1、Designation: C12 13C12 13aStandard 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.Anumber in paren
2、theses indicates the year of last reapproval.Asuperscriptepsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the U.S. Department of Defense.1. Scope1.1 This practice covers the proper methods of installing vitrified cl
3、ay pipe lines in order to fully utilize the structural propertiesof such pipe.1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematicalconversions to SI units that are provided for information only and are not considered standard.1.3 T
4、his standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Document
5、s2.1 ASTM Standards:2C301 Test Methods for Vitrified Clay PipeC403/C403M Test Method for Time of Setting of Concrete Mixtures by Penetration ResistanceC425 Specification for Compression Joints for Vitrified Clay Pipe and FittingsC684 Test Method for Making, Accelerated Curing, and Testing Concrete C
6、ompression Test Specimens (Withdrawn 2012)3C700 Specification for Vitrified Clay Pipe, Extra Strength, Standard Strength, and PerforatedC828 Test Method for Low-Pressure Air Test of Vitrified Clay Pipe LinesC896 Terminology Relating to Clay ProductsC1091 Test Method for Hydrostatic Infiltration Test
7、ing of Vitrified Clay Pipe LinesD2487 Practice for Classification of Soils for Engineering Purposes (Unified Soil Classification System)D5821 Test Method for Determining the Percentage of Fractured Particles in Coarse AggregateD6103 Test Method for Flow Consistency of Controlled Low Strength Materia
8、l (CLSM) (Withdrawn 2013)33. Terminology3.1 GeneralTerminology C896 can be used for clarification of terminology in this specification.DESIGN CONSIDERATIONS4. Supporting Strength4.1 The field supporting strength of vitrified clay pipe is materially affected by the methods of installation. The field
9、supportingstrength of a pipe is defined as its capacity to support dead and live loads under actual field conditions. It is dependent upon twofactors: (1) the inherent strength of the pipe and (2) the bedding of the pipe.4.2 The minimum bearing strength requirement in accordance with Specification C
10、700, as determined by the 3-edge-bearing testof Test Methods C301, is a measure of the inherent strength of the pipe.1 This practice is under the jurisdiction of ASTM Committee C04 on Vitrified Clay Pipe and is the direct responsibility of Subcommittee C04.20 on Methods of Test andSpecifications.Cur
11、rent edition approved March 1, 2013Dec. 1, 2013. Published April 2013December 2013. Originally approved in 1915. Last previous edition approved in 20092013as C12 09.C12 13. DOI: 10.1520/C0012-13.10.1520/C0012-13A.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Cus
12、tomer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.3 The last approved version of this historical standard is referenced on www.astm.org.This document is not an ASTM standard and is intended only to
13、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 users consult prior editions as appropriate. In all cases only the current versionof
14、the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States14.3 The tests used to measure bearing strength determine relative pipe strengths but do not represent actual f
15、ield conditions.Therefore, an adjustment called a load factor is introduced to convert minimum bearing strength to field supporting strength. Themagnitude of the load factor depends on how the pipe is bedded. The relationship is:Field supporting strength5minimum bearing strength3load factor4.4 Afact
16、or of safety 1.0 and 1.5 shall be applied to the field supporting strength to calculate a safe supporting strength. Therelationship is:Safe supporting strength5Field supporting strengthFactor of safety5. External Loads5.1 The external loads on installed vitrified clay pipe are of two general types:
17、(1) dead loads and (2) live loads.FIG. 1 TerminologyFIG. 2 Class DC12 13a25.2 For pipes installed in trenches at a given depth, the dead load increases as the trench width, measured at the top of the pipe,increases. Pipe failure may result if the design trench width is exceeded. If the trench width
18、exceeds the design width, a higherclass of bedding, stronger pipe, or both, must be investigated.5.3 Live loads that act at the ground surface are partially transmitted to the pipe. Live loads may be produced by wheel loading,construction equipment or by compactive effort. Compaction of embedment an
19、d backfill materials, beside and above the sewerpipe, produces a temporary live load on the pipe. The magnitude of the live load from compactive effort varies with soil type,FIG. 3 Class CFIG. 4 Class BFIG. 5 Crushed Stone EncasementC12 13a3degree of saturation, degree of compaction and depth of cov
20、er over the pipe. Care must be used in selection of compaction methodsso that the combined dead load and live load does not exceed the field supporting strength of the pipe, or cause a change in itsline or grade.NOTE 1For generally accepted criteria and methods for determining loads and supporting s
21、trengths, see Gravity Sanitary Sewer Design andConstruction, Water Pollution Control Federation Manual of Practice No. FD-5, American Society of Civil EngineersManuals and Report onEngineering PracticeNo. 60.46. Bedding and Encasement6.1 Classes of bedding and encasements for pipe in trenches are de
22、fined herein. The load factors indicated are for conversionof minimum bearing strength to field supporting strength.6.2 Class D (Fig. 2)The pipe shall be placed on a firm and unyielding trench bottom with bell holes provided (Fig. 8). Theinitial backfill shall be of selected material (Note 2).6.2.1
23、The load factor for Class D bedding is 1.1.NOTE 2Selected material is finely divided material free of debris, organic material, and large stones.6.3 Class C (Fig. 3)The pipe shall be bedded in clean coarse-grained gravels and sands as defined in Practice D2487, Table1, (types SW, SP, GW, GP) (Note 4
24、). Angular, non-consolidating bedding material not subject to migration may be specified (asin Note 3). The bedding shall have a minimum thickness beneath the pipe of 4 in. (100 mm) or one sixth of the outside diameterof the pipe, whichever is greater, and shall extend up the haunches of the pipe on
25、e sixth of the outside diameter of the pipe. Theinitial backfill shall be of selected material (Note 2).6.3.1 The load factor for Class C bedding is 1.5.NOTE 3Suitable material is well-graded 34 to 14 in. (19 to 6.4 mm) crushed stone, having a minimum of one fractured face, or other angular,non-cons
26、olidating bedding material not subject to migration. Where high or changing water tables, or both, are present in the pipe zone, this material shallhave a minimum percentage by particle count of one fractured face-100 %, two fractured faces-85 %, and three fractured faces-65 % in accordance withTest
27、 Mehod D5821. Well-graded angular, non-consolidating bedding materials are more stable than rounded bedding materials of equal gradation.Material shall be shovel-sliced so the material fills and supports the haunch area and encases the pipe to the limits shown in the trench diagrams (Figs.3-6).NOTE
28、4Sand is suitable as a bedding material in a total sand environment but may be unsuitable where high and rapidly changing water tables arepresent in the pipe zone. It may also be undesirable for bedding, or haunching in a trench cut by blasting or in trenches through clay type soil. Regardlessof the
29、 trench condition or bedding class, the maximum load factor for sand bedding is 1.5.6.4 Class B (Fig. 4)The pipe shall be bedded in suitable material (Note 3). The bedding shall have a minimum thicknessbeneath the pipe of 4 in. (100 mm) or one sixth of the outside diameter of the pipe, whichever is
30、greater, and shall extend up thehaunches of the pipe to the springline. The initial backfill shall be of selected material (Note 2).4 Available from American Society of Civil Engineers (ASCE), 1801 Alexander Bell Dr., Reston, VA 20191, http:/www.asce.org.NOTE 1This type of construction requires the
31、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.This type of construction requires the fill to extend from the pipe to the trench wall, not to extend abov
32、e the top of the pipe or below the bottom of the pipe. Where nativesoils are expansive, further investigation may be necessary.FIG. 6 Controlled Low Strength Material (CLSM)C12 13a46.4.1 The load factor for Class B bedding is 1.9.6.5 Crushed Stone Encasement (Fig. 5)There are specific sites where cr
33、ushed stone encasement may be desirable.The crushedstone shall extend to the specified trench width and shall have a minimum thickness beneath the pipe of 4 in. (100 mm) or onesixth of the outside diameter of the pipe, whichever is greater, and shall extend upward to a horizontal plane at the top of
34、 the pipebarrel (see Note 5). Encasement shall consist of well-graded 34 to 14 in. (19 to 6.4 mm) crushed stone or other non-consolidatingbedding material not subject to migration. Material shall be carefully placed into the pipe haunches (Note 3). The initial backfillshall be of selected material (
35、Note 2).NOTE 5Sufficient crushed stone or other suitable material (Note 3) shall be placed so that the bedding extends to a horizontal plane at the top of thepipe barrel following removal of any trench sheeting or boxes.6.5.1 The load factor for crushed stone encasement is 2.2.6.6 Controlled Low Str
36、ength Material (Fig. 6)Controlled low strength material (CLSM) is used as an effective material forthe bedding of vitrified clay pipe.NOTE 1Minimum width of concrete cradle: Bc + 8 in. (205 mm) or 1-14 Bc.Minimum width of concrete cradle: Bc + 8 in. (205 mm) or 1-14 Bc.p is the ratio of the area of
37、steel to the area of concrete. (It is recommended that wire mesh reinforcement or uniformly distributed small diameter rebar be used in allconcrete design.)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 smal
38、ldiameter rebar be used in all concrete design.)FIG. 7 Concrete CradleFIG. 8 Uniform Pipe SupportC12 13a56.6.1 The pipe shall be bedded on crushed stone or other suitable material (Note 3 and Note 4). The bedding shall have aminimum thickness beneath the pipe of 4 in. (100 mm) or one sixth of the ou
39、tside diameter of the pipe, whichever is greater.6.6.2 For pipe diameters 8 to 21 in., in. (205 to 535 mm), CLSM shall extend a minimum of 9 in. (230 mm) on each side ofthe pipe barrel. For pipe diameters 24 in. (610 mm) and larger, CLSM shall extend a minimum of 12 in. (305 mm) on each sideof the p
40、ipe barrel (Fig. 6).6.6.3 When placed, CLSM shall have a measured flowability of 8 6 1 in.861 in. (205625 mm) spread diameter asdetermined by Test Method D6103.6.6.4 28-day compressive strength shall be 100 to 300 psi (0.69 to 2.07 MPa) as determined by Test Method C684.6.6.5 CLSM shall be directed
41、to the top of the pipe to flow down equally on both sides to prevent misalignment. Place CLSMto the top of the pipe barrel.6.6.6 Initial backfill shall only commence after a 500 psi (3.45 MPa) minimum penetrometer reading is achieved as determinedby Test Method C403/C403M. The penetrometer shall hav
42、e a maximum load capability of 700 psi (4.83 MPa) and have a one 1in.2 1 in. 1 in. (645 mm2 25 mm) long cylinder foot attached to a 14 in. (6 mm) diameter pin.6.6.7 The load factor for controlled low strength material is 2.8.6.7 Concrete Cradle (Fig. 7)The pipe shall be bedded in a monolithic cradle
43、 of reinforced concrete having a thickness underthe barrel of at least 6 in. (150 mm) or one fourth of the outside diameter of the pipe, whichever is greater, and extending up thehaunches to a height of at least one half the outside diameter of the pipe. The cradle width shall be at least equal to t
44、he outsidediameter of the pipe plus 4 in. (100 mm) on each side or one and one fourth times the outside diameter of the pipe, whicheveris greater. If the trench width is greater than either of these dimensions, concrete may be placed to full trench width. Suitablematerial shall extend upward to a ho
45、rizontal plane at the top of the pipe barrel. The initial backfill shall be selected material.6.7.1 The load factor for Class A concrete cradle bedding is 3.4 for reinforced concrete with p = 0.4 %, where p is thepercentage of the area of transverse steel to the area of concrete at the bottom of the
46、 pipe barrel as shown in Fig. 7.6.8 Concrete Encasement:6.8.1 There are specific sites where concrete encasement may be desirable. Concrete encasement shall completely surround thepipe and shall have a minimum thickness, at any point, of one fourth of the outside diameter of the pipe or 4 in. (100 m
47、m),whichever is greater.6.8.2 The encasement shall be designed by the engineer to suit the specific use.6.9 Construction joints shall be installed in concrete cradle or concrete encasement construction. These joints shall be alignedwith the face of the socket.CONSTRUCTION TECHNIQUES7. Trench Excavat
48、ion7.1 Trenches shall be excavated to a width that will provide adequate working space, but not more than the maximum designwidth. Trench walls shall not be undercut.7.2 The trench walls can be sloped to reduce trench wall failure. This sloping will not increase the load on the pipe providedthe meas
49、ured trench width at top of pipe does not exceed the design trench width.7.3 Trenches, other than for Class D bedding, shall be excavated to provide space for the pipe bedding.7.4 Sheet, shore, and brace trenches, as necessary, to prevent caving or sliding of trench walls, to provide protection forworkmen and the pipe, and to protect adjacent structures and facilities.7.5 Sheeting shall not be removed below the top of the pipe if the resulting slope of native soil increases the trench width tosuch an extent that the load on the pipe exceeds
