02225 Earthwork.doc

Base Pavements IDIQ

JCGU 09-1700

DIVISION 2 - SITE WORK

SECTION 02225 - EARTHWORK

PART 1 – GENERAL:

1.1 REFERENCES: The publications listed below form a part of this specification to the extent referenced. The publications are referred to in the text by basic designation only. All publications shall be the latest version/edition/revision of the documents listed below, in effect on the date of this solicitation, except where a date is given.

American Society for Testing and Materials (ASTM)

ASTM C 136

Sieve Analysis of Fine and Coarse Aggregates

ASTM D422

Particle-Size Analysis of Soils

ASTM D1140

Amount of Material in Soils Finer than the No. 200 (75-mm) Sieve

ASTM D1556

Density of Soil In Place by the Sand-Cone Method

ASTM D1557

Moisture-Density Relations of Soils and Soil-Aggregate Mixtures Using 10-Lb.(4.54-kg) Rammer and 18-In. (457-mm) Drop

ASTM D2487

Classification of Soils for Engineering Purposes

ASTM D2922

Density of Soil and Soil-Aggregate In Place by Nuclear Methods (Shallow Depth)

ASTM D2937

Density of Soil In Place by the Drive-Cylinder Method

ASTM D3017

Moisture Content of Soil and Soil-Aggregate In Place by

Nuclear Methods (Shallow Depth)

ASTM D4318

Liquid Limit, Plastic Limit, and Plasticity Index of Soils

1.2 DEFINITIONS:

1.2.1 Satisfactory Materials: Satisfactory materials shall comprise any materials classified by, ASTM D2487 as GW, GP, SW, GC, SC, SP, and CL. Select borrow/fill to be used for topsoil shall be as approved by the Contracting Officer or Representative.

1.2.2 Unsatisfactory Materials: Unsatisfactory materials shall comprise any materials not satisfactory. Included but not limited to those classified by ASTM D2487 as PT, OH, OL, ML, and MH.

1.2.3 Cohesion less and Cohesive Materials: Cohesion less materials include materials classified in ASTM D2487 as GW, GP, SW and SP. Cohesive materials include materials classified as GC, SC, ML, CL, MH and CH. Materials classified as GM and SM shall be identified as cohesion less only when the fines are nonplastic. Testing required for classifying materials shall be in accordance with ASTM C 136, ASTM D422, ASTM D1140, and ASTM D4318.

1.2.4 Degree of Compaction: Degree of Compaction required is expressed as a percentage of the maximum density obtained by the test procedure presented in ASTM D1557. This shall be abbreviated below as a percent of laboratory maximum density.

1.3 CLASSIFICATION OF EXCAVATION:

No consideration shall be given to the nature of the materials, and all excavation will be designated as unclassified excavation.

1.4 UTILIZATION OF EXCAVATED MATERIALS:

All unsatisfactory materials removed from excavations shall be disposed of. Satisfactory material removed from excavations shall be used, insofar as practicable, in the construction of fills, embankments, subgrades, shoulders, bedding (as backfill), and for similar purposes. No satisfactory excavated material shall be wasted without specific written authorization. Satisfactory material authorized to be wasted shall be disposed of in areas designated by the Contracting Officer. Coarse rock from excavations shall be stockpiled and used for constructing slopes or embankments adjacent to streams, or sides and bottoms of channels, and for protecting against erosion. No excavated material shall be disposed of in such a manner as to obstruct the flow of any stream, endanger a partly finished structure, impair the efficiency or appearance of any structure, or be detrimental to the completed work in any way.

PART 2 – PRODUCTS:

2.1 BORROW MATERIAL:

Borrow material shall be selected to meet requirements and conditions of the particular fill for which it is to be used. Necessary clearing grubbing, disposal of debris, and satisfactory drainage of borrow pits shall be performed by the Contractor as incidental operations to the borrow excavation.

2.1.1 Selection: Borrow materials shall be obtained from sources outside the limits of Government-controlled land. Borrow materials shall be subject to approval unless specifically provided, no borrow shall be obtained within the limits of the project site without prior written approval.

PART 3 – EXECUTION:

3.1 STRIPPING OF TOPSOIL:

Where indicated or directed, topsoil shall be stripped to a depth of six (6) inches. Topsoil shall be spread on areas already graded and prepared for topsoil, or when so specified topsoil shall be transported and deposited in stockpiles convenient to areas that are to receive application of the topsoil later, or at locations indicated or specified. Topsoil shall be kept separate from other excavated materials, brush, litter, objectionable weeds, roots stones larger than 2 inches in diameter, and other materials that would interfere with planting and maintenance operations.

3.2 EXCAVATION:

The Contractor shall perform excavation of every type of material encountered within the limits of the project, to the lines, grades, and elevations indicated and as specified herein. Grading shall be in conformity with the typical sections shown and the tolerances specified in paragraph 3.11, FINISHING. Satisfactory excavated materials shall be transported to and placed in fill or embankment within the limits of the work. Unsatisfactory materials encountered within the limits of the work shall be excavated below grade and replaced with satisfactory material as directed. Such excavated material and the satisfactory material ordered as replacement shall be included in excavation. Surplus satisfactory excavated material not required for fill or embankment shall be disposed of in areas approved for surplus material storage or designated waste areas or as directed. Unsatisfactory excavated material shall be disposed of in designated waste or spoil areas. During construction, excavation and fill shall be performed in a manner and sequence that will provide proper drainage at all times. Material required for fill or embankment in excess of that produced by excavation within the grading limits shall be excavated from the borrow areas indicated or from other approved areas selected by the Contractor as specified herein.

3.2.1 Ditches, Gutter, and Channel Changes: Excavation of ditches, gutters and channel changes shall be accomplished by cutting accurately to the cross sections, grades or elevations as described in the Task Order. Care shall be taken not to excavate ditches and gutters below grades. Excessive open ditch or gutter excavation shall be backfilled with satisfactory thoroughly compacted material or with suitable stone or cobble to grades shown at no additional cost to the Government. Material excavated shall be disposed of as shown or as directed, except that in no case shall material be deposited less than 4 feet from the edge of the ditch. The Contractor shall maintain all excavations free from detrimental quantities of leaves, brush, sticks, trash, and other debris until final acceptance of the work.

3.2.2 Protection or Removal of Utility Lines: Existing utility lines, the locations of which are made known to the contractor prior to excavation and that are to be retained as well as utility lines constructed during excavation operations, shall be protected from damage during excavation and backfilling and if damaged, shall be repaired by the Contractor at no expense to the Government. Contractor shall be responsible for physically locating marked utility lines within 18” either side of the Government marked utility.

3.2.3 Drainage Structures: Excavations shall be made accurately to the lines, grades, and elevations shown or as directed by the Contracting Officer. Trenches and foundation pits shall be of sufficient size to permit the placement and removal of forms for the full length and width of structure footings and foundations as shown. Rock or other hard foundation material shall be cleaned of loose debris and cut to a firm surface either level, stepped, or serrated, as shown or as directed. Loose disintegrated rock and thin strata shall be removed. When concrete or masonry is to be placed in an excavated area, special care shall be taken not to disturb the bottom of the excavation. Excavation to the final grade level shall not be made until just before the concrete or masonry is to be placed.

3.3 SELECTION OF BORROW MATERIAL:

Borrow material shall be selected to meet the requirements and conditions of the particular fill or embankment for which it is to be used. Borrow material shall be obtained from the borrow areas off-base selected by the Contractor. Unless otherwise provided in the contract, the Contractor shall obtain from the owners the right to procure material, pay all royalties and other charges involved, and bear all expense of developing the sources, including rights-of-way for hauling. Unless specifically provided, no borrow shall be obtained within the limits of the project site without prior written approval. Necessary clearing, grubbing, and satisfactory drainage of borrow pits and disposal of debris thereon shall be considered related operations to the borrow excavation and shall be performed by the Contractor.

3.4 OPENING AND DRAINAGE OF EXCAVATION AND BORROW PITS:

Borrow pits and other excavation areas shall be excavated in such a manner as shall afford adequate drainage. All spoil material shall be transported to designated spoil areas or otherwise disposed of as directed. Borrow pits shall be neatly trimmed and drained after the excavation is completed. The Contractor shall ensure that excavation of any area, operation of borrow pits, or dumping of spoil material results in minimum detrimental effects on natural environmental conditions.

3.5 GRADING AREAS:

When so provided and where indicated, work under contract shall be divided into grading areas, within which satisfactory excavated material shall be placed in embankments, fills, and required backfills. The Contractor shall not haul satisfactory material excavated in one grading area to another grading area except when so directed in writing.

3.6 BACKFILL:

Backfill adjacent to any and all types of structures shall be placed and compacted to at least 95 percent laboratory maximum density for cohesion less materials or 90 percent laboratory maximum density for cohesive materials, in such a manner as to prevent wedging action or eccentric loading upon or against any structure. Ground surface on which backfill is to be placed shall be prepared as specified in paragraph 3.7 - PREPARATION OF GROUND SURFACE FOR EMBANKMENTS. Compaction requirements for backfill materials shall also conform to the applicable portions of paragraphs 3.7 and 3.8, PREPARATION OF GROUND SURFACE FOR EMBANKMENTS and EMBANKMENTS, below. Compaction shall be accomplished by sheepsfoot rollers, pneumatic tired rollers, steel wheeled rollers or other approved equipment well suited to the material being compacted.

3.7 PREPARATION OF GROUND SURFACE FOR EMBANKMENTS:

Ground surface on which fill is to be placed shall be stripped of live, dead or decayed vegetation, rubbish, debris and other unsatisfactory material; plowed, disked or otherwise broken up; pulverized; moistened or aerated as necessary; thoroughly mixed and compacted to at least 90 percent laboratory maximum density for cohesive materials or 95 percent laboratory maximum density for cohesion less materials. Compaction shall be accomplished by sheepsfoot rollers, pneumatic tired rollers, steel-wheeled rollers, vibratory compactors, or other approved equipment well suited to the material being compacted. The prepared ground surface shall be scarified and moistened or aerated as required just prior to placement of embankment materials to assure adequate bond between embankment material and the prepared ground surface.

3.8 EMBANKMENTS:

Earth embankments shall be constructed from satisfactory materials free of organic or frozen material and rocks with any dimension greater than 3 inches. The material shall be placed in successive horizontal layers of loose material not more than 8 inches in depth. Each layer shall be spread uniformly on a soil surface that has been moistened or aerated as necessary and scarified or otherwise broken up in such a manner that the fill shall bond with the surface on which it is placed. After spreading, each layer shall be plowed, disked, or otherwise broken up; moistened or aerated as necessary; thoroughly mixed; and compacted to at least 90 percent laboratory maximum density for cohesive materials or 95 percent laboratory maximum density for cohesion less materials. Compaction requirements for the upper portion of earth embankments forming subgrade for pavements shall be the same as specified in paragraph 3.9 - SUBGRADE PREPARATION. Compaction shall be accomplished by sheepsfoot rollers, pneumatic tired rollers, steel-wheeled rollers or other approved equipment well suited to the type of material being compacted.

3.9 SUBGRADE PREPARATION:

3.9.1 Subgrade shall be shaped to line, grade, and cross section, and compacted to specification. This operation shall include plowing, disking and any moistening or aerating required to obtain specified compaction. Soft or otherwise unsatisfactory material shall be removed and replaced with satisfactory excavated material or other approved material as directed. Rock encountered in the cut section shall be excavated to a depth of 6 inches below finished grade for the subgrade. Low areas resulting from removal of unsatisfactory material or excavation of rock shall be brought up to required grade with satisfactory materials, and the entire subgrade shall be shaped to line, grade, and cross section and compacted as specified. After rolling, the surface of the subgrade for roadways shall not show deviation greater than 0.05 inches when tested with a 12-foot straightedge applied both parallel and at right angles to the centerline of the area. The elevation of the finished subgrade shall not vary more than 0.05 feet from the established grade and cross section.

3.9.2 Compaction: Compaction shall be accomplished by sheepsfoot rollers, pneumatic tired rollers, steel-wheeled rollers, vibratory compactors, or other approved equipment well suited to the type of material being compacted.

3.9.2.1 Subgrade for Pavements and curb and gutter: Subgrade for pavements and curb and gutter shall be compacted to at least 95 percent of laboratory maximum density for the depth below the surface of the pavement shown on the drawings.

3.9.2.2 Subgrade for Shoulders: Subgrade for shoulders shall be compacted to at least 90 percent of laboratory maximum density for the full depth of the shoulder.

3.10 SHOULDER CONSTRUCTION:

Shoulders shall be constructed of satisfactory excavated or borrow materials or as otherwise shown or specified herein. Shoulders shall be constructed as soon as possible after adjacent paving is complete, but in the case of rigid pavements, shoulders shall not be constructed until permission of the Contracting Officer has been obtained. The entire shoulder area shall be compacted to at least the percentage of maximum density as specified in paragraph 3.9 - SUBGRADE PREPARATION above. Compaction shall be accomplished by sheepsfoot rollers, pneumatic-tired rollers, steel-wheeled rollers, vibratory compactors, or other approved equipment well suited to the type of material being compacted. Shoulder construction shall be done in proper sequence in such a manner that adjacent ditches will be drained effectively and that no damage of any kind is done to the adjacent completed pavement. The completed shoulders shall be true to alignment and grade and shaped to drain in conformity with the cross section shown.

3.11 FINISHING:

All areas covered by this project, including excavated and filled sections and adjacent transition areas, shall be uniformly smooth-graded. The finished surface shall be reasonably smooth, compacted, and free from irregular surface changes. The degree of finish shall be that ordinarily obtainable from blade-grader operations, except as otherwise specified. Ditches and gutters shall be finished to permit adequate drainage. The surface of areas to be turfed shall be finished to a smoothness suitable for the application of turfing materials. For subgrade areas to be paved, the following shall be accomplished as required:

3.11.1 Unsatisfactory Material: Soft or otherwise unsatisfactory material shall be replaced with satisfactory excavated material or other approved materials.

3.11.2 Rock: Rock encountered in the cut sections shall be excavated to a depth of 6 inches below finished grade for the subgrade.

3.11.3 Low Areas: Low areas resulting from removal of unsatisfactory material or from excavation of rock shall be brought up to required grade with satisfactory materials, and the entire subgrade shall be shaped to line, grade, and cross section and shall be compacted as specified. The surface of embankments or excavated areas for road construction or other areas on which a base course or pavement is to be placed shall vary not more than 0.05 feet from the established grade and approved cross section. Surfaces other than those that are to be paved shall be finished not more than 0.15 feet above or below the established grade or approved cross section.

3.11.4 Surface: The surface of all excavations, embankments, and subgrades shall be finished to a smooth and compact surface in accordance with the lines, grades and cross sections or elevations shown. The degree of finish for all graded areas shall be within 0.1 foot of the grades and elevations indicated except that the degree of finish for subgrades shall be specified in paragraph 3.9 - SUBGRADE PREPARATION. Gutters and ditches shall be finished in a manner that shall result in effective drainage. The surface of areas to be turfed shall be finished to a smoothness suitable for the application of turfing materials.

3.12 TESTING:

The first inspection and any subsequent inspection required because of failure of the first inspection shall be charged to the Contractor. Field in-place density shall be determined in accordance with ASTM D2922. When ASTM D2922 is used, the calibration curves shall be checked and adjusted using only the sand cone method as described in ASTM D1556. ASTM D2922 results in a wet unit weight of soil and when using this method ASTM D3017 shall be used to determine the moisture content of the soil. The calibration curves furnished with the moisture gauges shall also be checked along with density calibration checks as described in ASTM D3017, the calibration checks of both the density and moisture gauges shall be made at the beginning of a job on each different type of material encountered and in intervals as directed by the Contracting Officer. ASTM D2937, the Drive Cylinder Method shall be used only for soft, fine-grained, cohesive soils. Within 24 hours of conclusion of physical tests, 4 copies of test results, including calibration curves and results of calibration tests, shall be furnished to the Contracting Officer. When test results indicated, as determined by the Contracting Officer, that compaction is not as specified, the material shall be removed, replaced and recompacted to meet specification requirements. Tests on recompacted areas shall be performed to determine conformance with specification requirements. These certifications shall state that the tests and observations were performed by or under the direct supervision of the engineer and that the results are representative of the materials or conditions being certified by the tests. The following number of tests, if performed at the appropriate time, shall be the minimum acceptable for each type of operation.

3.12.1 Fill and Backfill Material Gradation: One test per 2,500 cubic yards/or a minimum of one test per Task Order stockpiled or in-place source material, or as required by the Contracting Officer. Gradation of fill and backfill material shall be determined in accordance with ASTM C136, ASTM D422, and ASTM D1140.

3.12.2 In-Place Densities test shall be as follows, or as required by the Contracting Officer:

3.12.2.1 Other than Hand-Operated: One test per 5000 square feet/or a minimum of one test per Task Order, or fraction thereof, of each lift of fill or backfill areas compacted by other than hand-operated machines.

3.12.2.2 Hand-Operated Machines: One test per 1000 square feet/or a minimum of one test per Task Order, or fraction thereof, of each lift of fill or backfill areas compacted by hand-operated machines.

3.12.2.3 Roads: One test per 250 linear feet/or a minimum of one test per Task Order at location(s) selected by the Contracting Officer, or his designated representative, or fraction thereof, of each lift of embankment or backfill for roads.

3.12.2.4 Curb and Gutter/Sidewalks: One test per 250 linear feet/or a minimum of one test per Task Order at location(s) selected by the Contracting Officer, or his designated representative, or fraction thereof, of each lift of embankment or backfill for sidewalks.

3.12.3 Check Tests on In-Place Densities: If ASTM D2922 is used, calibration curves shall be checked by ASTM D1556 as follows, or as required by the Contracting Officer:

3.12.3.1 Other than Hand-Operated: One check test per lift for each 2500 square yards/or a minimum of one test per Task Order, or fraction thereof, of each lift of fill or backfill compacted by other than hand-operated machines.

3.12.3.2 Hand-Operated: One check test per lift for each 1000 square yards/or a minimum of one test per Task Order of fill or backfill areas compacted by hand-operated machines

3.12.3.3 Roads: One check test per lift for each 1000 linear feet/or a minimum of one test per Task Order, or fraction thereof, of embankment or backfill for roads.

3.12.3.4 Curb and Gutter/Sidewalks: One check test per lift for each 1000 linear feet/or a minimum of one test per Task Order, or fraction thereof, of embankment or backfill for sidewalks.

3.12.4 Moisture Contents: In the stockpile, excavation or borrow areas, a minimum of two tests per day per type of material or source of material being placed during stable weather conditions, or as required by the Contracting Officer. During inclement weather, tests shall be made as dictated by local conditions and approved by the Contracting Officer.

3.12.5 Optimum Moisture and Laboratory Maximum Density: Tests shall be made for each type or source of material including borrow material to determine the optimum moisture content and laboratory maximum density values. One representative test shall be taken per 2,500 cubic yards of fill and backfill/or a minimum of one test per Task Order, or when any change in material occurs which may affect the optimum moisture content or laboratory maximum density, or as required by the Contracting Officer.

3.12.6 Tolerance Tests for Subgrades: Continuous checks on the degree of finish specified in paragraph 3.9 - SUBGRADE PREPARATION shall be made during construction of the subgrades.

3.13 SUBGRADE AND EMBANKMENT PROTECTION:

During construction, fills, embankments and excavations shall be kept shaped and drained. Ditches and drains along subgrade shall be maintained in such a manner as to drain effectively at all times. The finished subgrade shall not be disturbed by traffic of other operation and shall be protected and maintained by the contractor in a satisfactory condition until the next course of payment is placed. The storage or stockpiling of materials on the finished subgrade will not be permitted. No course of pavement shall be laid until the subgrade has been checked and approved, and in no case shall base course, or pavement be placed on a muddy, spongy, or frozen subgrade.

END OF SECTION

Section 02225 - Page 9 of 9