Project Beats Opening Day Deadline

The city of Pawtucket, R.I., used a trenchless lining system to rehabilitate a deteriorated sewer beneath its McCoy Stadium. The project was completed over a five-day period, without digging up the baseball field or delaying the start of the spring season for the Boston Red Sox?s AAA farm team. The project was part of a $16 million stadium renovation program.

While no official records exist, Pawtucket officials believe the 30-inch clay sewer beneath the stadium was installed in the 1930s, when the property was used as a landfill. The stadium came later, as a project of the 1942 Works Progress Administration.

Workers ran into problems while inspecting the lines.

?About halfway up the pipe, workers found major blockage from what appeared to be solid concrete,? said Richard Chiodini, P.E., chief engineer of Siegmund & Associates of Providence, engineering consultants to the city of Pawtucket.

Upon further investigation, engineers discovered a spur line from a ballpark maintenance area, where stadium personnel cleaned the machines that lay the white lines around the diamond. ?Lines made of lime,? Chiodini said.

Unbeknownst to the maintenance crew, every time they cleaned the machines, the excess lime deposited inside the sewer line. Over the years, the deposits accumulated into a rock-hard structure.

After removing the lime deposits, workers conducted a TV inspection of the line and confirmed the city?s fears. Substantial cracks had formed at several points in the 30-inch-diameter sewer, making it a potential candidate for collapse. An adjoining 18-inch drainpipe showed similar problems.

?Considering the shape the stadium was in, it was fair to assume that the sewer beneath it was in similar condition,? said Ron Leitao, superintendent of Pawtucket?s streets and bridges department.

Beating the Deadline

The city awarded the repair contract to Insituform Technologies ? with a major stipulation that the repairs be completed well in advance of the April 14 Opening Day of the 1999 season.

The Insituform ?cured-in-place? technology restored structural integrity of the deteriorated sewer without digging up the existing pipe or the field. A custom-made felt tube filled with a liquid thermosetting resin was turned inside out within the deteriorated pipe. Workers accessed the lines through manholes buried in the outfield and beneath second base. Water pressure propelled the tube through the sewer. Hot water circulated through the tube, cured the resin and formed a jointless and corrosion-resistant pipe-within-a-pipe.

The crew completed two inversions. The 30-inch-diameter line required a 650-foot inversion, beginning just outside the right field wall, and then making a 30-degree bend toward second base before leaving the stadium at third base. The 18-inch drain line started outside the left center field wall and ended at second base, requiring a 310-foot inversion.

Pawtucket Mayor James Doyle said, ?The sewer infrastructure in Pawtucket is old. Any time we can get to a line before it collapses, the savings are incredible.?