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.01 Excavation--Backfill
  1. Proper placement of all erosion-control facilities shall occur prior to any earthwork activity.
  2. Puddling will not be permitted.
    1. All backfill must be mechanically tamped, in layers not to exceed 6 inches in depth, and thoroughly compacted to prevent settlement.
  3. If blasting is required, refer to standard blasting requirement, Section F.
  4. Unclassified Excavation:
    • All excavation for projects funded by the University will be unclassified and will include (without limitation thereto) the excavation and removal of all soil, shale, rock or rock formations, boulders, existing foundations, fill, and any type of subsurface condition encountered in the contract area.
    • No claims for extra compensation or extension of contract time because of the nature of subsurface conditions encountered will be considered by the University.
  5. General:  All excavation shall be to the lines and grades as shown:
    1. Six inches below finished grades in seeded areas.
    2. To grades indicated at paved areas minus thickness of base course and surface materials.
    3. Where new work meets existing, grades shall be adjusted to allow new work to meet and match existing finished grades at paved areas.
  6. Excavation shall provide sufficient clearance for bracing, shoring, formwork, inspection and installations, as required.
  7. The bottoms of all excavations shall be trimmed, by hand if necessary, to grades indicated or required.
  8. The Contractor, at his option, shall make any exploration of the subgrade and areas requiring excavation as he may see fit, at his own cost and expense.
    1. Prior to starting any excavation, the Contractor shall thoroughly familiarize himself with the location of all existing underground utilities that may be affected by his work.
    2. All excavation within three feet of any existing underground utility line shall be accomplished by hand labor.  Extreme caution shall be used in this area to prevent any damage to existing facilities.
    3. All underground utilities and/or facilities uncovered or exposed shall be adequately protected by the Contractor, as necessary.  Utilities serving existing facilities must not be interrupted until the Contractor has made the necessary arrangements with and received approval from the University.
  9. All existing topsoil shall be removed to a depth of six inches and stockpiled on the site.  All topsoil is the property of the University.  Excess topsoil removed and not required for finish grading shall be removed by the Contractor and stockpiled as directed by the University at a location on University property.
  10. Excavated materials to be used for filling may be stored at the site.
  11. Excavated materials not required or not suitable for filling or other purposes shall be hauled from the site as excavated and disposed of off University property.

.02 Stockpiling, Furnishing, and Placing Topsoil

 

  1. General
    1. Intent:
      1. The work in this section includes the labor, materials, and installation methods for the separation and salvaging of topsoil, furnishing of topsoil from an outside source and the placing of topsoil.
    2. Protection of Existing Utilities
      1. Prior to any work being performed the Contractor shall insure that all existing utilities within and surrounding the project site have been clearly marked in accordance with the Pennsylvania Underground Utility Line Protection Act, Act 287 as amended by Act 199.
    3. Quality Assurance:
      1. Topsoil shall consist of friable surface soils reasonably free of grass, roots, weeds, sticks, rocks or other unsuitable materials as determined under Part A.4. – Submittals.
    4. Submittals:
      1. Salvaged and Stockpiled Topsoil:
        1. Prior to the start of any seeding activity, the Contractor shall have the existing soil tested by an approved soils testing laboratory.  Copies of the soil test results shall be furnished to the University Representative prior to any grading, excavating, or other construction activity.
      2. Furnished Topsoil:
        1. The Contractor shall have the soil tested by an approved soils testing laboratory and shall make copies of the soil test available to the University Representative prior the hauling or delivery of any soil to the project site.
        2. The Contractor shall submit a one-gallon sample, source, and letter of certification from the supplier to the University Representative for approval prior to installation.
    5. Delivery, Storage, and Handling:
      1. Stockpiling
        1. Select a stockpile location to avoid slopes and natural drainageways, and to avoid traffic routes.  Perimeter pollution controls shall be implemented as outlined in 31 01 00.01 - Earth Disturbance Management Guidelines and as outlined on the Erosion and Sedimentation Control Plan.  Stockpiles shall not exceed 35’ above grade.
    6. Job Conditions:
      1. Areas where topsoil will be placed will be free of waste or debris developed by other trades.  Any discrepancy from such conditions shall be reported to the University Representative before beginning any installation.
  2. Materials
    1. Salvaged and Stockpiled Topsoil: 
      1. Acceptable friable loam that is reasonably free of subsoil, clay, brush, roots, weeds, other objectionable vegetation, stones, other foreign material larger than 2 inches in any dimension, litter, and/or other material unsuitable or harmful to the growing of vegetation.
    2. Furnished Topsoil: Same criteria as outlined for Salvaged and Stockpiled Topsoil and containing not less than 2.0% or more than 10% organic matter.  The soils shall be obtained from a site where the soil quality has proven ability to grow crops.
      1. The Contractor is responsible for the reconditioning of the area from which the topsoil is obtained, and in accordance with all Local, State, and Federal regulations.
      2. The contractor shall supply necessary documentation verifying that topsoil is free of contamination.
  3. Execution
    1. Protection of Existing Soils and Vegetation:  All existing vegetation to remain shall be protected at all times in accordance with sections 31 01 00.04 - Soil Protection Zones and 32 90 00.01 - Tree Canopy / Tree Root Protection Zones.
    2. Preparation of the Subgrade:
      1. Using acceptable methods, the Contractor shall loosen the subgrade to a depth of 6 inches or otherwise required to provide adequate drainage before placing the topsoil.  Remove stones and other foreign materials 2 inches or larger in any dimension. Remove stones and other foreign materials 2 inches or larger in any dimension.  Remove and satisfactorily dispose of unsuitable and surplus material.
      2. Areas on a project site that were originally paved such as parking lots, sidewalks, patios, plazas or similar shall be completely removed including all base material and compacted subgrade, no matter the depth of these conditions.  Backfill need not be topsoil but rather fill soil as approved by the University Representative up to the required depth or 6 inches as outlined in 32 90 00.02 – Lawns and Grasses or 12 inches as outlined in 32 90 00.03 – Trees, Shrubs, and Groundcovers.
      3. Temporary construction access roads, laydown areas, crane pads, or similar that were installed during the construction of the facility shall be completely removed, no matter the depth, prior to placing topsoil.  The entire depth shall then be backfilled using approved soil.  Backfill need not be topsoil but rather fill soil as approved by the University Representative up to the required depth or 6 inches as outlined in 32 90 00.02 – Lawns and Grasses or 12 inches as outlined in 32 90 00.03 – Trees, Shrubs, and Groundcovers.
    3. Spreading of Topsoil:
      1. Spreading shall not be conducted when the ground or topsoil is frozen, excessively wet as to render it not friable (i.e. not readily crumbled), or otherwise in a condition detrimental to uniform spreading operations.
      2. Topsoil shall be spread to the following depths:
        1. Turf Areas (Seed or Sod): Minimum depth of 6 inches as outlined in 32 90 02-Lawns and Grasses .
        2. Planting Beds:  Minimum depth of 12 inches as outlined in 32 90 03-Trees, Shrubs ,and Groundcovers.
    4. Finishing of Topsoil:
      1. The topsoil surface shall be left reasonably smooth and without ruts or surface irregularities that could contribute to concentrated water flow down slope or surface ponding conditions,  Rake and grade planting beds.
      2. Compact the topsoil enough to ensure good contact with the underlying soil, but avoid excessive compaction, as it increases runoff and inhibits seed germination and seedling growth. This is particularly important adjacent to sidewalks and other fixed built features.
      3. All topsoil areas are to be finished in accordance with specified planting type for that area.  Reference:
        1. 32 90 00.02 - Lawns and Grasses
        2. 32 90 00.03 - Trees, Shrubs, and Groundcovers
    5. Percolation Rate Test
      1. Quantities
        1. Trees Pits: Test 1 out of every 5 tree planting pits, spaced uniformly across the site.
        2. Planting Beds: A minimum of 1 test for every planting bed.  For larger beds 1 test for every 1,000 sf of bed area, spaced uniformly over the entire planting bed.
        3. Turf Areas: A minimum of 1 text for every 5,000 sf of turf area, spaced uniformly over the entire turf area.
      2. Execution
        1. With a shovel or posthole digger, dig a hole 18”-24” deep with a minimum diameter of 4”.  The diameter of the hole should be uniform from top to bottom with the bottom being flat.
        2. Fill hole with water to the top and let stand for at least an hour to pre-wet the soil.
        3. Refill hole to within a couple inches of the top.  Don’t overflow the hole.
        4. Allow the hole to drain for at least one hour and measure the drop in water level.
        5. Results

          <1” per hour

          Poorly drained; Contact University Representative for mitigation

          ½”-1” per hour

          Moderately drained; Acceptable for most species; Review plant types to determine suitability

          >1” per hour

          Well drained; Suitable for all species

  4. Maintenance:
    1. Once all topsoil areas have been finished and ready for planting and/or seeding, no vehicles will be allowed to drive on the placed topsoil at any time.
  5. Inspections:
    1. Pre-grading Inspection:  Prior to the commencement of site work, contact the University Representative to provide an inspection to verify the delineation and protection of native soils and vegetation to remain in place, as outlined in 32 90 00.01 - Tree Canopy / Tree Root Protection Zones and 31 01 00.04 - Soil Protection Zones.
    2. Interim Grading Inspection: Prior to the placement of topsoil, contact the University Representative to provide an inspection of the subgrade.  Make corrections and adjustments as directed by the University Representative.
    3. Post Grading Inspection: Prior to planting and/or seeding, contact the University Representative to provide an inspection to verify that the placement of soil and soil preparation is consistent with guidelines listed in this specification and on the grading plan.  Make corrections and adjustments as directed by the University Representative.
    4. Final Inspection:  After all planting, seeding, sodding, paving, and/or other construction related activities are complete the Contractor shall contact the University Representative to provide an inspection to verify that all conditions are as stipulated in this specification.  Make corrections and adjustments as directed by the University Representative.
    5. Secondary Verification for Failing Sites:  If the University Representative determines that the installation does not meet the conditions outlined in this specification or on the approved grading plan, additional testing by an independent soils testing laboratory will be ordered by the University Representative and paid for by the Contractor.  Make corrections and adjustments as directed by the University Representative.
  6. Establishment Period:
    1. All Establishment Periods pertaining to 32 90 00.02 - Lawns and Grasses and .03 - Trees, Shrubs, and Groundcovers will pertain to the establishment of topsoil on the project site.  If at any time during the 120 day Establishment Period it is determined that the topsoil does not meet the conditions outlined in this specification or on the approved grading plan, the University Representative reserves the right for additional testing, paid for by the Contractor, to determine the correct course of action.
  7. Acceptance:
    1. Final acceptance for soil preparation will be contingent on the approval of all inspections and that the soil preparation is consistent with these specifications and with the approved grading plan.

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