Astm C12
Astm C12
Astm C12
1. Scope
1.1 This practice covers the proper methods of installing
vitrified clay pipe lines in order to fully utilize the structural
properties of such pipe.
1.2 The values stated in inch-pound units are to be regarded
as the standard. The values given in parentheses are for
information only.
1.3 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
2. Referenced Documents
2.1 ASTM Standards:
C 301 Test Methods for Vitrified Clay Pipe2
C 425 Specification for Compression Joints for Vitrified
Clay Pipe and Fittings2
C 700 Specification for Vitrified Clay Pipe, Extra Strength,
Standard Strength, and Perforated2
C 828 Test Method for Low-Pressure Air Test of Vitrified
Clay Pipe Lines2
C 896 Terminology Relating to Clay Products2
C 1091 Test Method for Hydrostatic Infiltration and Exfiltration Testing of Vitrified Clay Pipe Lines2
4.4 A factor of safety greater than 1.0 and less than or equal
to 1.5 shall be applied to the field supporting strength to
calculate a safe supporting strength. The relationship is:
Safe supporting strength 5
5. External Loads
5.1 The external loads on installed vitrified clay pipe are of
two general types: (1) dead loads and (2) live loads.
5.2 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 the design trench width is exceeded. If 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.
Compaction of embedment and backfill materials, beside and
above the sewer pipe, 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 compaction and depth of cover over the pipe. Care must be used in
selection of compaction methods so that the combined dead
load and live load does not exceed the field supporting strength
of the pipe, or cause a change in its line or grade.
3. Terminology
3.1 GeneralTerminology C 896 can be used for clarification of terminology in this specification.
DESIGN CONSIDERATIONS
4. Supporting Strength
4.1 The field supporting strength of vitrified clay pipe is
materially affected by the methods of installation. The field
supporting strength of a pipe is defined as its capacity to
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 and Specifications.
Current edition approved February 10, 2003. Published June 2003. Originally
approved in 1915. Last previous edition approved in 2001 as C 1201.
2
Annual Book of ASTM Standards, Vol 04.05.
Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
C 12 03
6.2 Class D (Fig. 2)The pipe shall be placed on a firm and
unyielding trench bottom with bell holes provided (Fig. 9). The
initial 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 finely divided material free of debris,
organic material, and large stones.
FIG. 2 Class D
3
Available from American Society of Civil Engineers, 1801 Alexander Bell Dr.,
Reston, VA 20191.
C 12 03
FIG. 3 Class C
FIG. 4 Class B
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 the
bottom of the pipe. Where native soils are expansive, further investigation may be necessary.
FIG. 6 Controlled Low Strength Material (CLSM)
Fill to the top of the pipe. The initial backfill may be placed
when the pour is capable of supporting the backfill material
without intermixing.
C 12 03
NOTE 1Minimum width of concrete cradle: Bc + 8 in. (200 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 small
diameter rebar be used in all concrete design.)
FIG. 7 Concrete Cradle
CONSTRUCTION TECHNIQUES
7. Trench Excavation
7.1 Trenches shall be excavated to a width that will provide
adequate working space, but not more than the maximum
design width. 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
4
Available from American Concrete Institute, P.O. Box 9094, Farmington Hills,
MI 48333.
C 12 03
NOTE 1Minimum width of concrete arch: Bc + 8 in. (200 mm) or 114 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 small
diameter rebar be used in all concrete design.)
FIG. 8 Concrete Arch
C 12 03
TABLE 1 Joint Deflection Limits
NOTE 1For calculating the minimum radius of curvature use the following:
pipe3 in. (75 mm) to 12 in. (305 mm) Diameter
radius = 24 3 pipe length
pipe15 in. (380 mm) to 24 in. (610 mm) Diameter
radius = 32 3 pipe length
pipe27 in. (685 mm) to 36 in. (915 mm) Diameter
radius = 48 3 pipe length
pipe39 in. (990 mm) to 42 in. (1065 mm) Diameter
radius = 64 3 pipe length
NOTE 2Material is applicable to compression joints for vitrified clay pipe and fittings in accordance with Specification C 425.
Nominal Diameter,
in. (mm)
312
1524
2736
3942
Maximum Angular
Deflection per Joint,
degrees
Maximum Deflection
of Pipe,
in./linear ft (mm/linear m)
2.4
1.8
1.2
0.9
(42)
(31)
14 (21)
316 (16)
(75305)
(380610)
(685915)
(9901065)
12
38
13.4 In order for the performance of the line to be acceptable, all tests shall be made on pipe laid in accordance with the
bedding provisions of Section 6. Joining procedures shall
follow the recommendation of the pipe manufacturer.
14. Keywords
14.1 backfilling; bedding; clay pipe; compaction; construction; design; excavation; installation; load factors; perforated
pipe; pipe; sewers; trench foundation; trenching; vitrified
C 12 03
APPENDIX
(Nonmandatory Information)
X1. INSTALLATION CRITERIA FOR PERFORATED VITRIFIED CLAY PIPE
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