ASTM F2787-09
(Practice)Standard Practice for Structural Design of Thermoplastic Corrugated Wall Stormwater Collection Chambers
Standard Practice for Structural Design of Thermoplastic Corrugated Wall Stormwater Collection Chambers
SIGNIFICANCE AND USE
This practice provides a rational method for structural design of thermoplastic stormwater chambers. The loads, capacities, and limit states are based on accepted load and resistance factor design for thermoplastic pipes; however, existing design specifications for thermoplastic pipes do not adequately address the design of chambers due to (1) open-bottom geometry, (2) support on integral foot, (3) varying circumferential corrugation geometry, and (4) manufacture with alternative thermoplastic resin. This practice standardizes recommendations for designers to adequately address these aspects of chamber design.
This practice is written to allow chamber manufacturers to evaluate chambers meeting existing classifications and to design chambers for new classifications as they are developed.
SCOPE
1.1 This practice standardizes structural design of thermoplastic corrugated wall arch-shaped chambers used for collection, detention, and retention of stormwater runoff. The practice is for chambers installed in a trench or bed and subjected to earth and live loads. Structural design includes the composite system made up of the chamber arch, the chamber foot, and the soil envelope. Relevant recognized practices include design of thermoplastic culvert pipes and design of foundations.
1.2 This practice standardizes methods for manufacturers of buried thermoplastic structures to design for the time dependent behavior of plastics using soil support as an integral part of the structural system. This practice is not applicable to thermoplastic structures that do not include soil support as a component of the structural system.
1.3 This practice is limited to structural design and does not provide guidance on hydraulic, hydrologic, or environmental design considerations that may need to be addressed for functional use of stormwater collection chambers.
1.4 Stormwater chambers are most commonly embedded in open graded, angular aggregate which provide both structural support and open porosity for water storage. Should soils other than open graded, angular aggregate be specified for embedment, other installation and functional concerns may need to be addressed that are outside the scope of this practice.
1.5 Chambers are produced in arch shapes to meet classifications that specify chamber rise, chamber span, minimum foot width, minimum wall thickness, and minimum arch stiffness constant. Chambers are manufactured with integral footings.
1.6 Polypropylene chamber classifications are found in Specification F 2418. Specification F 2418 also specifies chamber manufacture and qualification.
1.7 This practice is applicable to design in inch-pound units. The SI units in parenthesis are given for information only.
1.8 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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Standards Content (Sample)
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An American National Standard
Designation: F2787 – 09
Standard Practice for
Structural Design of Thermoplastic Corrugated Wall
Stormwater Collection Chambers
This standard is issued under the fixed designation F2787; 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 (´) indicates an editorial change since the last revision or reapproval.
1. Scope responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica-
1.1 This practice standardizes structural design of thermo-
bility of regulatory limitations prior to use.
plastic corrugated wall arch-shaped chambers used for collec-
tion, detention, and retention of stormwater runoff. The prac-
2. Referenced Documents
tice is for chambers installed in a trench or bed and subjected
2.1 ASTM Standards:
to earth and live loads. Structural design includes the compos-
D2487 Practice for Classification of Soils for Engineering
ite system made up of the chamber arch, the chamber foot, and
Purposes (Unified Soil Classification System)
thesoilenvelope.Relevantrecognizedpracticesincludedesign
D2990 Test Methods for Tensile, Compressive, and Flex-
of thermoplastic culvert pipes and design of foundations.
ural Creep and Creep-Rupture of Plastics
1.2 This practice standardizes methods for manufacturers of
D6992 Test Method for Accelerated Tensile Creep and
buried thermoplastic structures to design for the time depen-
Creep-Rupture of Geosynthetic Materials Based on Time-
dent behavior of plastics using soil support as an integral part
Temperature Superposition Using the Stepped Isothermal
of the structural system. This practice is not applicable to
Method
thermoplastic structures that do not include soil support as a
F2418 Specification for Polypropylene (PP) Corrugated
component of the structural system.
Wall Stormwater Collection Chambers
1.3 This practice is limited to structural design and does not
2.2 AASHTO LRFD Bridge Design Specifications:
provide guidance on hydraulic, hydrologic, or environmental
Section 3 Loads and Load Factors, 3.5 Permanent Loads;
design considerations that may need to be addressed for
3.6 Live Loads
functional use of stormwater collection chambers.
Section 10 Foundations, 10.6 Spread Footings
1.4 Stormwater chambers are most commonly embedded in
Section 12 Buried Structures and Tunnel Liners, 12.12
open graded, angular aggregate which provide both structural
Thermoplastic Pipes
support and open porosity for water storage. Should soils other
2.3 AASHTO Standard Specifications:
than open graded, angular aggregate be specified for embed-
M43 Standard Specification for Size ofAggregate for Road
ment,otherinstallationandfunctionalconcernsmayneedtobe
and Bridge Construction
addressed that are outside the scope of this practice.
M 145 Standard Specification for Classification of Soils and
1.5 Chambers are produced in arch shapes to meet classifi-
Soil-Aggregate Mixtures for Highway Construction Pur-
cationsthatspecifychamberrise,chamberspan,minimumfoot
poses
width, minimum wall thickness, and minimum arch stiffness
T99 Standard Method of Test for Moisture-Density Rela-
constant. Chambers are manufactured with integral footings.
tions of Soils Using a 2.5-kg (5.5-lb) Rammer and a
1.6 Polypropylene chamber classifications are found in
305-mm (12-in.) Drop
Specification F2418. Specification F2418 also specifies cham-
ber manufacture and qualification.
1.7 Thispracticeisapplicabletodesignininch-poundunits.
The SI units in parenthesis are given for information only.
1.8 This standard does not purport to address all of the
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
safety concerns, if any, associated with its use. It is the
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website.
1 3
This practice is under the jurisdiction of ASTM Committee F17 on Plastic AASHTO LRFD Bridge Design Specifications-Dual Units, 4th Edition, 2007
Piping Systems and is the direct responsibility of Subcommittee F17.65 on Land and AASHTO Standard Specifications for Transportation Materials and Sampling,
Drainage. 28th edition, 2008. Available from American Association of State Highway and
Current edition approved Aug. 1, 2009. Published September 2009. DOI: Transportation Officials (AASHTO), 444 N. Capitol St., NW, Suite 249, Washing-
10.1520/F2787-09. ton, DC 20001.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
F2787 – 09
2.4 AWWA Manual: 3.1.9 foot area—the actual contact area of the foot with the
M 45 Manual of Water Supply Practices: Fiberglass Pipe foundation.
Design
3.1.10 local buckling—compressionfailureofbuilt-upplate
sections with high width-to-thickness ratios.
3. Terminology
3.1.11 nominal height—a designation describing the ap-
3.1 Definitions—Definitions used in this specification are in
proximate outside vertical dimension of the chamber at its
accordance with the definitions in Terminology F412, and
crown (see Fig. 1).
abbreviations are in accordance with Terminology D1600,
3.1.12 nominal width—a designation describing the ap-
unless otherwise indicated.
proximate outside horizontal dimension of the chamber at its
3.1.1 chamber—an arch-shaped structure manufactured of
feet (see Fig. 1).
thermoplastic with an open-bottom that is supported on feet
3.1.13 rise—the vertical distance from the chamber base
and may be joined into rows that begin with, and are termi-
(bottom of the chamber foot) to the inside of a chamber wall
nated by, end caps (see Fig. 1).
valley element at the crown as depicted in Fig. 1.
3.1.2 classification—the chamber model specification that
identifies nominal height, nominal width, rise, span, minimum
3.1.14 span—the horizontal distance from the interior of
foot width, wall thickness, and arch stiffness constant.
one sidewall valley element to the interior of the other sidewall
3.1.3 corrugated wall—awallprofileconsistingofaregular
valley element as depicted in Fig. 1.
pattern of alternating crests and valleys connected by web
3.1.15 valley—the element of a corrugation located at the
elements (see Fig. 2).
interior surface of a chamber wall, spanning between two web
3.1.4 crest—the element of a corrugation located at the
elements (see Fig. 2).
exterior surface of the chamber wall, spanning between two
3.1.16 viscoelasticity—the response of a material to load
web elements (see Fig. 2).
thatisdependentbothonloadmagnitude(elastic)andloadrate
3.1.5 crown—the center section of a chamber typically
(viscous).
located at the highest point as the chamber is traversed
3.1.17 web—the element of a corrugated wall that connects
circumferentially.
a crest element to a valley element (see Fig. 2).
3.1.6 embedment—backfill material against the sides of
chambers and end caps and in between rows of chambers from
4. Significance and Use
the foundation stone below to a specified dimension over the
top of the chambers (see Fig. 3).
4.1 This practice provides a rational method for structural
3.1.7 end cap—a bulkhead provided to begin and terminate
design of thermoplastic stormwater chambers. The loads,
a chamber, or row of chambers, and prevent intrusion of
capacities, and limit states are based on accepted load and
surrounding embedment materials.
resistance factor design for thermoplastic pipes; however,
3.1.8 foot—a flat, turned out section that is manufactured
existing design specifications for thermoplastic pipes do not
with the chamber to provide a bearing surface for transfer of
adequately address the design of chambers due to (1) open-
vertical loads to the foundation (see Fig. 1).
bottom geometry, (2) support on integral foot, (3) varying
circumferential corrugation geometry, and (4) manufacture
with alternative thermoplastic resin. This practice standardizes
AWWA Manual of Water Supply Practices M45: Fiberglass Pipe Design, 2nd
recommendations for designers to adequately address these
Edition, 2005. Available from the American Water Works Association (AWWA),
aspects of chamber design.
6666 W. Quincy Ave., Denver, CO 80235.
NOTE—The model chamber shown in this standard is intended only as a general illustration.
FIG. 1 Chamber Terminology (Typical)
F2787 – 09
NOTE—The corrugation profile shown in this standard is intended only as a general illustration.
FIG. 2 Corrugation Terminology (Typical)
FIG. 3 Installation Terminology (Typical)
4.2 This practice is written to allow chamber manufacturers 5.5 Chambers shall be designed using closed-form solutions
to evaluate chambers meeting existing classifications and to (verified by analysis) or finite element analysis (FEA). Designs
design chambers for new classifications as they are developed. shall be validated by testing.
NOTE 1—The soil-chamber system complexity generally precludes the
5. Basis of Design
use of closed-form solutions for determination of design force effects.
While specific solutions may be developed for individual chamber
5.1 Design is based on AASHTO LRFD Bridge Design
geometries, general solutions have not been developed to accurately
Specifications and publications for static soil-structure-
predict behavior for the many possible variations in chamber geometry. In
interaction analysis for thermoplastic pipes. Users should
most cases FEAmust be employed to calculate design force effects on the
verify that these recommendations meet particular project
chamber or as verification of closed-form solutions.
needs.
5.6 Chamber material properties shall be based on tests.
5.2 Chamber installations shall be designed for the critical
5.7 Chamber section properties shall be calculated from the
combination of live load and dead load, see Section 7.
geometry of the chamber cross-section.
5.3 Chambers shall be designed for service limit states and
5.8 Soil properties shall be based on generally accepted
safety against structural failure, see Section 8.
published properties for the specified soil classifications or by
5.3.1 Service Limit State—Service design shall limit verti-
tests on site-specific materials.
cal displacements at the ground surface. Chambers shall be
evaluated for detrimental structural deformation.
6. Analysis for Design
5.3.2 Safety Against Structural Failure—Structural design
shall evaluate chambers for buckling, compression, tension,
6.1 The design shall include structural modeling of the
and foundation bearing. chamberunderloadsintheinstalledsoilenvironment.Analysis
5.4 Buckling capacity is based on material stress limits. models shall include critical anticipated live loads and soil
Compression and tension capacities are based on material cover heights that provide deflections for serviceability design
strain limits. Foundation bearing capacity is based on soil and force effects to design for safety against structural failure.
ultimate bearing capacity. 6.2 Analysis shall consider the following:
F2787 – 09
6.2.1 Chamber Structure—Two-dimensional FEA shall use 7.4.1 HL-93—The HL-93 load is a combination of the
beam elements with effective section properties to model the design truck or design tandem, whichever is critical, applied
chamber wall. Each beam element shall represent not more with the design lane load.
than 10 degrees of the chamber circumference. Nodes at beam 7.4.2 Design Truck—The design truck shall be the
ends shall be located at the center of the gravity (cg) of the
AASHTO Design Truck as specified in AASHTO LRFD
corrugated chamber wall cross-section. Three-dimensional Bridge Design Specifications, Section 3.6.1.2.2.
FEA shall employ shell elements.
7.4.3 Design Tandem—The design tandem shall be the
6.2.2 FEAProgram—AcceptableFEAprogramsinclude (1)
AASHTO Design Tandem as specified in AASHTO LRFD
CANDE (Culvert Analysis and Design), (2) similarly featured
Bridge Design Specifications, Section 3.6.1.2.3.
and verified culvert design software, or (3) general purpose
7.4.4 Thermoplastic chamber structures have a structural
finite element analysis software with capability to model
response that is dependent on load duration. Chamber response
nonlinear static soil-structure-interaction.
to live load is computed using appropriate creep moduli for
6.2.3 Creep—The time-dependent response (creep) of ther-
instantaneous response (transient loads) and longer-duration
moplastic chamber materials shall be included in the analysis.
response (sustained loads).As a minimum, design for live load
Acceptable methods are (1) multiple linear-elastic models with
shall include evaluation of instantaneous response (due to
successive stiffness reductions for creep effects, and (2) non-
moving vehicles), using a short duration (# 1 min) creep
linear chamber models that include the creep response. Values
modulus, with multiple presence and impact factors in the live
of creep modulus shall be determined by test in accordance
loadcomputation,andasustainedloadresponse(duetoparked
with Test Methods D2990 or Test Method D6992.
vehicle) using a 1 week creep modulus with no multiple
6.2.4 Soil—Models shall include accurate representation of
presence or impact factors included in the live load computa-
the structural backfill envelope and boundary conditions. The
tion.
backfill envelope includes foundation, embedment, and cover.
7.5 Live Load Factor (g )—The live load factor shall be
LL
Boundary conditions typically include the size of the soil
1.75.
embedment zone, distance to trench walls, subgrade under the
backfill envelope, weight and stiffness of soils above the
8. Structural Design
backfill envelope, and boundary for application of live loads.
8.1 The resistance of a chamber to design loads shall be
Structural backfill soils shall be modeled with nonlinear
based on the critical limit state for (1) serviceability require-
properties that incorporate the effects of confinement. Accept-
ments, (2) stability of the chamber to global buckling, (3)
ablesoilmodelsinclude(1)soilhardeningmodelsthatincrease
strength of the chamber to local buckling, (4) strength of the
soil stiffness for confinement, (2) elastic-plastic models that
chambermaterialrelativetotensilestrainlimits,(5)capacityof
allow failure in shear, or (3) large-deformation models. Soils
the foundation material to bearing from the chamber foot, and
outside the backfill envelope and further than two times the
(6) capacity of the subgrade material to bearing from the
chamber span from the chamber may be modeled as
...
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