Narragansett Bay CSO Project Wins Award

Gilbane Building Company of Providence, R.I., along with partner Jacob Associates, and the Narragansett Bay Commission have been awarded the 2009 Project of the Year by the Underground Construction Association.

The project, one of the largest civil works project in the history of Rhode Island, is Phase 1 of what will eventually be a three-phase combined sewage overflow (CSO) abatement program. Constructed from 2001 to 2008 at a cost of $350 million, it includes 3 miles of a 26-foot finished diameter tunnel, 250-  to 300-feet below grade in solid rock; 4,000-feet of drill and shoot, concrete-lined adits, 6- to 16-feet in diameter; a 120-feet x 60-feet x 60-feet deep rock cavern housing a pump room; fand our deep shafts 240- to 290-feet deep, ranging from 11- to 32-feet finished diameter.

“The challenges on this project were great,” noted Gilbane’s Project Manager John Kaplin. “In many places soil deposits greater than 150-feet thick were present and capable of producing heavy water inflows into the excavations if not adequately addressed. Bedrock included formations of weak rock with soil-like properties and short stand-up time, an issue for large span openings such as the rock cavern and the 30-foot diameter bored tunnel. Much of the new construction was near historic structures, along the waterfront with buried wharves and obstructions, or near live or abandoned utilities. A full slate of underground construction techniques was employed including drill and blast, TBM mining, pipe jacking, ground freezing jet grouting, microtunneling, and many others.”

“It gives me great pleasure to announce that the Combined Sewer Overflow Abatement Program has been selected to receive the 2009 UCA Project of the Year Award which recognizes an individual or group that has shown insight and understanding of underground construction in a significant project,” said Brenda Bohlke, chair of the Underground Construction Association.

The Phase 1 system is now in full operation, actively keeping overflows within the Phase 1 area out of Narragansett Bay, a waterbody of national estuarine significance with wide-spread recreational and commercial use. 

Gilbane Inc. is a full-service construction and real estate development company comprising Gilbane Building Company and Gilbane Development Company.