A.
Soil erosion. All soil erosion control devices shall be installed
in accordance with the sequence of construction shown on the approved
soil erosion control plan.
B.
Grading. The entire site for all new developments shall be graded
to within six inches of the finish grade prior to the construction
of any permanent improvements.
C.
Materials. No secondhand or salvage materials will be allowed without
prior approval by the Director.
D.
Staking requirements. Staking and layout shall be performed by a
registered land surveyor or registered civil engineer. The following
are the minimum requirements for staking:
(1)
Sanitary sewer, storm sewer and water main.
(a)
Records (cut sheet) shall be provided to the contractor and
inspector prior to construction.
(b)
Stakes for alignment and grades shall be set at fifty-foot intervals
and at all deflection points and changes in slope.
(c)
Top of casting grades shall be provided at all structures.
(d)
Two witness stakes shall be provided at all hydrants, road catch
basins and for other structures where more-precise locations are required.
(2)
Grading. Stakes may be set at one-hundred-foot intervals for enough
grading. Stakes for finish grading must be placed at fifty-foot intervals
and at all high and low points.
(3)
Road and drives. Stakes for alignment and grades shall be placed
on both sides of the road or drive at fifty-foot intervals and at
all points of curvature. Radii stakes must be placed. A radius point
stake shall be placed and protected at each curve.
The contractor shall do all the excavation required for the
construction of the project, including clearing of the site for the
work, and the removal and disposal of all materials necessary for
construction.
A.
Excavated materials may be temporarily stored along the trench, unless
otherwise noted, in a manner that will not cause damage to trees,
shrubs, fences or other property, nor that will endanger the bank
stability of the trench by imposing too great a load thereon.
B.
Excavations shall be adequately braced and/or sheeted to prevent
caving or squeezing of the soil, or disturbing existing utilities
or pavement, and shall be completely dewatered prior to construction
of the sewer.
C.
The subgrade shall be accurately prepared to line and grade so that
the pipe, when laid, shall have uniform bearing upon the approved
backfill, throughout its length.
D.
The trench shall be backfilled closely behind the pipelaying. Unless
otherwise directed or permitted by the Director, the backfilling shall
follow at least two lengths behind pipelaying and shall be completed
to the top of the trench not more than 10 lengths behind pipelaying.
E.
Pavement cutting, maintenance and reinstatement shall be done in
a manner satisfactory to the WCDPS and the Director.
F.
Excavations which are to be left open overnight shall be completely
enclosed with suitable fencing and have adequately lighted barricades,
unless approved otherwise by the Director.
Pipe bedding defined. "Pipe bedding" is defined as that material
placed from a minimum of four inches below the pipe to the spring
line of the pipe. It shall consist of stone or sand, and noted on
the bedding detail. The bedding shall be removed under the bell so
that the pipe barrel will be uniformly supported for its full length.
A.
The bedding material shall be placed and compacted uniformly on both
sides of the pipe to prevent lateral movement. Mechanical methods
of tamping shall be used when it is possible to do so without damaging
the pipe. Bedding shall be placed in layers of six inches or less,
as necessary to obtain thorough compaction around the pipe.
B.
In the event density testing becomes necessary to resolve a question
of the sufficiency of compaction of bedding material, the minimum
acceptable density shall be 95% of maximum density, as determined
by the AASHTO T180 method.
C.
Sand shall conform to granular material Class II, as defined in MDOT
8.02.05.
D.
Unless otherwise authorized by the Director, all excavations shall
be backfilled at least to a point one foot above the pipe immediately
after installation.
Concrete cradle shall be constructed using MDOT Grade P1 concrete.
The cradle shall extend up on the sides of the pipe to a horizontal
plane located a minimum of 1/4 the outside diameter of the pipe above
the bottom of the pipe. The pipe shall be anchored to prevent floating
during the concrete pour.
A.
Handling material.
(1)
Care shall be taken to prevent the coating of cast- or ductile-iron
pipe from being damaged. Pipe, valves, hydrants and fittings strung
along the route shall be placed so that they will not be submerged.
Dropping of material directly from a truck or platform is prohibited.
(2)
All pipe and castings shall be carefully examined for defects before
being placed. If the Director finds any materials to be defective,
said materials shall be removed from the site by the contractor.
B.
Cleaning pipe and fittings.
(1)
All lumps, blisters and excess coal tar coating shall be removed
from both the bell and spigot ends of each length of pipe and each
fitting. The outside of each spigot and the inside of each bell shall
be wiped clean dry and free from oil or grease immediately prior to
installation. The inside of the pipe shall be free of dirt and debris.
(2)
Any damage to exterior pipe coating shall be repaired with an approved
coating before the pipe is laid.
C.
Laying pipe.
(1)
Pipelaying operations shall follow immediately behind the excavation.
(2)
Pipe shall be laid upstream from the lower end of sewer with bell
ends upgrade. The use of brick, lumps of clay, wood, etc., to level
the pipe will not be permitted. Under no circumstances shall pipe
be dropped directly into the trench.
(3)
All pipe shall be laid to line and grade as called for on the plans.
The trench shall be excavated to provide equal clearance on both sides
of the pipe. After the pipe is set, care shall be taken in backfilling
so as not to disturb its line or grade. As work progresses, the interior
of the pipe shall be thoroughly cleaned. At all times, the open ends
of the pipe shall be covered to prevent foreign matter from entering.
(4)
When the trench contains water, the exposed end of the pipe shall
be closed with a watertight plug. If water is in the trench, the seal
shall remain in place until the trench is pumped completely dry.
D.
Width of trench.
(1)
If the maximum trench widths noted on the plans are exceeded, the
contractor shall construct a concrete cradle, or other type of approved
bedding, to provide support for the additional load.
(2)
When sand bedding is used, the maximum trench widths shall be used
to permit compaction of the bedding around the pipe.
(3)
If stone bedding is used, a minimum of six inches of clearance shall
be provided on each side of the pipe.
A.
General requirements. All backfill material shall be free from cinders,
refuse, vegetation or organic matter, boulders, rocks, or stones,
frozen earth, or other material which, in the opinion of the Director,
is unsuitable.
(1)
Backfilling to grade shall not fall more than 100 feet behind pipelaying
unless otherwise permitted by the Director. In locations where compaction
of the backfill to a specific density is not required by these standards,
or on the plans, backfill shall be machine-placed to ninety-percent
maximum unit density. Excavated material, other than blue clay and
organic material, shall be compacted in lifts of not over 12 inches
loose measure.
(2)
Settlement occurring in trenches within one year after acceptance
of the work shall be filled, regraded and restored with sod or topsoil,
seed and mulch by the contractor upon request by the Township.
(3)
The trench backfill under existing and proposed streets, alleys,
sidewalks, drives and parking areas shall be of granular material
MDOT Class II placed in layers not exceeding 12 inches in depth and
thoroughly compacted. This backfill shall include the area located
under the pavement to a point to the outside of shoulders or three
feet from back of curb and thence down on a ratio of one-to-one slope,
unless otherwise required by the governing agency having jurisdiction
over the area affected. The minimum acceptable density shall be 95%
of maximum density as determined by the AASHTO T180 modified method.
The maximum thickness of each layer shall generally be no greater
than 12 inches and in all cases shall be of such thickness that the
equipment used will provide density for the full depth of the backfill.
In all cases, this fill shall be constructed to elevation determined
by the proposed surface grade.
(4)
For sidewalks, the sand backfill shall be constructed to the original
sidewalk grade and maintained until the sidewalk is replaced.
B.
Backfilling in freezing weather. No frozen material shall be buried
below the final elevation of ground. At no time shall frozen materials
be permitted for use as backfill, under pavement structures, or public
roads.
C.
Backfilling around structures. All backfill placed within three feet
of all structures shall be granular material MDOT Class II placed
in one-foot layers, and compacted, after the structure and/or exterior
masonry plaster has set up sufficiently to resist damage. Backfilling
shall be performed in a manner that will not cause unequal pressure
on the structure.
A.
Pipe and pipe appurtenances must be supported on a firm foundation.
The trench bottom shall remain stable during pipelaying and all subsequent
operations.
B.
When unstable trench bottoms (wet clays, sands, etc.) are encountered,
it will be necessary to excavate below design depth to stable, noncompressible
ground and backfill to grade with approved select materials (slag,
crushed stone, gravel, etc.) 1/4 inch to 3/4 inch in size.
C.
Where organic materials (peat, marl, muck, etc.) exist at the trench
bottom, it shall be necessary to remove such material down to stable
soils and backfill to grade with the aforementioned select materials.
Where the material below plan grade is unstable to such a depth that
it cannot be removed and replaced with an approved material, the contractor
shall construct supports as directed by the Director.
Unstable or unsuitable material shall be removed. The embankment
shall be of suitable material with one vertical on two horizontal
fill slopes and shall be placed in one-foot layers to the proposed
top of pipe, and compacted top 95% of maximum density as determined
by the AASHTO T180 method. The embankment shall be 12 feet wide plus
four times the diameter of the pipe.
Rocks, boulders, and stones over two inches in diameter shall
be removed to provide a clearance of at least six inches from any
part of the pipe or appurtenances.
When trees are to be saved, the following rules apply:
A.
Trees two inches in diameter or less may be removed, temporarily
planted, and then replanted to the final location.
A.
Requirement. Steel casings shall be bored and jacked in any areas
which, in the opinion of the Director, are considered to be detrimentally
affected by open-cut construction. The open cutting of public paved
roadways will not be permitted.
B.
Materials.
(1)
Casing pipe. Steel casing pipe shall be electric-fusion welded pipe,
conforming to the requirements of ASTM A-39, Grade B, with minimum
wall thickness indicated below, or as required by the WCDPS where
it has road jurisdiction. Pipe ends shall be prepared for field welding
of circumferential joints.
|
Nominal Size
(inches)
|
Nominal Outside Diameter
(inches)
|
Wall Thickness
(inches)
| |
|---|---|---|---|
|
6
|
6.625
|
0.188
| |
|
8
|
8.625
|
0.188
| |
|
10
|
10.750
|
0.188
| |
|
12
|
12.750
|
0.188
| |
|
14
|
14.000
|
0.250
| |
|
16
|
16.000
|
0.250
| |
|
18
|
18.000
|
0.250
| |
|
20
|
20.000
|
0.250
| |
|
24
|
24.000
|
0.250
| |
|
30
|
30.000
|
0.312
| |
|
36
|
36.000
|
0.312
| |
|
42
|
42.000
|
0.438
| |
|
48
|
48.000
|
0.500
| |
|
54
|
54.000
|
0.563
|
(2)
Carrier pipe. Pipe materials shall conform to that specified in the
applicable sections of these standards.
(3)
Pipe skids. Necessary skidding materials required to protect the
pipe during installation shall be approved by the Director and furnished
by the contractor.
C.
Installation.
(1)
Casing pipe. Casing pipe shall be installed in a continuous auguring
(or mining) and jacking operation with the casing pipe installation
following directly behind the face of the excavation. Water shall
not be introduced during the boring-jacking operation.
(2)
Grouting. The annular space between the outside surface of carrier
pipe and the inside surface of casing pipe shall be pressure-grouted
with approved materials. The diameter of the casing pipe shall be
of sufficient size to ensure proper placement of the pipe to plan
line and grade and to allow the proper installation of pressure-grouted
material. The ends of the casing pipe shall be closed with a masonry
bulkhead at least eight inches thick.
(3)
Minimum boring distances. All work shall be performed from boring
and jacking pits adequately sheeted to prevent damage to the roadway,
railway, etc. The minimum distance from the edge of the pavement to
the trench or boring and jacking pit for dual-highway and interstate
routes shall be 30 feet. For curb or guardrail section, railway track,
or two-lane highway, the minimum distance will vary from shoulder
point to the toe of slope as shown on the plans or directed by the
Director.
A.
Clay brick shall conform to the requirements for Grade NA Brick,
ASTM Designation: C32. Brick shall conform to one of the following
sizes, and all brick for any structure shall be the same nominal size:
|
Depth
(inches)
|
Width
(inches)
|
Length
(inches)
| |
|---|---|---|---|
|
2 1/4
|
2 3/4
|
8
| |
|
2 1/2
|
3 3/4
|
8
|
B.
Concrete brick shall conform to the requirements for Grade P-1 brick
ASTM Designation: C55.
C.
Mortar shall consist of one part of masonry cement, or two parts
of mortar sand, measured by volume. The cement and sand shall be mixed
dry to a uniform color in a suitable box of batch mixer and then mixed
thoroughly with water, which shall be added gradually until the required
consistency is obtained.
D.
Masonry cement shall conform to the requirements of the Standard
Specifications for portland cement, ASTM Designation: C150, Type I
or II.
E.
Portland cement for mortar shall conform to the requirements of the
Standard Specifications for portland cement, ASTM Designation: C150,
Type I or II.
F.
Hydrated lime shall conform to the requirements of the Standard Specifications
for Normal Finishing Hydrated Lime, ASTM Designation: C6.
G.
Masonry sand shall conform to the requirements of Michigan Department
of Transportation Standard Specifications.
H.
Concrete shall conform to the current requirements of Michigan Department
of Transportation Standard Specifications.
I.
Water for mortar, for concrete and for testing and flushing mains
shall be potable water.
J.
All block, mortar, and concrete work shall be properly cured and
protected from freezing for a minimum of 48 hours. When the temperature
is 40° F. and falling, block mortar and concrete shall be heated
to a minimum temperature of 60° F.
