ASTM F1759-97
(Practice)Standard Practice for Design of High-Density Polyethylene (HDPE) Manholes for Subsurface Applications
Standard Practice for Design of High-Density Polyethylene (HDPE) Manholes for Subsurface Applications
SCOPE
1.1 This specification covers general and basic procedures related to the design of manholes and components manufactured from high-density polyethylene (HDPE) for use in subsurface applications and applies to personnel access structures. The practice covers the material, the structural design requirements of the manhole barrel (also called vertical riser or shaft), floor (bottom), and top, and joints between shaft sections.
1.2 This practice offers the minimum requirements for the proper design of an HDPE manhole. Due to the variability in manhole height, diameter, and the soil each manhole must be designed and detailed individually. When properly used and implemented, this practice can help ensure a safe and reliable structure for the industry.
1.3 Disclaimer-The reader is cautioned that independent professional judgment must be exercised when data or recommendations set forth in this practice are applied. The publication of the material contained herein is not intended as a representation or warranty on the part of ASTM that this information is suitable for general or particular use, or freedom from infringement of any patent or patents. Anyone making use of this information assumes all liability arising from such use. The design of structures is within the scope of expertise of a licensed architect, structural engineer, or other licensed professional for the application of principles to a particular structure.
1.4 The values stated in inch-pound units are to be regarded as the standard. The SI units given in parentheses are provided for information only.
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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An American National Standard
Designation: F 1759 – 97
Standard Practice for
Design of High-Density Polyethylene (HDPE) Manholes for
Subsurface Applications
This standard is issued under the fixed designation F 1759; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope D 653 Terminology Relating to Soil, Rock, and Contained
Fluids
1.1 This specification covers general and basic procedures
D 1600 Terminology for Abbreviated Terms Relating to
related to the design of manholes and components manufac-
Plastics
tured from high-density polyethylene (HDPE) for use in
D 2321 Practice for Underground Installation of Thermo-
subsurface applications and applies to personnel access struc-
plastic Pipe for Sewers and Other Gravity-Flow Applica-
tures. The practice covers the material, the structural design
tions
requirements of the manhole barrel (also called vertical riser or
D 2657 Practice for Heat Joining of Polyolefin Pipe and
shaft), floor (bottom), and top, and joints between shaft
Fittings
sections.
D 2837 Test Method for Obtaining Hydrostatic Design
1.2 This practice offers the minimum requirements for the
Basis for Thermoplastic Pipe Materials
proper design of an HDPE manhole. Due to the variability in
D 3035 Specification for Polyethylene (PE) Plastic Pipe
manhole height, diameter, and the soil each manhole must be
(DR-PR) Based on Controlled Outside Diameter
designed and detailed individually. When properly used and
D 3212 Specification for Joints for Drain and Sewer Plastic
implemented, this practice can help ensure a safe and reliable
Pipes Using Flexible Elastomeric Seals
structure for the industry.
D 3350 Specification for Polyethylene Plastics Pipe and
1.3 Disclaimer—The reader is cautioned that independent
Fittings Materials
professional judgment must be exercised when data or recom-
F 412 Terminology Relating to Plastic Piping Systems
mendations set forth in this practice are applied. The publica-
F 477 Specification for Elastomeric Seals (Gaskets) for
tion of the material contained herein is not intended as a
Joining Plastic Pipe
representation or warranty on the part of ASTM that this
F 714 Specification for Polyethylene (PE) Plastic Pipe
information is suitable for general or particular use, or freedom
(SDR-PR) Based on Outside Diameter
from infringement of any patent or patents. Anyone making use
F 894 Specification for Polyethylene (PE) Large Diameter
of this information assumes all liability arising from such use.
Profile Wall Sewer and Drain Pipe
The design of structures is within the scope of expertise of a
licensed architect, structural engineer, or other licensed profes-
3. Terminology
sional for the application of principles to a particular structure.
3.1 Definitions:
1.4 The values stated in inch-pound units are to be regarded
3.1.1 Definitions used in this practice are in accordance with
as the standard. The SI units given in parentheses are provided
Terminology F 412 and Terminology D 1600 unless otherwise
for information only.
indicated.
1.5 This standard does not purport to address all of the
3.2 Definitions of Terms Specific to This Standard:
safety concerns, if any, associated with its use. It is the
3.2.1 anchor connection ring—an HDPE ring attached to
responsibility of the user of this standard to establish appro-
the manhole riser on which to place an antiflotation device,
priate safety and health practices and determine the applica-
such as a concrete anchor ring.
bility of regulatory limitations prior to use.
3.2.2 arching—mobilization of internal shear resistance
2. Referenced Documents within a soil mass that results in a change in soil pressure
acting on an underground structure.
2.1 ASTM Standards:
This specification is under the jurisdiction of ASTM Committee F-17 on Plastic
Piping Systems and is the direct responsibility of Subcommittee F17.26 on Olefin Annual Book of ASTM Standards, Vol 04.08.
Based Pipe. Annual Book of ASTM Standards, Vol 08.01.
Current edition approved Jan. 10, 1997. Published September 1997. Annual Book of ASTM Standards, Vol 08.04.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
F1759–97
3.2.3 benching—the internal floor of a manhole when it is
elevated above the manhole invert, usually provided as a place
for personnel to stand.
3.2.4 closed profile—a manhole barrel construction that
presents an essentially smooth internal surface braced with
projections or ribs which are joined by an essentially smooth
outer wall. Solid wall construction is considered a special case
of the closed profile.
3.2.5 downdrag—downward shear force acting on the
shaft’s external surface and resulting from settlement of the
manhole backfill.
3.2.6 extrusion welding—a joining technique that is accom-
plished by extruding a molten polyethylene bead between two
prepared surface ends.
3.2.7 floor—the lowest internal surface of the manhole. The
floor and bottom are often the same.
3.2.8 inlet/outlet—pipe (conduit) passing through the wall
of the manhole.
3.2.9 invert—the flow channel in the floor of a manhole.
This may consist of the lower half of a pipe, thus the name
“invert”.
3.2.10 manhole—an underground service access structure
which can access pipelines, conduits, or subsurface equipment.
3.2.11 manhole bottom—the lowest external surface of the
manhole.
FIG. 1 Manhole Terminology
3.2.12 manhole cone—the top portion of the manhole
through which entrance to the manhole is made and where the
diameter may increase from the entrance way to the larger
density or a concrete slab. The foundation soils under the base
manhole barrel. Sometimes referred to as the manway reducer.
must provide adequate bearing strength to carry downdrag
3.2.13 open profile—a manhole barrel construction that
loads.
presents an essentially smooth internal surface with a ribbed or
4.2.1 Manholes installed in sanitary landfills or other fills
corrugated external surface. Open profile barrel constructions
experiencing large settlements may require special designs
are normally not used for manholes.
beyond the scope of this practice. The designer should evaluate
3.2.14 performance limits—mechanisms by which the func-
each specific site to determine the suitability for use of HDPE
tion of a structure may become impaired.
manholes and the designer should prepare a written specifica-
3.2.15 riser—the vertical barrel or “shaft” section of a
tion for installation which is beyond the scope of this practice.
manhole.
3.3 See Fig. 1 for illustration of manhole terminology.
5. Materials
5.1 HDPE Material—Manhole components, such as the
4. Significance and Use
riser, base, and anchor connection ring, shall be made of HDPE
4.1 Uses—The requirements of this practice are intended to
plastic compound having a cell classification of 334433C or
provide manholes suitable for installation in pipeline or conduit higher, in accordance with Specification D 3350.
trenches, landfill perimeters, and landfills with limited settle-
NOTE 1—Materials for use in manholes may be subjected to significant
ment characteristics. Direct installation in sanitary landfills or
tensile and compressive stresses. The material must have a proven
other fills subject to large (in excess of 10 %) soil settlements
capacity for sustaining long term stresses. There are no existing ASTM
may require special designs outside the scope of this practice. standards that establish such a stress rating except for Test Method
D 2837. Work is currently in progress to develop an alternate method for
4.1.1 Manholes are assumed to be subject to gravity flow
stress rating materials and when completed, this standard will be altered
only.
accordingly.
4.2 Design Assumption—The design methodology in this
5.2 Other Material—Manhole components such as tops and
practice applies only to manholes that are installed in backfill
lids, may be fabricated from materials other than HDPE as long
consisting of Class I, Class II, or Class III material as defined
as agreed to by the user and manufacturer.
in Practice D 2321, which has been compacted to a minimum
of 90 % standard proctor density. The designs are based on the
6. Subsurface Loading on Manhole Riser
backfill extending at least 3.5 ft (1 m) from the perimeter of the
manhole for the full height of the manhole and extending 6.1 Performance Limits—The manhole riser’s performance
laterally to undisturbed in situ soil. Manholes are assumed limits include ring deflection, ring (hoop) and axial stress (or
placed on a stable base consisting of at least 12 in. (30.5 cm) strain), and ring and axial buckling. Radially directed loads
of Class I material compacted to at least 95 % standard proctor acting on a manhole cause ring deformation and ring bending
F1759–97
stresses. The radial load varies along the length of the manhole.
See Fig. 2. In addition to radial stresses, considerable axial
stress may exist in the manhole wall as a result of “downdrag”.
Downdrag occurs as the backfill soil surrounding the manhole
consolidates and settles. Axial load is induced through the
frictional resistance of the manhole to the backfill settlement.
See Fig. 3. The manhole must also be checked for axial
compressive stress and axial buckling due to downdrag forces.
6.2 Earth Pressure Acting on Manhole Riser:
6.2.1 Radial Pressure—Radial pressure along the length of
the manhole riser may be calculated using finite element
methods, field measurements or other suitable means. See
Hossain and Lytton (1). In lieu of the preceding, the active
earth pressure modified for uneven soil compaction around the
FIG. 3 Downdrag Force Acting on Manhole (Assumed for Design)
perimeter of the riser can be used.
NOTE 2—Use of the active pressure is based on measurements taken by
where:
Gartung et al. (2) and on the ability of the material placed around the
f = angle of internal friction of manhole embedment
manhole to accept tangential stresses and thus relieve some of the lateral
pressure. It may actually understate the load on the manhole, however this material, °.
appears to be offset by the stress relaxation that occurs in the HDPE
6.2.2 Downdrag (Axial Shear Stress)—The settlement of
manhole as shown by Hossain (3). Stress relaxation permits mobilization
backfill material surrounding a manhole riser develops a shear
of horizontal arching, thus the active earth pressure can be assumed for
stress between the manhole and the fill, which acts as “down-
design purposes.
drag” along the outside of the manhole. The settling process
6.2.1.1 If the active earth pressure is modified to take into
begins with the first lift of fill placed around the manhole and
account uneven compaction around the perimeter of the pipe as
continues until all the fill is placed and consolidated. As fill is
described by Steinfeld and Partner (4), the radially-directed
placed around a manhole, the axial force coupled into the
design pressure is given by Eq 1.
manhole by downdrag shear will increase until it equals the
frictional force between the soil and manhole. When this limit
P 5 1.21 K gH (1)
R A
is reached, slippage of the fill immediately adjacent to the
where:
manhole occurs. This limits the axial force to the value of the
P = applied radial pressure, psf (KPa),
R
frictional force.
3 3
g = soil unit weight, lbs/ft (kN/m ),
6.2.2.1 Downdrag loads can be calculated using finite ele-
H = weight of fill, ft (m), and
ment methods, field measurements or other procedures. In lieu
K = active earth pressure coefficient as given by Eq 2.
A
of these, the following method may be used. The average shear
f
stress is given by Eq 3, for an active earth pressure distribution
K 5 tan 45 2 (2)
S D
A
as shown in Fig. 2.
P 1 P
R1 R2
T 5 μ (3)
F G
A
where:
The boldface numbers given in parentheses refer to a list of references at the
T = average shear (frictional) stress, psf (kPa),
A
end of the text.
P = radial earth pressure at top of manhole, psf (kPa),
R1
P = radial earth pressure at bottom of manhole, psf
R2
(kPa), and
μ = coefficient of friction between manhole and soil.
6.2.2.2 The coefficient of friction between a HDPE manhole
with an essentially smooth outer surface and a granular or
granular-cohesive soil can be taken as 0.4. See Swan et al. (5)
and Martin et al. (6). In some applications the coefficient of
friction may be reduced by coating the exterior of the manhole
with bentonite or some other lubricant.
NOTE 3—The use of external stiffeners or open profiles to stiffen the
riser greatly increases the downdrag load due to their impeding the
settlement of soil beside the manhole. This has the effect of increasing the
average shear stress in Eq 3. Where open profiles are used, the coefficient
of friction may equal or exceed 1.0.
6.2.2.3 The downdrag creates an axial-directed load (down-
drag load) in the manhole wall that increases with depth. The
FIG. 2 Radial Pressure Acting on Manhole (Assumed Distribution
for Design) axial force developed on the manhole can be found by
F1759–97
integrating the shear stress (or frictional stress) between the the submerged soil. In this case, H8 as given in Eq 6 should be
manhole and soil over the height of the fill. This integration is substituted for H in Eq 5. See Appendix X2.
equal to the product of the surface area of the manhole times
H8 5 H 2 Z (6)
the average shear stress acting on the surface. The maximum
where:
downdrag force can be found using Eq 4. Whether or not to
H = weight of manhole, ft (m), and
include surface vehicular loads in this term depends on the
Z = distance to water from surface grade, ft (m).
manhole top design. See 7.3.
6.3.4 Radial pressure obtained with Eq 5 should not be used
D
o
to calculate downdrag pressure as the groundwater does not
P 5 T p H (4)
S D
D A
carry shear and thus does not contribute to downdrag. Calcu-
late downdrag forces assuming a dry installation using Eq 1 for
where:
radial pressure as described in 6.2.1. Use either the dry weight
= downdrag load, lb (kN),
P
D
D = outside diameter of manhole, in. (m), or the saturated weight of the soil. The saturated weight applies
o
T = average shear stress, psf (kPa), and where the groundwater might be drawn down rapidly.
A
H = height of fill, ft (m).
6.3.5 Where manholes are located beneath the groundwater
level, consideration should be given to restraining the manhole
NOTE 4—When SI units are used, the 12 in the denominator of Eq 4
to prev
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