28-02260 Finish Grading.pdf

02260-1

SECTION 02260

FINISH GRADING

PART 1 GENERAL

1.1 DESCRIPTION OF WORK

A. This Section describes placing, compacting and rolling finish grade materials prior to landscaping work.

B. Finished grading is to be completed within thirty (30) days after completion of the work in unpaved areas unless an extension is granted by the Engineer.

1.2 RELATED WORK SPECIFIED ELSEWHERE

A. Rough Grading - Section 02210.

B. Lawns and Grasses - Section 02930.

1.3 PROTECTION

A. Prevent damage to existing fencing, trees, landscaping, natural features, bench marks, pavement, utility lines and other existing site features. Correct damage at no cost to the Owner.

PART 2 PRODUCTS

2.1 MATERIALS

A. Onsite Topsoil: Onsite soil material from the top six (6”) inches of ground surface, as available in stockpiles, and as approved by Engineer.

02260-2

B. Offsite Topsoil: If on-site topsoil is insufficient in quantity to provide specified thickness, provide topsoil from approved off-site sources as required to complete the work. Off-site topsoil shall meet the following minimum requirements.

1. Topsoil shall be fertile, friable, well drained, pH range of 6.0 to 6.5, free of sub-soil, toxic substances harmful to plant growth without clay lumps, stones, roots or debris. Analysis of content shall be as follows:

Sand - 35% to 40%

Clay - 15% to 20%

Organic Matter - 2.5%

Silt - Balance

2. Test off-site topsoil by a soils testing laboratory retained and compensated by the Contractor and approved by the engineer and submit copy of test report for approval by the engineer.

PART 3 EXECUTION

3.1 SUBSOIL PREPARATION

A. Rough grade subsoil systematically to allow for a maximum amount of natural settlement and compaction. Eliminate uneven areas and low spots. Remove debris, roots, branches, stones, etc. in excess of two (2”) inches in size. Remove subsoil which has been contaminated with petroleum products, or other toxic substances.

B. Cut out areas, to sub-grade elevation, which are to receive stabilizing base for paving, sidewalks, and planting beds.

C. Bring subsoil to required levels, profiles and contours. Make changes in grade gradually. Blend slopes into level areas.

D. Slope grade away from building minimum two (2%) percent, unless indicated otherwise on drawings.

E. Cultivate subgrade to a depth of six (6”) inches where topsoil is to be placed. Repeat cultivation in areas where equipment, used for hauling and spreading topsoil, has compacted subsoil.

02260-3

F. Compact subsoil as specified.

1. General: Control soil compaction during construction providing minimum percentage of density specified for each area classification.

2. Control soil compaction during construction for compliance with the percentage of maximum dry density specified in accordance with ASTM D

1557.

3. Place fill in approximately horizontal lifts with a loose thickness of not more than eight (8”) inches for material compacted by heavy compaction equipment four (4”) inches for material compacted by hand operated tampers.

4. Percentage of Maximum Density Requirements: All fill and backfill, shall be compacted in maximum eight (8”) inch thick lifts to a minimum of ninety-five (95%) percent of maximum dry density. During placement and compaction, the moisture content of fill, backfill and structural backfill material shall be not more than two (2%) percent above or below the optimum moisture content. Non-structural compacted fill (lawns and unpaved areas) shall be compacted to a minimum of ninety-two

(92%) percent of maximum dry density.

5. The moisture content of the fill materials shall be adjusted, if necessary, by aeration or sprinkling, so as to be within plus or minus two (2%) percentage points of the optimum moisture content determined in the laboratory.

6. Remove and replace, or scarify and air dry, soil material that is too wet to permit compaction to specified density.

3.2 PLACING TOPSOIL

A. Place topsoil in areas where seeding and sodding is to be performed. Place to the following minimum depths, up to finished grade elevations.

1. Six (6”) inches for seeded areas.

2. Six (6”) inches for sodded areas.

B. Use topsoil in relatively dry state. Place during dry weather.

C. Fine grade topsoil eliminating rough and low areas to ensure positive drainage.

Maintain levels, profiles and contours of finish grades. Unless indicated otherwise on the drawings, the finish grades shall conform to the grades that exist prior to construction.

D. Remove stone larger than one (1”) inch, roots, grass, weeds, debris, and other foreign material while spreading.

02260-4

E. Manually spread topsoil around trees, plants, and building to prevent damage which may be caused by grading equipment.

F. Lightly compact or roll placed topsoil.

3.3 SURPLUS MATERIAL

A. Leave stockpile areas and entire job site clean and raked.

END OF SECTION