1、Designation: C1786 17C1786 18Standard Specification forSegmental Precast Reinforced Concrete Box Sections forCulverts, Storm Drains, and Sewers Designed According toAASHTO LRFD1This standard is issued under the fixed designation C1786; the number immediately following the designation indicates the y
2、ear oforiginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope Scope*1.1 This specification covers precast reinforced c
3、oncrete box sections comprised of separate segments that once properly fieldassembled make the final structure. These structures are intended to be used for the construction of culverts and for the conveyanceof storm water, industrial wastes and sewage.NOTE 1This specification is primarily a manufac
4、turing and purchasing specification. However, box culverts manufactured to this standard areintended to meet the design requirements of the AASHTO LRFD Bridge Design Specifications, and as such, design guidance is included in AppendixX1.NOTE 2The successful performance of this product depends upon t
5、he proper selection of the box section, bedding, backfill, and care that theinstallation conforms to the construction specifications. The purchaser of the precast reinforced concrete box sections specified herein is cautioned thatproper correlation of the loading conditions and the field requirement
6、s 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 thisstandard.1.3 This international standard was developed in accordance with i
7、nternationally recognized principles on standardizationestablished in the Decision on Principles for the Development of International Standards, Guides and Recommendations issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2A61
8、5/A615M Specification for Deformed and Plain Carbon-Steel Bars for Concrete ReinforcementA706/A706M Specification for Deformed and Plain Low-Alloy Steel Bars for Concrete ReinforcementA1064/A1064M Specification for Carbon-Steel Wire and Welded Wire Reinforcement, Plain and Deformed, for ConcreteC33/
9、C33M Specification for Concrete AggregatesC150/C150M Specification for Portland CementC260/C260M Specification for Air-Entraining Admixtures for ConcreteC309 Specification for Liquid Membrane-Forming Compounds for Curing ConcreteC494/C494M Specification for Chemical Admixtures for ConcreteC497 Test
10、Methods for Concrete Pipe, Manhole Sections, or TileC595/C595M Specification for Blended Hydraulic CementsC618 Specification for Coal Fly Ash and Raw or Calcined Natural Pozzolan for Use in ConcreteC822 Terminology Relating to Concrete Pipe and Related ProductsC989/C989M Specification for Slag Cemen
11、t for Use in Concrete and MortarsC1017/C1017M Specification for Chemical Admixtures for Use in Producing Flowing ConcreteC1116/C1116M Specification for Fiber-Reinforced ConcreteC1602/C1602M Specification for Mixing Water Used in the Production of Hydraulic Cement Concrete1 This test method is under
12、the jurisdiction of ASTM Committee C13 on Concrete Pipe and is the direct responsibility of Subcommittee C13.07 on AcceptanceSpecifications and Precast Concrete Box Sections.Current edition approved Oct. 1, 2017Jan. 1, 2018. Published October 2017February 2018. Originally approved in 2014. Las previ
13、ous edition approved in 20162017 asC1786 16.17. DOI: 10.1520/C178617.10.1520/C178618.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary p
14、age on the ASTM website.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. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that
15、 users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Co
16、nshohocken, PA 19428-2959. United States12.2 AASHTO Standards:3AASHTO LRFD Bridge Design SpecificationsAASHTO LRFD Bridge Construction Specifications2.3 ACI Standards:4ACI 318 Building Code Requirements for Structural Concrete3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 box
17、 sectionthe completed box culvert unit with all segments adjoined (see Fig. 1 for configuration options).3.1.2 box segmentthe individual piece (top slab, bottom slab, or three-sided structure) that gets adjoined to other pieces tocomplete the final box section3.2 DefinitionsFor definitions of terms
18、relating to concrete box culvert sections not found above, see Terminology C822.4. Basis of Acceptance4.1 Acceptability of the box sections produced in accordance with this standard shall be determined by the results of theconcrete compressive strength tests described in Section 10, by the material
19、requirements described in Section 5, and by inspectionof the finished box sections by the owner or their designee.NOTE 3The box culvert structure itself is not complete until it is fully assembled in the field. Field assembly is not included in this specification.However, a final field inspection is
20、 recommended before the box culvert is considered fit for duty.5. Material5.1 Reinforced ConcreteThe reinforced concrete shall consist of cementitious materials, mineral aggregates, admixtures ifused, and water, in which steel has been embedded in such a manner that the steel and concrete act togeth
21、er.5.2 Cementitious Materials:5.2.1 CementCement shall conform to the requirements for portland cement of Specification C150/C150M or shall beportland blast-furnace slag cement, portland-limestone cement, or portland-pozzolan cement conforming to the requirements ofSpecification C595/C595M, except t
22、hat the pozzolan constituent in the Type IP portland-pozzolan cement shall be fly ash.5.2.2 Fly AshFly ash shall conform to the requirements of Specification C618, Class F or Class C.5.2.3 Slag CementSlag cement shall conform to the requirements of Grade 100 or 120 of Specification C989/C989M.5.2.4
23、Allowable Combinations of Cementitious MaterialsThe combination of cementitious materials used in concrete shall beone of the following:5.2.4.1 Portland cement only,5.2.4.2 Portland blast-furnace slag cement only,5.2.4.3 Portland-pozzolan cement only,5.2.4.4 Portland-limestone cement only,5.2.4.5 A
24、combination of portland cement or portland-limestone cement and fly ash,5.2.4.6 A combination of portland cement or portland-limestone cement and slag cement, or5.2.4.7 A combination of portland cement or portland-limestone cement, slag cement, and fly ash, or5.2.4.8 A combination of portland-pozzol
25、an cement and fly ash.5.3 AggregatesAggregates shall conform to Specification C33/C33M, except that the requirements for gradation shall notapply.5.4 AdmixturesThe following admixtures and blends are allowable:5.4.1 Air-entraining admixture conforming to Specification C260/C260M;5.4.2 Chemical admix
26、ture conforming to Specification C494/C494M;5.4.3 Chemical admixture for use in producing flowing concrete conforming to Specification C1017/C1017M.5.4.4 Chemical admixture or blend approved by the owner.5.5 Steel ReinforcementReinforcement shall consist of welded wire reinforcement conforming to Sp
27、ecification A1064/A1064M or billet-steel bars conforming to Specification A615/A615M, Grade 60 or A706/A706M, Grade 60. The box culvertsegments shall be manufactured with reinforcement meeting the yield strengths designated in the design of the box culvert, butthe yield strength shall not be less th
28、an 60 ksi.3 Available from American Association of State Highway and Transportation Officials (AASHTO), 444 N. Capitol St., NW, Suite 249, Washington, DC 20001,http:/www.transportation.org.4 Available from American Concrete Institute (ACI), P.O. Box 9094, Farmington Hills, MI 48333-9094, http:/www.c
29、oncrete.org.C1786 182FIG. 1 Segment Configuration OptionsC1786 1835.6 FibersSynthetic and non-synthetic fibers shall be allowed to be used, at the manufacturers option, in concrete boxes asa nonstructural manufacturing material. Synthetic fibers (Type II and Type III) and non-synthetic fiber (Type I
30、) designed andmanufactured specifically for use in concrete and conforming to the requirements of Specification C1116/C1116M shall beaccepted.5.7 WaterWater used in the production of concrete shall be potable, or non-potable water that meets the requirements ofSpecification C1602/C1602M.6. Design6.1
31、 Each segment of the box shall meet the requirements of the AASHTO LRFD Bridge Design Specifications. Guidance isgiven in Appendix X1.6.2 The manufacturer shall maintain on file a copy of a sealed “stamped” design by a professional engineer in accordance withthe AASHTO LRFD Bridge Design Specificati
32、ons and this standard for each structure manufactured.6.3 The minimum compressive strength of concrete segments produced to this standard shall be 4000 psi, unless otherwisedesignated by the engineer.6.4 The manufacturer shall produce box culvert segments meeting the design requirements designated i
33、n the design of thesegmental precast box structure.As a minimum, the box culvert segments shall meet the reinforcement layout, concrete cover, andall other manufacturing details required by this standard.6.5 The manufacturer may request approval by the purchaser for modified designs which differ fro
34、m the requirements in thisstandard. When such modified designs are approved, it shall be so indicated on the manufactured box with the designation“C1786Modified.”NOTE 4(Advisory)Construction procedures, such as heavy equipment movement or stockpiling of material over or adjacent to a box structure c
35、aninduce higher loads than those used for the structures final design. These construction and surcharge loads are allowable as long as the final steel areasin the box are equal to or larger than those required for the construction phase. The design engineer shall take into consideration the potentia
36、l for higherloads induced by construction procedures in determining the final design of the box structure.7. Reinforcement7.1 Placement of ReinforcementReinforcement shall be assembled utilizing any combination of single or multiple layers ofwelded wire reinforcement, not to exceed three layers, or
37、utilizing single or double layers of deformed billet steel bars. The coverof concrete over the circumferential reinforcement shall be 1 in. except for when the box culvert has less than 2 ft of earth cover,then the concrete cover over the top slab reinforcement shall be 2 inches (see Figs. 2 and 3).
38、 Concrete cover shall be subject tothe provisions of Section 11. The welded wire reinforcement shall be composed of circumferential and longitudinal wires meetingthe spacing requirements of 7.2 and shall contain sufficient longitudinal wires extending through the box section to maintain theshape and
39、 position of reinforcement. Longitudinal distribution reinforcement shall be welded-wire reinforcement or deformedFIG. 2 Top Slab Reinforcement Placement(Joint configuration is for illustration purposes only, and other configurations are acceptable.)C1786 184billet-steel bars and shall meet the spac
40、ing requirements of 7.2. The ends of the longitudinal distribution reinforcement shall notbe more than 2 in. from the ends of the box section. The exposure of the ends of longitudinals, stirrups, and spacers used to positionthe reinforcement shall not be a cause for rejection.7.2 Laps, Welds, and Sp
41、acingWhen deformed billet steel bars are utilized for the primary reinforcing, the requirements in theAASHTO LRFD Bridge Design Specifications, Section 5.11 for splices and development of reinforcement shall be followed.Whenwire reinforcement is utilized, the requirements of this section shall be fo
42、llowed. Splices in the circumferential reinforcement shallbe made by lapping. The overlap measured between the outermost longitudinal wires of each reinforcement sheet shall not be lessthan the space containing two longitudinal wires of each mesh plus 2 in., but not less than 10 inches. No splicing
43、is permitted inindividual slab segments. The outside circumferential reinforcement in the top or bottom slab of a three-sided segment shall becontinuous with, or lapped with the outside circumferential reinforcement in the sides. If welds are made to welded wirecircumferential reinforcement, they sh
44、all be made only to selected circumferential wires that are not less than 18 in. apart alongthe longitudinal axis of the three-sided section. When spacers are welded to circumferential wires, they shall be welded only tothese selected circumferential wires. There shall be no welding to other circumf
45、erential wires. No welds shall be made to the insidecircumferential wires in the middle third of the top span. No welds shall be made to the outside circumferential wires in the topspan within one fourth of the span from the corners or in any location in either leg. Welding of deformed billet steel
46、barcircumferential reinforcement is prohibited in all cases. When distribution reinforcement is fastened to a cage by welding, it shallbe welded only to longitudinal wires or bars and only near the ends of the three-sided section. The spacing center to center of thecircumferential reinforcement shal
47、l not be less than 2 in. nor more than 4 in. for welded wire reinforcement, or less than 2 in. normore than 8 in. for deformed billet steel bars. The spacing center to center of the longitudinal reinforcement shall not be more than8 in. for welded wire reinforcement or more than 12 in. for deformed
48、billet steel bars. If welds are made to Grade 60 reinforcingbars, weldable bars conforming to Specification A706/A706M shall be used.NOTE 5(Advisory)The AASHTO LRFD Bridge Design Specifications should be consulted for weld requirements and development lengths notdirectly addressed in this standard.7
49、.3 Minimum ReinforcementBox culvert sections with less than 2 ft of earth or pavement cover shall contain distributionreinforcement in the bottom of the top slab in accordance withArticle 9.7.3.2 of theAASHTO LRFD Bridge Design Specifications,but shall be no less than 0.002*Ag in accordance with Article 12.11.4.3.8. Joints8.1 The ends of the box segments shall be of such design that each segment can be fitted together to form a complete box sectionunit. The ends of the box section units shall be so formed that the sections can be laid together to
