[Ord. 1223, 6/9/1975, § II; as amended by Ord.
1437, 3/28/1983, § I; and by Ord. 2288, 4/12/2010]
1.
From and after the effective date of this Part all sanitary sewers constructed in the Township of Ross shall be constructed in accordance with the specifications for sanitary sewers construction, as more fully set forth in § 18-402 hereof, as the same may be amended by resolution from time to time by the Board of Commissioners of the Township of Ross. The standards of construction for sanitary sewers as herein set forth are intended to apply to those sanitary sewers which will be or become Township maintained sanitary sewers.
2.
From and after the effective date of this Part, sanitary sewers to
be constructed in the Township of Ross may be constructed of poly-vinyl-chloride
(PVC) Pipe in accordance with specifications on file in the office
of the Ross Township Building Code Official.
[Ord. 1223, 6/9/1975]
1.
Trench and bed for rigid and flexible pipe.
A.
General. The trench shall have a width specified as follows:
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Specified Trench Width*
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Pipe Size Inside Diameter
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Concrete Pipe
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Metal Pipe
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48 inches and less
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Outside diameter of pipe measured at the bell, plus 1.0 foot
on each side of the pipe.
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Outside diameter of pipe, measured at the end of the pipe section
without band, plus 1.0 foot on each side of the pipe
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Over 48 inches
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Outside diameter of pipe, measured at the bell, plus 1.25 feet
on each side of the pipe.
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Outside diameter of pipe, measured at the end of the pipe section
without band, plus 1.25 feet on each side of the pipe
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NOTES:
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* Specified trench widths may be increased by a tolerance one
foot on each side of the trench.
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When rock, hard, shale, or any unyielding material is encountered in the trench, it shall be excavated for the full width of the trench below the proposed elevation of the bottom of the pipe for a depth of 1/4 inch per foot of fill over the pipe to a minimum depth of 12 inches and a maximum of 24 inches. The trench below the elevation of the bottom of the pipe shall be backfilled with selected fine compressible material and lightly compacted in four-inch layers, or when directed, with coarse aggregate meeting the requirements of § 18-402, Subsection 4B(3). The bed shall be shaped as specified in § 18-402, Subsection 2A, B, or C, for rigid pipe and § 18-402, Subsection 2C, for flexible pipe.
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When the material encountered is unstable, it shall be entirely removed under the pipe for the full width of the trench or as otherwise required for the particular condition, replaced with suitable material compacted to a satisfactory density, and the bed shaped as specified in § 18-402, Subsection 2A, B, or C.
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B.
The trench shall be excavated through natural ground or as specified
herein.
(1)
Where pipe structures with an inside diameter of less than eight
feet are to be placed under embankment, the contractor shall, unless
otherwise directed by the Engineer, complete the construction of the
embankment to a minimum of four feet, where practicable, above the
top of the pipe before placing. Shallow installations, with less than
four feet of cover over the top of the pipe, shall be constructed
after all heavy hauling is completed over the pipe location. Where
running water is encountered and cannot be diverted, a temporary pipe
or structure shall be placed prior to constructing the embankment.
(2)
Where pipe structures with an inside diameter of eight feet
or more are to be placed under embankment, the contractor will not
be required to construct the embankment, and trench, prior to placing
the pipe.
2.
Bedding Classification. Pipe shall be bedded in accordance with the
class of bedding directed by the Engineer:
A.
Class A Bedding. The pipe shall be bedded in a continuous cradle
consisting of Class B concrete (or better), reinforced when directed,
placed under and around the pipe, having a thickness under the pipe
of one-quarter inside diameter but in no case less than four inches,
and extending up each side of the pipe for a depth of 25% of the outside
diameter. The cradle width shall be the outside diameter of the pipe
plus four inches on each side.
B.
Class B Bedding. The trench shall be shaped approximately to the
curvature of the outside surface of the pipe to a minimum depth of
30% of the outside diameter 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. The fine aggregate for use in Class B Bedding shall meet the
requirements of § 703.1(b) or § 703.2 of the PennDOT
From 408.
C.
Class C Bedding. The pipe shall be bedded with care in soil foundation
shaped to fit the pipe exterior to a minimum depth of 15% of the outside
diameter.
3.
Laying Rigid and Flexible Pipe.
A.
All pipe, unless otherwise permitted, shall be placed at least two
weeks prior to placing the base course or pavement. No pipe shall
be placed unless a suitable outlet is provided. Pipe laying shall
begin at the downstream end. The pipes shall be laid carefully in
the bedding, bells, or grooves up grade in shaped recesses when required,
spigot ends fully entered into the hubs, and true to the lines and
grades staked. Batter boards shall be placed at intervals of not over
25 feet, to eliminate sag in the line used in making the installation.
B.
In lieu of using batter boards, the contractor may use a laser beam
system for controlling the pipe alignment.
C.
The grade line shall be cambered if directed to offset anticipated
settlement due to height of embankment and type of bedding used.
D.
The minimum cover over the pipe, under subgrade elevation, shall
be three inches for cast iron pipe, and six inches for all other types
of pipe, unless otherwise indicated or directed.
E.
All pipe shall be laid with mortared joints, except the interlocking
style and pipe joined with bands. Before the succeeding sections of
pipe are placed, the lower 1/2 of the joint shall be plastered with
cement mortar meeting the requirements of § 705.8(a) of
the PennDOT Form 408 to bring the inner surface of the abutting pipe
flush and even. Before placing mortar the pipe shall be wetted with
as much water as it will readily absorb. The outside of the joint
of bell and spigot pipe shall be filled with the plastic mortar flush
with the end of the bell. The joint of tongue and groove pipe shall
be filled flush with the outside surface of the pipe. On the inside
of the pipe, the lower half of the joint shall be filled flush with
mortar, wiped clean, and finished smoothly for all sizes of pipe;
but for twenty-four-inch diameters and over, the joints shall be filled
flush with mortar for the entire inside periphery, and finished smoothly
in the same manner. Voids for lift holes shall be filled with mortar
after the pipe is placed.
F.
Backfilling may proceed immediately after the joints are mortared
as long as the operation avoids damage to the joint, maintains the
pipe in the proper alignment and grade, and provides satisfactory
curing conditions for the mortar.
G.
When permitted by the Engineer, either a preformed joint or a caulking
compound of an approved type may be used to join sections of the pipe
in lieu of cement mortar.
H.
When pipes are protected by endwalls, or connected with drainage
structures, the exposed ends of the pipe shall be placed as directed
by the Engineer, or cut off flush with the face of the structure.
Where pipe culverts are constructed in conjunction with existing drainage
structures, provision shall be made for satisfactory connections.
4.
Backfilling of Trench and Placing Embankment.
A.
After the pipe is laid and approved, the trench shall be backfilled
with coarse aggregate meeting the requirements of § 350.2
of the PennDOT Form 408 to a height of not less than one foot above
the top of the pipe. The remaining height shall be backfilled with
suitable material. All pipe backfill material shall be placed in four-inch
layers, except eight-inch layers will be permitted when approved vibratory
compaction equipment is used and in those areas accessible to the
equipment and provided the backfill material is suitable for testing
for compaction. When coarse aggregate is not specified the entire
trench shall be backfilled with suitable material. Pipe with an inside
diameter of eight feet or more shall be backfilled simultaneously
with the construction of the embankment and as specified herein, and
the limits for coarse aggregate shall be the same as for the trench
condition. All backfilling shall be thoroughly compacted with mechanical
tampers or other approved methods to a density satisfactory to the
engineer.
B.
Rigid Pipe. The embankment over rigid pipe shall not exceed the heights
in the following table for the ultimate strength of the pipe, the
class of bedding, and method of backfilling.
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Ultimate Strength of Pipe
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Case 1, Maximum Embankment in Feet
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Case 2, Maximum Embankment in Feet Imperfect Trench
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|---|---|---|---|---|---|---|---|
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Class of Bedding
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Class of Bedding
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Pipe Class D Load*
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A
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B
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C
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A
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B
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C
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Class I**
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1,200D
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Class II**
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1,500D
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Class III
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2,000D
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25
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15
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13
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121
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44
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33
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Class IV
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3,000D
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40
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23
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18
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142
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69
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53
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Class V
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3,750D
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47
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29
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24
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180
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87
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67
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4,000D***
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NOTES:
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* Ultimate strength of pipe per linear foot when tested by three
edge bearing method, where D is the nominal inside diameter of pipe
in feet.
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** Class I and II shall be used only for special designs.
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*** 4,000 D Cast-Iron Pipe shall be used when cover is shallow
and high impact and concentrated loading are involved.
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(1)
When the depth of material over rigid pipe is equal to or less
than that given in Case 1, the trench shall be backfilled and the
embankment shall be constructed as specified in § 206 of
the PennDOT Form 408.
(2)
Imperfect Trench. When the height of material over a rigid pipe exceeds the maximum as given in Case 1 but is equal to or less than the maximum height as given in Case 2 of the table, an imperfect trench shall be constructed. The pipe culvert shall first be installed in accordance with the requirements for Class A, B, or C bedding. The trench shall be backfilled in accordance with the requirements of § 18-402, Subsection 4A, and the embankment over the culvert shall be constructed in accordance with § 206 of the PennDOT Form 408, to an elevation equal to the outside diameter of the pipe plus one foot above the top of the pipe. Next, a trench equal in width to the outside diameter of the pipe shall be dug in the fill directly over the culvert, down to an elevation of one foot above the top of the pipe. Care shall be taken to keep the sides of this trench as nearly vertical as possible. After the trench is excavated, it shall be refilled with loose, highly compressible earth or other approved material. After the trench is backfilled, the embankment shall be placed and compacted in accordance with § 206 of the PennDOT Form 408.
(3)
Rigid Pipes Placed Through Structures other than Endwalls and
Dry Masonry Walls. Where rigid pipe are placed through structures
other than endwalls and dry masonry walls, they shall be wrapped with
two layers of two-ply bituminous paper over the entire surface of
the pipe so encased.
C.
Materials. The aggregate shall be stone, gravel, or slag meeting
the requirements of § 703.3 of the PennDOT Form 408 for
Type C, or better, No. 2A material. The size and gradation of the
material shall be determined in accordance with PTM No. 619.
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Approved granulated blast-furnace slag will be acceptable. Approved
granulated blast-furnace slag is the glassy granular material formed
when molten blast-furnace slag is rapidly quenched by immersion in
water. Further, it is normally light gray or tan in color and it shall
not weigh more than 90 pounds per cubic foot nor less than 55 pounds
per cubic foot (dry rodded unit weight, PTM No. 609). The material
shall be reasonably uniform and free from harmful amounts of clay,
silt, vegetation or other substances determined to be deleterious.
It shall have a maximum size of two inches and not more than 20% passing
the No. 100 sieve.
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A change in the source of material may be made only with the
written permission of the Engineer. References given are to PennDOT
Form 408, Published in 1973.
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[Ord. 1223, 6/9/1975, §§ II-IV]
From and after the effective date of this Part, all stormwater
drainage facilities constructed in the Township of Ross shall be constructed
in accordance with the specifications for stormwater drainage facilities
construction, as the same may be amended by resolution from time to
time by the Board of Commissioners of the Township of Ross. The standards
for construction for stormwater drainage facilities are intended to
apply to those stormwater drainage facilities which will be or become
Township maintained stormwater drainage facilities.
