1、Designation: A 798/A 798M 07Standard Practice forInstalling Factory-Made Corrugated Steel Pipe for Sewersand Other Applications1This standard is issued under the fixed designation A 798/A 798M; the number immediately following the designation indicates the yearof original adoption or, in the case of
2、 revision, the year of last revision. A number in parentheses indicates the year of last reapproval.A superscript epsilon (e) indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1. Scope1.1 This practice
3、 covers procedures, soils, and soil place-ment for the proper installation of corrugated steel pipe andpipe-arches produced to Specification A 760/A 760M orA 762/A 762M, in either trench or embankment installations.Atypical trench installation and a typical embankment (projec-tion) installation are
4、shown in Figs. 1 and 2, respectively. Thepipes described in this practice are manufactured in a factoryand furnished to the job in lengths ordinarily from 10 to 30 ft3 to 9 m, with 20 ft 6 m being common, for field joining.This practice applies to structures designed in accordance withPractice A 796
5、/A 796M.1.2 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.1.3 Thi
6、s specification is applicable to design in inch-poundunits as A 798 or in SI units as A 798M. Inch-pound units andSI units are not necessarily equivalent. SI units are shown inbrackets in the text for clarity, but they are the applicablevalues when the installation is to be performed in accordancewi
7、th A 798M.2. Referenced Documents2.1 ASTM Standards:2A 760/A 760M Specification for Corrugated Steel Pipe,Metallic-Coated for Sewers and DrainsA 762/A 762M Specification for Corrugated Steel Pipe,Polymer Precoated for Sewers and DrainsA 796/A 796M Practice for Structural Design of Corru-gated Steel
8、Pipe, Pipe-Arches, and Arches for Storm andSanitary Sewers and Other Buried ApplicationsA 902 Terminology Relating to Metallic Coated Steel Prod-uctsA 978/A 978M Specification for Composite Ribbed SteelPipe, Precoated and Polyethylene Lined for Gravity FlowSanitary Sewers, Storm Sewers, and Other Sp
9、ecial Appli-cationsA 1019/A 1019M Specification for Closed Rib Steel Pipewith Diameter of 36 in. 900 mm or Less, PolymerPrecoated for Sewers and DrainsA 1042/A 1042M Specification for Composite CorrugatedSteel Pipe for Sewers and DrainsD 698 Test Methods for Laboratory Compaction Character-istics of
10、 Soil Using Standard Effort (12 400 ft-lbf/ft3(600kN-m/m3)D 1556 Test Method for Density and Unit Weight of Soil inPlace by Sand-Cone MethodD 2167 Test Method for Density and Unit Weight of Soil inPlace by the Rubber Balloon MethodD 2487 Practice for Classification of Soils for EngineeringPurposes (
11、Unified Soil Classification System)D 2922 Test Methods for Density of Soil and Soil-Aggregate in Place by Nuclear Methods (Shallow Depth)3D 2937 Test Method for Density of Soil in Place by theDrive-Cylinder Method3. Terminology3.1 DefinitionsFor definitions of general terms used inthis practice, ref
12、er to Terminology A 902. For definition ofterms specific to this standard, refer to 3.2.3.2 Definitions of Terms Specific to This Standard:3.2.1 bedding, nthe earth or other material on which apipe is supported.3.2.2 haunch, nthe portion of the pipe cross sectionbetween the maximum horizontal dimens
13、ion and the top of thebedding.3.2.3 invert, nthe lowest point on the pipe cross section;also, the bottom portion of a pipe.3.2.4 pipe, na conduit having full circular shape; also, ina general context, all structure shapes covered by this practice.1This practice is under the jurisdiction of ASTM Comm
14、ittee A05 on Metallic-Coated Iron and Steel Products and is the direct responsibility of SubcommitteeA05.17 on Corrugated Steel Pipe Specifications.Current edition approved Sept. 15, 2007. Published October 2007. Originallyapproved in 1982. Last previous edition approved in 2001 as A 798/A 798M - 01
15、.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Withdrawn.1Copyright ASTM International, 100 Barr Harbor Dr
16、ive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.2.5 pipe-arch, nan arch shape with an approximatesemicircular crown, small-radius corners, and large-radiusinvert.4. Significance and Use4.1 Corrugated steel pipe functions structurally as a flexiblering which is supported by and in
17、teracts with the compactedsurrounding soil. The soil constructed around the pipe is thusan integral part of the structural “system.” It is thereforeimportant to ensure that the soil structure or backfill is made upof acceptable material and well-constructed. Field verificationof soil structure accep
18、tability using Test Methods D 1556,D 2167, D 2922, or D 2937, as applicable, and comparing theresults with Test Method D 698 in accordance with thespecifications for each project is the most reliable basis forinstallation of an acceptable structure. The required density andmethod of measurement are
19、not specified by this practice butmust be established in the specifications for each project.5. Trench Excavation5.1 To obtain anticipated structural performance of corru-gated steel pipe it is not necessary to control trench widthbeyond the minimum required for proper installation of pipeand backfi
20、ll. However, the soil on each side beyond theexcavated trench must be able to support anticipated loads.When a construction situation calls for a relatively wide trench,it may be made as wide as required, for its full depth if sodesired. However, trench excavation must be in compliancewith any local
21、, state, and federal codes and safety regulations.6. Foundation6.1 The supporting soil beneath the pipe must provide areasonably uniform resistance to the imposed load, bothlongitudinally and laterally. Sharp variations in the foundationmust be avoided. When rock is encountered, it must beexcavated
22、and replaced with soil. If the pipe runs along acontinuous rock foundation, it is necessary to provide asuitable soil bedding under the pipe. See Fig. 3.6.2 Lateral changes in foundation shall never be such thatthe pipe is firmly supported while the backfill alongside is not.When soft material is en
23、countered and must be removed inorder to maintain the pipe on grade during construction, it mustbe removed for at least three pipe widths, unless the engineerhas set another limit.FIG. 1 Typical Trench InstallationFIG. 2 Typical Embankment (Projection) InstallationA 798/A 798M 0726.3 Performance of
24、buried pipe is enhanced by allowing thepipe to settle slightly under load compared to the columns ofsoil alongside. Thus, for larger pipes it can be beneficial topurposely create a foundation under the pipe itself which willyield under load more than will the foundation under thecolumns of soil to e
25、ach side. It can usually be obtained byplacing beneath the structure a suitable-thickness layer ofcompressible soil, less densely compacted than the soil along-side. This creates “favorable” relative movement between pipeand the soil on each side. It is of particular importance onpipe-arches.6.4 Pip
26、e-ArchesAll pipe-arch structures shall have excel-lent soil support at their corners by both the in-situ foundationand the structural backfill. See Figs. 4 and 5. They do notrequire the same degree of support under their large-radiusinverts.NOTE 1d =12 in./ft 40 mm/m of fill over pipe, with a 24 in.
27、 600 mm maximum.NOTE 2Section BB is applicable to all continuous rock foundations.FIG. 3 Foundation Transition Zones and Rock FoundationsNOTE 1W = D for round pipe, and W = width of flat bottom arc for pipe-arch.FIG. 4 Soft Foundation TreatmentA 798/A 798M 0736.5 The engineer is encouraged to develo
28、p details specific tothe site based on the general principles for foundation condi-tions given in 6.1 through 6.4.7. Bedding7.1 .Material used for bedding beneath the pipe shall meetthe requirements of this section. Material in contact with thepipe shall not contain rock retained on a 3-in. 75-mm ri
29、ng,frozen lumps, chunks of highly plastic clay, organic matter,corrosive material, or other deleterious material. It is notrequired to shape the bedding to the pipe geometry. However,for pipe-arches, it is recommended to either shape the beddingto the relatively flat bottom arc or fine-grade the fou
30、ndation toa slight v-shape. This avoids the problem of trying to backfillthe difficult area beneath the invert of pipe-arches. See Fig. 5.8. Pipe Installation8.1 All pipe shall be unloaded and handled with reasonablecare. Pipe shall not be rolled or dragged over gravel or rock andshall be prevented
31、from striking rock or other hard objectsduring placement on bedding. Pipe with protective coatingsshall be handled with special care to avoid damage. Pavedinverts shall be placed and centered in the invert. Riveted pipeshould be installed so that outside circumferential joints pointupgrade.8.2 Joini
32、ng Systems:8.2.1 Purpose of Joining SystemsJoining systems forcorrugated steel pipe serve several purposes: to maintain pipealignment during installation; to join the ends of the pipesections that will subsequently be buried; to create a continu-ous flow line; to limit the amount of infiltration of
33、backfillmaterial into the pipe and to limit exfiltration of the flowthrough the pipe line.8.2.2 Joining System ComponentsThe joining systemshall be specified by the project engineer. It shall conform tothe requirements of Specification A 760/A 760M. The pipefabricator shall provide the components sp
34、ecified for theproject or as designated by the fabricator in accordance withthe Ordering Information section of Specification A 760/A 760M. Conformance of the joining system components withthe project requirements shall be verified upon delivery to theproject site.8.2.3 Joining System InstallationTh
35、e performance of thepipe line and the joining system will be achieved only when allcomponents of the pipe system are properly installed. As anintegral portion of the pipe system, the joining system must beassembled in accordance with the details in the project draw-ings or the recommendations provid
36、ed by the pipe fabricator.8.2.3.1 GasketsIf gaskets are a required component of thejoining system, they shall be placed on the pipe ends, at therequired location on the pipe, prior to installation of the coupleror bands or prior to stabbing a bell and spigot joint. For joiningsystems incorporating O
37、-rings, the O-ring shall be placed onthe spigot end of the pipe when the joint is a stab-type joiningsystem, or one shall be placed on the end of each pipe thatforms a joining system that incorporates a coupling band. If thejoining system includes a single flat gasket, the gasket shall beplaced over
38、 the end of the pipe previously placed and thenextended over the end of the adjacent pipe after it is positioned,such that approximately half the gasket width is on each pipe.Instead of a single flat gasket, two smaller gaskets may be usedwith one gasket placed on each end of the pipes forming thejo
39、int. For pipe supplied with a factory installed band orcoupler, no field installed gasket will be required on the pipeend with the factory installed device. When recommended byFIG. 5 Bedding and Corner Zone Treatment for Pipe Arch StructuresA 798/A 798M 074the pipe manufacturer, lubricant shall be a
40、pplied to the desig-nated surfaces. Once installed, the gasket shall be protectedagainst damage until the joint is completely installed.8.2.3.2 Coupling BandsCoupling bands shall be placedon the end of the last pipe installed. When installing two partbands, the first portion of the band shall be pla
41、ced to cover thebottom portion of the pipe. When the subsequent pipe is placedthe installation of the joining system is completed to ensureproper alignment of the pipeline. The width of the openingbetween pipe ends shall be as recommended by the pipefabricator. The band shall be tightened around the
42、 pipe ends tothe extent necessary to achieve proper performance of thejoining system. The band shall be placed over the pipe beingjoined in a manner that matches any corrugations or dimples inthe band with the corrugations in the pipe. Follow the pipefabricators instructions and methods for tighteni
43、ng the bands.8.2.3.3 Sleeve Coupler and Bell and Spigot JoiningSystemsIf a field installed sleeve coupler is utilized it shall beplaced on the end of the pipe previously placed. With a bell andspigot system, the first pipe is to be oriented so the bell is openin the direction in which construction w
44、ill proceed. Thesubsequent pipe is installed by inserting the spigot, or pipe endwithout the sleeve coupler, to the maximum depth permitted bythe joining system. Follow the pipe fabricators instructions forthe method of assembly and use of insertion force.8.2.4 Joint BackfillThe joining system shall
45、 be selectedbased on the expected site conditions, specifically the type andgradation of backfill material. The structural backfill materialused around the pipe shall be in accordance with the projectspecifications. Backfill material shall conform to Section 9, andshall be placed in accordance with
46、Section 10. Care shall beexercised during backfill placement not to damage or dislodgethe joining system.9. Structural Backfill Material9.1 Structural backfill is that material which surrounds thepipe, extending laterally to the walls of the trench, or to the fillmaterial for embankment construction
47、, and extending verti-cally from the invert to an elevation of 1 ft 300 mm, or18 thediameter or span, whichever is greater, over the pipe. Thenecessary width of structural backfill depends on the quality ofthe trench wall or embankment material, the type of materialand compaction equipment used for
48、the structural backfill, andin embankment construction, the type of construction equip-ment used to compact the embankment fill. The width ofstructural backfill shall meet the requirements given in Table 1.9.2 Structural backfill material shall be readily compactedsoil or granular material with no m
49、aterial retained on a 3-in75-mm ring. Select materials such as bank-run gravels orprocessed granular materials with excellent structural charac-teristics are preferred. Desired end results can be obtained withthis type of material with a minimum of compaction effort overa wide range of moisture content, lift depth, and compactionequipment characteristics. Excavated native soils used asstructural backfill shall not contain frozen lumps, highly plasticclay, organic material, corrosive material, or other deleteriousforeign materials. Soils meeting
