02300_02Earthwork.doc

SECTION 02300

EARTHWORK

spec writer: this section specifies excavating, filling and backfilling, compacting, and grading inside and outside building limits. this section also includes base and subbase materials for pavements; granular drainage course under slabs-on-grade; drainage and separation geotextile fabrics; and trench excavation and backfilling for utility and underground services.

PART 1 - GENERAL

1.1 SUMMARY

A. This Section includes the following:

spec writer: adjust list below to suit project

1. On-site disposal of pool area concrete and masonry rubble in the pool below the wall cut-off elevation.

2. Compacted subgrade and aggregate base for new prefabricated slab-on-grade modular showerhouse and perimeter slab.

3. Trenching and backfill for site utility extensions to the new showerhouse.

4. Preparing subgrades for lawns.

5. Final site grading at pool and borrow sites and haul routes.

6. Compacted fill in the Pool Pumphouse Building for installation of a concrete slab.

B. Water for compaction, if needed, will be paid for by Bid Item No. 10.

1.2 DEFINITIONS

A. Borrow: Satisfactory soil imported from off-site for fill or backfill.

B. Fill: Soil materials used to raise existing grades.

C. Subgrade: Surface or elevation remaining after completing excavation, or top surface of a fill or backfill immediately below subbase, aggregate base, drainage fill, initial or subsequent backfill, or topsoil materials.

PART 2 - PRODUCTS

1.3 Backfill and Fill

A. Satisfactory soil materials from designated borrow site.

1.4 Aggregate base

A. Aggregate shall be crushed and have the grading limits as shown on Table 1033.08 of the Standard Specifications for Highway Construction, Nebraska Department of Roads, 1997 English Units Edition:

Table 1033.08

Crushed Rock for Surfacing Gradation Limits

Percent Passing

Sieve Size

Target Value

Tolerance

1 inch

No. 4

+20

No. 10

+15

No. 50

No. 200

+5 spec writer: if bedding and initial backfill is used modify bedding or initial backfill paragraph

PART 3 - EXECUTION

1.5 excavation, general

A. If excavated materials intended for fill and backfill include unsatisfactory soil materials and rock, replace with satisfactory soil materials.

B. Topsoil shall be removed from the pool area work limits before starting other work.

1.6 storage of soil materials

A. Stockpile, topsoil and satisfactory excavated soil materials. Stockpile soil materials without intermixing. Place, grade, and shape stockpiles to drain surface water.

1.7 fill spec writer: delete paragraph below if preparation is in division 2 section “site clearing.”

A. Preparation: Remove vegetation, topsoil, debris, unsatisfactory soil materials, obstructions, and deleterious materials from ground surface before placing fills.

spec writer: retain below if backfill or fill beneath footings and foundations is required. coordinate material selection with geotechnical engineer’s written recommendations.

1.8 moisture control spec writer: revise percentage in paragraph below to follow geotechnical engineer’s written recommendations. replace “unit weight” with “density” if required.

A. Uniformly moisten or aerate subgrade and each subsequent fill or backfill or aggregate base layer before compaction to a moisture content that will provide good compaction.

1. Do not place backfill or fill material on surfaces that are muddy, frozen, or contain frost or ice.

1.9 compaction of backfills and fills

A. The minimum compaction requirements are:

1. Under showerhouse building slabs and perimeter slab, place fill in uniform layers of 9 inches or less. Compact each layer with mechanical equipment suitable for use until no more deformation occurs.

2. In utility trenches place, backfill material shall be placed and compacted with approved tampers to a height of at least one foot above the utility pipe or conduit. The backfill shall be brought up evenly on both sides of the pipe for the fill length of the pipe. Care shall be taken to ensure through compaction of the fill under the haunches of the pipe. Higher than one foot above the utility pipe or conduit, backfill and compact as specified for under building slabs or under lawn or unpaved areas.

3. In the pool bottom below the wall cut-off line, install a layer of concrete debris. Debris layer thickness shall be no more than the larger of 6” or the thickness of individual pieces of concrete/masonry rubble. Install a layer of borrow over the concrete. Operate a vibratory compactor over the entire surface until the sand fill is worked in between the concrete debris. Repeat the layer process until all of the pool area concrete and masonry debris is disposed in the pool or until the pool wall cut-off elevation is reached.

4. Under lawn or unpaved areas including area above the pool concrete debris disposal: Scarify and recompact top 6 inches of existing grade. Add fill in layers not to exceed 12” and compact with vibratory roller until no more deformation occurs.

5. Under concrete walks, shape and compact the subgrade until no more deformation occurs.

1.10 compaction of base course

A. Place and compact the aggregate base in layers that not to exceed 4” thickness. Compact each layer with a vibratory steel roller until no more deformation occurs. Make a minimum of three passes. Scarify, blade and compact as necessary to obtain a uniform, flat base for installation of the precast modular building.

1.11 grading

A. General: Uniformly grade areas to a smooth surface, free from irregular surface changes. Comply with compaction requirements and grade to cross sections, lines, and elevations indicated.

1. Provide a smooth transition between adjacent existing grades and new grades.

spec writer: delete subparagraph below if finish grade is not in a manicured area.

2. Cut out soft spots, fill low spots, and trim high spots to comply with required surface tolerances.

B. Site grading at pool site: Slope grades to direct water away from buildings and to prevent ponding.

C. Site grading at borrow source: Slope the area within 20’ of the lagoon cells away from the lagoons at 2% or less. Reduce the existing steep slopes along the north and east fence to the extent possible.

D. Grading inside Building Lines: Finish subgrade to a tolerance of 1/2 inch (13 mm) when tested with a 10-foot straightedge.

spec writer: include subparagraphs below if finish grade is not in a manicured area.

1.12 Finishing Slopes:

A. Finished slopes shall conform reasonably to the lines staked on the ground or shown on the drawings. The finished slope shall be left in a roughened condition to facilitate the establishment of vegetative growth. Loose rock, loose debris, and other loose material shall be removed from the slope.

1.13 protection

A. Protecting Graded Areas: Protect newly graded areas from traffic, freezing and erosion. Keep free of trash and debris.

B. Repair and reestablish grades to specify tolerances where completed or partially completed surfaces become eroded, rutted, settled, or where they lose compaction due to subsequent construction operations or weather conditions.

1. Scarify or remove and replace soil material to depth as directed by CO, reshape and recompact.

C. Where settling occurs before Project correction period elapses, remove finished surfacing, backfill with additional soil material, compact, and reconstruct surfacing.

1. Restore appearance, quality, and condition of finished surfacing to match adjacent work, and eliminate evidence of restoration to the greatest extent possible.

1.14 surface finish

A. In unpaved areas topsoil the steepest slopes with the available stockpiled topsoil.

END OF SECTION 02300

02300 - 4

EARTHWORK