3.2.2
Drainage Structures
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NOTE: The last two sentences will be removed except
when pile foundations are to be used.
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Excavations shall be made to the lines, grades, and elevations shown, or as
directed. 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, level,
stepped, or serrated surface. Loose disintegrated rock and thin strata
shall be removed. When concrete or masonry is to be placed in an excavated
area, the bottom of the excavation shall not be disturbed. Excavation to
the final grade level shall not be made until just before the concrete or
masonry is to be placed. Where pile foundations are to be used, the
excavation of each pit shall be stopped at an elevation 300 mm 1 foot above
the base of the footing, as specified, before piles are driven. After the
pile driving has been completed, loose and displaced material shall be
removed and excavation completed, leaving a smooth, solid, undisturbed
surface to receive the concrete or masonry.
3.2.3
Drainage
Provide for the collection and disposal of surface and subsurface water
encountered during construction. Completely drain construction site during
periods of construction to keep soil materials sufficiently dry. The
Contractor shall establish/construct storm drainage features (ponds/basins)
at the earliest stages of site development, and throughout construction
grade the construction area to provide positive surface water runoff away
from the construction activity and/or provide temporary ditches, swales,
and other drainage features and equipment as required to maintain dry
soils. When unsuitable working platforms for equipment operation and
unsuitable soil support for subsequent construction features develop,
remove unsuitable material and provide new soil material as specified
herein. It is the responsibility of the Contractor to assess the soil and
ground water conditions presented by the plans and specifications and to
employ necessary measures to permit construction to proceed.
3.2.4
Dewatering
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NOTE: Check depth of proposed utilities and
foundations relative to the existing ground water
elevation prior to editing.
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Groundwater flowing toward or into excavations shall be controlled to
prevent sloughing of excavation slopes and walls, boils, uplift and heave
in the excavation and to eliminate interference with orderly progress of
construction. French drains, sumps, ditches or trenches will not be
permitted within 0.9 m 3 feet of the foundation of any structure, except
with specific written approval, and after specific contractual provisions
for restoration of the foundation area have been made. Control measures
shall be taken by the time the excavation reaches the water level in order
to maintain the integrity of the in situ material. While the excavation is
open, the water level shall be maintained continuously, at least [_____] m
feet below the working level. [Operate dewatering system continuously
SECTION 02300
Page 24
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