1、Designation: C12 09C12 13Standard 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 parent
2、heses 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 Department of Defense.1. Scope1.1 This practice covers the proper methods of installing vitrified clay pip
3、e 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 This st
4、andard 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 Documents2.1 A
5、STM 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 Compres
6、sion Test Specimens (Withdrawn 2012)3C700 Specification for Vitrified Clay Pipe, Extra Strength, Standard Strength, and PerforatedC828 Test Method for Low-Pressure Air Test of Vitrified Clay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 Testing of
7、 Vitrified Clay Pipe LinesD2487 Practice for Classification of Soils for Engineering Purposes (Unified Soil Classification System)D6103 Test Method for Flow Consistency of Controlled Low Strength Material (CLSM)3. Terminology3.1 GeneralTerminology C896 can be used for clarification of terminology in
8、 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 supportingstrength of a pipe is defined as its capacity to support dead and live loads under actual field condition
9、s. 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 C700, as determined by the 3-edge-bearing testof Test Methods C301, is a measure of the inherent strength of the pip
10、e.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.Current edition approved Oct. 1, 2009March 1, 2013. Published October 2009April 2013. Originally approved in 1915. Las
11、t previous edition approved in 20082009 asC12 08.C12 09. DOI: 10.1520/C0012-09.10.1520/C0012-13.2 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 Documen
12、t 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 provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit
13、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 the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Ha
14、rbor 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 field conditions.Therefore, an adjustment called a load factor is introduced to convert minimum bearing strength to fi
15、eld supporting strength. Themagnitude of the load factor depends on how the pipe is bedded. The relationship is:Field supporting strength5minimum bearing strength3load factor4.4 Afactor of safety greater than 1.0 and less than or equal to 1.5 1.0 and 1.5 shall be applied to the field supporting stre
16、ngthto calculate a safe supporting strength. The relationship is:Safe supporting strength5Field supporting strengthFactor of safety5. External Loads5.1 The external loads on installed vitrified clay pipe are of two general types: (1) dead loads and (2) live loads.FIG. 1 TerminologyFIG. 2 Class DC12
17、1325.2 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. Consequently, the trench width at the top of the pipe shall be kept as narrow as possible. Pipe failure may result if thedesign trench width is exceeded. I
18、f the trench width exceeds the design width, a higher class 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. Compact
19、ion of embedment and backfill materials, beside and above the sewerFIG. 3 Class CFIG. 4 Class BFIG. 5 Crushed Stone EncasementC12 133pipe, produces a temporary live load on the pipe. The magnitude of the live load from compactive effort varies with soil type,degree of saturation, degree of compactio
20、n and depth of cover 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 load
21、s and supporting strengths, 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
22、in trenches are defined 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 materi
23、al (Note 2).6.2.1 The load factor for Class D bedding is 1.1.1.1.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 S
24、W, SP, GW, GP) (Note 4). 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 eighthsixth of the outsidediameter of the pipe, whichever is greater, and shall extend up
25、 the haunches of the pipe one sixth of the outside diameter of thepipe. The initial 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. in. (19 to 6.4 mm) crushed stone, having a minimum of one fractured
26、 face, or other angular,non-consolidating bedding material not subject to migration. Well-graded angular, non-consolidating bedding materials are more stable than roundedbedding materials of equal gradation. Material shall be shovel-sliced so the material fills and supports the haunch area and encas
27、es the pipe to the limitsshown in the trench diagrams (Figs. 3-6).NOTE 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
28、cut by blasting or in trenches through clay type soil. Regardlessof the 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. (
29、100 mm) or one eighthsixth of the outside diameter of the pipe, whichever is greater, and shall extendup the haunches of the pipe to the springline. The initial backfill 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
30、 are specific sites where crushed 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 oneeighthsixth of the outside diameter of the pipe, whichever is greater, and shall extend upward t
31、o a horizontal plane at the top ofthe pipe barrel (see Note 5). Encasement shall consist of well-graded 34 to 14 in. (19 to 6.4 mm) crushed stone or other4 Available from American Society of Civil Engineers (ASCE), 1801 Alexander Bell Dr., Reston, VA 20191, http:/www.asce.org.NOTE 1This type of cons
32、truction 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 Controlled Low Strength Material (CLSM)C12 134non-consolidating bedding mater
33、ial not subject to migration. Material shall be carefully placed into the pipe haunches (Note 3).The initial backfill shall be of selected material (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
34、 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 Strength Material (Fig. 6)Controlled low strength material has been shown to be an economic alternativeto compacted bedding material. It assists in utiliz
35、ing the inherent strength of the pipe, completely filling the haunch area, andreducing the trench load on the (CLSM) is used as an effective material for the bedding of vitrified clay pipe.6.6.1 The pipe shall be bedded on crushed stone or other suitable material (Note 3 and Note 4). The bedding sha
36、ll have aminimum thickness beneath the pipe of 4 in. (100 mm) or one eighthsixth of the outside diameter of the pipe, whichever is greater.Controlled low strength material shall be directed to the top of the pipe to flow down on both sides to prevent misalignment. Fillto the top of the pipe. The ini
37、tial backfill may be placed when the pour is capable of supporting the backfill material withoutintermixing.NOTE 6Attention is directed to terminology and material references. See American Concrete Institute Report: ACI 229R-94 Controlled Low StrengthMaterials (CLSM).4NOTE 1Minimum width of concrete
38、 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.)FIG. 7 Concrete CradleFIG. 8 Uniform Pipe SupportC12 1356.6.2 For pi
39、pe diameters 8 to 21 in., CLSM shall extend a minimum of 9 in. on each side of the pipe barrel. For pipe diameters24 in. and larger, CLSM shall extend a minimum of 12 in. on each side of the pipe barrel (Fig. 6).6.6.3 When placed, CLSM shall have a measured flowability of 861 in. spread diameter as
40、determined byTest Method D6103.6.6.4 28-day compressive strength shall be 100 to 300 psi as determined by Test Method C684.6.6.5 CLSM shall be directed 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 sh
41、all only commence after a 500 psi minimum penetrometer reading is achieved as determined by TestMethod C403/C403M. The penetrometer shall have a maximum load capability of 700 psi and have a one 1 in.2 1 in. longcylinder foot attached to a in. diameter pin.6.6.7 The load factor for controlled low st
42、rength material is 2.8.6.7 Concrete Cradle (Fig. 7)The pipe shall be bedded in a monolithic cradle 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
43、 at least one half the outside diameter of the pipe. The cradle width shall be at least equal to the 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 dim
44、ensions, concrete may be placed to full trench width. Suitablematerial shall extend upward to a horizontal 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 %, whe
45、re p is thepercentage of the area of transverse steel to the area of concrete at the bottom of the 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
46、minimum thickness, at any point, 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 to suit the specific use.6.9 Construction joints shall be installed in concrete cradle or concrete encasement construction.
47、 These joints shall be alignedwith the face of the socket.CONSTRUCTION TECHNIQUES7. Trench Excavation7.1 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 t
48、o reduce trench wall failure. This sloping will not increase the load on the pipe providedthe measured 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 brac
49、e 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 the safe field supporting strength of the pipe and bedding system.7.6 When a movable box is used in place of sheeting or shoring, secure the installed pipe to prevent it from moving when thebox is moved.TA
