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A. STREETS AND ROADWAYS
- Clearing, Grubbing and Excavation
The entire area within the right-of-way shall be cleared of all
trees, stumps, brush roots, rocks or boulders and all unsuitable
materials. No loam suitable for reuse shall be removed from the
Subdivision unless adequate loam will remain or is otherwise assured
to provide all disturbed areas within the Subdivision with a loam
depth of at least four (4) inches and also that there is assurance
that all streets from which loam is being removed will be brought
to sub-grade with the approved foundation materials within six
(6) months.
The entire area to be occupied by the roadway and an additional
four (4) feet wider than the paved width or extending outward
to the top of slopes in fill areas, shall be excavated a minimum
of fifteen and one-half (15 ½) inches below finished grade
in cut sections or as necessary to remove the topsoil in fill
sections. Only areas directly in path of pavement, sidewalks and
Cape Cod Berms are to be excavated. The Planning Board Engineer
or his representative may require greater depths of excavation
if soft or yielding material detrimental to the sub-grade is encountered.
All fill or undisturbed material shall be non-frost susceptible
for a minimum depth of three (3) feet below the finished road
grade.
- Gravel Base
A minimum of twelve (12) inches of clean gravel, approved by the
Planning Board Engineer, shall be deposited for the full width
of the traveled way and shoulders, so as to form a roadway centerline
grade, allowing for the pavement thickness, below the proposed
finished grade at all points.
The gravel shall be compacted to 98% of the maximum dry density
as determined by the modified Proctor Test in accordance with
ASTMD 1557, Method "D".
Gravel shall consist of the following as set forth in the Standard
Specifications for Highways and Bridges for the Massachusetts
Department of Public Works.
a. M 1.03.0 Gravel Borrow
Gravel Borrow shall consist of inert material that is hard,
durable stone and coarse sand free from loam and clay, surface
coatings and deleterious materials. Gradation requirements for
gravel shall be determined by AASHO-T11 and T27 shall conform
to the following:
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Sieve
½"
#4
# 50
# 200
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Percent Passing
50-85
40-85
8-28
0-8 |
Maximum size of stone in gravel shall be as follows:
Three (3) inch largest dimension.
The following may be considered as alternative specifications
only if the Planning Board Engineer gives approval.
b. M1.03.1 Processed Gravel for Sub-base gravel shall consist
of inert material that is hard, durable stone and coarse sand,
free from loam and clay, surface coatings and deleterious materials.
The coarse aggregate shall have a percentage of wear, by the Los
Angeles Abrasion Test, of not more than 50.
The gradation shall meet the following requirements:
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Sieve
3"
1-1 ½"
¾" 50-80
#4
#200
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Percent Passing
100
70-100
30-60
0-12 (based on fraction passing #4) |
The approved source of bank run gravel shall be processed by
mechanical means. The equipment for producing crushed gravel
shall be of adequate size and with sufficient adjustments to
produce the desired materials. The processed material shall
be stockpiled in such a manner to minimize segregation of particle
sizes. All processed gravel shall come from approved stockpiles
c. M2.01.7 Dense graded crushed stone for sub-base.
This specification covers the quality and gradation requirements
for a sub-base material combining crushed run coarse aggregates
of crushed stone or gravel and fine aggregates of natural sand
or stone screenings uniformly mixed with a pre-determined quantity
of water.
Coarse aggregate shall consist of hard durable particles or
fragments of stone or gravel. Materials that break up when alternately
frozen and thawed or wetted and dried shall not be used.
Coarse aggregate shall have a percentage of wear by the Los
Angeles test, of not more than 42.
Fine aggregate shall consist of natural or crushed sand. The
composite material shall be free from clay, loam or other plastic
material and shall conform to the following grading requirements.
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Sieve
2"
1-1 ½"
¾"
#4
#50
#200
|
Percent Passing
100
70-100
50-85
30-55
8-24
3-10 |
Sampling and testing shall be in accordance with the following
standard methods:
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Sieve
Analysis T 27
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Passing #200 Sieve T 11
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- Roadway Surface.
a. All roadways shall be paved to conform with the finished grade
and width as specified, with Class I Bituminous Concrete Paving,
Type I-1 in accordance with the standard specifications and subject
to the approval of the Planning Board Engineer. The applicant
shall submit a specification job mix formula to the Planning Board
Engineer for approval prior to starting work. All material shall
conform to the current Standard Specifications for Highways and
Bridges for the Mass. D.P.W.
b. The total thickness of bituminous concrete (compacted) shall
be three and one-half (3 ½) inches. It shall be applied
in two (2) courses: two (2) inches binder and one and one-half
(1 ½) inches top course. Spreading and rolling shall also
be in conformance with these specifications. Bituminous concrete
shall not be placed on muddy or frozen surface. The air temperature
must be at least 40 degrees F and rising.
B. UTILITIES
- Underground utilities.
All utilities within a subdivision shall be placed underground
and shall be shown on the plan. Adequate provisions for street
lighting shall be made where underground electrical service is
provided.
- Disposal of Surface Water.
Adequate disposal of surface water shall be provided in the following
manner:
a. DESIGN ANALYSIS: Each drainage plan submitted for approval
shall be accompanied by a design analysis prepared by a qualified
Registered Professional Engineer. The analysis shall clearly
indicate all the computations for the drain including determination
of pipe size and strength, and a statement concerning the disposition
of flow. If the flow is discharged to the ground surface on
land not belonging to the applicant, and a statement to that
effect shall be included with the design analysis.
b. DESIGN STORM: A rainfall having a frequency of occurrence
of once in fifteen (15) years has been selected for design computations
for drain lines. This storm amounts to 2.0 total inches of rain
in one (1) hour. Intensities for small areas correspond to the
time of the concentration for the area. A rainfall having a
frequency of once in fifty (50) years shall be used for roadway
culvert design.
c. COMPUTATION IF RUNOFF: Runoff for any area may be calculated
by using the "Rational Formula", which allows for
infiltration, filling minor depressions, and other losses. The
factors used in the Rational Formula are based on the assumption
of built up areas throughout the Town. Pipe sizes computed on
this basis will be slightly oversized for present land development,
but will allow adequate capacity for future land development.
d. SELECTION OF DRAIN SIZE: The proper drain size may be calculated
by using "Manning's Formula" with a "Kutter's"
"n" value of .013 for concrete pipe, and .024 for
corrugated metal pipe. Standard charts for deriving runoff and
drain sizes using these figures may be obtained upon request
from the Planning Board or its agent. For culverts less than
thirty (30) feet in length and all drains, the minimum size
of pipe shall be twelve (12) inches in diameter. The culverts
and drains shall be large enough to pass the design storm without
surcharge.
e. TYPE OF PIPE: All storm drains shall be reinforced concrete
of adequate strength except that in off-street locations bituminous
coated, galvanized, corrugated metal pipe or pipe arch may be
used if approved by the Planning Board. Concrete pipe shall
conform to the Commonwealth of Massachusetts Standard Specifications
for Highways and Bridges, as amended.
f. SLOPE OF PIPE: All pipes shall be laid on a slope so that
the minimum velocity with the pipe flowing full shall be 2.0
feet per second. Drain lines shall be laid on a slope of not
less than 0.5%. Consideration may be given to flatter slopes
if adequate provisions are made for cleaning the pipes. All
plans having drains with slopes that will produce pipe velocities
less than 2.0 feet per second, flowing full, shall be accompanied
by a letter stating the reason for the flat slope. The letter
shall have a space for approval by the Planning Board or its
agent, and the drain shall not be constructed until the letter
has been approved. The maximum allowable velocity with the pipe
flowing full shall be the 10.0 feet per second.
g. INLETS: Inlets shall have an adequate waterway opening to
pass the design storm with not more than 0.2 feet of surcharge.
Grates and frames shall be cast iron suitable for the loads
that can occur either during the construction or afterward.
Inlets shall be constructed either of brick and mortar with
eight (8) inch thick walls, precast segmental concrete blocks
not less than six (6) inches thick mortared in place, or of
precast pipe sections. Inlets shall be set on a base of either
poured concrete eight (8) inches in thickness, or precast segmental
base blocks not less than four (4) inches in thickness. Inlets
shall be used in off-street locations and the grate frame shall
be mortared in position with the top 0.2 feet below the grade
of the finished ground surface. Side openings may be used in
lieu of a grate if the quantity of runoff exceeds the capacity
of a grate of reasonable size as approved by the Planning Board
or its agent. Inlets shall be 4.0 feet inside diameter below
the corbelling and shall not be used on drains greater than
thirty (30) inches in diameter. A shaped invert is not required
but the bottom of the inlet shall be finished at the same grade
as the lowest pipe invert. At inlets where the outlet pipe is
larger than the inlet pipe, the crown of the outlet pipe shall
be at the same elevation or lower than the crown of the inlet
pipe.
h. CATCH BASINS - MANHOLES: Catch basins shall be installed
on both sides of the roadway on continuous grades at intervals
not to exceed three hundred (300) feet, at low points and sags
in the roadway, and at or near the corners of the roadway at
intersecting streets. The Planning Board may require a lesser
distance if deemed advisable by the Board because of unusual
local conditions. All catch basins must have a three (3) foot
sump and discharge directly into manholes. Basins shall be provided
with granite headers containing storm inlets as necessary. (See
detail plate 4-A) Manholes shall be required at every change
in direction, slope, or diameter in the drainpipe and also at
every intersection of drainpipes (see detail plates 1, 1A, 2,
2A, 3, 3A, 3B).
i. EXCAVATION: The trench for the pipe shall be excavated to
the required line and grade including earth boulders and ledge.
Trenches for storm drains shall be no wider than the outside
diameter of the pipe plus sixteen (16) inches for pipes through
eighteen (18) inches nominal diameter, and the outside diameter
plus twenty-four (24) inches for pipes larger than eighteen
(18) inches. This trench width shall apply from the top of the
pipe to the bottom of the trench. Above the top of the pipe
the trench may be as necessary to properly install the pipe.
Trenches with side slopes steeper than the natural angle of
repose of the soil shall be sheeted in an approved manner, as
necessary to avoid cave-ins and sloughing. All excavations shall
be property barricaded and lighted at night where they are close
to pedestrian or vehicular traffic. Before any pipe is placed
in a newly constructed fill, the Contractor shall, as directed,
place the filling two (2) feet above the top of the pipe after
which the pipe trench may be excavated. If any cross pipes,
conduits, drains or other unforeseen obstacles are encountered
in the excavation which cannot be relocated, the drain shall
be redesigned to avoid the obstruction in a manner suitable
to the Planning Board or its agent. Possible obstructions to
the line shall be investigated prior to the construction of
the drain in its immediate vicinity.
j. BEDDING: Trenches may be excavated with a flat bottom but
the full length of the pipe, except the bell, must rest upon
undisturbed soil except as herein after specified where trenches
have been over-excavated with a flat bottom or gravel foundation,
thoroughly compacted, shall be provided for proper pipe bedding.
Soil, which is considered to be unstable by the Planning Board
or its agent, shall be removed to a depth of not less than two
(2) feet below the bottom of the pipe and replaced with compacted
sand and gravel to the bottom of the pipe. Unstable soil or
other excavated material shall be disposed of off site as directed
by the Planning Board or its agent.
k. PIPE LAYING: Pipes shall be laid starting with the downstream
end. Grade boards, lasers, or other approved devices shall be
provided to insure that the pipe is laid true to line and grade.
Reference benchmarks shall be clearly marked to elevations.
The joints of all pipes shall be filled with mortar composed
of one (1) part Portland Cement to three (3) parts clean sharp
sand. Lime may be added up to 25% of the cement and enough water
to make a workable mix. The downstream pipe shall be laid with
groove or bell end facing upstream in the proper position, and
a dab of mortar shall be placed in the bell or groove. The spigot
or tongue end shall be placed in the bell or groove, such that
the inverts match and, the peripheral space shall be filled
with stiff mortar. All mortar squeezed out on the inside of
the pipe shall be removed before it sets.
l. BACKFILLING: After the pipe has been laid and inspected,
the trench shall be backfilled. The space under the pipe haunches
shall be carefully filled with selected material, free from
stones or frozen earth, and compacted carefully to prevent the
pipe from moving. The layer of backfill up to twelve (12) inches
over the top of the pipe shall also be of selected material
free from stones and frozen earth, well compacted. The remainder
of the trench shall be backfilled in twelve (12) inch layers
except as noted below, and each layer shall be fully compacted
in an approved manner. Under roads or other traffic areas the
trench shall be backfilled in six (6) inch layers with each
layer compacted to the density of the surrounding soil. Pavement
and base course materials removed during the excavation process
shall be replaced with pavement and base course to match those
removed. When, in the opinion of the Planning Board or its agent,
the excavation is deep enough to warrant it, temporary pavement
shall be provided as directed. Trenches not in pavement shall
be left in a mounded condition as directed by the Planning Board
or its agent.
m. SECURITY BARS: Security bars shall be provided at the entrance
and outface of all culverts or open pipe drains. Bars shall
be constructed according to the detail indicated on Plate 9
or of a design approved by the Planning Board or its agent,
and the grate shall be installed in a manner approved by the
Planning Board or its agent. A suitable drawing of the grate
and method of installation shall be submitted for approval with
the plans for the drains and appurtenances.
n. HEADWALLS: Concrete or Field Stone masonry headwalls shall
be provided at both ends of culverts and the discharge ends
of storm drains. They shall conform to the tables on Detail
Plate 8 and be placed at a distance of not less than sixty-five
(65) feet from the way line.
o. SCOUR PROTECTION: The discharge of all drains with flowing
full velocities of four (4) feet per second or more shall be
protected with a rip-rap apron of a width not less than ten
(10) times the normal pipe diameter from the end of the discharge
pipe. The rip-rap for exit velocities of ten (10) feet per second
or less shall be composed of a layer of stones twelve (12) inches
in thickness or more, placed upon a bed of sand and gravel six
(6) inches in thickness. The stones shall be sized so that not
less than sixty percent (60%) shall have one (1) dimension twelve
(12) inches or more. The stones after being laid shall be carefully
chinked by hand to make a reasonably smooth and shaped surface.
Where exit velocities are greater than ten (10) feet per second,
the thickness of stones and the dimensions of the individual
pieces shall be sized to prevent displacement by the flow. In
this case, details shall be submitted to the Planning Board
or its agent for approval. In addition, rip-rap will be required
for all drainage channels having design flow velocities greater
than five (5) feet per second and for any change in direction
or intersection of drainage channels.
D. SIDEWALKS AND BIKEWAYS
- General
Two (2) sidewalks shall be required for all minor, major, and
secondary streets. Bikeways shall be considered as separate from
sidewalks and should be located according to Planning Board recommendations.
Where bikeways and sidewalks are adjacent, the minimum right-of-way
shall be twenty-five (25) feet. The profile dimensions and location
of separately located sidewalks and bikeways shall be subject
to the approval of the Planning Board. The grade shall be at least
one (1) inch above curb elevation. Sidewalks and bikeways shall
be in accordance with either specification (a) or (b) below.
a. Four (4) inch thick cement concrete, reinforced with #4,
4"x 6" mesh, 3000 lb. concrete, wood float finished,
laid on a base of at least six (6) inches of well compacted
bank gravel. An expansion joint (3/4"open) shall be provided
at least every twenty (20) feet dividing joints shall be scored
into walk every four (4) feet. Base gravel material shall be
in accordance with the specifications outlined above for street
construction, provided that no stone shall have a dimension
in excess of 2 ½". It shall be thoroughly compacted,
using a sidewalk roller weighing at least two (2) tons. (See
detail plate 4A)
b. Bituminous Concrete: The foundation shall be eight (8) inches
of bank gravel as specified in (a) above (material and compaction).
The wearing surface shall be laid in two (2) courses, a 1 ½"
binder course and a 1" top course, the thickness to be
measured after compaction. The material and application shall
conform to the specifications for roadway surfacing. All edges
of the walks shall be formed with wood screens that are securely
anchored and left in place. (See detail plate 4A)
- Design Standards
The following design guidelines shall be observed during the design
and construction of bikeways:
a. Minimum pavement width: ten (10) feet.
b. Maximum gradient: five (5) percent.
c. Minimum centerline radius: twenty-five (25) feet.
d. Vertical curves shall be required for changes in grade which
exceed one (1) percent.
e. Curb cuts shall be provided at the intersection of bikeways
and streets.
f. Signs of a design approved by the Board shall clearly mark
each "Bikeway".
E. CURBING AND BERMS
- General
Curbing is required on one side of the roadway as it abuts the
sidewalk and shall be one of the types specified under subsection
D as determined by the Planning Board except that granite curb
shall be used in the following cases:
a. All finished grades over six (6) percent. Vertical Granite
- Granite curbing will be required on both sides of the roadway
in this case.
b. All headers for catch basins: vertical granite
c. All street intersections along turning radii and extending
six (6) feet tangent along each side of each roadway at the
intersection.
d. Approved types of curbing:
- Sloped granite curb (See detail plate 5)
- Granite curbing type VA 4 (See detail plate 6)
e. Terminal curb section. A tapered terminal curb section of
vertical granite curb construction having a minimum length of
four (4) feet and a tapered section two (2) feet in length will
be required as the first and last stones along each section
of granite curbing and adjacent to each separately placed curb
inlet.
- Cape Cod Berms will be required on all cul de sacs and in other
locations as specified by the Planning Board. Berms shall consist
of Class I bituminous concrete, Type I-1, and shall conform to
the requirements for either top course or dense mix. All berms
to be placed over a suitable foundation for support. (See Detail
Plate 5A)
F. SIDE SLOPES
The area in back of the sidewalk shall be sloped at the rate of three
to one (3:1) (maximum) to a point where it precisely coincides with
the finished grade of abutting lots.
G. TOPSOIL AND ITS REMOVAL AND LOAMING AND SEEDING
On all areas within roadway, walkway and bikeway right of ways except
areas not receiving treatment or areas requested by the Board to be
left in a "natural condition" the ground shall be cleared
and grubbed and at least six (6) inches of an approved loam topsoil
shall be applied. These areas shall be protected from erosion and
seeded with an acceptable perennial lawn grass or other approved ground
cover. Planted areas will not be accepted until there is a substantial,
uniform and healthy growth for a period of not less than two (2) years
and until construction has been completed. This portion of the passbook
account will be held for this period in an amount to be determined
by the Planning Board and the Town Engineer.
A six (6) inch thickness of loam shall be provided throughout the
entire disturbed area of all lots and on the planting strips along
the roadway. Only such areas as roadway, driveways, building sites
and areas requiring filling may be stripped of topsoil. Areas on a
lot where cut or fill is not required for construction of the building
on that lot, shall not be stripped of topsoil.
H. MONUMENTS
Monuments shall be installed at all street intersections, at all points
of change in directions or curvature of streets and at other points
where, in the opinion of the Board, permanent monuments are necessary.
Such monuments shall be at least 5" x 5" reinforced concrete
or granite posts and must extend to not more than four (4) inches
above finished ground unless otherwise specifically authorized by
the Board in writing.
No permanent monuments shall be installed until all construction that
could destroy or disturb the monuments is completed.
I. STREET TREES
Existing trees, which, in the opinion of the Planning Board, are suitable
for street trees, shall be maintained and left as such. Where trees
are inadequate, new trees of at least two (2) inch caliper measured
at a height of forty-two (42) inches from the ground and at least
twelve (12) feet in height shall be planted. All trees shall be planted
within the right-of-way at a distance not to exceed thirty (30) feet.
The species and variety of the trees shall be selected and approved
by the Tree Warden. No evergreen trees such as fir, pine, hemlock
or spruce shall be planted along the way. No trees shall be planted
at any intersection so as to obstruct vision or safe vehicle traffic.
All planted trees shall be planted in one-half (1/2) cubic yards of
loam, mulched with four (4) inches of wood chips and guyed in a manner
to ensure their survival. Developer shall warrantee all planted trees
for two (2) years as determined by the Tree Warden.
J. STREET SIGNS
The developer shall furnish and erect necessary street signs to designate
the name of each street in his/her development. Said signs to conform
to those used by the Town.
K. STREET LIGHTS
The developer shall be responsible for furnishing and erecting streetlights
at locations approved by the Planning Board and the Board of Selectmen.
L. CLEANING UP
The entire area must be cleaned up so as to leave a neat and orderly
appearance free from debris and other objectionable materials.
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