Designation: C 478 – 09
Standard Specification for
Precast Reinforced Concrete Manhole Sections1
This standard is issued under the fixed designation C 478; 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.
This standard has been approved for use by agencies of the Department of Defense.
PART I—GENERAL
1. Scope
1.1 This specification covers the manufacture and purchase
requirements of products used for the assembly and construc-
tion of circular vertical precast reinforced concrete manholes
and structures used in sewer, drainage, and water works.
1.2 Part I, Sections 1-11, of this specification presents
general requirements and requirements that are common to
each precast concrete product covered by this specification.
1.3 Part II of this specification presents specific require-
ments for each manhole product in the following sections:
Product Section
Grade Rings 12
Flat Slab Tops 13
Risers and Conical Tops 14
Base Sections 15
Steps and Ladders 16
NOTE 1—Future products will to be included in Part II in a future
revision of this specification.
1.4 This specification is the inch-pound companion to
Specification C 478M; therefore, no SI equivalents are pre-
sented in the specification.
NOTE 2—This specification is a manufacturing and purchase specifica-
tion only and does not include requirements for backfill, or the relation-
ship between field load conditions and the strength requirements of the
manhole products and appurtenances. Experience has shown, however,
that the successful performance of this product depends upon the proper
selection of the product strength, type of foundation and backfill, and care
in the field installation of the manhole products and connecting pipes. The
owner of the project for which these products are specified herein is
cautioned to require inspection at the construction site.
2. Referenced Documents
2.1 ASTM Standards:2
A 82/A 82M Specification for Steel Wire, Plain, for Con-
crete Reinforcement
A 185/A 185M Specification for Steel Welded Wire Rein-
forcement, Plain, for Concrete
A 496/A 496M Specification for Steel Wire, Deformed, for
Concrete Reinforcement
A 497/A 497M Specification for Steel Welded Wire Rein-
forcement, Deformed, for Concrete
A 615/A 615M Specification for Deformed and Plain
Carbon-Steel Bars for Concrete Reinforcement
A 706/A 706M Specification for Low-Alloy Steel De-
formed and Plain Bars for Concrete Reinforcement
C 33 Specification for Concrete Aggregates
C 39/C 39M Test Method for Compressive Strength of Cy-
lindrical Concrete Specimens
C 150 Specification for Portland Cement
C 260 Specification for Air-Entraining Admixtures for Con-
crete
C 309 Specification for Liquid Membrane-Forming Com-
pounds for Curing Concrete
C 494/C 494M Specification for Chemical Admixtures for
Concrete
C 497 Test Methods for Concrete Pipe, Manhole Sections,
or Tile
C 595 Specification for Blended Hydraulic Cements
C 618 Specification for Coal Fly Ash and Raw or Calcined
Natural Pozzolan for Use in Concrete
C 822 Terminology Relating to Concrete Pipe and Related
Products
1 This specification is under the jurisdiction of ASTM Committee C13 on
Concrete Pipe and is the direct responsibility of Subcommittee C13.06 on Manholes
and Specials.
Current edition approved Feb. 1, 2009. Published February 2009. Originally
approved in 1961. Last previous edition approved in 2008 as C 478 – 08.
2 For referenced ASTM standards, visit the ASTM website, www.astm.org, or
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
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
C 989 Specification for Slag Cement for Use in Concrete
and Mortars
C 1017/C 1017M Specification for Chemical Admixtures
for Use in Producing Flowing Concrete
2.2 ACI Standard:3
318 Building Code, Requirements for Reinforced Concrete
3. Terminology
3.1 Definitions—For definitions of terms relating to precast
reinforced concrete manholes, see Terminology C 822.
4. Materials and Manufacture
4.1 General material requirements for precast reinforced
concrete manhole products are presented in 4.1.1-4.1.8. Other
materials or additional requirements for a product, if any, are
covered in the Part II section for that specific product.
4.1.1 Reinforced Concrete—Reinforced concrete shall con-
sist of cementitious materials, mineral aggregates, and water, in
which steel reinforcement has been embedded in such a
manner so that the steel reinforcement and concrete act
together.
4.1.2 Cementitious Materials:
4.1.2.1 Cement—Cement shall conform to the requirements
for portland cement of Specification C 150, or shall be portland
blast-furnace slag cement or portland-pozzolan cement con-
forming to Specification C 595, except that the pozzolan
constituent of the Type IP portland-pozzolan cement shall be
fly ash.
4.1.2.2 Fly Ash—Fly ash shall conform to the requirements
of Class F or Class C of Specification C 618.
4.1.2.3 Ground Granulated Blast-Furnace Slag (GGBFS)—
GGBFS shall conform to the requirements of Grade 100 or 120
of Specification C 989.
4.1.3 Allowable Combinations of Cementitious Materials—
The combination of cementitious materials used in the concrete
shall be one of the following:
4.1.3.1 Portland cement only,
4.1.3.2 Portland blast-furnace slag cement only,
4.1.3.3 Slag modified Portland cement only,
4.1.3.4 Portland pozzolan cement only,
4.1.3.5 A combination of Portland cement and ground
granulated blast-furnace slag,
4.1.3.6 A combination of Portland cement and fly ash, or
4.1.3.7 A combination of Portland cement, ground granu-
lated blast-furnace slag (not to exceed 25 % of the total
cementitious weight) and fly ash (not to exceed 25 % of the
total cementitious weight).
4.1.4 Aggregates—Aggregates shall conform to Specifica-
tion C 33, except that the requirements for gradation shall not
apply.
4.1.5 Admixtures and Blends—The following admixtures
and blends are allowable:
4.1.5.1 Air-entraining admixture conforming to Specifica-
tion C 260;
4.1.5.2 Chemical admixture conforming to Specification
C 494/C 494M;
4.1.5.3 Chemical admixture for use in producing flowing
concrete conforming to Specification C 1017/C 1017M;
4.1.5.4 Chemical admixture or blend approved by the
owner.
4.1.6 Steel Reinforcement—Reinforcement shall consist of
wire conforming to Specification A 82/A 82M or Specification
A 496/A 496M, of wire fabric conforming to Specification
A 185/A 185M or Specification A 497/A 497M, or of bars of
Grade 40 steel conforming to Specification A 615/A 615M or
of bars conforming to Specification A 706/A 706M.
4.1.7 Secondary Synthetic Fiber—Collated fibrillated
polypropylene virgin fibers shall not be prohibited when used
in steel reinforced concrete manholes as a non-structural
manufacturing enhancement. Only fibers designed and manu-
factured specifically for use in concrete and so certified by the
manufacturer shall be accepted.
4.1.8 Other Materials—Other materials required for a prod-
uct and not covered in Section 4 will be covered in the Part II
section for that specific product.
5. Design
5.1 Design requirements for a product are prescribed in the
specific Part II section for that product.
5.1.1 The minimum compressive strength of concrete man-
hole products covered by this specification shall be 4000 psi
unless specified otherwise in Part II of this specification.
5.2 Modified or Special Design
5.2.1 Manufacturers are not prohibited from submitting to
the owner, for approval prior to manufacture, designs other
than those prescribed in the specific section for a product. If
such approval is obtained, then the product shall meet all the
tests and performance requirements specified by the owner in
accordance with the appropriate sections on manufacture and
physical requirements.
5.2.2 If permitted by the owner, the manufacturer is not
prohibited from requesting approval of designs of special
sections, such as reducers, tees, and bases.
6. Reinforcement
6.1 This section presents requirements for reinforcement
cover, continuity, laps, welds, and splices. Other reinforcement
requirements are presented in Section 4, and any additional
requirements are given in the Part II section for a specific
product.
6.2 Cover—The exposure of the ends of reinforcement,
stirrups or spacers used to position the reinforcement during
placement of the concrete shall not be cause for rejection.
6.3 Continuity—The continuity of the circumferential rein-
forcement shall not be destroyed during the manufacture of the
product, except when lift holes or pipe openings are provided
in the product.
6.4 Welded Steel Cage Laps, Welds, and Splices:
6.4.1 If splices are not welded, the reinforcement shall be
lapped not less than 20 diameters for deformed bars, and 40
diameters for plain bars and cold-drawn wire. In addition,
where lapped cages of welded wire fabric are used without
welding, the lap shall contain a longitudinal wire.
3 Available from American Concrete Institute (ACI), P.O. Box 9094, Farmington
Hills, MI 48333-9094, http://www.aci-int.org.
C 478 – 09
2
6.4.2 When splices are welded and are not lapped to the
minimum requirements in 6.4.1, pull tests of representative
specimens shall develop at least 50 % of the minimum speci-
fied strength of the steel, and there shall be a minimum lap of
2 in. For butt welded splices in bars or wire, permitted only
with helically wound cages, pull tests of representative speci-
mens shall develop at least 75 % of the minimum specified
strength of the steel.
6.5 Steel Hoop Splices—A representative sample steel hoop
with welded splices shall develop at least 50 % of the mini-
mum specified strength of the steel, and there shall be a
minimum lap of 2 in. For butt welded splices, the representa-
tive steel hoop sample shall develop at least 75 % of the
minimum specified strength of the steel.
7. Precast Concrete Manufacture
7.1 Mixture—The aggregates shall be sized, graded, propor-
tioned, and mixed with such proportions of cementitious
materials and water as will produce a homogeneous concrete
mixture of such quality that the products will conform to the
test and design requirements of this specification. All concrete
shall have a water-cementitious ratio not exceeding 0.53 by
weight. Cementitious materials shall be as specified in 4.1.2
and shall be added to the mix in a proportion not less than 470
lb/yd3, unless mix designs with a lower cementitious materials
content demonstrate that the quality and performance of the
product meet the requirements of this specification.
7.2 Curing—Concrete products shall be subjected to any
one of the methods of curing prescribed in 7.2.1-7.2.4 or to any
other method or combination of methods approved by the
owner that will give satisfactory results.
7.2.1 Steam Curing—Concrete products are placed in a
curing chamber, free of outside drafts, and cured in a moist
atmosphere maintained by the injection of steam for such time
and such temperatures as needed to enable the products to meet
the strength requirements. The curing chamber shall be so
constructed as to allow full circulation of the steam around the
entire product.
7.2.2 Water Curing—Concrete products are water-cured by
covering with water-saturated material, or by a system of
perforated pipes, mechanical sprinklers, porous hose, or by any
other approved method that will keep the products moist during
the curing period.
7.2.3 Sealing Membrane—A sealing membrane conforming
to the requirements of Specification C 309 is applied and shall
be left intact until the required concrete strength requirements
are met. The concrete at the time of application of the
membrane shall be within 10°F of the atmospheric tempera-
ture. All concrete surfaces shall be kept moist prior to the
application of the membrane and shall be damp when the
membrane is applied.
7.2.4 The manufacturer is not prohibited from combining
the methods prescribed in 7.2.1-7.2.3 provided the required
concrete compressive strength is attained.
8. Acceptance
8.1 Acceptance Procedures:
8.1.1 Unless otherwise designated by the owner at the time
of, or before, placing an order, acceptance procedures for
precast reinforced concrete manhole products shall be as
specified in the Part II section for a particular product, and shall
not be prohibited from consisting of one or more of the
following:
8.1.1.1 Acceptance of a product on the basis of tests of
materials, including concrete compressive strength and absorp-
tion.
8.1.1.2 Acceptance of a product on the basis of inspection of
the finished product, including amount and placement of
reinforcement to determine conformance with the design
prescribed under this specification, and freedom from defects.
8.2 Test Methods:
8.2.1 Concrete Compressive Strength Test:
8.2.1.1 Type of Specimen—Compression tests for satisfying
the minimum specified concrete strength requirement shall be
made on either concrete cylinders or, at the option of the
manufacturer, on cores cut from the concrete manhole product.
8.2.1.2 Compression Testing of Cylinders—Cylinders shall
be made in accordance with Test Methods C 497, and shall be
tested in accordance with Test Method C 39. For manhole
products, an owner shall not be prohibited from requiring
concrete compressive tests on cylinder specimens numbering
in the amount of 5 % of the total order of a manhole product,
but not to exceed two cylinders for each day’s production. The
average compressive strength of all cylinders tested shall be
equal to or greater than the specified strength of the concrete.
Not more than 10 % of the cylinders tested shall fall below the
specified strength of the concrete. In no case shall any cylinder
tested fall below 80 % of the specified strength of the concrete.
8.2.1.3 Compression Testing of Cores—Cores shall be cut
from the concrete manhole product and tested in accordance
with Test Methods C 497, except that the requirements for
moisture conditioning shall not apply. One core shall be taken
from a manhole product selected at random from each day’s
production run of a single concrete strength. When the concrete
compressive strength of the core is equal to or greater than
80 % of the specified strength of the concrete, the concrete
strength of the production run is acceptable. If the core does
not meet the preceding concrete strength requirement, another
core from the same manhole product shall be taken and tested.
8.2.1.4 If the concrete compressive strength of the recore is
equal to or greater than 80 % of the specified strength of the
concrete, the concrete strength of the production run is accept-
able. If the recore does not meet the preceding concrete
strength requirement, that manhole product shall be rejected.
Two manhole products from the remainder of the day’s
production run shall be selected at random and one core taken
from each manhole product and tested. When the average
concrete strength of the two cores is equal to or greater than
80 % of the specified strength of the concrete with no core
below 75 % of the specified strength of the concrete, the
concrete strength of the day’s production run shall be accept-
able.
8.2.1.5 If the concrete strength of the two cores does not
meet the preceding concrete strength requirement, then the
remainder of the day’s production run shall be either rejected,
or, at the option of the manufacturer, each manhole product of
C 478 – 09
3
the remainder of the day’s production run is not prohibited
from being cored and accepted individually.
8.2.1.6 Plugging Core Holes—Core holes on accepted con-
crete manhole products shall be plugged and sealed by the
manufacturer in a manner such that the manhole products will
meet all of the requirements of this specification. Manhole
sections so sealed shall be considered as satisfactory for use.
8.2.2 Absorption Test:
8.2.2.1 The absorption of a specimen from a concrete
product, as determined in Test Methods C 497, shall not exceed
9 % of the dry mass for Test Method A procedure or 8.5 % for
Test Method B procedure. All specimens shall be free of visible
cracks and shall represent the full thickness of the product.
8.2.2.2 Specimens for Test Method B shall meet the require-
ments of Test Methods C 497.
8.2.2.3 Each specimen tested by Test Method A shall have a
minimum weight of 2.2 lbs.
8.2.2.4 When the initial absorption specimen from a con-
crete product fails to conform to this specification, the absorp-
tion test shall be made on another specimen from the same
product and the results of the retest shall be substituted for the
original test results.
8.2.3 Retests—When not more than 20 % of the concrete
test specimens tested under either 8.2.2.1 or 8.2.2.2 fail to pass
the requirements of this specification, the manufacturer is not
prohibited from culling his stock and eliminating whatever
quantity of product he desires and shall so mark the culled
product that they will not be shipped for the order. The required
tests shall be made on the balance of the order and the products
shall be accepted if in conformance with the requirements of
this specification.
8.3 Test Equipment—Every manufacturer furnishing man-
hole products under this specification shall furnish all facilities
and personnel necessary to carry out the tests required for
acceptance.
9. Repairs
9.1 Repair of manhole products shall not be prohibited, if
necessary, because of imperfections in manufacture or damage
during handling, and will be acceptable if, in the opinion of the
owner, the repaired products conform to the requirements of
this specification.
10. Inspection
10.1 The quality of materials, the process of manufacture,
and the finished manhole products shall be subject to inspec-
tion and approval by the owner.
11. Product Marking
11.1 The following information shall be legibly marked on
each precast concrete product:
11.1.1 Specification and product designation: MH for man-
hole base, riser, conical tops, and grade rings,
11.1.2 Date of manufacture, and
11.1.3 Name or trademark of the manufacturer.
11.2 Marking shall be indented into the concrete or shall be
painted thereon with waterproof paint.
PART II—PRODUCTS
12. Grade Rings
12.1 Scope—This section covers precast reinforced con-
crete grade rings used for final adjustment of manholes to
grade.
12.2 Acceptance—Acceptability of grade rings covered by
this specification shall be determined by the results of such
tests of materials as are required by Section 4; by compressive
strength tests on concrete cores or concrete cylinders required
by Section 8; and by inspection of the finished product,
including amount and placement of reinforcement as pre-
scribed by 12.4, 12.5, and 12.6, to determine its conformance
with the design prescribed under this specification and its
freedom from defects.
12.3 Design—The minimum wall thickness shall be one
twelfth of the internal diameter of the grade ring or 4 in.,
whichever is greater.
12.3.1 Joints—Grade rings are not required to have the joint
formed with male and female ends.
12.4 Circumferential Reinforcement:
12.4.1 The circumferential reinforcement shall have an
equivalent area of not less than 0.07 in.2/vertical ft, but not less
than 0.024 in.2 in any one grade ring.
12.4.2 The circumferential reinforcement shall be one line
in the center third of the wall of the grade ring.
12.5 Permissible Variations:
12.5.1 Internal Diameter—The internal diameter of grade
rings shall not vary more than 6 1 %.
12.5.2 Wall Thickness—The wall