexural or compressive strength.
a.Excavation and Fill . Do not drive or redrive piles until completion of excavation, fill, or both, unless otherwise required. If piles MDOT Standard Specifications for Construction Section 705
7-17 require driving or redriving through fills, compact the embankment
to the bottom of the concrete substructure unit before driving piles . Remove material forced up between the piles to the required elevation before placing concrete foundation.
b.Pile Preboring to Facilitate Driving . Prebore holes to the prebore elevation shown on the plans . Provide a finished hole with a diameter equal to or not more than 6 inches greater than the diameter of the pile. Maintain a stable, open hole to the bottom of the bore until pile installation. Do not begin final drive for bearing until the pile reaches the prebore elevation shown on the plans . Control caving or unstable soil layers using temporary casing or non-toxic and non-hazardous drilling slurry . Handle and dispose of drilling slurry on the project or at an off -site location where structures will be unaffected, in accordance with the Natural Resources a nd Environmental Protection Act (NREPA), Part 91, Soil Erosion and Sedimentation Control (MCL 324. 91101 et seq. ). Obtain the Engineer ’s approval for on-site disposal. Remove or clear boulders, cobbles, or other obstructions . Provide rock chisels, extractors, core barrels, or other equipment to clear obstructio ns. To the extent possible, complete preboring in a foundation unit and advance piles to the prebore elevation before beginning the final drive . If preboring within 20 feet of a completed pile, recheck the pile capacity by redriving the pile. The Engineer will select the piles for re drive . Redrive with the same driving equipment from the initial installation . If a reduction in capacity occurs, redrive piles to the nominal pile driving resistance. Backfill voids after the final drive with granular material Class II or a Department -approved equal. Prebore pile holes within ¼ inch per foot from the vertical or batter line shown on the plans . Upon completion, the center of the hole at cutoff elevation must be within 6 inches of the position shown on the plans. If driving piles through compacted fill deeper than 5 feet, drive piles in holes prebored to natural ground unless otherwise shown on the plans.
2.Driving . During driving, maintain pile tops square with the axis of the pile. MDOT Standard Specifications for Construction Section 705
7-18 a. Obstructions . If an impenetrable obstruction is encountered
during pile driving, remove and reuse the pile or cut the pile off and drive a new pile. Reusing the pile is subject to approval by the Engineer . If cutting off the pile, cut the pile at the lowest possible elevation. Adjust the pile laterally and drive in accordance with subsection 705.03.C.2. If adjusting the pile laterally does not bypass the obstruction, remove the obstruction. Provide rock chisels, extractors, core barrels, or other equipment to clear obstructions.
b.Penetration . For design pile lengths, install piles to the design pile tip elevation shown on the plans unless driving operations attain absolute refusal. If the plans show the estimated pile length, install piles to a penetration that meets the following: The nominal pile driving resistance equals at least the required nominal pile driving resistance shown on the plans; and The bottom of the pile is at or below the minimum pile penetration elevation shown on the plans. Do not drive piles past absolute refus al unless d ynamic testing is required. If dynamic testing is required, pile stresses must not exceed the stresses specified in Table 705- 1, as determined by the Engineer.
c.Test Piles. If test piles are required by the contract, use the pile lengths shown on the plans for estimating purposes . Provide actual pile lengths to achieve the required nominal pile driving resistance and minimum pile length. If test piles are not required, provide the piles in accordance with the design pile length shown on the plans. Complete the excavation or embankment to within 2 feet of the proposed grade at test pile locations . Install test piles at locations shown on the plans with approved impact hammer equipment . Drive test piles to the m inimum pile length or practical refusal, whichever is greater. The Engineer will prepare a record of test pile driving, including the number of hammer blows per foot for the driven length, the as-driven length of the test pile, cutoff elevation, penetratio n in ground, and other pertinent information. Cut off test piles, driven in production pile locations and incorporated in the structure as permanent piles . Cut off or pull test MDOT Standard Specifications for Construction Section 705
7-19 piles not driven in production pile locations, as directed by the
Engineer. Provide CIP pile shell and steel H -pile lengths to obtain the required nominal pile driving resistance and penetration. The Engineer will evaluate test pile results and determine the ordered pile lengths for timber piles. Test piles are not required if the pl ans show a design pile length.
d.Pile Splicing. Do not splice timber piles. Provide steel piles in full -length sections or splice sections together as shown on the plans and approved by the Engineer as required to obtain the required nominal pile driving resistance and penetration. Furnished pile up to 40 feet in length must not contain more than three shop or field splices . Furnished pile in excess of 40 feet in length must not contain more than four shop or field splices . The Department reserves the right to conduct ultrasonic testing (UT) or any other nondestructive testing (NDT) on shop or field-welded splices. Main Member Piles. The plans will designate which piles are considered main members . Weld pile splices in accordance with AASHTO/AWS D1.5 – Bridge Welding Code (AWS D1.5) as modified herein. Complete and submit MDOT Form 0395 AASHTO/AWS D1.5 – Field Welding Plan to the Engineer for review and approval prior to welding. Give 14 calendar day s of notice to the Engineer before beginning pile shop welding. Submit to the Engineer a visual test (VT) report from an AWS Certified Welding Inspector (CWI) , ensuring that all welds meet the contract. Non-Main Member Piles. Weld pile splices in accordanc e with the AWS D1.1, Structural Welding Code – Steel (AWS D1.1) except as modified herein. Complete and submit MDOT Form 5627 Pile Welding Quality Control Plan to the Engineer for review and approval prior to welding. If piling is to be shop welded, give 1 4 calendar days of notice to the Engineer before beginning shop welding. Submit to the Engineer a VT report from an AWS CWI ensuring that all welds meet the contract. Welder Endorsements. Welding personnel such as welders, welding operators, and tack welders must be qualified in accordance with AWS D1.5 for main member pile welding and MDOT Standard Specifications for Construction Section 705
7-20 AWS D1.1 for non-main member pile welding. Testing is
required in accordance with MDOT ’s Welder Qualification Program for main member welding and must be witnessed by the Engineer . Testing is required in accordance with MDOT ’s Welder Certification Program for non-main member welding. Welder performance endorsements from other agencies will not be accepted. The period of effectiveness for shop welding personnel is 3 years unless welding personnel are not engaged in a welding process for at least 6 months or a specific reason exists to question the welder ’s ability . The period of effectiveness for field welding personnel is 2 years unless welding personnel are not engaged in a welding process for at least 6 months or a specific reason exists to question the welder ’s ability . The Engineer may require a confirming performance test during the progress of the work. Welding Requirements. Perform pile main member and non-main member welding in accordance with AWS D1.5 and AWS D1.1, respectively . Weld using the shielded metal arc welding (SMAW) process using E7015, E7016, or E7018 electrodes . Do not use gas metal arc welding (GMAW) or other gas-shielded processes . The Engineer may approve the submerged arc welding (SAW) process . Prepare pile base metal for welding in accordance with Clause 3 of AWS D1.5 for main members or Clause 5 of AWS D1.1 for non-main members . Surfaces and edges to be welded must be smooth, uniform, and free from fins, tears, cracks, scale, slag, rust, moisture, grease, foreign material, and other discontinuities that would prevent proper welding. Grind joints before welding to remove pitting and irregularities . When pile splice plates are allowed by the contract, bring the splice plates into as close contact as practical . If the separation between the pile section and splice plate exceeds 1⁄16 inch, increase the fillet weld leg equal to the joint root opening. Do not weld if the joint root opening exceeds 3⁄16 inch. Misalignment of pile splice plates or lack of full -bearing contact for partial -joint-penetration groove welds requires approval by the Engineer. Smoothly transition weld profiles by grinding stop-start areas or other irregularities. MDOT Standard Specifications for Construction Section 705
7-21 Do not perform pile welding when the ambient temperature is
below 0°F or during periods of precipitation (rain, snow, or fog) unless heating and housing the area as approved by the Engineer . When the ambient temperature is below 32°F, preheat the pile metal a minimum distance of 3 inches in all directions from the weld joint to a minimum of 70°F and maintain the temperature during welding. Store and use filler metal for main member pile welding and non-main member pile welding in accorda nce with AWS D1.5 and AWS D1.1, respectively . Dry all electrodes in an oven at a temperature of at least 500°F for at least 2 hours before use unless the electrodes are from a hermetically sealed container . Store the electrodes in a hot box at a temperature of at least 250°F after drying. Use electrodes within 2 hours of exposure to the atmosphere or redry as described above. Do not redry electrodes more than once. Do not use electrodes that have been wet. Main Member Weld Testing . Perform NDT on all shop and field welds and any associated weld repairs in accordance with subsection 707.03.E.7.e. The Engineer must witness testing. Non-Main Member Weld Testing . Remove slag from all weld passes , including finished welds prior to inspection. Ensure that the surface of welded joints is sufficiently uniform ; the surface should not be coarse or contain ripples, sharp corners, interpass valleys, underfill , or undercut . Welds must not contain cracks or have lack of fusion, excessive porosity, or lack of penetration . Verify fillet weld size using a fillet weld gau ge. Repair cracked welds or welds the Engineer determines are unacceptable. Repair welds in accordance with AWS D1.1 . Grind all arc strikes and tack welds to base metal . Do not peen welds . Repair unacceptable welds at no additional cost to the Department. NDT of pile welds will be determined by the Engineer if VT does not result in an acceptable weld. NDT must be performed in accordance with AWS D1.1 by personnel certified as Level II in acc ordance with ASNT Recommended Practice No. SNT-TC-1A. Blast clean or grind welds before the NDT can be performed. The Engineer will determine the frequency, location, and type of NDT to be performed for each weld. Generally, liquid dye penetrant testing (P T) or magnetic particle testing (MT) is performed for fillet and partial -penetration butt MDOT Standard Specifications for Construction Section 705
7-22 welds, while UT is performed for complete- joint-penetration
(CJP) butt welds . The Engineer may perform additional NDT of any or all welds in accordance with AWS D1.1. All costs associated with performing NDT will be paid by the Department if initial testing indicates an acceptable weld. If testing identifies defects warranting rejection, repair the welds and hire qualified NDT personnel to retest the welds until the welds are acceptable to the Engineer . All costs associated with performing the initial test, weld repairs , and retests of unacceptable welds will be at no additional cost to the Department . No additional compensation will be granted for delays, downtime, or idle equipment or labor for NDT of pile welds. PT CJP groove weld terminations if cope holes are used at the web flange juncture. Perform PT in accordance with ASTM E165/E165M .
e.Accuracy . Drive piles for foundation work within ¼ inch per foot from the verti cal or batter line shown on the plans . After driving, the position of each pile at the cutoff elevation must be within 6 inches of the position shown on the plans . The distance between the edges of piles and the outline of the superimposed concrete must be at least 9 inches . Drive pile bents to allow the adjustment of piles to the positions and elevations shown on the plans without damaging or overstressing piles . Do not pull laterally on piles to correct misalignment or splice an aligned section on a misaligned section. Drive timber piles to allow adjustment to the position shown on the plans at the elevation of cap or wale without damaging or overstressing piles . Draw and hold piles requiring capping in position before cutoff . If the pile cutoff di ameter is greater than the width of the cap, trim the pile to eliminate horizontal projections outside the cap. Do not drive timber piles to the exact grade shown on the plans; cut them off below the tapered head to provide an unfractured bearing with a full cross section of the pile. Increase pile cap dimensions or reinforcing to accommodate out-of-position piles at no additional cost to the Department.
f.Redriving of Heaved Piles. At the start of pile driving operations, the Engineer will make level readings to measure pile heave after driving until the Engineer determines that checking is no longer MDOT Standard Specifications for Construction Section 705
7-23 required. If piles heave up during driving adjacent piles, redrive
heaved-up piles to the required bearing capacity or penetration. Adjust upheaval or settlement of material between the piles to the correct elevation before placing concrete for the foundation. If the Engineer detects pile heave for CIP concrete pile shells filled with concrete, redrive the piles to the original position after concrete obtains the required strength using a pile-cushion system that is approved by the Engineer.
D.Determination of Nominal Pile Resistance
1.Static Load Test . Perform load tests as required by the contract.
2.Dynamic Formula . Do not use the dynamic formula to install production piles with a required nominal pile driving resistance greater than 600 kips or the contract requires dynamic testing with signal matching. Do not use the dynamic formula for pile restrikes. The Engineer will determine the nominal pile driving resistance for test piles using the same method specified for production piles. 𝑅𝑅𝑛𝑛𝑑𝑑𝑛𝑛=1.75�𝐸𝐸𝑑𝑑log10(10𝑁𝑁𝑏𝑏)−100 Formula 705-3 Where: 𝑁𝑁𝑏𝑏 = Number of hammer blows per inch of pile penetration; 𝐸𝐸𝑑𝑑 = Energy developed by the hammer per blow in foot-pounds; and 𝑅𝑅𝑛𝑛𝑑𝑑𝑛𝑛 = Nominal pile driving resistance measure during pile driving in kips . The Engineer will determine the value of “ Ed.” For piles driven on a batter, multiply the value of “ Ed” by the hammer energy reduction coefficient “U “ as follows : 𝑈𝑈=sin(𝛼𝛼)0.975 Formula 705-4 𝛼𝛼=tan−1(𝑚𝑚) Formula 705-5 Where: 𝑈𝑈 = Hammer energy reduction coefficient, less than unity; 𝛼𝛼 = Angle of batter from horizontal (less than 90 degrees for battered piles); and 𝑚𝑚 = Vertical component of batter. For drop, single-acting air hammers and open-type diesel hammers, the Engineer will measure the ram velocity using the kinetic energy . If measuring ram velocity is not possible, the Engineer may approximate MDOT Standard Specifications for Construction Section 705
7-24 the velocity using the potential energy calculated by multiplying the
weight of hammer striking parts by the observed fall or stroke height. For double-acting air hammers and closed-type diesel hammers, the Engineer will calculate the energy using ram weight and bounce chamber pressure. Submit hammer literat ure and correlation charts to the Engineer to determine the hammer energy of each blow . The Engineer will reduce the calculated value of “ Ed” for battered piles by the hammer energy reduction coefficient “ U“ before calculating the nominal pile driving resi stance. For piles driven with a drop hammer, Formula 705- 3, Formula 705-4, and Formula 705-5 are applicable under the following conditions:
a.Hammers have an unrestricted free fall;
b.Pile tops are not broomed, crushed, or splintered;
c.The hammer exhibits no ap preciable bounce after striking the pile; and
d.Penetration is at a uniform or uniformly decreasing rate. If required or if a hydraulic hammer is used, the Engineer will determine the nominal pile driving resistance using the results of a wave equation analysis . The Engineer will consider the hammer driving system, site -specific subsurface data, and project pile geometry to develop driving criteria that will not overstress the pile and indicate the nominal pile driving resistance.
3.Dynamic Testin g and Analysis. Perform dynamic testing with signal matching as required by the contract.
E.Defective Piles. Protect piles from splitting, splintering, and brooming of the wood or excessive deformation of the steel . Do not manipulate piles to force them into position using excessive force, as determined by the Engineer. At no additional cost to the Department, use one of the following methods to correct piles damaged by internal defects , improper driving , driv ing below the cutoff elevation, or piles driven outside the required location:
1.Remove the pile and replace with a new, longer pile;
2.Drive a second pile adjacent to the defective pile; or
3.For steel and CIP concrete piles, s plice or build up the pile or extend a portion of the footing to properly embed the pile. MDOT Standard Specifications for Construction Section 705
7-25 F. Placing Concrete in CIP Concrete Piles. Before placing concrete,
inspect piles to confirm the full pile length and dry bottom condition. Provide a mirror or light to the Engineer for inspection. Do not place concrete in piles until after driving, redriving, cleaning, and obtaining the Engineer ’s acceptance of pile shells within a radius of 20 feet. Place the concrete in the pile shells to the cutoff elevation as soon as practical after driving. Place concrete in accordance with subsection 706.03.H, ex cept that concrete may free fall more than 5 feet. During placement, vibrate the concrete in the upper one-third of the pile shell to a depth no greater than 25 feet without causing segregation.
G.Protective Coating for Steel Piles and CIP Concrete Piles. If required, galvanize steel H -piles and steel shells exposed to air or water in the finished structure, in accordance with ASTM A123/A123M . Do not use corrosive embankment material within 30 feet of piles . Repair damage to galvanization in accordance with subsection 716.03.E at no additional cost to the Department.
H.Cleaning Steel Piles and Steel Pile Shells. If embedding steel piles or pile shells in structural concrete, exclusive of tremie concret e, clean dirt and loose scale from the portion requiring embedding.
I.Pile Cutoff. Cut off piles as shown on the plans and within 1 inch of the required elevation and anchor to the structure as required by the contract. Take possession of piling cutoff lengt hs. Dispose of cutoff lengths in accordance with local, state, and federal regulations. Cut off timber piles to completely remove material damaged by driving.
J.Pile Protection . Provide pile protection w here the plans require it by utilizing one of the follo wing methods:
1.Prime the piling and uniformly coat with asphalt . Heat the asphalt between 200 and 300°F and apply by one or more mop coats or other approved means to obtain a uniform minimum coating thickness of ¼ inch. Continuously coat the pile from the b ottom of excavation to the bottom of concrete pile cap as designated on the plans.
2.Wrap piles with the extruded corrugated polypropylene sheet material . Cover all exposed surfaces . Install panels with a minimum of a 2-inch (shingle style) overlap or as approved by the Engineer . Attach sheets to the piling according to the manufacturer ’s recommendations. MDOT Standard Specifications for Construction Section 705
7-26 705.04. Measurement and Payment
Pay Item Pay Unit Pile, Treated Timber, Furn ......................................................................... Foot Pile, Treated Timber, Driven ...................................................................... Foot Pile, CIP Conc, Furn and Driven, __ inch .................................................. Foot Pile, Steel, Furn and Driven, __ inch ......................................................... Foot Pile, Galv (Structure Identification) .................................................. Lump Sum Test Pile, Treated Timber .......................................................................... Each Test Pile, CIP Conc, __ inch ..................................................................... Each Test Pile, Steel, __ inch ............................................................................ Each Pile Point, CIP Conc ................................................................................. Each Pile Point, Steel ........................................................................................ Each Pile, Steel, Splice ...................................................................................... Each Prebore, Fdn Piling .................................................................................... Foot Pile Driving Equipment, Furn (Structure Identification) .................... Lump Sum Pile Protection ........................................................................................... Foot All cost s associated with shop or field welder endorsement to MDOT ’s Welder Qualification Program testing , including, but not limited to, providing the specimen test plates, completing performance testing, and submitt ing the qualification specimen will be at the Contractor ’s expense.
A.Piles
1.Driven Piles . The unit prices for Pile, CIP Conc, Furn and Driven, __ inch and Pile, Steel, Furn and Driven, __ inch include the cost of redrive due to preboring. For piles that are removed, adjusted, and reused due to obstructions, the Engineer will measure the total length of the pile driven, including the length of pile embedded in the ground and remov ed. For piles that require cutting off due to obstructions, the Engineer will measure the total length of the new pile driven, including the length of obstructed pile cut off and left in the ground. The Department will pay for redriving heaved piles as ext ra work. The Engineer will measure Pile, Treated Timber, Driven by the piling length left in place below cutoff . The unit price for Pile, Treated Timber, Driven includes the cost of cutting off piles . Cutoff material will remain the property of the Contrac tor. The Engineer will measure Pile, CIP Conc, Furn and Driven and Pile, Steel, Furn and Driven by the length of piling left in place below cutoff. MDOT Standard Specifications for Construction Section 705
7-27 The unit prices for Pile, CIP Conc, Furn and Driven and Pile, Steel,
Furn and Driven include the cost of providing ungalvanized pile shells or steel piles and the cost of driving the galvanized pile length. The unit price for Pile, CIP Conc, Furn and Driven includes the cost of furnishing and installing steel end plates as detailed on the plans. The unit prices for Pile, CIP Conc, Furn and Driven and Pile, Steel, Furn and Driven do not include the cost of the length of the pile point extending beyond the pile.
2.Pile, Treated Timber, Furnished. The Department will pay for Pile, Treated Timber, Furn at the ordered pile length.
3.Galvanized Piles. The unit price for Pile, Galv includes the cost associated with galvanizing the required length of pile as shown on the plans.
4.Pile Driving Equipment . The Engineer will measure Pile D riving Equipment, Furn as a unit for each structure. The unit price for Pile Driving Equipment, Furn includes the cost of providing and removing equipment for driving piles. The unit price for the length of pile driven includes the cost of operating equipment for driving piles.
5.Prebore Foundation Piling . The Engineer will measure Prebore, Fdn Piling from the bottom of the foundation to the prebore elevation shown on the plans . The unit price for Prebore, Fdn Piling includes the cost of the f ollowing:
a.Boring pile holes;
b.Disposing of excavated material;
c.Backfilling voids;
d.Installing and removing temporary casings;
e.Providing and disposing of drilling slurry;
f.Redriving completed piles within a radius of 20 feet; and
g.Equipment operating costs. If Prebore, Fdn Piling is shown on the plans, the unit price for Pile Driving Equipment, Furn includes the cost of providing equipment for prebore. If the plans do not show preboring, but the Engineer authorizes preboring in writing, the Department will pay f or providing equipment as extra work. MDOT Standard Specifications for Construction Section 705
7-28 6. Pile Points . If the contract includes the pay item Pile Points for a
specific structure , the Department will pay separately for Pile Points , of the type required for that structure. If the plans do not include Pile Points for a specific structure , but the Engineer requires pile points, the Department will pay for pile points as extra work for that structure.
7.Test Piles. The Department will pay for test piles in addition to the contract unit prices for furnished and driven pile pay items.
8.Pile, Steel, Splice . The unit price for Pile , Steel, Splice includes the cost to splice and inspect steel H and CIP piles. The Engineer will measure and the Department will pay for each pile splice completed below the pile cutoff but not to exceed the number of splices in Table 705-3. Table 705- 3: Maximum Number of Splices Measured per Pile Length Pile Length (L) Installed Below Cutoff (feet) Number of Splices L ≤ 50 0 50 < L ≤ 100 1 100 < L ≤ 150 2 150 < L ≤ 200 3 200 < L ≤ 250 4 Payment for splices of piles considered to be main members includes the cost of the required NDT for acceptance in accordance with AWS D1.5.
9.Pile Protection . Pile Protection will be measured in feet along the exposed length of individual H -piles fr om the bottom of excavation to the bottom of footing elevation unless otherwise specified on the plans .
B.Obstruction Removal . The Engineer will measure and the Department will pay for the removal of obstructions that require the use of special equipment or tools specified in subsection 705.03.C.2.a at the unit price for Obstruction Removal in accordance with subsection 718.04.D.
Source: Michigan Standard Specifications for Construction, 2020 Edition. Pages 375–392 of 1,146.