ASTM C1786-14
(Specification)Standard Specification for Segmental Precast Reinforced Concrete Box Sections for Culverts, Storm Drains, and Sewers Designed According to AASHTO LRFD
Standard Specification for Segmental Precast Reinforced Concrete Box Sections for Culverts, Storm Drains, and Sewers Designed According to AASHTO LRFD
SCOPE
1.1 This specification covers precast reinforced concrete box sections comprised of separate segments that once properly field assembled make the final structure. These structures are intended to be used for the construction of culverts and for the conveyance of storm water, industrial wastes and sewage.
Note 1: This specification is primarily a manufacturing and purchasing specification. However, box culverts manufactured to this standard are intended to meet the design requirements of the AASHTO LRFD Bridge Design Specifications, and as such, design guidance is included in Appendix X1.
Note 2: The successful performance of this product depends upon the proper selection of the box section, bedding, backfill, and care that the installation conforms to the construction specifications. The purchaser of the precast reinforced concrete box sections specified herein is cautioned that proper correlation of the loading conditions and the field requirements with the box section specified, and provision for inspection at the construction site, are required.
1.2 The values stated in inch-pound units are to be regarded as standard. No other units of measurement are included in this standard.
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Designation:C1786 −14
StandardSpecification for
Segmental Precast Reinforced Concrete Box Sections for
Culverts, Storm Drains, and Sewers Designed According to
AASHTO LRFD
This standard is issued under the fixed designation C1786; 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 C260 Specification for Air-Entraining Admixtures for Con-
crete
1.1 This specification covers precast reinforced concrete
C309 Specification for Liquid Membrane-Forming Com-
box sections comprised of separate segments that once prop-
pounds for Curing Concrete
erly field assembled make the final structure. These structures
C494/C494M Specification for Chemical Admixtures for
are intended to be used for the construction of culverts and for
Concrete
the conveyance of storm water, industrial wastes and sewage.
C497 Test Methods for Concrete Pipe, Manhole Sections, or
NOTE 1—This specification is primarily a manufacturing and purchas-
Tile
ing specification. However, box culverts manufactured to this standard are
C595 Specification for Blended Hydraulic Cements
intended to meet the design requirements of the AASHTO LRFD Bridge
C618 Specification for Coal Fly Ash and Raw or Calcined
Design Specifications, and as such, design guidance is included in
Natural Pozzolan for Use in Concrete
Appendix X1.
NOTE 2—The successful performance of this product depends upon the
C822 Terminology Relating to Concrete Pipe and Related
proper selection of the box section, bedding, backfill, and care that the
Products
installation conforms to the construction specifications. The purchaser of
C989 Specification for Slag Cement for Use in Concrete and
the precast reinforced concrete box sections specified herein is cautioned
Mortars
thatpropercorrelationoftheloadingconditionsandthefieldrequirements
C1116 Specification for Fiber-Reinforced Concrete and
with the box section specified, and provision for inspection at the
construction site, are required.
Shotcrete
1.2 The values stated in inch-pound units are to be regarded
2.2 AASHTO Standards:
as standard. No other units of measurement are included in this
AASHTO LRFD Bridge Design Specifications
standard.
AASHTO LRFD Bridge Construction Specifications
2.3 ACI Standards:
2. Referenced Documents
ACI 318 Building Code Requirements for Structural Con-
2.1 ASTM Standards:
crete
A615/A615M SpecificationforDeformedandPlainCarbon-
Steel Bars for Concrete Reinforcement
3. Terminology
A706/A706M Specification for Deformed and Plain Low-
3.1 Definitions of Terms Specific to This Standard:
Alloy Steel Bars for Concrete Reinforcement
3.1.1 box section—the completed box culvert unit with all
A1064/A1064M Specification for Carbon-Steel Wire and
segments adjoined (see Fig. 1 for configuration options).
Welded Wire Reinforcement, Plain and Deformed, for
Concrete
3.1.2 box segment—the individual piece (top slab, bottom
C33 Specification for Concrete Aggregates
slab, or three-sided structure) that gets adjoined to other pieces
C150 Specification for Portland Cement
to complete the final box section
3.2 Definitions—Fordefinitionsoftermsrelatingtoconcrete
box culvert sections not found above, see Terminology C822.
This test method 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 Nov. 1, 2014. Published December 2014. DOI:
10.1520/C1786–14. Available from American Association of State Highway and Transportation
For referenced ASTM standards, visit the ASTM website, www.astm.org, or Officials (AASHTO), 444 N. Capitol St., NW, Suite 249, Washington, DC 20001,
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM http://www.transportation.org.
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
C1786−14
FIG. 1Segment Configuration Options
C1786−14
4. Basis of Acceptance mentmeetingtheyieldstrengthsdesignatedinthedesignofthe
box culvert, but the yield strength shall not be less than 60 ksi.
4.1 Acceptability of the box sections produced in accor-
5.6 Synthetic Fibers—Collated fibrillated virgin polypropyl-
dance with this standard shall be determined by the results of
the concrete compressive strength tests described in Section ene fibers may be used at the manufacturer’s option, in
concreteboxesasanonstructuralmanufacturingmaterial.Only
10, by the material requirements described in Section 5, and by
inspection of the finished box sections by the owner or their Type III synthetic fibers designed and manufactured specifi-
cally for use in concrete and conforming to the requirements of
designee.
Specification C1116 shall be accepted.
NOTE 3—The box culvert structure itself is not complete until it is fully
assembled in the field. Field assembly is not included in this specification.
6. Design
However, a final field inspection is recommended before the box culvert
is considered fit for duty. 6.1 Each segment of the box shall meet the requirements of
the AASHTO LRFD Bridge Design Specifications. Guidance
5. Material
is given in Appendix X1.
5.1 Reinforced Concrete—The reinforced concrete shall 6.2 The manufacturer shall maintain on file a copy of a
consist of cementitious materials, mineral aggregates and sealed “stamped” design by a professional engineer in accor-
water, in which steel has been embedded in such a manner that dance with the AASHTO LRFD Bridge Design Specifications
the steel and concrete act together. and this standard for each structure manufactured.
6.3 The minimum compressive strength of concrete seg-
5.2 Cementitious Materials:
ments produced to this standard shall be 4000 psi, unless
5.2.1 Cement—Cement shall conform to the requirements
otherwise designated by the engineer.
for portland cement of Specification C150 or shall be portland
blast-furnace slag cement or portland-pozzolan cement con-
6.4 The manufacturer shall produce box culvert segments
forming to the requirements of Specification C595, except that
meetingthedesignrequirementsdesignatedinthedesignofthe
the pozzolan constituent in the Type IP portland-pozzolan
segmental precast box structure. As a minimum, the box
cement shall be fly ash.
culvert segments shall meet the reinforcement layout, concrete
5.2.2 Fly Ash—Fly ash shall conform to the requirements of
cover, and all other manufacturing details required by this
Specification C618, Class F or Class C.
standard.
5.2.3 Ground Granulated Blast-Furnace Slag—GGBFS
6.5 The manufacturer may request approval by the pur-
shall conform to the requirements of Grade 100 or 120 of
chaser for modified designs which differ from the requirements
Specification C989.
in this standard. When such modified designs are approved, it
5.2.4 Allowable Combinations of Cementitious Materials—
shall be so indicated on the manufactured box with the
The combination of cementitious materials used in concrete
designation “C1786–Modified.”
shall be one of the following:
NOTE 4—(Advisory)—Construction procedures, such as heavy equip-
5.2.4.1 Portland cement only,
ment movement or stockpiling of material over or adjacent to a box
5.2.4.2 Portland blast furnace slag cement only,
structure can induce higher loads than those used for the structure’s final
5.2.4.3 Portland pozzolan cement only,
design. These construction and surcharge loads are allowable as long as
5.2.4.4 A combination of portland cement and fly ash,
the final steel areas in the box are equal to or larger than those required for
the construction phase. The design engineer shall take into consideration
5.2.4.5 A combination of portland cement and ground
the potential for higher loads induced by construction procedures in
granulated blast-furnace slag, or
determining the final design of the box structure.
5.2.4.6 A combination of portland cement, ground granu-
lated blast-furnace slag (not to exceed 25 % of the total 7. Reinforcement
cementitious weight) and fly ash (not to exceed 25 % of the
7.1 Placement of Reinforcement—Reinforcement shall be
total cementitious weight).
assembled utilizing any combination of single or multiple
5.3 Aggregates—Aggregates shall conform to Specification layersofweldedwirereinforcement,nottoexceedthreelayers,
orutilizingsingleordoublelayersofdeformedbilletsteelbars.
C33, except that the requirements for gradation shall not apply.
The cover of concrete over the circumferential reinforcement
5.4 Admixtures and Blends—The following admixtures and
shall be 1 in. except for when the box culvert has less than 2 ft
blends are allowable:
of earth cover, then the concrete cover over the top slab
5.4.1 Air-entraining admixture conforming to Specification
reinforcement shall be 2 inches (see Figs. 2 and 3). Concrete
C260;
cover shall be subject to the provisions of Section 11. The
5.4.2 Chemical admixture conforming to Specification
welded wire reinforcement shall be composed of circumferen-
C494/C494M;
tial and longitudinal wires meeting the spacing requirements of
5.4.3 Chemical admixture or blend approved by the owner.
7.2 and shall contain sufficient longitudinal wires extending
5.5 Steel Reinforcement—Reinforcement shall consist of through the box section to maintain the shape and position of
welded wire reinforcement conforming to Specification reinforcement.Longitudinaldistributionreinforcementshallbe
A1064/A1064M or billet-steel bars conforming to Specifica- welded-wire reinforcement or deformed billet-steel bars and
tion A615/A615M, Grade 60 or A706/A706M, Grade 60. The shall meet the spacing requirements of 7.2. The ends of the
box culvert segments shall be manufactured with reinforce- longitudinal distribution reinforcement shall not be more than
C1786−14
FIG. 2Top Slab Reinforcement Placement
(Joint configuration is for illustration purposes only, and other configurations are acceptable.)
FIG. 3Bottom Slab Reinforcement Placement
(Joint configuration is for illustration purposes only, and other configurations are acceptable.)
2in.fromtheendsoftheboxsection.Theexposureoftheends 10inches.Nosplicingispermittedinindividualslabsegments.
of longitudinals, stirrups, and spacers used to position the The outside circumferential reinforcement in the top or bottom
reinforcement shall not be a cause for rejection.
slab of a three-sided segment shall be continuous with, or
lapped with the outside circumferential reinforcement in the
7.2 Laps, Welds, and Spacing—When deformed billet steel
sides. If welds are made to welded wire circumferential
bars are utilized for the primary reinforcing, the requirements
reinforcement, they shall be made only to selected circumfer-
in the AASHTO LRFD Bridge Design Specifications, Section
ential wires that are not less than 18 in. apart along the
5.11 for splices and development of reinforcement shall be
longitudinal axis of the three-sided section. When spacers are
followed. When wire reinforcement is utilized, the require-
welded to circumferential wires, they shall be welded only to
ments of this section shall be followed. Splices in the circum-
these selected circumferential wires. There shall be no welding
ferential reinforcement shall be made by lapping. The overlap
to other circumferential wires. No welds shall be made to the
measured between the outermost longitudinal wires of each
inside circumferential wires in the middle third of the top span.
reinforcement sheet shall not be less than the space containing
twolongitudinalwiresofeachmeshplus2in.,butnotlessthan No welds shall be made to the outside circumferential wires in
C1786−14
the top span within one fourth of the span from the corners or 9.2 Curing—The box segments shall be cured for a suffi-
in any location in either leg. Welding of deformed billet steel cient length of time so that the concrete will develop the
bar circumferential reinforcement is prohibited in all cases. specifiedcompressivestrengthbythetimeofdelivery.Anyone
When distribution reinforcement is fastened to a cage by of the following methods of curing or combinations thereof
welding, it shall be welded only to longitudinal wires or bars shall be used:
and only near the ends of the three-sided section. The spacing 9.2.1 Steam Curing—The box segments shall be low
center to center of the circumferential reinforcement shall not pressure, steam-cured by a system that will maintain a moist
be less than 2 in. nor more than 4 in. for welded wire atmosphere.
reinforcement, or less than 2 in. nor more than 8 in. for 9.2.2 Water Curing—The box segments shall be water-
deformed billet steel bars. The spacing center to center of the cured by any method that will keep the sections moist.
longitudinal reinforcement shall not be more than 8 in. for 9.2.3 Membrane Curing—A sealing membrane conforming
welded wire reinforcement or more than 12 in. for deformed to the requirements of Specification C309 shall be applied and
billetsteelbars.IfweldsaremadetoGrade60reinforcingbars, shall be left intact until the required concrete compressive
weldable bars conforming to Specification A706/A706M shall strength is attained. The concrete temperature at the time of
be used. application shall be within 10°F of the atmospheric tempera-
ture.All surfaces shall be kept moist prior to the application of
NOTE 5—(Advisory)—The AASHTO LRFD Bridge Design Specifica-
the compounds and shall be damp when the compound is
tions should be consulted for weld requirements and development lengths
applied.
not directly addressed in this standard.
7.3 Minimum Reinforcement—Box culvert sections with 9.3 Forms—The forms used in manufacture shall be suffi-
less than 2 ft of earth or pavement cover shall contain ciently rigid and accurate to maintain the box section dimen-
distribution reinforcement in the bottom of the top slab in sions within the permissible variations given in Section 10.All
accordance withArticle 9.7.3.2 of theAASHTO LRFD Bridge casting surfaces shall be of smooth nonporous material.
Design Specifications, but shall be no less than 0.02*Ag in
9.4 Handling—Handling devices or holes are not prohibited
accordance with Article 12.11.4.3.
in each box segment for the purpose of handli
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