B.
Quality assurance.
(1)
Reference standards.
(a)
(b)
American Society for Testing and Materials (ASTM).
(2)
Testing agency. Compaction testing shall be performed by a PennDOT-approved
soils testing laboratory approved by the municipality.
(3)
Compaction testing.
(a)
Conduct compaction tests as directed by the municipality during
backfilling operations.
(b)
Determine compaction in state highways and shoulders by the
testing procedure contained in PTM No. 106, Method B, or PTM No. 402.
(c)
Determine compaction in areas other than state highways and
shoulders by the testing procedure contained in ASTM D698 or ASTM
D2922.
C.
Submittals.
(1)
Certificates. Submit certification from aggregate suppliers attesting
that the pipe bedding and select material stone backfill materials
conform to the specifications herein.
(2)
Compaction equipment list. Submit a list of all equipment to be utilized
for compacting, including manufacturers' lift thickness limitations.
D.
Job conditions.
(1)
Classification of excavation. Excavation work includes excavation
and removal of all soil, shale, rock, boulders, fill, and all other
materials encountered of whatever nature.
(2)
Compaction of backfill. The degree of compaction required at each location is indicated in the Backfill and Surface Restoration Requirements Table in Article XIII.[2]
[2]
Editor's Note: Said table is included as an attachment to this chapter.
(3)
Control of traffic. Employ traffic control measures in accordance
with Publication 203, Work Zone Traffic Control.
(4)
Protection of existing utilities and structures.
(a)
Take all precautions and utilize all facilities required to
protect existing utilities and structures. Comply with the requirements
of the Pennsylvania Underground Utility Protection Law.[3] Request cooperative steps of the utility and suggestions
for procedures to avoid damage to its lines.
[3]
Editor's Note: See 73 P.S. § 176 et seq.
(b)
Advise each person in physical control of powered equipment
or explosives used in excavation or demolition work of the type and
location of utility lines at the job site, the utility assistance
to expect, and procedures to follow to prevent damage.
(c)
Immediately report to the utility and the municipality any break,
leak or other damage to the lines or protective coatings made or discovered
during the work and immediately alert the occupants of premises of
any emergency created or discovered.
(d)
Allow free access to utility personnel at all times for purposes
of maintenance, repair and inspection.
A.
Pipe-bedding material.
B.
Backfill material.
(1)
Select material backfill. Crushed stone or gravel aggregate conforming
to Select Granular Material (2RC), Section 703.3, Publication 408
Specifications. Do not use slag or cinders.
(2)
Flowable backfill material. Material conforming to PennDOT Special
Provision S94 (S2060130), Type A or B as shown in Table 1.
(4)
Suitable backfill material (other than highways, driveways, and shoulders).
(a)
From top of pipe-bedding material to 24 inches over top of pipe.
Material excavated from the trench if free of stones larger than two
inches in size and free of wet, frozen, or organic materials.
(b)
From 24 inches above pipe to subgrade elevation. Material excavated
from the trench if free of stones larger than eight inches in size
and free of wet, frozen, or organic materials.
|
Table I
| ||||||
|---|---|---|---|---|---|---|
|
Flowable Fill
| ||||||
|
Properties and Criteria
|
Type A
|
Type B
|
Type C
|
Type D
| ||
|
Mix Design (/cy)
| ||||||
|
Cement (lbs)*
|
100
|
50
|
150-200
|
300-700
| ||
|
Fly ash (lbs)*
|
2,000
|
300
|
300
|
100-400
| ||
|
Bottom ash (lbs)*
|
0
|
2,600
|
2,600
|
**
| ||
|
or coarse aggregate
| ||||||
|
or fine aggregate
| ||||||
|
Flow cone (seconds) ASTM C93930-60
|
30-60
|
—
|
—
|
30-60****
| ||
|
Slump (inches) PTM No. 600—
|
—
|
7-11
|
7-11
|
7-11****
| ||
|
Density (pcf) PTM No. 613
|
95-100***
|
120-135***
|
125 min.***
|
30-70 or as specified***
| ||
|
Water absorption of aggregate, PTM No. 506—
|
—
|
—
|
20 (max. %)
| |||
|
Compressive strength (psi) PTM No. 604
| ||||||
|
3 days (minimum
|
25
|
25
|
300
|
40
| ||
|
28 days (range)
|
50-125
|
50-125
|
800 min.
|
90-400
| ||
|
*
|
Quantities may be varied or alternate designs submitted to adapt
mix to meet density and strength requirements or to adapt to specific
site conditions.
|
|
**
|
Requires the use of suitable lightweight aggregate or air-entraining
admixture. Provide a mix design that achieves the specified strength
and density requirements.
|
|
***
|
Approximate value. Use of air-entraining agent may reduce these
values.
|
|
****
|
As appropriate, depending on whether lightweight aggregate or
air-entraining admixture is used to obtain lightweight properties.
|
A.
Maintenance and protection of traffic.
(1)
Maintain traffic in one or more unobstructed lanes and provide access
to all streets and private drives.
(2)
Provide and maintain protective devices as required by state and
local codes, permits, and regulations.
(3)
Notify municipality at least 72 hours in advance of any operations
requiring changes to existing traffic patterns.
B.
Cutting paved surfaces prior to trenching.
(1)
Where installation of pipelines, miscellaneous structures, and appurtenances
necessitate breaking a paved surface, make cuts in a neat uniform
fashion forming straight lines parallel with the center line of the
trench. Cut offsets at right angles to the center line of the trench.
(2)
Protect edges of cut pavement during excavation to prevent raveling
or breaking; square edges prior to pavement replacement.
(3)
The requirement for neat line cuts, in other than state highways,
may be waived if the final paving restoration indicates overlay beyond
the trench width.
D.
Trench excavation.
(1)
Depth of excavation.
(a)
Gravity pipelines.
[1]
Excavate mainline trenches to the required depth and grade for
the invert of the pipe, plus that excavation necessary for placement
of pipe-bedding material.
(b)
Pressure pipelines. Excavate trenches to the minimum depth necessary
to place required pipe-bedding material and to provide a minimum of
42 inches from the top of the pipe to the finished ground elevation,
except where specific depths are otherwise shown on the drawings.
(c)
Where unsuitable bearing material is encountered in the trench
bottom, continue excavation until the unsuitable material is removed,
solid bearing is obtained or can be established, or concrete cradle
can be placed. If no concrete cradle is to be installed, refill the
trench to required pipeline grade with pipe-bedding material.
(d)
Where the contractor, by error or intent, excavates beyond the
minimum required depth, backfill the trench to the required pipeline
grade with pipe-bedding material.
(2)
Width of excavation.
(a)
Excavate trenches, including laterals, to a width necessary
for placement and jointing of the pipe, and for placing and compacting
pipe bedding and trench backfill around the pipe, but not less than
16 inches or more than 24 inches, plus the pipe outside diameter from
the bottom of the trench to a point 12 inches above the crown of the
pipe.
(b)
Shape trench walls completely vertical from trench bottom to
at least two feet above the top of the pipe. Trench walls from two
feet above the top of the pipe to grade to be benched and sloped,
or shaved, to comply with federal and state laws and codes.
(c)
For pressure pipeline fittings, excavate trenches to a width
that will permit placement of concrete thrust blocks. Provide earth
surfaces for thrust blocks that are perpendicular to the direction
of thrust and are free of loose or soft material.
(3)
Length of open trench. Do not advance trenching operations more than
100 feet ahead of completed pipeline, except as specified in the state
highway occupancy permit.
E.
Support of excavation.
(1)
The adequacy of the design of sheeting, shoring and bracing installations
relative to the nature of the material to be encountered and retained
is the sole responsibility of the contractor and no duty is assumed
or to be exercised by the municipality relative thereto.
(2)
Support excavations with sheeting, shoring, and bracing or a trench
box as required to comply with federal and state laws and codes.
(3)
Install adequate excavation supports to prevent ground movement or
settlement of adjacent structures, pipelines or utilities. Damage
due to settlement because of failure to provide support or through
negligence or fault of the contractor in any other manner shall be
repaired at the contractor's expense.
(4)
Removal of sheeting, shoring and bracing as backfilling proceeds
is the contractor's responsibility.
F.
Control of excavated material.
(1)
Keep the ground surface on both sides of the excavation free of excavated
material to comply with federal and state laws and codes.
(2)
Provide temporary barricades to prevent excavated material from encroaching
on private property, walks, gutters, and storm drains.
(3)
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 the work.
(4)
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.
(5)
Work shall be in accordance with approved SESPC plan and guidelines
of the York County Conservation District.
G.
Dewatering.
(1)
Keep excavations dry and free of water. Dispose of precipitation
and subsurface water clear of the work.
(2)
Maintain pipe trenches dry until pipe has been jointed, inspected,
and backfilled, and concrete work has been completed. Prevent trench
water from entering pipelines under construction.
(3)
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.
(4)
Comply with federal and state requirements for dewatering to any
watercourse, prevention of stream degradation, and erosion and sediment
control.
H.
Pipe bedding requirements.
(1)
Type III bedding.
(a)
Depth of pipe bedding aggregate as shown on Standard Detail
DT 02221-1.[1]
[1]
Editor's Note: Said Standard Detail is included as an attachment to this chapter.
(b)
Provide Type III bedding when installing reinforced concrete
storm drain pipe.
(2)
Type IV bedding.
(a)
Depth of pipe bedding aggregate as shown on Standard Detail
DT 02221-1.[2]
[2]
Editor's Note: Said Standard Detail is included as an attachment to this chapter.
(b)
Provide Type IV bedding when installing all other pipes larger
than two-inch diameter.
(3)
Type V bedding.
(a)
Depth of pipe bedding aggregate as shown on Standard Detail
DT 02221-1.[3]
[3]
Editor's Note: Said Standard Detail is included as an attachment to this chapter.
(b)
Provide Type V bedding when installing piping two-inch diameter
and smaller.
(4)
Shape recesses for the joints or bell of the pipe by hand. Assure
that the pipe is supported on the lower quadrant (under haunches)
and the pipe bottom for the entire length of the barrel. Fill all
voids below the pipe.
(5)
Pipe embedment material shall be placed, worked by hand or compacted
until a minimum density of 90% in yards and 95% under roadways and
sidewalks is achieved (at optimum moisture content, ±2%, standard
proctor).
I.
Pipe laying.
(1)
Provide required pipe bedding placed in accordance with the Standard
Details.[4]
[4]
Editor's Note: Said Standard Details are included as an attachment to this chapter.
(2)
Lay pipe as specified in the appropriate section of these specifications
for pipeline construction.
J.
Thrust restraint. Provide pressure pipe with concrete thrust blocking
or use restrained joint fittings at all bends, tees, valves, and changes
in direction, in accordance with the drawings.[5]
[5]
Editor's Note: Said drawings are included as an attachment to this chapter.
K.
Backfilling trenches.
(1)
After pipe installation and inspection, backfill trenches to 12 inches above the crown of the pipe with specified backfill material placed and carefully compact with approved compaction equipment in layers of suitable thickness to provide specified compaction. Backfill and compact the remainder of the trench with specified backfill material. Refer to drawings and Backfill and Surface Restoration Requirements Table in Article XIII for trench backfill material and compaction requirements at each specific location.[6]
[6]
Editor's Note: Said table is included as an attachment to this chapter.
(2)
Lift thickness limitations.
(a)
Submit a list of the compaction equipment to be utilized on
the project, the recommendations of the equipment manufacturer as
to the maximum lift thickness which can be placed, and the method
of compaction to be used with this equipment to achieve the required
compaction. In no case shall maximum lift thickness placed exceed
the maximum limits specified by the manufacturer's recommendations.
However, if the equipment manufacturer's lift thickness recommendation
is followed and the specified compaction is not obtained, the contractor
shall, at his own expense, remove, replace, and retest as many times
as is required to obtain the specified compaction.
(b)
Lift thickness limitations specified for state highways, shoulders,
or embankments shall govern over the compaction equipment manufacturer's
recommendations.
(3)
Jetting. When approved by the municipality in writing, jetting methods
may be used to consolidate backfill. Quality assurance methods to
verify adequate compaction will be a condition of the approval by
the municipality.
(4)
Uncompacted backfill. Where uncompacted backfill is indicated on
the drawings, backfill the trench from one foot above the pipe to
the top of the trench with material excavated from the trench, crowned
over the trench to a sufficient height to allow for settlement to
grade after consolidation, providing for surface water drainage.
(5)
Unsuitable backfill material. Where the municipality deems backfill
material to be unsuitable and rejects all or part thereof due to conditions
prevailing at the time of construction, remove the unsuitable material
and replace with select material backfill.
L.
Disposal of excavated material. Excavated material remaining after
completion of backfilling shall be removed from the construction area
and legally disposed of.
M.
Rough grading.
(1)
Rough subgrade areas disturbed by construction to a uniform finish.
Form the bases for terraces, banks, and lawns.
(2)
Grade areas to be paved to depths required where placing subbase
and paving materials.
(3)
Rough grade areas to be topsoiled and seeded to four inches below
indicated finish contours.
