ASCE Manual of Practice No. 118 For Belowground Pipeline Networks For Utility Cables

U-Tech: Underground Technology Cutting Edge Technical Information for Utility Construction and Rehabilitation
By Dr. Lawrence M. Slavin, Dr. Oleh Kinash, Dr. Mohammad Najafi | January 2010 Vol. 65 No. 1
Figure 2 Typical Underground Conduit Construction (Courtesy of Underground Devices, Inc.)

Two initially vacant, relatively large diameter (e.g., four to 6-inch) main duct paths would be routed along the right-of-way (ROW), in the same main trench as the direct-buried distribution cables, but otherwise have no initial connections to the terminals, equipment or hardware. One duct could, for example, be used for future electric power upgrades or maintenance, and the other duct for communications (telephone and/or CATV), although the actual final implementation may vary, based upon the actual needs. The present architecture comprising only two main ducts is based upon the probability that not all utilities would require an upgrade in the foreseeable future, and that such duct capacity would be sufficient for practical cable upgrade or replacement needs.

A flush mounted handhole is an essential element in this example BCN. The BCN employs a joint-use (shared) handhole to serve the needs of all participating utilities or organizations. For residential (or small business) applications, a handhole may be co-located with each group of above-ground service pedestal terminals. For non-residential applications (highways, thoroughfares), the handholes would be located adjacent to required equipment or terminals or other convenient locations; e.g., to facilitate cable installation and/or accomplish a splice.

BCN – status
The incorporation of a belowground cable network, such as described above, into the design standards or procedures of road authorities would necessarily only occur over an extended period of time. MOP No. 118 represents an important item in the support of such a trend. Another essential element in the ability to encourage the implementation of a BCN, or equivalent, is the successful demonstration of its practical application in a variety of construction projects. In this regard, several related field trials have been successfully accomplished at the time of the writing of this article:

  • Arlington, TX: Mitchell Street (600 feet); South Davis Drive (1,600 feet)
  • Monroe, NC: NC State Road 1223 (720 feet)

In addition, a 400-foot segment is planned for installation, parallel to U.S. Highway No. 1, in the city of Danvers, MA.