The specifications outlined herein are for specific
application to the backfilling of utility trenches, including but
not limited to sanitary sewer, water main, gas, electric, cable and
telephone.
Trench for pipe shall not be wider than twice the
outside diameter of the pipe. The bottom of the trench shall be shaped
carefully to fit the bottom of the pipe for a depth of approximately
30% of the outside diameter of the pipe plus four inches. A fine aggregate
bedding not less than four inches thick shall be placed thereon and
accurately shaped by means of a template to provide a uniform contact
under the pipe. (PennDOT Class B Bedding.) Do not advance trenching
operations more than 100 feet ahead of completed pipeline, except
as specified in the state highway occupancy permit.
Material obtained in trench excavation in the
legal or dedicated right-of-way of existing or proposed Township streets
and state highways shall not be utilized for backfill. Granular material
(PennDOT 2A minimum) shall be used to bed the pipe and to backfill
the pipe within two inches of the road surface.
Temporary repaving of the existing macadam surface
shall consist of one-inch thick ID-2A binder course applied and rolled
prior to opening to traffic. Temporary paving repairs shall be maintained
and repaired or replaced as needed until such time as permanent paving
restoration is made.
Permanent surface restoration within the cartway
of the streets shall consist of excavation to a depth of six inches
below finished grade over the trenches, and a width sufficient to
provide a one-foot wide bearing on undisturbed subgrade on each side
of the trench. The sides of this excavation shall be neatly cut, parallel
lines, and vertical throughout their complete six-inch depth. Upon
completion of the cut back and on a properly prepared subbase, the
contractor shall construct a five-inch thick, when compressed, bituminous
concrete base course, and a one-and-one-half-inch thick, when compressed,
ID-2A bituminous surface course. Construction shall be in accordance
with PennDOT Form 408, latest revision. In no case shall permanent
paving repairs be made in less than 60 days after completion of temporary
repairs unless authorized by the Township Engineer.
In areas outside of existing or proposed legal/dedicated
right-of-way, material obtained in trench excavation may be used for
backfill. Material shall be placed in layers not to exceed four inches
and thoroughly compacted using mechanical tampers. Special care shall
be taken to ensure adequate compaction under the haunches and along
the side of the pipe. Puddling or jetting may be considered if test
demonstrations indicate that compaction requirements can be met.
In areas outside of existing or proposed legal/dedicated
right-of-way, material obtained in trench excavation may be used for
backfill. Material shall be free of any large debris, roots etc.,
and approved by the Township inspector.
Flowable backfill material may be substituted
for the 2A aggregate, within right-of-way, or material obtained in
trench excavation, outside right-of-way, conforming to PennDOT Special
Provision S94 (52060130), Type A or B.
Maintain accessibility to all fire hydrants,
valve pit covers, valve boxes, curb boxes, fire and police call boxes,
and other utility controls at all times. Keep gutters clear or provide
other satisfactory facilities for street drainage. Do not obstruct
natural watercourses. Where necessary, provide temporary channels
to allow the flow of water either along or across the site of work.
In areas where pipelines parallel or cross-streams,
ensure that no material slides, is washed, or is dumped into the stream
course. Remove cofferdams immediately upon completion of pipeline
construction.
Intercept and divert surface drainage away from
excavations. Design surface drainage systems so that they do not cause
erosion on or off the site, or cause unwanted flow of water.