[Res. 97-6, 6/11/1997, Part 1]
1. Description.
A. Work Included. Backfill, compact and restore utility trenches to
match the existing elevations as specified herein and as needed to
meet the requirements of other local codes.
2. Quality Assurance.
A. Use an adequate numbers of skilled workmen, including supervisory
personnel, who are thoroughly trained and experienced in the necessary
crafts and who are completely familiar with the specified requirements
and the methods needed for the proper performance of the work.
B. Use equipment adequate in size, capacity and number to accomplish
the work in a timely manner.
C. Comply with requirements and directions of governmental agencies
having jurisdiction.
[Res. 97-6, 6/11/1997, Part 2]
1. Backfill Materials.
A. Suitable Material.
(1)
Suitable material is that material removed from the excavation
or imported from off-site borrow areas subject to the approval of
the Board of Commissioners.
(2)
Provide soil materials free from organic matter, debris and
deleterious substances, containing no rocks or lumps over six inches
in greatest dimension, and with no more than 15% of the rock or lumps
larger than two inches in their greatest dimension.
(3)
Provide material meeting the following specifications:
(a)
Required density, percentage of standard proctor:
1)
Within top two feet: 95%.
(b)
Tolerable range of moisture about optimum: 2%.
(c)
Minimum California bearing ratio: five.
(d)
For clay materials, compaction moisture and density shall be
determined through material testing to minimize expansion and to provide
the required CBR value.
B. Select Material.
(1)
If suitable material is unavailable or unacceptable, provide
select material (2RC) consisting of durable bank or crushed gravel,
stone or slag, mixed or blended with suitable filler materials to
provide a uniform mixture.
(2)
Use material free from vegetation, organic matter, lumps, excessive
clay, foreign substances and not more than 10% of deleterious shale
by weight.
(3)
Material shall conform to the following gradation, determined
in accordance with PTM No. 619:
(a)
Passing two-inch sieve: 100%.
(b)
Pass No. 4 sieve: 15% to 60%.
(c)
Passing No. 100 sieve: 0% to 30%.
2. Bituminous Material.
A. Bituminous Concrete Base Course. All material shall conform to PennDOT
Publication 408, latest edition, § 305.
B. Bituminous Wearing Course ID-2 (Standard). All material shall conform
to PennDOT Publication 408, latest edition, § 420.
C. Other Bituminous Materials. All material shall conform to PennDOT
Publication 408, latest edition.
[Res. 97-6, 6/11/1997, Part 3]
1. Surface Conditions. Upon completion of utility work, examine the
work area and conditions and correct any detrimental conditions. These
shall include but not be limited to trench dewatering, removal of
unstable soils and removal of debris.
2. Backfilling.
A. Placing and Compacting.
(1)
Place backfill material in level horizontal layers not more
than eight inches in loose depth.
(2)
Before compacting, moisten or aerate each layer as necessary
to provide the optimum moisture content.
(3)
Compact each layer to the required percentage of maximum density
as follows:
(a)
Within top two feet: 95%.
(4)
Do not place backfill on surfaces that are muddy or frozen or
that contain frost or ice. Do not use backfill that is frozen or contains
ice.
(5)
Place backfill evenly adjacent to structures. Take care to prevent
wedging action of backfill against structures by carrying material
uniformly around the structure.
(6)
Place backfill material to within 12 inches of the adjacent
paving elevation.
3. Paving Restoration.
A. Temporary.
(1)
After completion of trench backfill and compaction, place an
eight-inch layer of select material in two lifts and compact.
(2)
Place a two-inch course of temporary bituminous material and
compact with a roller weighing not less than eight tons. The temporary
paving shall be maintained to provide a firm and level road surface
until such time as permanent restoration is completed.
(3)
The temporary paving shall remain for a period of at least one
month or as directed.
B. Permanent.
(1)
After expiration of the one-month period or as directed, the
paving shall be mechanically cut back 12 inches from the edge of the
trench. The area shall be excavated to a depth of eight inches, and
the subgrade shall be compacted. All excavated material shall be removed
from the site.
(2)
Place a minimum six-inch layer of bituminous concrete base course
(BCBC) in two lifts of three inches each. Compact each lift with a
roller weighing not less than eight tons.
(3)
Place a two-inch layer of ID-2 wearing course and compact with
a roller weighing not less than eight tons.
(4)
All joints in the paving shall be sealed with a twelve-inch-wide
strip of AC-20 sealer applied by pressure distribution. The sealer
shall be coated with sand or cement to allow traffic movement over
the joint.
(5)
All striping and pavement markings shall be restored.
4. Traffic and Maintenance Protection.
A. All traffic control shall be in accordance with PennDOT Publication
203.
B. No road closures or detours shall be established without approval
of the appropriate agency.
C. All trenches left below the existing road surface shall be protected
by a steel plate to allow unimpeded traffic flow.