508STRUCTURAL FILL

New Hampshire Department of Transportation Standard Specifications – 2016 Description

1.1This work shall consist of the formation of embankments which are intended to support structures.

Materials

2.1Structural fill shall consist of crushed gravel unless bank -run gravel, clean stone fill, or other material i s specified on the

plans or permitted by the Engineer. When not otherwise limited the word gravel as used below will refer to both bank -run gravel and crushed gravel. 2.1.1 Crushed Gravel for Structural Fill. 2.1.1.1 Required Grading:

Sieve Size Percentage by Weight Passing 3” 100 2” 95 - 100 1” 55 - 85 No. 4 27 - 52 No. 200 (Based on the fraction passing the No. 4 sieve) 0 - 12

2.1.1.2 At least 50 percent by weight of the materials retained on the 1” sieve shall have a fractured face. 2.1.2 Bank-run Gravel for Structural Fill. Bank-run gravel shall be graded as follows: 25 to 70 percent shall pass a No. 4 sieve. Not more than 15 percent of the portion which passes the No. 4 sieve shall pass a No. 200 sieve. No stone shall be included which cannot be incorporated in a 6” course. 2.1.3 Clean Stone Fill for Structural Fill. 2.1.3.1 Required Grading:

Sieve Size Percentage by Weight Passing 2” 100 1-1/2” 95 - 100 3/4” 35 - 70 3/8” 10 - 30 No. 4 0 - 5

2.1.3.2 At least 50 percent by weight of the materials retained on the 3/4” sieve shall have a fractured face. 2.1.4 Wear. The percent of wear of gravel or clean stone fill shall not exceed 50 percent as determined in accordance with AASHTO T 96.

2.2Concrete class F, flowable fill may be requested in writing as a substitute for structural fill. Approval in the form of a

supplementary agreement shall be in consideration of, but not limited to, differential frost heaving due to dissimilar materials, unit weight, structural requirements, lack of permeability, and damming resulting from water flow cut off. Construction Requirements

3.1The area upon which the fill is to be constructed, regardless of the height of the proposed fill, shall be stripped of all loa m,

refuse, roots, stumps, boulders, and the like and shall be backfilled with the same type of material as that found at the sit e. All excavation shown on the plans or ordered shall be completed before constructing the fill. When fills are to be made on hillsides or when fill is built one half width at a time, the slopes of the original hillside or new fill shall be cut into or terraced as the work is brought up in layers. 3.1.1 Before the first layer of structural fill is placed, the entire work area of the original ground shall be compacted with approved compacting equipment.

3.2Structural fill to be placed adjacent to new embankment material shall be placed concurrently with the embankment material

to obtain lateral support.

New Hampshire Department of Transportation Standard Specifications – 2016

3.3The fill shall be placed in horizontal layers of uniform thickness not exceeding 8” loose depth and compacted to the required

density prior to placing the next layer. Each layer shall be compacted with power rollers, power tampers or vibratory compac tors until the required density is obtained. The surface of the fill shall be kept approximately level at all times and the portion of the fill to be occupied by the structure shall be maintained at the proper density by moistening and tamping if necessary, until the concrete or structure is in place.

3.4The density of structural fill will be determined by AASHTO T 191 (Sand Cone Method), or by AASHTO T 310 (Nuclear

Method) and shall be not less than 98 percent of the maximum density determined in accordance with AASHTO T 99 (Standard Proctor Test). This maximum density may also be determined by the control strip procedure in 304.3.8.

3.5The Contractor shall notify the Engineer of the anticipated date of completion of the structural fill at lea st 3 working days

prior to completion of the fill. Upon completion, the Contractor shall not proceed with any further operations on the fill until the Engineer has taken all of the necessary proof borings. When approval has been given, the Contractor shall backfill any drilled holes with saturated sand or other approved material.

3.6The use of clean 1 -1/2” stone fill as structural fill may be permitted by the Engineer under special circumstances, such as

when dewatering problems occur during foundation c onstruction. The total thickness of stone fill shall not exceed 12 ”. All compaction and density requirements of this specification shall apply when using stone fill. Method of Measurement

4.1Structural fill will be measured by the cubic yard as determined from the ground elevation immediately before the placement

of any fill and the neat lines for the compacted material as shown on the plans. Basis of Payment

5.1The accepted quantity of structural fill will be paid for at the Item Bid Price per cubic ya rd complete in place.

5.1.1 Concrete class F, flowable fill substituted for structural fill will be paid for at the Contract unit price for structural fi ll.

5.2Excavation in preparation for this item will be paid for under 504 unless otherwise indicated on the plans. Any excavation

for terracing and any backfilling of proof boring holes will not be measured but will be incidental to the work. Pay item and unit: 508. Structural Fill Cubic Yard

New Hampshire Department of Transportation Standard Specifications – 2016

Description

General. This work shall consist of furnishing all types of bearing piles, furnishing pile driving equipment, and driving

bearing piles to the required penetration, and when required, test loading, splicing, and cutting, as shown on the plans or o rdered. Materials & Equipment

Materials

2.1.1 Concrete piles, precast or cast -in-place, shall be Class A unless otherwise shown on the plans and shall conform to Section 520. All concrete for cast -in-place piles shall be designed with the necessary admixtures to maintain the required slump and sufficient workability throughout the entire concrete placement operation. Reinforcing steel shall conform to Section 544. 2.1.2 Steel Piles. 2.1.2.1 Steel H -piles shall conform to the general requirements for rolled steel plates, shapes, sheet piling and bars for structural use, ASTM A6. 2.1.2.2 Unless otherwise specified, high-strength, low-alloy steel shall be furnished for all H-piles and conform to AASHTO M270 (ASTM A709) Grade 50 or ASTM A572 Grade 50. 2.1.2.3 Steel pipe piles shall conform to ASTM A 252, Grade 2, unless otherwise specified. 2.1.2.4 The use of foreign steel will be permitted only after approval by the Engineer upon suitable certification from a recognized domestic laboratory. 2.1.3 Driving points for steel piles shall conform to AASHTO M 103 , (ASTM A27) Grade 65-35 or ASTM A 1 48, Grade 90-60 and shall be as included on the Qualified Products List.

Equipment for Driving Piles.

2.2.1 Pile hammers. Piles may be driven with steam, air, hydraulic or diesel hammers capable of driving piles at least 10 ft. longer than the longest pile length shown on the plans. 2.2.1.1 Gravity hammers shall be subject to approval. When gravity hammers are permitted, the ram shall have a mass between 2,000 and 3,500 lb. and the height of drop shall not exceed 15 ft. In no case shall the weight of gravity hammers be less than the combined weight of drive head and pile. All gravity hammers shall be equipped with hammer guides to ensure concentric impact on the drive head. 2.2.1.2 Open-end (single acting) diesel hammers shall be equipped with a device such as rings on the ram or a scale extending above th e ram cy linder, to permit the Engineer to determine hammer stroke at all times during pile driving operations. The Contractor shall provide the Engineer a chart from the hammer manufacturer equating stroke and blows per minute for the open - end diesel hammer to be used. Closed -end (double acting) diesel hammers shall be equipped with a bounce chamber pressure gauge, in good working order, mounted near ground level so as to be easily read by the Engineer. In addition, for closed-end diesel hammers, the Con tractor shall provide to the Engineer a chart calibrated to actual hammer performance within 90 days of use equating bounce chamber pressure to either equivalent energy or stroke. 2.2.1.3 Non-impact hammers, such as vibratory hammers, or driving aids such as jets, followers, and prebored holes shall not be used unless specifically permitted in writing by the Engineer. When permitted, such equipment and driving aids shall be used only for production piles and only after the pile tip elevation necessary to p rovide the required ultimate resistance is established by load testing and/or test piles driven with an impact hammer. As a condition of approval of the non-impact hammers or driving aids, the Contractor shall perform, at no cost to the State, pile load tests and/or any additional 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, or other means acceptable to the Engineer which assure pile load capacity equals or exceeds the test pile capacity. In addition, one of every ten piles driven with a vibratory hammer shall be retapped with an impact hammer of suitable energy to verify pile capacity. 2.2.1.4 The plant and equipment furnished for steam and air hammers shall have sufficient capacity to maintain, under working conditions, the volume and pressure specified by the manufacturer. The plant and equipment shall be equipped with accurate pressure gauges. The weight of the striking parts of air and steam hammers shall not be less than 1/3 the weight of drive head and pile being driven, and in no case shall the striking parts have a mass less than 2,750 lb. 2.2.2 Driving Appurtenances. 2.2.2.1 Hammer cushion. All pile driving equipment shall be equipped with a suitable thickness of hammer cushion material to prevent pile damage and ensure uniform driving behavior. Hammer cushions shall be made of durable, manufactured materials, provided in accordance with the hammer manufacturer's guidelines except that all wood, wire rope, and asbestos hammer