1、Designation: C12 09Standard Practice forInstalling Vitrified Clay Pipe Lines1This standard is issued under the fixed designation C12; the number immediately following the designation indicates the year of originaladoption or, in the case of revision, the year of last revision. A number in parenthese
2、s indicates the year of last reapproval. A superscriptepsilon () 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 covers the proper methods of installingvitrified clay pipe l
3、ines in order to fully utilize the structuralproperties of such pipe.1.2 The values stated in inch-pound units are to be regardedas standard. The values given in parentheses are mathematicalconversions to SI units that are provided for information onlyand are not considered standard.1.3 This standar
4、d 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.2. Referenced Documents2.1 ASTM
5、 Standards:2C301 Test Methods for Vitrified Clay PipeC425 Specification for Compression Joints for VitrifiedClay Pipe and FittingsC700 Specification for Vitrified Clay Pipe, Extra Strength,Standard Strength, and PerforatedC828 Test Method for Low-Pressure Air Test of VitrifiedClay Pipe LinesC896 Ter
6、minology Relating to Clay ProductsC1091 Test Method for Hydrostatic Infiltration Testing ofVitrified Clay Pipe LinesD2487 Practice for Classification of Soils for EngineeringPurposes (Unified Soil Classification System)3. Terminology3.1 GeneralTerminology C896 can be used for clarifica-tion of termi
7、nology in this specification.DESIGN CONSIDERATIONS4. Supporting Strength4.1 The field supporting strength of vitrified clay pipe ismaterially affected by the methods of installation. The fieldsupporting strength of a pipe is defined as its capacity tosupport dead and live loads under actual field co
8、nditions. It isdependent upon two factors: (1) the inherent strength of thepipe and (2) the bedding of the pipe.4.2 The minimum bearing strength requirement in accor-dance with Specification C700, as determined by the 3-edge-bearing test of Test Methods C301, is a measure of the inherentstrength of
9、the pipe.4.3 The tests used to measure bearing strength determinerelative pipe strengths but do not represent actual field condi-tions. Therefore, an adjustment called a load factor is intro-duced to convert minimum bearing strength to field supportingstrength. The magnitude of the load factor depen
10、ds on how thepipe is bedded. The relationship is:Field supporting strength 5 minimum bearing strength 3 load factor4.4 A factor of safety greater than 1.0 and less than or equalto 1.5 shall be applied to the field supporting strength tocalculate a safe supporting strength. The relationship is:Safe s
11、upporting strength 5Field supporting strengthFactor of safety5. External Loads5.1 The external loads on installed vitrified clay pipe are oftwo general types: (1) dead loads and (2) live loads.5.2 For pipes installed in trenches at a given depth, the deadload increases as the trench width, measured
12、at the top of thepipe, increases. Consequently, the trench width at the top of thepipe shall be kept as narrow as possible. Pipe failure may resultif the design trench width is exceeded. If the trench widthexceeds the design width, a higher class of bedding, strongerpipe, or both, must be investigat
13、ed.5.3 Live loads that act at the ground surface are partiallytransmitted to the pipe. Live loads may be produced by wheelloading, construction equipment or by compactive effort.Compaction of embedment and backfill materials, beside andabove the sewer pipe, produces a temporary live load on the1This
14、 practice is under the jurisdiction of ASTM Committee C04 on VitrifiedClay Pipe and is the direct responsibility of Subcommittee C04.20 on Methods ofTest and Specifications.Current edition approved Oct. 1, 2009. Published October 2009. Originallyapproved in 1915. Last previous edition approved in 20
15、08 as C12 08. DOI:10.1520/C0012-09.2For 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.1Copyright ASTM Internatio
16、nal, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.pipe. The magnitude of the live load from compactive effortvaries with soil type, degree of saturation, degree of compac-tion and depth of cover over the pipe. Care must be used inselection of compaction methods
17、 so that the combined deadload and live load does not exceed the field supporting strengthof the pipe, or cause a change in its line or grade.NOTE 1For generally accepted criteria and methods for determiningloads and supporting strengths, see Gravity Sanitary Sewer Design andConstruction, Water Poll
18、ution Control Federation Manual of Practice No.FD-5, American Society of Civil EngineersManuals and Report onEngineering PracticeNo. 60.36. Bedding and Encasement6.1 Classes of bedding and encasements for pipe in trenchesare defined herein. The load factors indicated are for conver-sion of minimum b
19、earing strength to field supporting strength.6.2 Class D (Fig. 2)The pipe shall be placed on a firm andunyielding trench bottom with bell holes provided (Fig. 8). Theinitial backfill shall be of selected material (Note 2).6.2.1 The load factor for Class D bedding is 1.1.NOTE 2Selected material is fi
20、nely divided material free of debris,organic material, and large stones.6.3 Class C (Fig. 3)The pipe shall be bedded in cleancoarse-grained gravels and sands as defined in Practice D2487,Table 1, (types SW, SP, GW, GP) (Note 4). Angular, non-consolidating bedding material not subject to migration ma
21、y bespecified (as in Note 3). The bedding shall have a minimumthickness beneath the pipe of 4 in. (100 mm) or one eighth ofthe outside diameter of the pipe, whichever is greater, and shallextend up the haunches of the pipe one sixth of the outsidediameter of the pipe. The initial backfill shall be o
22、f selectedmaterial (Note 2).6.3.1 The load factor for Class C bedding is 1.5.NOTE 3Suitable material is well-graded34 to14 in. (19 to 6.4 mm)crushed stone, having a minimum of one fractured face, or other angular,non-consolidating bedding material not subject to migration. Well-gradedangular, non-co
23、nsolidating bedding materials are more stable thanrounded bedding materials of equal gradation. Material shall be shovel-sliced so the material fills and supports the haunch area and encases thepipe to the limits shown in the trench diagrams (Figs. 3-6).NOTE 4Sand is suitable as a bedding material i
24、n a total sandenvironment but may be unsuitable where high and rapidly changingwater tables are present in the pipe zone. It may also be undesirable forbedding, or haunching in a trench cut by blasting or in trenches throughclay type soil. Regardless of the trench condition or bedding class, themaxi
25、mum load factor for sand bedding is 1.5.6.4 Class B (Fig. 4)The pipe shall be bedded in suitablematerial (Note 3). The bedding shall have a minimum thick-ness beneath the pipe of 4 in. (100 mm) or one eighth of theoutside diameter of the pipe, whichever is greater, and shallextend up the haunches of
26、 the pipe to the springline. The initialbackfill shall be of selected material (Note 2).6.4.1 The load factor for Class B bedding is 1.9.6.5 Crushed Stone Encasement (Fig. 5)There are specificsites where crushed stone encasement may be desirable. Thecrushed stone shall extend to the specified trench
27、 width andshall have a minimum thickness beneath the pipe of 4 in. (100mm) or one eighth of the outside diameter of the pipe,whichever is greater, and shall extend upward to a horizontalplane at the top of the pipe barrel (see Note 5). Encasementshall consist of well-graded34 to14 in. (19 to 6.4 mm)
28、 crushedstone or other non-consolidating bedding material not subjectto migration. Material shall be carefully placed into the pipehaunches (Note 3). The initial backfill shall be of selectedmaterial (Note 2).3Available from American Society of Civil Engineers (ASCE), 1801 AlexanderBell Dr., Reston,
29、 VA 20191, http:/www.asce.org.FIG. 1 TerminologyFIG. 2 Class DC12092NOTE 5Sufficient crushed stone or other suitable material (Note 3)shall be placed so that the bedding extends to a horizontal plane at the topof the pipe barrel following removal of any trench sheeting or boxes.6.5.1 The load factor
30、 for crushed stone encasement is 2.2.6.6 Controlled Low Strength Material (Fig. 6)Controlledlow strength material has been shown to be an economicalternative to compacted bedding material. It assists in utilizingthe inherent strength of the pipe, completely filling the hauncharea, and reducing the t
31、rench load on the pipe.6.6.1 The pipe shall be bedded on crushed stone or othersuitable material (Note 3 and Note 4). The bedding shall havea minimum thickness beneath the pipe of 4 in. (100 mm) or oneeighth of the outside diameter of the pipe, whichever is greater.Controlled low strength material s
32、hall be directed to the top ofthe pipe to flow down on both sides to prevent misalignment.Fill to the top of the pipe. The initial backfill may be placedwhen the pour is capable of supporting the backfill materialwithout intermixing.FIG. 3 Class CFIG. 4 Class BFIG. 5 Crushed Stone EncasementC12093NO
33、TE 6Attention is directed to terminology and material references.See American Concrete Institute Report: ACI 229R-94 Controlled LowStrength Materials (CLSM).46.6.2 The load factor for controlled low strength material is2.8.6.7 Concrete Cradle (Fig. 7)The pipe shall be bedded ina monolithic cradle of
34、 reinforced concrete having a thicknessunder the barrel of at least 6 in. (150 mm) or one fourth of theoutside diameter of the pipe, whichever is greater, and extend-ing up the haunches to a height of at least one half the outside4Available from American Concrete Institute (ACI), P.O. Box 9094, Farm
35、ingtonHills, MI 48333-9094, http:/www.concrete.org.NOTE 1This type of construction requires the fill to extend from the pipe to the trench wall, not to extend above the top of the pipe or below thebottom of the pipe. Where native soils are expansive, further investigation may be necessary.FIG. 6 Con
36、trolled Low Strength Material (CLSM)NOTE 1Minimum width of concrete cradle: Bc+ 8 in. (205 mm) or 1-14 Bc.NOTE 2p is the ratio of the area of steel to the area of concrete. (It is recommended that wire mesh reinforcement or uniformly distributed smalldiameter rebar be used in all concrete design.)FI
37、G. 7 Concrete CradleFIG. 8 Uniform Pipe SupportC12094diameter of the pipe. The cradle width shall be at least equal tothe outside diameter of the pipe plus 4 in. (100 mm) on eachside or one and one fourth times the outside diameter of thepipe, whichever is greater. If the trench width is greater tha
38、neither of these dimensions, concrete may be placed to fulltrench width. Suitable material shall extend upward to ahorizontal plane at the top of the pipe barrel. The initial backfillshall be selected material.6.7.1 The load factor for Class A concrete cradle bedding is3.4 for reinforced concrete wi
39、th p = 0.4 %, where p is thepercentage of the area of transverse steel to the area of concreteat the bottom of the pipe barrel as shown in Fig. 7.6.8 Concrete Encasement:6.8.1 There are specific sites where concrete encasementmay be desirable. Concrete encasement shall completely sur-round the pipe
40、and shall have a minimum thickness, at anypoint, of one fourth of the outside diameter of the pipe or 4 in.(100 mm), whichever is greater.6.8.2 The encasement shall be designed by the engineer tosuit the specific use.6.9 Construction joints shall be installed in concrete cradleor concrete encasement
41、 construction. These joints shall bealigned with the face of the socket.CONSTRUCTION TECHNIQUES7. Trench Excavation7.1 Trenches shall be excavated to a width that will provideadequate working space, but not more than the maximumdesign width. Trench walls shall not be undercut.7.2 The trench walls ca
42、n be sloped to reduce trench wallfailure. This sloping will not increase the load on the pipeprovided the measured trench width at top of pipe does notexceed the design trench width.7.3 Trenches, other than for Class D bedding, shall beexcavated to provide space for the pipe bedding.7.4 Sheet, shore
43、, and brace trenches, as necessary, to pre-vent caving or sliding of trench walls, to provide protection forworkmen and the pipe, and to protect adjacent structures andfacilities.7.5 Sheeting shall not be removed below the top of the pipeif the resulting slope of native soil increases the trench wid
44、th tosuch an extent that the load on the pipe exceeds the safe fieldsupporting strength of the pipe and bedding system.7.6 When a movable box is used in place of sheeting orshoring, secure the installed pipe to prevent it from movingwhen the box is moved.7.7 Maintain the water level in the trench to
45、 an elevationbelow the bell of the pipe being laid. Exercise caution whenterminating the dewatering procedure to avoid disturbing thepipe installation.NOTE 7The purpose of controlling the water in the trench is tomaintain the lubricant on the joint surfaces, the integrity of the bell hole,and the ab
46、ility to visually observe the cleanliness of the joint surfaces.8. Trench Foundation8.1 The trench foundation is the area below the pipe andbedding which supports the pipe bedding structure.8.2 The trench foundation shall be firm and unyielding.9. Pipe Bedding9.1 Bell holes shall be excavated to pre
47、vent point loading ofthe bells or couplings of laid pipe, and to establish full-lengthsupport of the pipe barrel (Fig. 8).9.2 Bedding shall be placed so that the pipe is true to lineand grade and to provide uniform and continuous support ofthe pipe barrel.10. Pipe Handling10.1 Pipe and fittings shal
48、l be handled carefully to protectfrom damage.10.2 Carefully examine each pipe and fitting before instal-lation, for soundness and specification compliance. Pipe ac-cepted may be plainly marked by the inspector. Rejected pipeshall not be defaced, but shall be replaced with pipe that meetsspecificatio
49、n.10.3 Handle pipe so that premolded jointing surfaces orattached couplings do not support the weight of the pipe. Donot damage the jointing surfaces or couplings by dragging,contact with hard materials, or by use of hooks.11. Pipe Laying11.1 Clean joint contact surfaces immediately prior tojoining. Use joint lubricants and joining methods, as recom-mended by the pipe manufacturer.11.2 Unless otherwise required, lay all pipe straight betweenchanges in alignment and at uniform grade between changes inTABLE 1 Joint Deflection LimitsNOTE 1For calculating the
