Big strides underground: New approach saving time and money in Boston construction.

Communications Engineering Digest/The Magazine of Broadband Technology
August 1983

Boston- State-of-the-art in underground cable system construction appears to be on the verge of taking a quantum leap forward, thanks to successful employment of new technologies in the Cablevision Systems Development new build here.

McCourt Cable Systems Inc., primary contractor for the 800-mile Boston system, has brought together several techniques to produce and installation procedure that cuts underground construction time by at least 40 percent, with attendant cost savings in the 25 percent range.

According to Jerry Crusan, Cablevision’s director of group engineering, the McCourt Approach, while employing a variety of advances developed by other firms, represents a unique synthesis that constitutes a significant improvement over other techniques the MOS has investigated.

Crusan said the most import elements of the McCourt Boston Integral (MBI) construction system are us of “rock saw” pavement cutting equipment and pre-construction installation of cable in specially designed conduit lines developed by Integral Corp. of Dallas, Texas.

Heretofore, the underground installation construction process typically has involved digging a deep, wide trench; placing plastic conduits that connect at 10- and 20-foot intervals; encasing the ducts in concrete; refilling the trench with gravel; and then pulling the cables through the conduits.

In the new approach, the rock saw, a giant self-propelled saw, moves slowly along the street, cutting a narrow trench. The flexible conduit with cable already installed, is pulled from a seven-foot reel into the trench. The conduit is encased with a specially developed concrete, which is capped with a bituminous concrete that has been infrared treated.

Cablevision Systems has been using the new Integral conduit-encased cable approach for the past year or so, but the Boston project represents the first time the Integral technique has been wedded to the rock saw cutting process, according approaches together in a way that permits efficient construction without damage to underground wiring and conduits already in place.

The McCourt technique required approval of the city government in Boston, which initially frowned on the idea out o concern for potential property damage or injuries to people that might result from flying debris generated by the giant saw. The city eventually agreed to permit the new approach on a conditional basis. In the period since MBI construction began reconsider its decision, and now the system has the full support of the administration.

Crusan said Cablevision Systems Development hopes to win approval for use of the MBI technique in its new franchises in Brooklyn and the Bronx, N.Y., as well as in Chicago and other systems requiring substantial underground wiring. He said New York, with some 700 miles of underground wiring require in the Cablevision franchises, is an especially important market for application of the MBI system.

About a 40 percent reduction in construction time…One of the nicest features of the system is that it allows us to get in and out of a neighborhood in a day or tow versus one to two weeks under the old method. That’s obviously helpful in reducing noise and traffic disruptions, which, in turn, makes life much easier for us.”

A 25 percent savings in underground construction costs would cut the current average of $250,00o per mile to $187,500. In the typical large urban system, requiring well over 100 miles of underground installation, this would translate into a savings of approximately $1 million or more system construction outlays.

Although, in Crusan’s opinion, McCourt’s marriage of rock saw and Integral conduit techniques makes the Boston-based contractor a prime candidate to employ the technique in other Cablevision franchises, there appears to be no reason why other contractor could not bring the two technologies together using their own methods. With McCourt actively marketing the techniques and others likely to follow suit, the innovations in Boston could portend significant savings and time advantages for the entire CATV industry.

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