Trenchless Pipe Replacement Overview

When a new use of old and new technologies saves a lot of money, greatly improves performance, and
achieves new levels of customer satisfaction, it's usually considered a breakthrough.

New underground technologies are permanently altering the landscape of the construction industry, capturing the imaginations and budgets of water departments, cable operators, public utilities, and others. Although it's a revolution going on right under our feet, the average water, cable, or energy user is barely aware of it.
 

Underground construction spending in the U.S. has reached almost $17 billion annually and is growing at twice the rate of the non-residential construction industry. In addition, scores of manufacturing, contracting, and engineering companies with special expertise in underground techniques are growing rapidly -- often over 40 percent annually -- and are increasingly becoming merger or acquisition targets.
 

So what is putting all this sizzle in an industry that has not exactly been known for its razzle-dazzle? The answer is that now underground construction capabilities, grouped under the heading of "trenchless construction," enable contractors to lay, rehabilitate, and upgrade pipe and cable without digging open trenches. Aside from the obvious aesthetic benefits, trenchless methods are finding applications that would have been unthinkable even a few years ago. In the process, it's saving significant amounts in construction, labor, and restoration costs, eliminating the frustrations and delays often associated with the older open trench technology and even enabling multi-year projects to come in on-time, on-budget and, often times, under-budget.
 

The "trenchless revolution" is important because almost without our knowing it, the pipe and cable industry has become as important to our culture and quality of life as the telephone, car, or air conditioning -- perhaps more important because properly laid pipe makes these things possible. Millions of miles of pipelines carry water, sewage, and electricity to and from homes and businesses, while over 1.8 million miles of pipelines carry oil, natural gas, gasoline, heating oil, and other petroleum products across the United States.

Advance cable systems connect televisions, telephones, and computers. New underground techniques enable environmental companies to remediate areas contaminated with hazardous materials.

Until the late 1980s, these miles and miles of pipe were laid by the laborious excavation of trenches. However, the need for alternatives to the open-cut methods for installing underground utilities and other types of lines was apparent to electrical and natural gas utility companies, which often faced conditions where conventional trenching was undesirable and costly. A second impetus for developing trenchless technology was the recognition that although much of the nation's pipe infrastructure needed upgrading, the process of digging up and replacing old pipe located under busy streets and thoroughfares is often cost prohibitive.

To address these needs, equipment manufacturers, contractors, engineers, and consultants began developing new methods for installing, repairing, and replacing underground pipe, leading to commercialization of new repair/replacement materials and, by 1989, the first horizontal directional drilling units for the underground construction marketplace.
 

Essentially, horizontal directional drilling equipment enables contractors to bore through ground and then "pullback" pipes or conduit through the pilot bores. Although relatively simple in principal, the first machines were crude by today's standards. Effective tracking methods had not yet been developed and equipment was difficult to operate. Pipeline and Utilities Construction magazine (recently renamed Underground Construction) recorded the fact that manufacturers of early models sometimes had difficulty making successful demonstrations for prospective buyers. Market acceptance of trenchless technology would depend upon improvements in drill bits, back-reamers, drill pipe and fluid mixing and delivery systems. In addition, drilling fluids had to be environmentally friendly and matched to various soil conditions. Perhaps most important, crews had to be educated in the use of the new machines.

Today, trenchless drilling has become the application of choice for many contractors for laying, remediation, or rehabilitating pipe and cable systems. Many industry experts are predicting that trenchless technologies will account for 20 percent of the market by the year 2000. In another measurement, only five percent of contractors today can provide directional drilling; that number is expected to jump to 40 percent in the next five years.

U.S. Water News Online
July 1997