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UPH Barracks
Fort Hunter Liggett, CA
3.2.3
***Safety Pays***
Certified Final Submittal
W912QR-13-R-0038
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
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 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. Operate dewatering system
continuously until construction work below existing water levels is
complete. Submit performance records weekly.
3.2.5
Trench Excavation Requirements
The trench shall be excavated as recommended by the manufacturer of the
pipe to be installed. Trench walls below the top of the pipe shall be
sloped, or made vertical, and of such width as recommended in the
manufacturer's installation manual. The Geotechnical Engineer shall provide
trench excavation, slope, and shoring design and requirements to be
implemented by the Contractor for pipe trenches and protection of
personnel. Special attention shall be given to slopes which may be
adversely affected by weather or moisture content. The trench width below
the top of pipe shall not exceed 24 inches plus pipe outside diameter
(O.D.) for pipes of less than 24 inches inside diameter and shall not
exceed 36 inches plus pipe outside diameter for sizes larger that 24 inches
inside diameter. Where recommended trench widths are exceeded, redesign,
stronger pipe, or special installation procedures shall be utilized by the
Contractor. The cost of redesign, stronger pipe, or special installation
procedures shall be borne by the Contractor without any additional cost to
the Government.
3.2.5.1
Bottom Preparation
The bottoms of trenches shall be accurately graded to provide uniform
bearing and support for the bottom quadrant of each section of the pipe.
Bell holes shall be excavated to the necessary size at each joint or
coupling to eliminate point bearing. Stones of 3 inches or greater in any
dimension, or as recommended by the pipe manufacturer, whichever is
smaller, shall be removed to avoid point bearing.
SECTION 31 00 00.00 06
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