2.
After the excavation has been made, and before forms are set for footings, mats,
slabs, or other structures, and before reinforcing is placed, all loose or
disturbed material shall be removed from the sub-grade. The bearing surface
shall then be compacted to meet the requirements of this specification.
If, in the opinion of the Engineer, the existing material at sub-grade elevation 1s
unsuitable for structural support, the Contractor shall excavate and dispose of
the unsuitable material to the required width and depth as directed by the
Engineer. If, in the opinion of the Engineer, filter fabric is required; the
Contractor shall place filter fabric, approved by the Engineer, as per
manufacturer's recommendations. Crushed stone shall then be placed in lifts
and compacted to required densities. Backfill shall be placed to the bottom of
the proposed excavation.
D. EXCAVATION NEAR EXISTING STRUCTURES:
1.
Attention is directed to the fact that there are pipes, manholes, drains, and
other utilities in certain locations. An attempt has been made to locate all
utilities on the drawings, but the completeness or accuracy of the given
information is not guaranteed.
As the excavation approaches pipes, conduits, or other underground structures,
digging by machinery shall be discontinued and excavation shall be done by
means of hand tools, as required. Such manual excavation, when incidental to
normal excavation, shall be included in the work to be done under items
involving normal excavation.
Where determination of the exact location of a pipe or other underground
structure 1s necessary for properly performing the work, the Contractor shall
excavate test pits to determine the locations.
3.03 BACKFILL PLACEMENT AND COMPACTION:
A. GENERAL:
1.
2.
Prior to backfilling, the Contractor shall compact the exposed natural sub-
grade to the densities as specified herein.
After approval of sub-grade by the Engineer, the Contractor shall backfill areas
to required contours and elevations with specified materials.
The Contractor shall place and compact materials to the specified density in
continuous horizontal layers. The degree of compaction shall be based on
maximum dry density as determined by ASTM Test D 1557, Method C. The
minimum degree of compaction for fill placed shall be as follows:
Percent of
Location Maximum Density
Below pipe centerline 95
Above pipe centerline 92
Below pavement (upper 3 ft.) 95
Embankments 95
Below pipe in embankments 95
Adjacent to structures 92
Below structures 95
02300-7
