Section 2501. Piles and Pile Driving.

2501.01 DESCRIPTION.
These requirements shall apply to furnishing and placing of piles for foundations, trestles, and other exposed work.

Piling for falsework shall be furnished and placed in accordance with Article 2403.17.

2501.02 MATERIALS.
The piles shall comply with the following requirements for the class of pile specified:

Untreated Timber Piles, Article 4165.03 shall apply.
Treated Timber Foundation Piles, Article 4165.04 shall apply.
Treated Timber Trestle Piles, Article 4165.05 shall apply.
Concrete Piles, Section 4166 shall apply.
Steel Pipe Piles, Section 4167 shall apply.
Steel H-Piles, Section 4167 shall apply.
Concrete Sheet Piles, Section 4166 shall apply.
Steel Sheet Piles, Section 4167 shall apply.

2501.03 CONCRETE PILES.
Concrete bearing piles shall have the form and dimensions specified in the contract documents and shall be placed as provided herein. Piles may be driven when the concrete compressive strength has reached a minimum of 5,000 psi (35 MPa), but not less than 7 calendar days after casting.

2501.04 STEEL PIPE PILES.
Steel pipe piles shall be constructed by driving steel pipe of the specified type and size in the locations specified in the contract documents and by filling the pipe with concrete. The piles shall be constructed in accordance with the following additional requirements:

A. Inspection.
The Contractor shall furnish a light suitable for visual interior inspection of driven pipe piles. This inspection will be conducted before cut off and filling is allowed. All piles which have been improperly driven, broken, or are otherwise defective shall be removed and replaced or otherwise corrected, as directed by the Engineer. At the time of inspection the interior of the pile shall be clean and free of water.

B. Cut Off.
Upon completion of driving, inspection, and approval, the pile shall be neatly cut on a horizontal plane at the elevation specified in the contract documents.

C. Filling.
After the piles have been cut off, any water present in the pile shall be removed, and after reinforcement has been accurately placed, the pile shall be completely filled with Class C structural concrete meeting requirements of Section 2403. At the time concrete is placed, the pile shall be free of accumulated water. In order to avoid formation of air pockets, concrete shall be placed by vibratory methods as specified in Article 2403.09, or concrete shall be placed in small charges of not over 2 cubic feet (0.05 m3) each.

D. Painting.
After the metal pipes have been filled with concrete, exposed sections shall be cleaned by hand methods and painted with three coats of paint from the cap to low water elevation or 2 feet (0.5 m) below finished ground line in accordance with provisions of Article 2508. All three coats of paint shall be applied in the field.

2501.05 STEEL H-PILES.
Steel H-piles shall be of the cross section, size, and weight per foot (mass per meter) specified in the contract documents. The contract documents may allow an option of pipe piles in lieu of steel H-piles. Pipe piles are also described in Section 4167. When driving is complete, the pile shall be cut off neatly at the elevation specified. The contract documents may require encasement of steel H-piles. The Contractor may increase the diameter of encasements with no additional payment, but the increase shall not be more than 4 inches (100 mm). All encasements for a structure shall be the same diameter. Steel H-piles that are exposed to the atmosphere in the finished structure shall be cleaned and painted with three coats of paint as specified in Article 2508.

The number of permitted welds used to develop plan specified lengths of steel H-piles shall be limited to the following:

Plan Pile Length
Feet (m)		 Number of Permitted Welds (splices)
0 – 50 (0-15.0) 0
51-100 (15.1-30) 1
101-150 (30.1-45.0) 2

Welds (splices) in excess of the number specified above will not be permitted unless required for a pile extension. When steel H-piles are to be spliced, the shortest pile length shall be the last added length.

2501.06 STEEL SHEET PILES.
Steel sheet piles that are to become a part of a finished structure shall be interlocking type with a web thickness not less than 3/8 inch (9 mm) and a section modulus not less than that specified in the contract documents. The interlock shall be of a type approved by the Engineer. Used sheet piles shall be put in proper condition before redriving. Where steel sheet piles are to receive a concrete cap, they shall be cut off neatly in straight lines at the required elevations after driving. The details at angles in sheet pile walls shall be adapted to the type of pile used and shall be subject to the approval of the Engineer. Steel sheet piles need not be painted unless specified.

2501.07 DETERMINATION OF LENGTH OF PILES.
When the length of piles is not specified, the Engineer will determine the length from the results obtained under the procedure specified in the contract documents. The length of wood piles will be in multiples of 2 feet (0.5 m) for lengths of 20 feet (6 m) and less, and in multiples of 5 feet (1.5 m) for lengths over 20 feet (6 m). Steel H-piles and steel pipe piles will be in multiples of 5 feet (1.5 m). Precast concrete piles may be specified in any length of whole feet (to the nearest 0.5 m).

2501.08 TEST PILES.
When the contract documents specify that the lengths of piles are to be determined from results of driving test piles, the Contractor shall furnish and drive piles of lengths and in locations designated in the contract documents or by the Engineer. The load carrying capacity of test piles shall be determined as provided in Article 2501.13. These test piles shall be driven with the same or comparable type of equipment as that which is to be used for driving other piles for the structure. The Contractor may be required to excavate the test pile area to the proposed footing elevation before driving the test pile. Within ten calendar days, the Engineer will determine the length of piles to be furnished by considering the results of the test pile.

2501.09 PILE DRIVING EQUIPMENT.
The hammer used for driving piles may be of gravity, steam, air, or diesel type. Equipment for driving piling shall be used in accordance with the following provisions:

A. Gravity Hammers.
When gravity hammers are permitted, the ram shall weigh (have a mass) between 3,000 pounds (1350 kg) and 6,000 pounds (2750 kg) and the height of drop shall not exceed 10 feet (3 m). All gravity hammers shall be equipped with hammer guides to insure concentric impact on the pile cap. The hammer guides shall have some method for visually determining the drop height during driving. For all gravity hammers, Paragraph J of this article shall apply.

B. Single or Double Acting Air and Steam Hammers.
The equipment furnished for steam and air hammers shall have sufficient capacity to maintain the hammer operation under working conditions as recommended by the manufacturer. The equipment shall have accurate pressure gauges which are easily accessible to the Engineer. Steam hammers may be air operated if the capacity and pressure of the compressor comply with recommendations of the hammer manufacturer. The weight (mass) of the striking parts of air and steam hammers shall not be less than 33% of the combined weight (mass) of the pile cap and pile being driven. In no case shall the striking parts have a weight (mass) less than 2,750 pounds (1250 kg).

C. Diesel Hammers.

1.Open end (single acting) diesel hammers shall be equipped with a method to visually determine drop height during driving. Examples of measurement devices are as follows:

a. a graduated scale (jump stick) extending above the ram cylinder

b. graduated rings or grooves on the ram

c. an electronic, sound activated, remote measuring instrument

The Contractor shall provide the Engineer a manufacturer's chart equating stroke to blows per minute for the open end diesel hammer used.

2. Closed end (double acting) diesel hammers shall be equipped with an accurate bounce chamber pressure gauge mounted in a manner to enable easy access for the Engineer. The Contractor shall also provide the Engineer a current, calibrated chart equating bounce chamber pressure and gauge hose length to either equivalent energy or stroke for the hammer being used.

For all diesel hammers, Paragraph J of this article shall also apply.

D. Driving Aids.
Vibratory hammers, hydraulic hammers, or driving aids such as jets, followers, and prebored holes shall not be used unless authorized in writing by the Engineer or stated in the contract documents. When permitted, vibratory hammers and hydraulic hammers can be used for installing production piles only after the pile tip elevation is established by load test or by test piles driven with an approved hammer. As condition for approval, the Contractor shall perform at no additional cost to the Contracting Authority, load tests and extra work required to drive test piles as determined by the Engineer.

Installation of production piles with vibratory hammers shall be controlled according to power consumption, rate of penetration, specified tip elevation, or other means acceptable to the Engineer. The assurance that the pile capacity equals or exceeds the design bearing will be the Contractor's responsibility. Piles driven to full penetration with a vibratory hammer shall be retapped with an approved hammer and bearing will be determined by an applicable wave equation analysis.

E. Hammer Cushion.
All impact pile driving equipment shall be equipped with suitable thickness hammer cushion material to prevent damage to the hammer or pile. The hammer cushion shall be inspected in the presence of the Engineer for condition, composition, and thickness before beginning pile driving at each structure, and regularly during driving. For hammers with internal cushions, the cushion shall be checked regularly at 100 hour intervals during driving. The beginning cushion thickness and composition shall be as recommended by the hammer manufacturer and as reported to the Engineer prior to driving. The hammer cushion shall be replaced when it has less than 70% of the recommended thickness, or has burned, or has been broomed.

F. Pile Cushion.
The head of all concrete piling shall be protected by a suitable pile cushion. When requested, the Contractor shall provide the pile cushion composition and thickness to the Engineer. The minimum thickness shall be determined by the wave equation or, if alternate pile driving control methods are used, be 6 inches (150 mm) of suitable wood. The pile cushion shall be inspected, in the presence of the Engineer, for condition, composition, and thickness, before beginning pile driving at each structure, and regularly during driving. Any pile cushion shall be replaced when it has less than 70% of the original reported thickness, has burned, or has been broomed.

G. Pile Driving Cap.
Piles driven with impact hammers require an adequate cap to distribute the hammer blow evenly to the top of the pile. The cap shall be axially aligned with the hammer and the pile, and shall be guided by the leads. The cap shall be appropriate for the type and size of pile, and shall fit around the top of the pile so that the driving unit is centered during driving.

For special types of piles, appropriate driving caps, mandrels, or other devices shall be provided in accordance with manufacturer's recommendations so that the piles may be driven without damage.

To ensure proper fit of the driving cap, all pile tops shall be cut squarely.

H. Followers.
The use of followers will not be permitted without authorization of the Engineer.

I. Water Jets.
The use of water jets will not be permitted without authorization of the Engineer. When jets are used, the size, number and location of jets and the volume and pressure of water at the jet nozzles shall be sufficient to freely erode material from under and adjacent to the pile.

J. Approval of Pile Driving Equipment.
On each project, all pile driving equipment furnished by the Contractor shall be subject to approval by the Engineer. All pile driving equipment shall be sized so that the project piles can be driven with reasonable effort to the required lengths without damage. Approval of pile driving equipment on Interstate and Primary projects will be based on the wave equation analysis. On other projects the alternate approval method shall be used unless otherwise specified.

1. Wave Equation Analysis.
For wave equation approval, the Contractor shall submit to the Engineer the required data forms detailing equipment to be used on the project. This information shall be submitted to the Engineer at least 20 calendar days prior to driving piles.

The Contractor will be notified of the acceptance or rejection of the driving system within 12 calendar days of the Engineer's receipt of the data forms. If the wave equation analysis indicates that pile damage could occur or if the pile could not be driven to the required bearing, the Contractor shall modify or replace the proposed methods or equipment at the Contractor's expense. The subsequent driving system shall result in wave equation analysis that indicates the piles can be reasonably driven to the desired capacity without damage. The Engineer will notify the Contractor of the acceptance or rejection of the revised driving system within 9 calendar days of receipt of a revised data form or method plan.

Equipment meeting the chart values in the alternate approval method will be acceptable for wave equation analysis.

2. Alternate Approval Method.
The tabulated energy values in Table 2501.09J shall be used as a basis for approval of pile driving equipment for the alternate approval method. This approval is subject to all requirements of this article and does not relieve the Contractor of the basic obligation to provide equipment suitable for driving the specified pile to the required bearing without damage.

TABLE 2501.09J (English Units)
ENERGY VALUES FOR GRAVITY AND DIESEL HAMMERS
Minimum Energy Required for Gravity Hammers (Ft. - Kips*)
Pile Length
(ft.)
 Wood Pile
Concrete Pile
Steel H-Pile
12" to 14"
16"
10
x 42
10
x 57
12
x 53
12
x 74
14
x 73
14
x 89
25' or less
26' to 40'
41' to 50'
51' to 65'
66' to 90'
15
15
15
(a)
(a)
25
25
25
(a)
(a)
27
27
27
(a)
(a)
23
23
25
25
30
23
23
25
25
30
23
23
25
25
30
25
30
30
30
33
25
30
30
30
33
32
35
36
36
36
Maximum Energy Allowed for Gravity Hammers (Ft. - Kips*)
Pile Length
(ft.)		 Wood Pile
Concrete Pile
Steel H-Pile
2" to 14"
16"
10
x 42
10
x 57
12
x 53
12
x 74
14
x 73
14
x 89
25' or less
26' to 40'
41' to 50'
51' to 65'
66' to 90'
25
25
25
(a)
(a)
34
34
34
(a)
(a)
36
36
36
(a)
(a)
28
32
38
35
35
28
35
38
38
38
28
35
42
38
38
35
38
42
42
42
35
38
42
42
42
42
45
48
48
50
Minimum Energy Required for Diesel Hammers (Ft. - Kips*)
Pile Length
(ft.)		 Wood Pile
Concrete Pile
Steel H-Pile
12" to 14"
16"
10
x 42
10
x 57
12
x 53
12
x 74
14
x 73
14
x 89
25' or less
26' to 40'
41' to 50'
>51' to 65'
66' to 90'
17
17
17
(a)
(a)
23
23
23
(a)
(a)
28
28
28
(a)
(a)
22
22
22
22
22
24
24
26
26
29
24
24
26
26
29
29
29
33
33
40
29
29
33
33
40
33
40
40
40
49
Maximum Energy Allowed for Diesel Hammers (Ft. - Kips*)
Pile Length
(ft.)		 Wood Pile
Concrete Pile
Steel H-Pile
12" to 14"
16"
10
x 42
10
x 57
12
x 53
12
x 74
14
x 73
14
x 89
25' or less
26' to 40'
41' to 50'
24
24
33
(a)
32
32
32
(a)
40
40
40
(a)
33
33
40
40
33
33
40
40
33
33
40
40
40
40
43
43
40
40
43
43
43
47
52
52

(a) Wave equation analysis.

*Ft. - Kips - 1,000 foot pounds

For design bearings under 40 tons, minimum diesel hammer energies listed may be reduced by 20% for concrete pile and 10% for steel pile.

TABLE 2501.09J (Metric Units)
ENERGY VALUES FOR GRAVITY AND DIESEL HAMMERS

Minimum Energy Required for Gravity Hammers (kilojoules)
Pile Length
(meters)
 Wood Pile
Concrete Pile
Steel H-Pile
305 mm
to
356 mm
406 mm
250 x
62
250 x
85
310 x
79
310 x
110
360 x
108
360 x
132
7.5 or less
7.6 to 12.0
12.1 to 15.0
15.1 to 20.0
20.1 to 28.0		 20
20
20
(a)
(a)		 34
34
34
(a)
(a)		 37
37
37
(a)
(a)		 31
31
34
34
41		 31
31
34
34
41		 31
31
34
34
41		 34
41
41
41
45		 34
41
41
41
45		 43
47
49
49
49
Maximum Energy Allowed for Gravity Hammers (kilojoules)
Pile Length
(meters)		 Wood Pile
Concrete Pile
Steel H-Pile
305 mm
to
356 mm		 406 mm 250 x
62		 250 x
85		 310 x
79		 310 x
110		 360 x
108		 360 x
132
7.5 or less
7.6 to 12.0
12.1 to 15.0
15.1 to 20.0
20.1 to 28.0
34
34
34
(a)
(a)
 46
46
46
(a)
(a)		 49
49
49
(a)
(a)		 38
43
47
47
52		 38
47
52
52
52		 38
47
52
52
57		 47
52
57
57
57		 47
52
57
57
57		 57
61
65
65
68
Minimum Energy Required for Diesel Hammers (kilojoules)
Pile Length
(meters)		 Wood Pile
Concrete Pile
Steel H-Pile
305 mm
to
356 mm		 406 mm 250 x
62		 250 x
85		 310 x
79		 310 x
110		 360 x
108		 360 x
132
7.5 or less
7.6 to 12.0
12.1 to 15.0
15.1 to 20.0
20.1 to 28.0		 23
23
23
(a)
(a)		 31
31
31
(a)
(a)		 38
38
38
(a)
(a)		 30
30
30
30
30		 33
33
35
35
39		 33
33
35
35
39		 39
39
45
45
54		 39
39
45
45
54		 45
54
54
54
66
Maximum Energy Allowed for Diesel Hammers (kilojoules)
Pile Length
(meters)		 Wood Pile
Concrete Pile
Steel H-Pile
305 mm
to
356 mm		 406 mm 250 x
62		 250 x
85		 310 x
79		 310 x
110		 360 x
108		 360 x
132
7.5 or less
7.6 to 12.0
12.1 to 15.0
15.1 to 20.0
20.1 to 28.0		 33
33
45
(a)
(a)		 43
43
43
(a)
(a)		 54
54
54
(a)
(a)		 45
45
54
54
54		 45
45
54
54
54		 45
45
54
54
64		 54
54
58
58
66		 54
54
58
58
66		 58
64
70
70
81
(a) Wave equation analysis. For design bearings under 355 kN, minimum diesel hammer energies listed may be reduced by 20% for concrete pile and 10% for steel pile.

K. Pile Driving Equipment.
The Contractor shall use an approved system or placement method. Variations in the driving system will not be permitted without the Engineer's approval. If the hammer performance deviates from the manufacturer's recommended specifications, the Contractor shall take immediate corrective action. The Engineer will not allow driving to continue until the system is performing as specified by the manufacturer.

Changes in the driving system will be considered after the Contractor has submitted the required data for review. The Contractor will be notified of the acceptance or rejection of the driving system changes within 9 calendar days of the Engineer's receipt of the requested change. Time required for submission, review, and approval of a revised driving system shall not constitute the basis for a contract time extension.

2501.10 PREPARATION OF WOOD PILES FOR DRIVING.
All wood piles shall be prepared for driving in accordance with the following provisions:

A. Preparation of Pile Heads.
The pile head shall be accurately trimmed to make a driving fit into the driving cap. If the head of the pile becomes broomed or crushed before driving is completed, the broomed fibers shall be trimmed off to provide sound wood accurately fitting the driving cap.

B. Preparation of Pile Points.
The lower end of a pile shall be cut square. If directed by the Engineer it shall be shaped to a point not less than 4 inches by 4 inches (100 mm by 100 mm). The tapered point shall be formed concentric to the center line of the pile.

2501.11 PROTECTION OF CONCRETE PILES DURING DRIVING.
The tops of all concrete bearing and sheet piles shall be protected from damage by the impact of the hammer. This protection shall be designed, maintained, and used to cause the minimum absorption of energy consistent with adequate protection of the top of the pile.

2501.12 ACCURACY IN PLACING AND DRIVING PILES.
In spotting the points of piles preparatory to driving, the Contractor shall use care to locate them as shown in the contract documents or as directed by the Engineer, and the deviation from such designated location shall not exceed 3 inches (75 mm) at the time driving is begun, except as may be made necessary by the presence of unavoidable obstructions.

While being driven, piles shall be held to deviate the minimum possible amount from the vertical or batter line shown in the contract documents. Leads used in driving piles shall be firmly and securely held in proper position to insure driving the pile in the line required.

Pile driving shall be suspended during and for 12 hours following concrete placement that is within 50 feet (15 m) of the pile driving operation.

2501.13 DETERMINATION OF BEARING VALUE OF PILES.
When load tests are not specified in the contract documents or are not directed by the Engineer, the bearing value of piles shall be determined by one of the following methods:

A. Wave Equation Analysis.
Wave equation analysis will be used on all Interstate and Primary projects, on other projects when specified in the contract documents, or as directed by the Engineer. Piles shall be driven with approved driving equipment to full penetration. Retaps or pile extensions may be necessary to obtain the required pile bearing capacity including potential adjustments for scour or downdrag conditions. Driving shall not continue beyond a depth at which acceptable pile stress is exceeded. Driving may be stopped when the rate of driving exceeds 160 blows per foot (0.3 m) with approval from the Engineer.

B. Bearing Determinations by Formula.
When wave equation analysis is not required, the bearing value of piles shall be computed from the following formulas:

For Gravity Hammers with Wood, Steel H, or Shell Piles:

(English)
P = 3 WH  x  W
     S+0.35  W+M

(Metric)
P = 2.5 WH x W
      S+8.9    W+M

For Gravity Hammers with Concrete Bearing Piles:

(English)
P = 4.5WH x W
      S+0.2   W+M

(Metric)
P = 3.7WH x W
      S+5.1   W+M

Height of fall shall be not less than 5 feet (1.5 m) or more than 8 feet (3 m), and the rate of driving, not less than 8 blows per minute.

Diesel Hammers with Wood, Steel H, or Steel Shell Piles and (Construction) Steam Hammers for all Piles:

(English)
P = 3E  x  W
    S+0.1 W+M

(Metric)
P = 0.25E x W
      S+2.5  W+M

Diesel Hammers with Concrete Piles:

(English)
P = 7E x   W
    S+0.1 W+M

(Metric)
P = 0.58E x W
      S+2.5  W+M

Where:

P = The bearing value in tons (kN),
W = The weight (mass) of the gravity hammer, or the ram of an air hammer or diesel hammer in tons (kilograms),
H = The height of free fall of the hammer or ram in feet (meters),
M = The weight (mass) in tons (kilograms) of the pile plus the weight (mass) in tons (kilograms) of the cap plus (for diesel hammers) the weight (mass) of the anvil in tons (kilograms),
E = The energy per blow in foot-tons (joules) (for single acting steam hammers E = W x H (E = 9.81 x W x H)),
S = The average penetration in inches (millimeters) of the pile per blow for the last 5 blows for gravity hammers and the last 10 blows for air or diesel hammers.

The following conditions shall apply in the use of the above formulas:

1. Unless the hammer has free fall, the value substituted for "W" shall be less than the weight (mass) of the hammer by an amount sufficient to compensate for all friction and drag tending to retard its fall.

2. Driving may be stopped when the rate of driving exceeds 160 blows per foot (0.3 m) with approval from the Engineer.

3. There is no excessive bounce to the hammer after the blow.

4. For the computation of the bearing value for battered piles driven with gravity hammers, the value obtained from the formulas shall be multiplied by the following factor:

(Cosine a) minus (f sine a), where "a" equals the angle the leads make with the vertical and "f" equals the coefficient of friction between the hammer or ram and the surface on which it slides. For gravity hammers sliding on greased steel surfaced leads, the value of "f" shall be assumed to be 0.1.

The above formulas may be modified by the Engineer on the basis of load tests. The Wave Equation Analysis may be used to evaluate the driving system, as well as determine the pile bearing, at the discretion of the Engineer.

C. Static Load Test.
When directed by the Engineer, the bearing value of piles will be determined by actual load test in which the entire load is applied concentric with the pile. Careful measurements will be made to determine the amount and rate of settlement. Gauges reading in thousandths of an inch (0.001 µm) will be used to determine the settlement. The designated test pile(s) shall stand, after being driven, at least 40 hours before the test load may be applied. This method is outlined in Section 5.6 and 6.4 of ASTM D 1143. The procedure in ASTM D 1143 will be followed except as modified below.

TEST PROCEDURE

1. Apply the test load in increments of 10% of the proposed design load.

2. The load shall be applied at 2.5 minute intervals. Readings of time, load, and settlement shall be recorded immediately before and after the application of each load. The test is to continue by adding load increments until continuous jacking is required to maintain the test load (i.e., failure by settlement), or the load limit of the jacking equipment is reached.

3. When the maximum load has been applied, take pile settlement readings immediately, and at 2.5 minutes and 5 minutes, after jacking has ceased. Remove the test load and immediately record pile rebound readings. Take additional rebound readings 2.5 minutes and 5 minutes later.

4. Use the data obtained to plot a load (tons (kilonewtons) versus settlement in inches (millimeters)) curve.

The failure load shall be defined as the intersection between the tangent of the linear portion of the load settlement curve and a line with a slope of 0.05 inches per ton (0.14 mm/kN) from the yield point. The yield point shall be defined as the intersection between the load settlement curve and a line which is parallel to the linear portion of the load settlement curve at 0.25 inches (6 mm) of settlement. The safe bearing value will be 50% of the load at the failure point.

D. Dynamic Pile Analyzer Tests.
Dynamic measurements will be taken by the Engineer during the driving of piles designated as dynamic load test piles, or as directed by the Engineer. Instruments for dynamic analysis will be attached near the top of the pile with bolts placed in approved masonry anchors, or bolted through drilled holes in the web of steel piles, or with wood lag screws for timber piles. The Engineer will furnish the instruments, material, and labor necessary for drilling the holes and mounting the instruments.

When specified in the contract documents, or ordered by the Engineer, the Contractor shall furnish a shelter to protect the dynamic test equipment from the elements.

The inside temperature of the shelter shall be maintained above 45°F (7°C). The shelter shall be located within 100 feet (30 m) of the test location.

1. Pretest, Pile Calibration.
Predriving wave speed measurements will be required for concrete or wood piles. The Contractor shall make each designated pile available for this measurement prior to placement of the pile in the leads. When predriving wave speed measurements are required, the piling shall be blocked up off the ground in a horizontal position and located to not contact other piling. Predriving wave speed measurements will not be required for steel piles.

2. Prior to Driving.
Prior to placing the designated pile in the leads the Contractor shall provide access to the pile and allow the Engineer time to predrill instrument mounting holes and/or conduct predriving wave speed measurements if required. When the designated test pile is placed in the leads and is ready to drive, the Contractor shall provide the Engineer reasonable access to the pile for testing purposes. The Contractor shall attach the instruments and associated test cables to the top of the pile as directed by the Engineer unless there is an acceptable personnel platform provided for the Engineer. The platform shall have a minimum size of 4 feet x 4 feet (1.2 m x 1.2 m) designed to be raised to the top of the pile. The Contractor shall allow time to attach or reattach and check the instruments as needed before beginning to drive.

3. Driving.
The Contractor shall drive the designated pile to at least the depth at which the dynamic test equipment indicates that the capacity shown in the contract documents has been achieved, unless otherwise directed by the Engineer. The stresses in the pile will be monitored during driving with the dynamic test equipment to ensure that damage, as determined by the Engineer, does not occur.

If an over-stress condition is indicated, the Engineer will suspend driving and determine if plan capacity has been achieved. If necessary, the Contractor shall reduce the driving energy transmitted to the pile by using additional cushion thickness, reducing the energy output of the hammer, or changing hammers in order to maintain monitored stresses below the accepted values.

If nonaxial driving is indicated by the dynamic test equipment measurements, the Contractor shall immediately realign the driving system.

When directed by the Engineer, the Contractor shall wait a minimum of 24 hours and retap the dynamic load test pile after the instruments are reattached. A cold hammer shall not be used for the retap. The hammer shall be warmed up before the retap by applying at least 20 blows to another pile. The maximum amount of penetration required during a retap shall be 6 inches (150 mm). After retapping, the Engineer will determine if desired bearing has been achieved or if additional pile penetration is required.

E. Retaps.
When piles do not achieve the specified driving resistance during driving, the Engineer may require one retap per 10 piles or a minimum of 2 piles in each foundation at no additional cost. Only piles with the lowest driving resistance will be considered for retap.

The retap shall be performed by allowing the pile to set up for 24 hours, or as directed by the Engineer.

Hammers other than gravity shall be warmed up by applying a minimum of 20 blows to another pile before the retap driving begins. Bearing for the retap shall be taken within the first 6 inches (150 mm) of penetration.

The first two blows of a retap are for seating the cap and assuring proper operation of the hammer and shall not be used to evaluate bearing.

Measure the penetration of the next ten blows, or record the number of blows it takes to drive the pile 6 inches (150 mm). Correct to the appropriate measurement and check for bearing.

1. If bearing is achieved, driving may be halted. However, if approved by the Engineer, driving may be continued to cut-off as long as acceptable pile stress is not exceeded.

2. If penetration is less than 1 inch (25 mm) for the first ten blows, driving shall be discontinued and the bearing shall be recorded as refusal.

Piles not achieving the specified driven resistance after a retap shall be evaluated by the Engineer and, if so ordered, shall be extended as required following the procedures of Article 2501.18.

2501.14 FOUNDATION PILES.
The term "foundation piles" shall mean all piles, whether of wood, concrete, or steel, which support superimposed loads and have no part of their length exposed above ground line.

Except as otherwise provided in the contract documents, excavation shall be completed before the driving of foundation piles is started. After driving is completed, all loose and displaced material forced up in driving shall be removed from around the piles, leaving a firm surface to receive the footing concrete.

After piles have been driven, the tops shall be cut to the plane indicated at the required elevation. All crushed or broomed wood, broken concrete, or deformed steel shall be removed. Tops of treated wood piles shall be painted with two coats of treatment material meeting the requirements of Section 4160. Steel pipe piles shall be inspected for damage in accordance with Article 2501.04.

2501.15 TRESTLE PILES.
The term "trestle piles" shall mean all piles, whether of wood, steel, or concrete, which support superimposed loads but which in the complete structure will be exposed above the ground level for a part of their length. Bents around which fills may later be constructed shall be considered trestle piles.

Wood and steel piles shall be driven with an accuracy that will permit them to be capped as shown in the contract documents with only such springing and bending that will not damage the pile. If, in the judgment of the Engineer, a pile has been deformed or cracked by springing after being driven, it shall be replaced. Any springing shall be done prior to placing the cap.

Concrete piles shall be driven to stand without springing within 4 inches (100 mm) of the intended location and in no case closer than 3 inches (75 mm) to the faces of the caps as shown in the contract documents. In case it is necessary to move a concrete pile after driving to secure the above accuracy, it shall be moved by loosening the soil surrounding the pile with jets until it can be moved and can stand without strain in the correct position. After being moved, the pile shall be driven a sufficient amount to assure the specified minimum bearing value.

Piles for trestles shall be cut off level or at the designed slope at the elevation of cut-off shown in the contract documents. The length of pile above this elevation shall be sufficient to permit complete removal of all material damaged by driving.

In treated wood piles, all bolt holes, cuts, daps, or chamfers made subsequent to treatment, as well as all abrasions of the surface and the tops of piles after cut-offs, shall be given two coats of an approved treatment material meeting requirements of Section 4160. When the tops of treated piles are not to be encased in concrete, they shall be protected as specified in Article 2409.05.

2501.16 PENETRATION.
Unless otherwise provided in the contract documents, all piles shall be driven until the design bearing, determined as provided in Article 2501.13, is at least equal to that specified in Article 2501.17. All piling for piers and abutments of stream crossings, and the piling for piers and abutments of other structures, when ordered by the Engineer, shall be driven until the following requirements for penetration have been met:

The length of all piles specified in the contract documents or ordered by the Engineer for any specific structure shall be construed as indicating the desired penetration, and the effort to secure this penetration shall be continued as long as the pile can be driven without damage to the pile. When the pile can not be driven to the required length without damage, the Engineer shall determine if additional penetration is required. If full penetration is required, the pile shall be advanced by jetting, preboring to a maximum depth of 20 feet (6 m), or other approved methods which will secure the required penetration and bearing without damage to the pile. The driving of wood piling in excess of 40 ton (350 kN) bearing will not be permitted. If soil conditions permit auguring, it shall be done in accordance with Article 2501.19, except the holes shall be drilled to the approximate size of the pile measured at mid length. Bentonite slurry shall not be used in prebored holes to gain additional penetration.

Piles which do not carry superimposed vertical loads, such as wingwall piles, fender piles, wing dam piles, and revetment piles, shall be driven to the penetration shown in the contract documents without regard to bearing values.

2501.17 BEARING REQUIRED.
Unless modified by the Engineer, all piles shall be driven to the design bearing specified in the contract documents. The specified design bearing shall be obtained below scour elevation for substructure subject to scour.

2501.18 EXTENSIONS AND SPLICES.
Article 2501.13, D, shall be followed when piles driven to the specified depth fail to develop the required design bearing. If pile extensions are ordered by the Engineer, driving will continue as long as practical, then the piles will be extended in the manner specified below:

A. When a concrete pile is to be extended and the pile does not require further driving, the concrete at the end is to be cut away to expose 24 inches (600 mm) of the existing extension bars cast in the upper end of the pile, as well as 24 inches (600 mm) of the prestressing tendons. Reinforcing equivalent in cross sectional area to the exposed extension bars shall be properly lapped and securely wired to the exposed steel. If for any reason extension bars do not exist at the splice, the concrete shall be cut off squarely with at least 24 inches (600 mm) of the prestressing tendons exposed, and eight No. 7 (No. 25) reinforcing bars, from full lap with the tendons to within 3 inches (75 mm) of the extension top, shall be used.

The concrete pile extension shall have 5 gauge (No. W 3.5) spiral reinforcing placed at a 3 inch (75 mm) pitch, and ending with six close turns at the top.

After the extension reinforcement is in place, the necessary forms shall be placed. Care shall be taken to prevent leakage along the face of the pile. The concrete used in the extension shall be of the same quality as that used to cast the original pile. Just prior to placing concrete for the extension, the joint shall be prepared in accordance with Article 2403.14 and shall be coated with a creamy mixture composed of 1 part of water and 1.5 parts of dry cement. The grout may be poured in at the top of the form, depositing it as nearly as possible in the center of the pile. After placement, the forms may be removed after 24 hours, and the extension cured by wrapping with two thicknesses of burlap kept wet for 4 calendar days. The entire surface of the exposed pile shall be finished to present a uniform color and texture. Piles that require further driving shall be spliced as specified in the contract documents or as directed by the Engineer.

B. For extensions of steel H-piles and steel pipe piles, after removing all damaged metal, the entire cross section of the pile shall be neatly welded. The axis of the extension shall coincide with the axis of the original pile. Welding of all steel piles shall be performed in accordance with Article 2408.13.

Field extensions of steel piles shall be made only by a welder qualified in accordance with Materials I.M. 560 using an approved welding procedure involving the use of backing plates in accordance with Article 2408.13. When designated in the contract documents, the Contractor shall have the option of extending steel piles by means of mechanical splices approved by the Engineer.

Splicing of wood piles shall be as directed by the Engineer.

2501.19 PREBORED HOLES AS PER PLAN.
When required by the contract documents, the Contractor shall bore holes greater than the maximum cross sectional dimension of the pile. Minimum diameter of the holes shall be 4 inches (100 mm) greater than the maximum cross sectional dimension of the pile 3 feet (1 m) from the butt. Holes shall be bored to the elevations shown. Piles shall be driven through the holes to at least the specified design bearing. The use of natural bentonite slurry will be required when piling is to be advanced in prebored holes. For holes drilled in noncollapsing soils the bentonite slurry may be placed after piles are driven. In collapsing soils the bentonite slurry shall be placed at the time the hole is drilled. Holes shall be covered to prevent footing concrete from entering the holes.

Prebored hole filling materials shall consist of polymer free sodium bentonite designed for sealing wells and bored holes. Materials may consist of American Petroleum Institute Specification 13A, sodium bentonites, high solids bentonite grout mixes, or granular bentonites composed of approximately 1/4 inch (6 mm) or larger particles.

For collapsing soils, a slurry shall be made by thoroughly mixing the bentonite with water according to the manufacturer's recommendation for the product used. In no case shall more than 100 gallons (500 L) of water be used per 80 pounds (50 kg) of bentonite. Slurry materials shall be placed by pumping or other applicable method which assures that the hole is filled from the bottom up.

For noncollapsing dry holes, coarse 1/4 inch (6 mm) or larger bentonite particles may be poured directly into the hole and hydrated with water after placement.

In all cases, the hole shall be completely stabilized and filled with bentonite prior to placing footing concrete.

2501.20 METHOD OF MEASUREMENT.

For the quantities of Wood Piles, Steel HP-Piles (either encased or not), Steel Pipe Piles, Concrete Piles, and Steel Sheet Piles; the length measured for payment will be the plan length. The quantity may be modified by Article 2501.20, D or F.

A. Wood Piles.
When a wood pile is broken in driving through no fault of the Contractor, the length measured for payment will be the plan length.

B. Sheet Piles.
The area of walls of sheet piles will be determined from the plan length and the horizontal center line length measured to the nearest 0.1 foot (0.1 m) of wall.

C. Concrete Encasement.
The length of concrete encasement of steel HP-piles constructed will be measured to the nearest 0.1 foot (0.1 m).

D. Extension and Splices.
Wood, steel HP (either encased or not), or steel pipe piles that are extended, the length measured for payment will be the length of the extension specified by the Engineer. Portions of pile cut-offs used as extensions on the same contract will not be remeasured as additional plan quantity.

Concrete piles that are extended, the length measured for payment will be the length of the extension specified by the Engineer, plus the additional length required to be removed for splicing the reinforcement.

E. Prebored Holes.
The length of prebored holes will be calculated in linear feet (meters) from elevations as shown in the contract documents to the nearest 0.1 foot (0.1 m).

Preboring required by Article 2501.16 will be measured for payment to the nearest 0.1 foot (0.1 m).

F. Extra Pile.
Extra piles ordered, in addition to the plan quantities, will be measured for payment.

2501.21 BASIS OF PAYMENT.
For the quantities of Wood Piles, Steel HP-Piles (either encased or not), Steel Sheet Piles, Steel Pipe Piles, and Concrete Piles measured as provided above, the Contractor will be paid the contract unit price. The price bid for piles shall be full compensation for delivering piles to the site, preparing, driving, cutting, and filling (concrete pipe piles only) piles; except as modified in this article.

A. Increased or Decreased Length or Size of Piles.
Unused piling; either ordered as directed by the Engineer or specified in the contract documents; and delivered to the job site, without having been placed in the leads; shall be returned to the supplier. Payment will be made for freight, restocking, and handling charges.

When the plans designate steel HP-piles 60 feet (18 m) or shorter and the Engineer subsequently orders steel H-piles longer than 60 feet (18 m), the adjusted price for such piles will, when required, also include payment for one extension splice for each pile at the rate specified in Paragraph C.

If extensions or extra piles are furnished by the Contracting Authority, payment for driving will be paid according to Article 1109.03, B.

The Contracting Authority may purchase unused piles at the invoice cost plus 10% overhead charge. The Contractor's cost for handling and transporting shall be included in this cost.

B. Extension of Concrete Piles.
When concrete piles are extended, the Contractor will be paid for the extension at twice the contract unit price per linear foot (meter) of pile. The length of extension shall be as directed by the Engineer.

C. Extension of Steel H-piles or Pipe Piles.
When steel HP-piles or pipe piles are required to be spliced to obtain lengths greater than specified in the contract, payment for each such splice, welded or mechanical, shall be at ten times the contract unit price per linear foot (three times per meter) and shall include all equipment, labor, and materials necessary to complete the splice.

D. Splicing of Wood Piles.
Splicing of wood piles will be paid for according to Article 1109.03, B.

E. Pile Cut-Offs.
Pile cut-offs not used as extensions on the same contract shall become the property of the Contractor. Steel pile cut-offs that are used as extensions on the same contract will not be paid for as additional plan quantity.

All piles, or portions thereof, which become the property of the Contractor, shall be removed from the project site.

F. Encasement.
For the length of concrete encasement measured as provided above, the Contractor will be paid the contract unit price per linear foot (meter).

G. Test Piles.
The contract may provide a lump sum item for test piles. If an item is not provided, test piles ordered by the Engineer and driven under the Engineer's supervision will be considered as extra work and will be paid for as provided in Article 1109.03, B.

H. Pile Points.
When the contract documents require that points of piles be protected with metal points, these points shall be furnished without extra compensation. When metal points are not specified in the contract documents, they shall be furnished only upon direction of the Engineer, in which case payment shall be made as provided in Article 1109.03, B.

I. Sheet Piles.
When sheet piles are specified to become a part of the permanent structure, they shall be paid for at the contract unit price per square foot (square meter) for steel sheet piles of the specified weight (mass) and cross section for the area of the wall or walls placed.

J. Pile Loading Tests.
When pile loading tests are required, they will be paid for at the contract lump sum price. This payment shall be full compensation for all labor, material, and equipment required to comply with the procedure shown in the contract documents, including the test and anchor piles, welding, and placing and removing the test beam.

For pile loading tests ordered by the Engineer, the Contractor will be paid a lump sum price of $3000. When this test is performed within a cofferdam, the lump sum price will be $6000. This payment shall be full compensation for all labor, material, welding, and equipment, for placing and removing the test beam, and for loss of time.

K. Prebored Holes.
When prebored holes are required by the contract documents, they will be paid for at the contract unit price per linear foot (meter). This payment shall be full compensation for all labor, equipment, and materials including bentonite slurry.

Prebored holes required by Article 2501.16 will be paid for according to Article 1109.03, B.

L. Dynamic Pile Test.
When required by the contract documents or ordered as directed by the Engineer the dynamic pile test will be paid for as a lump sum price. This payment will be $250 per test pile. The payment shall be full compensation for all labor, materials, equipment, and time associated with this test as outlined in Article 2501.13.

M. Jetting.
When required by Article 2501.16, jetting will be paid for according to Article 1109.03, B.