ASTM C1504-15

Standard Specification for Manufacture of Precast Reinforced Concrete Three-Sided Structures for Culverts and Storm Drains

ABSTRACT
This specification covers single-cell precast conventionally reinforced concrete three-sided structures intended to be used for the construction of culverts and for the conveyance of storm water. Precast reinforced concrete three-sided structures manufactured in accordance with this specification shall be designated by span, rise, and design earth cover. The reinforced concrete shall consist of cementitious materials, mineral aggregates and water, in which steel has been embedded in such a manner that the steel and concrete act together. The three-sided section's dimensions and reinforcement details shall be as required by design. Splices in the circumferential reinforcement shall be made by lapping. The precast reinforced concrete three-sided structures shall be produced with tongue and groove ends, flat butt ends or key-way ends. The aggregates shall be sized, graded, proportioned, and mixed with such proportions of cementitious materials and water as will produce a homogeneous concrete mixture of such quality that each section will conform to the test and design requirements. The three-sided sections shall be cured for a sufficient length of time so that the concrete will develop the required compressive strength. The forms used in manufacture shall be sufficiently rigid and accurate to maintain the three-sided section dimensions within the permissible variations. Handling devices or holes shall be permitted in each three-sided section for the purpose of handling and laying. Cylinders and cores shall be obtained and tested for compressive strength to meet the requirements prescribed.
SCOPE
1.1 This specification covers single-cell precast conventionally reinforced concrete three-sided structures intended to be used for the construction of culverts and for the conveyance of storm water.  
1.2 A complete metric companion to Specification C1504 has been developed—C1504M; therefore, no metric equivalents are presented in this specification.
Note 1: This specification is primarily a manufacturing and purchasing specification. The successful performance of this product depends upon the proper selection of the geometric section, bedding, backfill, and care that the installation conforms to the construction specifications. The purchaser of the precast reinforced concrete three-sided structure specified herein is cautioned that proper correlation of the loading conditions and the field requirements with the geometric section specified and provisions for inspection at the construction site are required.  
1.3 The values stated in inch-pound units are to be regarded as standard. No other units of measurement are included in this standard.

General Information

• Status: Historical
• Publication Date: 14-Jan-2015
• ICS: 23.040.50 - Pipes and fittings of other materials
• Technical Committee: C13 - Concrete Pipe
• Drafting Committee: C13.07 - Acceptance Specifications and Precast Concrete Box Sections

Relations

• Replaces: ASTM C1504-14 - Standard Specification for Manufacture of Precast Reinforced Concrete Three-Sided Structures for Culverts and Storm Drains
• Effective Date: 15-Jan-2015
• Replaced By: ASTM C1504-15e1 - Standard Specification for Manufacture of Precast Reinforced Concrete Three-Sided Structures for Culverts and Storm Drains
• Effective Date: 15-Jan-2015
• Referred By: ASTM C990-09(2019) - Standard Specification for Joints for Concrete Pipe, Manholes, and Precast Box Sections Using Preformed Flexible Joint Sealants
• Effective Date: 15-Jan-2015

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: C1504 −15
StandardSpecification for
Manufacture of Precast Reinforced Concrete Three-Sided
Structures for Culverts and Storm Drains
This standard is issued under the fixed designation C1504; 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 C39/C39M Test Method for Compressive Strength of Cylin-
drical Concrete Specimens
1.1 This specification covers single-cell precast convention-
C150 Specification for Portland Cement
ally reinforced concrete three-sided structures intended to be
C260/C260M Specification for Air-Entraining Admixtures
used for the construction of culverts and for the conveyance of
for Concrete
storm water.
C309 Specification for Liquid Membrane-Forming Com-
1.2 A complete metric companion to Specification C1504
pounds for Curing Concrete
has been developed—C1504M; therefore, no metric equiva-
C494/C494M Specification for Chemical Admixtures for
lents are presented in this specification.
Concrete
C497 Test Methods for Concrete Pipe, Manhole Sections, or
NOTE 1—This specification is primarily a manufacturing and purchas-
ing specification. The successful performance of this product depends
Tile
upon the proper selection of the geometric section, bedding, backfill, and
C595 Specification for Blended Hydraulic Cements
care that the installation conforms to the construction specifications. The
C618 Specification for Coal Fly Ash and Raw or Calcined
purchaser of the precast reinforced concrete three-sided structure specified
Natural Pozzolan for Use in Concrete
herein is cautioned that proper correlation of the loading conditions and
C822 Terminology Relating to Concrete Pipe and Related
the field requirements with the geometric section specified and provisions
for inspection at the construction site are required.
Products
C989 Specification for Slag Cement for Use in Concrete and
1.3 The values stated in inch-pound units are to be regarded
Mortars
as standard. No other units of measurement are included in this
C1116 Specification for Fiber-Reinforced Concrete and
standard.
Shotcrete
C1602/C1602M Specification for Mixing Water Used in the
2. Referenced Documents
Production of Hydraulic Cement Concrete
2.1 ASTM Standards:
2.2 AASHTO Standard:
A1064/A1064M Specification for Carbon-Steel Wire and
AASHTO LRFD Bridge Design Specification
Welded Wire Reinforcement, Plain and Deformed, for
Concrete 2.3 ACI Standard:
A615/A615M SpecificationforDeformedandPlainCarbon-
ACI 318 Building Code Requirements for Structural Con-
Steel Bars for Concrete Reinforcement crete and Commentary
A706/A706M Specification for Deformed and Plain Low-
Alloy Steel Bars for Concrete Reinforcement 3. Terminology
C31/C31M Practice for Making and Curing Concrete Test
3.1 Definitions—For definitions of terms relating to geomet-
Specimens in the Field
ric sections, see Terminology C822.
C33 Specification for Concrete Aggregates
4. Types
4.1 Precast reinforced concrete three-sided structures manu-
This specification is under the jurisdiction of ASTM Committee C13 on
factured in accordance with this specification shall be desig-
Concrete Pipe and is the direct responsibility of Subcommittee C13.07 on
nated by span, rise, and design earth cover.
Acceptance Specifications and Precast Concrete Box Sections.
Current edition approved Jan. 15, 2015. Published January 2015. Originally
approved in 2001. Last previous edition approved in 2014 as C1504 – 14. DOI:
10.1520/C1504-15.
2 3
For referenced ASTM standards, visit the ASTM website, www.astm.org, or American Association of State Highway and Transportation Officials
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM (AASHTO), 444 N. Capitol St., NW, Suite 249, Washington, DC 20001.
Standards volume information, refer to the standard’s Document Summary page on Available fromAmerican Concrete Institute (ACI), P.O. Box 9094, Farmington
the ASTM website. Hills, MI 48333-9094, http://www.concrete.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C1504 − 15
5. Basis of Acceptance or deformed billet-steel bars conforming to Specification
A706/A706M or A615/A615M, Grade 60.
5.1 Acceptability of the three-sided sections produced in
NOTE 2—This specification does not address reinforcement with pre-
accordance with Section 7 shall be determined by the results of
stressing strand or any other form of pre-tensioning or post-tensioning.
the concrete compressive strength tests described in Section
10, by the material requirements described in Section 6, and by 6.6 Synthetic Fibers—Collated fibrillated virgin polypropyl-
inspection of the finished three-sided sections.
ene fibers may be used, at the manufacturer’s option, in
three-sided structures as a nonstructural manufacturing mate-
5.2 Three-sided sections shall be considered ready for
rial. Only type III synthetic fibers designed and manufactured
acceptance when they conform to the requirements of this
specifically for use in concrete and conforming to the require-
specification.
ments of Specification C1116 shall be accepted.
6.7 Water—Water used in the production of concrete shall
6. Materials
be potable or non-potable water that meets the requirements of
6.1 Reinforced Concrete—The reinforced concrete shall
Specification C1602/C1602M.
consist of cementitious materials, mineral aggregates and
water, in which steel has been embedded in such a manner that
7. Design
the steel and concrete act together.
7.1 Design Criteria—The three-sided section’s dimensions
6.2 Cementitious Materials:
and reinforcement details shall be as required by design, in
6.2.1 Cement—Cement shall conform to the requirements
accordance with Section 3, 5 and 12.14 of the American
for portland cement of Specification C150 or shall be portland
Association of State Highway and Transportation Officials
blast-furnace slag cement or portland-pozzolan cement con-
(AASHTO) LRFD Bridge Design Specifications. The mini-
forming to the requirements of Specification C595, except that
mum concrete compressive strength shall be 5000 psi, and the
the pozzolan constituent in the Type IP portland pozzolan
minimum steel yield strength shall be 65 000 psi for welded-
cement shall be fly ash.
wire reinforcement and 60 000 psi for deformed billet-steel
6.2.2 Fly Ash—Fly ash shall conform to the requirements of bars.
Specification C618, Class F or Class C.
7.2 Placement of Reinforcement—The minimum cover of
6.2.3 Ground Granulated Blast-Furnace Slag (GGBFS)—
concrete over the circumferential reinforcing diameter shall be
GGBFS shall conform to the requirements of Grade 100 or 120
1 in. for bar reinforcement and welded wire reinforcement for
of Specification C989.
all structures up to 12 ft in span, and 1.5 in. for longer spans
6.2.4 Allowable Combinations of Cementitious Materials—
subject to the provisions of Section 11 for both bar reinforce-
The combination of cementitious materials used in concrete
ment and welded wire reinforcement. The clear distance of the
shall be one of the following:
end circumferential wires shall be not less than ⁄2 in. nor more
(1) Portland cement only,
than 2 in. from the ends of each section. For three-sided
(2) Portland blast-furnace slag cement only,
sectionscoveredbylessthan2ftoffill,minimumcoverforthe
(3) Portland pozzolan cement only,
reinforcement in the top of the top slab shall be 2-in., subject
(4) A combination of portland cement and fly ash,
to the provisions of Section 11. Reinforcement shall be
(5) A combination of portland cement and ground granu-
assembled utilizing any combination of single or multiple
lated blast-furnace slag
layers of welded-wire reinforcement, not to exceed three layers
(6) A combination of portland cement, ground granulated
or utilizing single or multiple layers of deformed billet steel
blast furnace slag, and fly ash.
bars, not to exceed two layers. The welded-wire reinforcement
(7) Acombinationofportlandpozzolancementandflyash.
on 7.3 shall be composed of circumferential and longitudinal
wires meeting the spacing requirements of 7.3 and shall
6.3 Aggregates—Aggregates shall conform to Specification
contain sufficient longitudinal wires extending through the
C33, except that the requirements for gradation shall not apply.
three-sided section to maintain the shape and position of
6.4 Admixtures and Blends—Admixtures and blends shall
reinforcement. Longitudinal distribution reinforcement may be
conform to Specification C494/C494M.
welded-wire reinforcement or deformed billet-steel bars and
6.4.1 Air Entraining Admixtures—Air entraining will be
shall meet the spacing requirements of 7.3. The ends of the
required on all products produced with positive slump, wet-
longitudinal distribution reinforcement shall not be more than
cast concrete and shall conform to the requirements of Speci-
2in.fromtheendsofathree-sidedsection.Theexposureofthe
fication C260/C260M.
ends of longitudinals, stirrups, and spacers used to position the
reinforcement shall not be a cause for rejection.
6.5 Steel Reinforcement—Reinforcement shall consist of
welded wire reinforcement conforming to Specification 7.3 Laps, Welds, and Spacing—Splices in the circumferen-
A1064/A1064M for steel wire and welded wire reinforcement, tial reinforcement shall be made by lapping. For welded wire
plain and deformed, for concrete. For circumferential reinforcement, the overlap measured between the outermost
reinforcement, deformed and plain steel bars for reinforced longitudinalwiresofeachreinforcementsheetortheoutermost
concrete are permitted conforming to Specification A706/ bars shall not be less than the spacing of the longitudinal wires
A706M or A615/A615M, Grade 60, and longitudinal distribu- plus 2 in. but not less than 10 in. For splices of deformed billet
tion reinforcement shall consist of welded wire reinforcement steel bars, the overlap shall meet the requirements of
C1504 − 15
AASHTO. The outside circumferential reinforcement in the 9.2.1 Steam Curing—The three-sided section may be low
top slab shall be continuous with or be lapped with the outside pressure, steam-cured by a system that will maintain a moist
circumferentialreinforcementinthesides.Ifweldsaremadeto atmosphere.
welded wire reinforcement circumferential reinforcement, they 9.2.2 Water Curing—The three-sided section may be water-
shall be made only to selected circumferential wires that are cured by any method that will keep the sections moist.
not less than 18 in. apart along the longitudinal axis of the 9.2.3 Membrane Curing—A sealing membrane conforming
three-sided section. When spacers are welded to circumferen- to the requirements of Specification C309 may be applied and
tial wires, they shall be welded only to these selected circum- shall be left intact until the required concrete compressive
ferential wires. There shall be no welding to other circumfer- strength is attained. The concrete temperature at the time of
ential wires. No welds shall be made to the inside application shall be within 10°F of the atmospheric tempera-
circumferential wires in the middle third of the top span. No ture.All surfaces shall be kept moist prior to the application of
welds shall be made to the outside circumferential wires in the the compounds and shall be damp when the compound is
top span within one fourth of the span from the corners or in applied.
any location in either leg. Welding of deformed billet steel bar
9.3 Forms—The forms used in manufacture shall be suffi-
circumferential reinforcement is prohibited in all cases. When
ciently rigid and accurate to maintain the three-sided section
distribution reinforcement is to be fastened to a cage by
dimensions within the permissible variations given in Section
welding, it shall be welded only to longitudinal wires or bars
11. All casting surfaces shall be smooth nonporous material.
and only near the ends of the three-sided section. The spacing
9.4 Handling—Handling devices or holes shall be permitted
center to center of the circumferential reinforcement shall not
in each three-sided section for the purpose of handling and
be less than 2 in. nor more than 4 in. for welded wire
laying.
reinforcement or less than 2 in. nor more than 8 in. for
deformed billet steel bars. The spacing center to center of the
10. Physical Requirements
longitudinal reinforcement shall not be more than 8 in. for
welded wire reinforcement or more than 12 in. for deformed
10.1 Type of Test Specimen—Compression tests for deter-
billetsteelbars.IfweldsaremadetoGrade60reinforcingbars,
mining concrete compressive strength shall be made on either
weldable bars conforming to Specification A706/A706M shall
standard rodded concrete cylinders or concrete cylinders com-
be used.
pacted and cured in like manner as the three-sided section, or
on cores drilled from the three-sided section.
8. Joints
10.2 Compression Testing of Cylinders:
8.1 The precast reinforced concrete three-sided structures
10.2.1 Cylinders shall be obtained and tested for compres-
shall be produced with tongue and groove ends, flat butt ends
sive strength in accordance with the provisions of Practice
or key-way ends.The ends shall be of such design and the ends
C31/C31M and Test Method C39/C39M, except that the
of the three-sided sections so formed that each section can be
cylinders may be prepared by methods comparable to those
laid together to make a continuous line of sections compatible
used to consolidate and cure the concrete in the actual
with the permissible variations given in Section 11.
three-sided section manufactured. Cylindrical specimens of
sizes other than 6 by 12 in. may be used provided all other
9. Manufacture
requirements of Practice C31/C31M are met. If the concrete is
of a consistency too stiff for compaction by rodding or internal
9.1 Mixture—The aggregates shall be sized, graded,
proportioned,andmixedwithcementitiousmaterialsandwater vibration, the alternate method described in Section II of Test
Methods C497 may be used. Cylinders shall be exposed to
andadmixtures,ifany,toproduceathoroughlymixedconcrete
similar curing time and temperature conditions as the manu-
of such quality that the structures will conform to the design
requirements of this specification. All concrete shall have a factured three-sided sections as demonstrated upon request by
fabricator cylinder and three-sided section curing records.
water-cementitious materials ratio not exceeding 0.53 by
weights except that for concrete exposed to cyclic freez
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: C1504 − 14 C1504 − 15
Standard Specification for
Manufacture of Precast Reinforced Concrete Three-Sided
Structures for Culverts and Storm Drains
This standard is issued under the fixed designation C1504; 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
1.1 This specification covers single-cell precast conventionally reinforced concrete three-sided structures intended to be used
for the construction of culverts and for the conveyance of storm water.
1.2 A complete metric companion to Specification C1504 has been developed—C1504M; therefore, no metric equivalents are
presented in this specification.
NOTE 1—This specification is primarily a manufacturing and purchasing specification. The successful performance of this product depends upon the
proper selection of the geometric section, bedding, backfill, and care that the installation conforms to the construction specifications. The purchaser of
the precast reinforced concrete three-sided structure specified herein is cautioned that proper correlation of the loading conditions and the field
requirements with the geometric section specified and provisions for inspection at the construction site are required.
1.3 The values stated in inch-pound units are to be regarded as standard. No other units of measurement are included in this
standard.
2. Referenced Documents
2.1 ASTM Standards:
A1064/A1064M Specification for Carbon-Steel Wire and Welded Wire Reinforcement, Plain and Deformed, for Concrete
A615/A615M Specification for Deformed and Plain Carbon-Steel Bars for Concrete Reinforcement
A706/A706M Specification for Deformed and Plain Low-Alloy Steel Bars for Concrete Reinforcement
C31/C31M Practice for Making and Curing Concrete Test Specimens in the Field
C33 Specification for Concrete Aggregates
C39/C39M Test Method for Compressive Strength of Cylindrical Concrete Specimens
C150 Specification for Portland Cement
C260/C260M Specification for Air-Entraining Admixtures for Concrete
C309 Specification for Liquid Membrane-Forming Compounds for Curing Concrete
C494/C494M Specification for Chemical Admixtures for Concrete
C497 Test Methods for Concrete Pipe, Manhole Sections, or Tile
C595 Specification for Blended Hydraulic Cements
C618 Specification for Coal Fly Ash and Raw or Calcined Natural Pozzolan for Use in Concrete
C822 Terminology Relating to Concrete Pipe and Related Products
C989 Specification for Slag Cement for Use in Concrete and Mortars
C1116 Specification for Fiber-Reinforced Concrete and Shotcrete
C1602/C1602M Specification for Mixing Water Used in the Production of Hydraulic Cement Concrete
2.2 AASHTO Standard:
AASHTO LRFD Bridge Design Specification
2.3 ACI Standard:
ACI 318 Building Code Requirements for Structural Concrete and Commentary
This specification is under the jurisdiction of ASTM Committee C13 on Concrete Pipe and is the direct responsibility of Subcommittee C13.07 on Acceptance
Specifications and Precast Concrete Box Sections.
Current edition approved Feb. 1, 2014Jan. 15, 2015. Published February 2014January 2015. Originally approved in 2001. Last previous edition approved in 20132014
as C1504 – 13a.C1504 – 14. DOI: 10.1520/C1504-14.10.1520/C1504-15.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
American Association of State Highway and Transportation Officials (AASHTO), 444 N. Capitol St., NW, Suite 249, Washington, DC 20001.
Available from American Concrete Institute (ACI), P.O. Box 9094, Farmington Hills, MI 48333-9094, http://www.concrete.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C1504 − 15
3. Terminology
3.1 Definitions—For definitions of terms relating to geometric sections, see Terminology C822.
4. Types
4.1 Precast reinforced concrete three-sided structures manufactured in accordance with this specification shall be designated by
span, rise, and design earth cover.
5. Basis of Acceptance
5.1 Acceptability of the three-sided sections produced in accordance with Section 7 shall be determined by the results of the
concrete compressive strength tests described in Section 10, by the material requirements described in Section 6, and by inspection
of the finished three-sided sections.
5.2 Three-sided sections shall be considered ready for acceptance when they conform to the requirements of this specification.
6. Materials
6.1 Reinforced Concrete—The reinforced concrete shall consist of cementitious materials, mineral aggregates and water, in
which steel has been embedded in such a manner that the steel and concrete act together.
6.2 Cementitious Materials:
6.2.1 Cement—Cement shall conform to the requirements for portland cement of Specification C150 or shall be portland
blast-furnace slag cement or portland-pozzolan cement conforming to the requirements of Specification C595, except that the
pozzolan constituent in the Type IP portland pozzolan cement shall be fly ash.
6.2.2 Fly Ash—Fly ash shall conform to the requirements of Specification C618, Class F or Class C.
6.2.3 Ground Granulated Blast-Furnace Slag (GGBFS)—GGBFS shall conform to the requirements of Grade 100 or 120 of
Specification C989.
6.2.4 Allowable Combinations of Cementitious Materials—The combination of cementitious materials used in concrete shall be
one of the following:
(1) Portland cement only,
(2) Portland blast-furnace slag cement only,
(3) Portland pozzolan cement only,
(4) A combination of portland cement and fly ash,
(5) A combination of portland cement and ground granulated blast-furnace slag
(6) A combination of portland cement, ground granulated blast furnace slag, and fly ash.
(7) A combination of portland pozzolan cement and fly ash.
6.3 Aggregates—Aggregates shall conform to Specification C33, except that the requirements for gradation shall not apply.
6.4 Admixtures and Blends—Admixtures and blends shall conform to Specification C494/C494M.
6.4.1 Air Entraining Admixtures—Air entraining will be required on all products produced with positive slump, wet-cast
concrete and shall conform to the requirements of Specification C260/C260M.
6.5 Steel Reinforcement—Reinforcement shall consist of welded wire reinforcement conforming to Specification A1064/
A1064M for steel wire and welded wire reinforcement, plain and deformed, for concrete. For circumferential reinforcement,
deformed and plain steel bars for reinforced concrete are permitted conforming to Specification A706/A706M or A615/A615M,
Grade 60, and longitudinal distribution reinforcement shall consist of welded wire reinforcement or deformed billet-steel bars
conforming to Specification A706/A706M or A615/A615M, Grade 60.
NOTE 2—This specification does not address reinforcement with prestressing strand or any other form of pre-tensioning or post-tensioning.
6.6 Synthetic Fibers—Collated fibrillated virgin polypropylene fibers may be used, at the manufacturer’s option, in three-sided
structures as a nonstructural manufacturing material. Only type III synthetic fibers designed and manufactured specifically for use
in concrete and conforming to the requirements of Specification C1116 shall be accepted.
6.7 Water—Water used in the production of concrete shall be potable or non-potable water that meets the requirements of
Specification C1602/C1602M.
7. Design
7.1 Design Criteria—The three-sided section’s dimensions and reinforcement details shall be as required by design, in
accordance with Section 3, 5 and 12.14 of the American Association of State Highway and Transportation Officials (AASHTO)
LRFD Bridge Design Specifications. The minimum concrete compressive strength shall be 5000 psi, and the minimum steel yield
strength shall be 65 000 psi for welded-wire reinforcement and 60 000 psi for deformed billet-steel bars.
7.2 Placement of Reinforcement—The minimum cover of concrete over the circumferential reinforcing diameter shall be 1 in.
for bar reinforcement and welded wire reinforcement for all structures up to 12 ft in span, and 1.5 in. for longer spans subject to
C1504 − 15
the provisions of Section 11 for both bar reinforcement and welded wire reinforcement. The clear distance of the end
circumferential wires shall be not less than ⁄2 in. nor more than 2 in. from the ends of each section. For three-sided sections covered
by less than 2 ft of fill, minimum cover for the reinforcement in the top of the top slab shall be 2-in., subject to the provisions of
Section 11. Reinforcement shall be assembled utilizing any combination of single or multiple layers of welded-wire reinforcement,
not to exceed three layers or utilizing single or multiple layers of deformed billet steel bars, not to exceed two layers. The
welded-wire reinforcement on 7.3 shall be composed of circumferential and longitudinal wires meeting the spacing requirements
of 7.3 and shall contain sufficient longitudinal wires extending through the three-sided section to maintain the shape and position
of reinforcement. Longitudinal distribution reinforcement may be welded-wire reinforcement or deformed billet-steel bars and
shall meet the spacing requirements of 7.3. The ends of the longitudinal distribution reinforcement shall not be more than 2 in.
from the ends of a three-sided section. The exposure of the ends of longitudinals, stirrups, and spacers used to position the
reinforcement shall not be a cause for rejection.
7.3 Laps, Welds, and Spacing—Splices in the circumferential reinforcement shall be made by lapping. For welded wire
reinforcement, the overlap measured between the outermost longitudinal wires of each reinforcement sheet or the outermost bars
shall not be less than the spacing of the longitudinal wires plus 2 in. but not less than 10 in. For splices of deformed billet steel
bars, the overlap shall meet the requirements of AASHTO. The outside circumferential reinforcement in the top slab shall be
continuous with or be lapped with the outside circumferential reinforcement in the sides. If welds are made to welded wire
reinforcement circumferential reinforcement, they shall be made only to selected circumferential wires that are not less than 18
in. apart along the longitudinal axis of the three-sided section. When spacers are welded to circumferential wires, they shall be
welded only to these selected circumferential wires. There shall be no welding to other circumferential wires. No welds shall be
made to the inside circumferential wires in the middle third of the top span. No welds shall be made to the outside circumferential
wires in the top span within one fourth of the span from the corners or in any location in either leg. Welding of deformed billet
steel bar circumferential reinforcement is prohibited in all cases. When distribution reinforcement is to be fastened to a cage by
welding, it shall be welded only to longitudinal wires or bars and only near the ends of the three-sided section. The spacing center
to center of the circumferential reinforcement shall not be less than 2 in. nor more than 4 in. for welded wire reinforcement or less
than 2 in. nor more than 8 in. for deformed billet steel bars. The spacing center to center of the longitudinal reinforcement shall
not be more than 8 in. for welded wire reinforcement or more than 12 in. for deformed billet steel bars. If welds are made to Grade
60 reinforcing bars, weldable bars conforming to Specification A706/A706M shall be used.
8. Joints
8.1 The precast reinforced concrete three-sided structures shall be produced with tongue and groove ends, flat butt ends or
key-way ends. The ends shall be of such design and the ends of the three-sided sections so formed that each section can be laid
together to make a continuous line of sections compatible with the permissible variations given in Section 11.
9. Manufacture
9.1 Mixture—The aggregates shall be sized, graded, proportioned, and mixed with cementitious materials and water and
admixtures, if any, to produce a thoroughly mixed concrete of such quality that the structures will conform to the design
requirements of this specification. All concrete shall have a water-cementitious materials ratio not exceeding 0.53 by weights
except that for concrete exposed to cyclic freeze/thaw the water-cementitious materials ratio shall not exceed 0.45. Cementitious
materials shall be as specified in 6.2 and shall be added to the mix in a proportion not less than 470 lb/yd unless mix designs with
a lower cementitious materials content demonstrate that the quality and performance of the three-sided sections meet the
requirements of this specification. Wet cast concrete subject to freeze/thaw cycle shall be air-entrained. Air entrainment amounts
shall be in accordance with ACI 318–11, Chapter 4, for the appropriate Exposure Class.
9.2 Curing—The three-sided sections shall be cured for a sufficient length of time so that the concrete will develop the required
compressive strength by the time of delivery. Any one of the following methods of curing or combinations thereof may be used:
9.2.1 Steam Curing—The three-sided section may be low pressure, steam-cured by a system that will maintain a moist
atmosphere.
9.2.2 Water Curing—The three-sided section may be water-cured by any method that will keep the sections moist.
9.2.3 Membrane Curing—A sealing membrane conforming to the requirements of Specification C309 may be applied and shall
be left intact until the required concrete compressive strength is attained. The concrete temperature at the time of application shall
be within 10°F of the atmospheric temperature. All surfaces shall be kept moist prior to the application of the compounds and shall
be damp when the compound is applied.
9.3 Forms—The forms used in manufacture shall be sufficiently rigid and accurate to maintain the three-sided section
dimensions within the permissible variations given in Section 11. All casting surfaces shall be smooth nonporous material.
9.4 Handling—Handling devices or holes shall be permitted in each three-sided section for the purpose of handling and laying
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