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1. SCOPE
The work shall consist of furnishing and installing the specified kinds and types of piles at the locations shown on the drawings.
2. MATERIALS
Piles shall conform to the requirements of Material Specifications 511, 512, 513, or 514 as appropriate to the kinds of piles specified. For piles of material other than that list above, the material requirements outlined in Section 14 of this specification shall apply.
3. SITE PREPARATION
All excavation within the area to be occupied by bearing piles shall be completed before the piles are driven.
4. PROTECTION OF PILE HEADS
The heads of all piles shall be protected during driving by suitable caps, rings, heads, blocks, mandrels and other devices.
The heads of timber piles shall be fitted into a steel head block or fitted with heavy steel or wrought iron rings or wire wrapping.
The heads of steel piles shall be cut square and fitted with a steel driving cap.
The heads of pre-cast concrete piles and casings shall be fitted into cushion type drive caps having a rope or other suitable cushion next to the pile head and fitting into a casting which in turn supports a timber shock block.
Driving heads, mandrels and other devices shall be provided by the Contractor as needed for special types of piles and shall conform to the recommendations of the pile manufacturer.
5. PILES, GENERAL
The Contractor shall notify the Engineer before pile driving operation commences. Such notice shall be far enough in advance, a minimum of 24 hours, to provide the Engineer adequate time to be present for the driving operations. Piles shall be driven only in the presence of the Engineer or authorized representative.
The determination of piling order lengths shall be the Contractor's responsibility, unless otherwise specified.
Unless otherwise approved, piles shall be driven with steam, air, diesel powered hammers or a combination of hammers, vibration or water jets. Water jets may be used only when specifically authorized by the Engineer. Where jetting is authorized, the jets shall be withdrawn before the specified depth or bearing capacity is obtained and the piles shall be driven with the hammer to the final penetration.
When drop hammers are permitted, the height of drop shall not be more than eight (8) feet for concrete piles or twelve (12) feet for steel and timber piles, unless otherwise specified.
The driving of piling with followers shall be allowed only when expressly approved by the Engineer.
Piles shall not be driven within 20 feet of concrete less than seven (7) days after placement, including concrete placed in cast-in-place piles with or without pre-driven shells or casings.
The Contractor shall not attempt to drive piles beyond the point of refusal, as indicated by excessive bouncing of the hammer or kicking of the pile.
6. BEARING PILES
Bearing piles shall be driven to the position, line, and batter specified on the drawings. Each pile shall be driven continuously and without interruption to the specified depth or until the specified bearing capacity is obtained. Deviation from this procedure will be permitted only when interruption of driving is caused by conditions that could not reasonably be anticipated.
When a diesel hammer is used, it shall be operated at full throttle when blows are counted for determination of bearing capacity except that throttle adjustments shall be made as necessary to prevent the non-striking parts of the hammer from rising from the pile on the ram upstroke.
7. SHEET PILES
The piling shall be driven in such a manner as to insure perfect interlocking throughout the entire length of each pile. The piles shall be held in proper alignment during driving by means of assembling frames or other suitable temporary guide structures. Temporary guide structures shall be removed when they have served their purpose.
At any time that the forward edge of the sheet pile wall is found to be out of correct alignment:
a. The piling already assembled and partly driven shall be driven to the required depth.
b. Taper piles shall then be driven to bring the forward edge into correct alignment before additional regular piling is assembled and driven. The maximum permissible taper in a single pile shall be one-fourth inch per foot of length.
8. ESTIMATING BEARING CAPACITY
When load tests are not required, the bearing capacity of each pile shall be estimated by use of one of the following formulas, as appropriate:
- For gravity hammers, R = 2WH / S+1
- For single-acting steam or air hammers and for diesel hammers having unrestricted rebound of the ram,
R = 2WH / S+0.1
- For double-acting steam or air hammers and diesel hammers having enclosed rams,
R = 2H(W+AP) / S=0.1 ; or,
R = 2E / S=0.1where:
R = safe bearing capacity in pounds,
W = weight, in pounds, of striking parts of hammer,
H = height of fall in feet,
A = area of piston in square inches,
P = pressure, in pounds per square inch, of steam, air or other gas exerted on the hammer piston or ram,
E = the manufacturer's rating for foot-pounds of energy developed by double-acting steam or air hammers, or 90 percent of the average equivalent energy, in foot-pounds, developed by diesel hammers having enclosed rams as evaluated by gauge and chart readings,
S = average penetration, inches per blow, for the last five (5) to ten (10) blows of a gravity hammer or the last ten (10) to twenty (20) blows for steam, air or diesel powered hammers.
The above formulas are applicable when:
a. The hammer has a free fall
b. The head of the pile is not crushed
c. The penetration is reasonably quick and uniform
d. There is no sensible bounce after the blow
e. A follower is not used.
Twice the height of the bounce shall be deducted from "H" to determine its value in the formula.
In case water jets are used in conjunction with the driving, the bearing power shall be determined by the above formulas from the results of driving after the jets have been removed.
9. LOAD TESTS
When load tests are specified, the test loads shall be applied gradually, without impact, and in a manner that no lateral forces are applied to the pile. Load testing shall not be started until twenty-four (24) hours after driving of the test pile is completed unless otherwise specified in Section 14 of this specification. Except as otherwise specified, load tests shall be performed according to the following procedures:
The total test load shall be twice the specified working load and shall be applied to the pile in increments equal to 25-percent of the working load. Settlement of the top of the pile shall be measured to an accuracy of 0.01-inch before and after the application of each load increment and at 2, 4, 8, 15, 30, and 60 minutes after, and then every two (2) hours until the next load increment is applied. Additional load shall not be applied until the rate of settlement is less than 0.01-inch in one (1) hour.
The total test load shall remain on the pile for a minimum period of twenty-four (24) hours. Settlement shall be measured at six (6) hour intervals during this period and at the end of the period, at least twice during removal of the load, and immediately after all of the test load is removed. The net settlement shall be measured approximately twenty-four (24) hours after the total load has been removed.
If settlement continues in excess of 0.01-inch per hour under less than the total test load, no additional load shall be applied, but the load that has been applied shall remain on the pile a minimum of twenty-four (24) hours, and settlement measurements while the load is on the pile, and during and after removal of the load shall be made as if it were the total test load.
10. CUTTING OFF PILES
The Contractor shall cut the piles at the specified elevations. The length of pile cut off shall be sufficient to permit the removal of all damaged material. Steel shells or concrete casings for cast-in-place concrete piles shall be cut off at the specified elevation before being filled with concrete.
Steel bearing piles shall be cut off in clean, straight lines as shown on the drawings. Any irregularities shall be leveled off with deposits of weld metal or by grinding before placement of bearing caps.
Pre-cast concrete piles and concrete casings shall be cut off in a manner such as to prevent damage to the remaining portion of the pile or casing or to the projecting reinforcement required for connecting the piles to the structure.
Timber piles that are to be capped shall be accurately cut off so that true bearing is obtained on every pile without the use of shims.
11. DEFECTIVE PILES
Any pile damaged in driving, driven out of proper location, driven below the specified cut off elevation or inaccurately cut off shall be corrected by one of the following methods, whichever is approved by the Engineer:
a. The defective pile shall be pulled and replaced or re-driven;
b. A new pile shall be driven adjacent to the defective pile; or
c. The defective pile shall be spliced or built up or a sufficient portion of the footing shall be extended to properly embed the pile.
Pile shells abandoned in place after driving shall be filled with concrete or sand-cement grout as appropriate to the conditions that are present.
All piles pushed up by the driving of adjacent piles or by any other cause shall be re-driven to final grade.
Any sheet pile ruptured in the interlock or otherwise damaged during driving shall be pulled and replaced.
12. CORRECTING SURFACE HEAVE
Any excess material resulting from displacement of earth by pile driving shall be removed. Materials disturbed by pile driving shall be conditioned and compacted to a minimum density equal to adjacent undisturbed material.
13. MEASUREMENT AND PAYMENT
Method 1 For items of work for which specific unit prices are established in the contract, the number of each type, kind, and length of pile driven in place will be counted. Payment for furnishing and driving each type, kind, and length of pile will be made at the contract unit price. Such payment will constitute full compensation for all labor, equipment, materials, and all other items necessary and incidental to the completion of the work.
Method 2 For items of work for which specific unit prices are established in the contract, the number of each type, kind, and length of pile furnished, accepted, and stockpiled in good condition at the site of the work will be counted. Payment for furnishing each type, kind, and length of pile will be made at the contract unit price. Payment for driving each type and kind of pile will be made at the contract unit price. Such payment will constitute full compensation for all labor, equipment, materials, and all other items necessary and incidental to the completion of the work.
Method 3 For items of work for which specific unit prices are established in the contract, the length of each type and kind of pile driven will be computed to the nearest foot as the difference between the measured length of pile before driving and measured length of pile cut off after driving. Payment for furnishing and driving each type and kind of pile will be made at the contract unit price. Such payment will constitute full payment for all labor, equipment, materials, and other items necessary and incidental to the completion of the work.
Method 4 For items of work for which specific unit prices are established in the contract, the area of sheet pile walls, acceptably placed in accordance and within the neat lines shown on the drawings, will be computed to the nearest square foot. Payment will be made at the contract unit price for each type, kind, and weight of piling. Such payment will constitute full payment for all labor, equipment, materials, and other items necessary and incidental to the completion of the work.
All Methods The following provisions apply to all methods of measurement and payment:
The measurement of the number of linear feet of piles (or number of piles) furnished and the number of piles driven shall include test and tension piles specified in the contract. Piles furnished and driven at the option of the Contractor will not be included. No payment will be made for furnishing or driving pile, including test piles, to replace piles lost or damaged prior to the completion of the contract while in stockpile or during handling and driving.
When load tests are specified, payment for each test will be made at the contract unit price per test. Such payment will constitute full compensation for all labor, equipment, materials, and all other items necessary and incidental to perform the test, except furnishing and driving piling.
When splices are specified, payment for each splice will be made at the contract unit price. Such payment shall constitute full compensation for labor, equipment, materials, and all other items necessary and incidental to the completion of the work.
Compensation for any item of work described in the contract but not listed in the bid schedule will be included in the payment for the item of work to which it is made subsidiary. Such items and the items to which they are made subsidiary are identified in Section 14 of this specification.