2007 Project of the Year Honorable Mention New Installation
October 1, 2007
New Installation Honorable MentionHDD Crossing Using Fusible PVC
Mears directionally drilled 5,120 ft of 10-in. fusible PVC pipe under the Beaufort River in Beaufort, S.C., in June 2007. The purpose of the new installation for the Beaufort Jasper Water & Sewer Authority was to supply reclaimed water to the Secession Golf Course from the Port Royal Water Reclamation Facility in Beaufort.
A Mears 300,000-lb rig was set up on the entry side of the crossing with a 60,000-lb rig on the exit side. The bore reached a maximum depth of 80 ft through sandy limestone and silty sand. Pullback operations took 17 hours, as site constraints made installation difficult. The pipe had to be pre-fabricated into five sections of approximately 1,000 ft each; therefore four tie-in fuses had to be made during pullback.
Installing fusible PVC is not yet that common in HDD.
This project marks the longest directionally drilled fusible PVC installation in this industry to date, according to project officials. Use of this type of pipe, supplied by Underground Solutions, was the key component in the successful completion of this project, they say.
New Installation Honorable Mention
Utah Transit Authority Pipe Ram
Stretching 45 miles across Utah, from Ogden to Salt Lake City, a new commuter rail ran parallel to the Union Pacific Railroad. The track, which was suffering from an inadequate drainage system, required an extension to its existing drainage crossing. Several utility crossings also called for attention and necessary repairs.
In order to complete the complex project, the Utah Transit Authority called on Nix Construction to undertake the task. The work required Nix to complete two 60-in. diameter steel casings that were previously installed, but never finished. The initial casing was fitted 40 ft into the ground, while the second stretched in 60 ft.
Being the most approved method for working under rail lines, pipe ramming was chosen to tackle the large project. Since the existing casings had been underground for months, pipe ramming was considered the most effective way to complete the installation through the tough ground conditions. With the method, the contractor was able to access and advance the existing casings that were in place, as well as install the bores.
While completing one 60-in. ramming job is deemed impressive in the industry, this difficult project involved 14 separate rams, four of them requiring 60-in. rams. Nix also included a pilot tube guided boring machine to its arsenal to complete construction on two of the bores (one 24-in. and the other 36-in.). The project was finished in April 2007.
