【国外标准】 Standard Practice for Installing Vitrified Clay Pipe Lines

This practice covers the proper methods of installing vitified clay pipe lines in order to fully utilize the structural properties of such pipe. The external loads on installed vitrified clay pipe are of two general types: (I) dead loads and (2) live loads. 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. 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. Classes of bedding and encasements for pipe in trenches are defined as Class D wherein the pipe shall be placed on a firm and unyielding trench bottom with bell holes provided, Class C wherein the pipe shall be bedded in clean coarse-grained gravels and sands, Class B wherein the pipe shall be bedded in suitable material and Class A. 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. Bell holes shall be excavated to prevent point loading of the bells or couplings of laid pipe, and to establish full-length support of the pipe barrel. Final backfill need not be compacted to develop field supporting strength of the pipe. Final backfill may require compaction to prevent settlement of the ground surface.1.1 This practice covers the proper methods of installing vitrified clay pipe lines by open trench construction methods 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 standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.