Seymour-Capilano Contract Awarded

Metro Vancouver has finalized negotiations and awarded a contract to the Seymour-Cap Partnership – comprising the companies Frontier-Kemper/J.F.Shea/Aecon – for completion of the twin tunnels component of the Seymour Capilano Filtration Project.

The Seymour-Cap Partnership bid $181 million to complete the tunnels, and will proceed using the original engineering design and the two tunnel boring machines currently in place. The project, which will provide filtration and ultra-violet disinfection of drinking water from two of Metro Vancouver’s three source water supplies, has four key elements: the filtration plant, located in the Lower Seymour Conservation Reserve; the Capilano pumping station; twin tunnels that will convey water from the Capilano source to the plant for treatment and return treated water for distribution; and an energy recovery facility.

While both the filtration plant and energy recovery facility are nearing completion, and the pumping station is complete, work on the twin tunnels was halted in January 2008 by Bilfinger-Berger Canada Inc., the original contractor. Citing unsafe working conditions, Bilfinger-Berger ceased work on the contract, which was terminated by the owner in May 2008. Metro Vancouver has filed suit to recover costs of completing the tunnels from Bilfinger-Berger.

In the late summer and fall 2008, Metro Vancouver conducted a pre-qualification and RFP process inviting proposals from potential contractors capable of completing the two 7.1-km, 3.8-m diameter tunnels. Following pre-qualification, three consortia were identified. Two of the three consortia submitted compliant bids.

Initially budgeted at $200 million, which included Bilfinger-Berger’s $105 million contract for tunnel construction as well as engineering, tunnel liner and other associated expenditures, overall costs for the tunnels component are projected to double to $400 million.

Work on the tunnels was expected to commence in April, with completion anticipated at the end of 2012 or early 2013. Filtration plant construction is expected to be completed this spring and the plant fully operational by the fall.

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Narragansett Bay Commission CSO Earns UCA Honors

Gilbane Building Co., 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 projects 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 consists of 3 miles of 26-ft finished diameter tunnel, 250 to 300 ft below grade in solid rock; 4,000 ft of drill-and-shoot, concrete lined adits, 6 to 16 ft diameter; a 120-ft by 60-ft by 60-ft deep rock cavern housing a pump room; four deep shafts 240 to 290 ft deep, ranging from 11 to 32 ft finished diameter; seven drop and vent shafts ranging from 2 to 9 ft diameter, up to 290 ft deep; new surface construction of CSO diversion structures, gate and screening structures, box conduits and connecting pipes totaling over 4,000 ft at seven sites around Providence; and construction of buildings to house electrical, mechanical, air handling and supervisory control systems for pumps, screening systems and remote sites.

“The challenges on this project were great,” notes Gilbane’s project manager John Kaplin. “In many places soil deposits greater than 150 ft 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-ft 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,” Brenda Bohlke, Chair of the Underground Construction Association, recently announced.

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

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Claremont Tunnel Seismic Upgrade Project Recognized by ASCE

With a seminal bypass tunnel and vault design, the Claremont Tunnel Seismic Upgrade Project effectively navigated the challenges in California’s Bay Area, one of the most seismically vulnerable regions in the world. The project was recently selected to receive the 2009 Charles Pankow Award for Innovation, presented by the American Society of Civil Engineers’ (ASCE). The award was presented at ASCE’s 2009 Outstanding Projects and Leaders (OPAL) Gala Thursday, April 23, 2009 at the Hyatt Regency Crystal City in Arlington, Va.

The Claremont Tunnel is a critical water tunnel that crosses the Hayward Fault in the San Francisco Bay area. It is 18,065 ft long, 9 ft in diameter and carries up to 175 million gallons of treated water per day. Originally constructed between 1927 and 1929, the existing tunnel was vulnerable to significant damage and potential collapse in the event of a large-magnitude earthquake. If the tunnel failed, approximately 63 percent of the more than 800,000 residents who depend on its flow would be left without adequate water for consumption and such safety measures as fire fighting.

The East Bay Municipal Utility District (EBMUD) owns and operates the Claremont Tunnel. EBMUD serves more than 1.2 million customers in Alameda and Contra Costa counties. After the magnitude-6.9 Loma Prieta earthquake in 1989, EBMUD examined its system and considered how major earthquakes could impact service. The result was a proactive 10-year seismic improvement program. The Claremont Tunnel was identified as the key facility requiring seismic upgrades.

The innovative design was the first of its kind and included an expanded vault section across the Hayward Fault, which was designed to accommodate up to 8.5 ft of lateral offset without interruption of water flow. The reinforcing around the vault was designed to curve like a spine in an earthquake, while two smaller tunnels excavated on both sides of the bypass tunnel were completely backfilled with concrete to prevent water from eroding the surrounding ground if the lining cracked after an earthquake.

Inside the bypass tunnel, a carrier pipe was placed as additional protection for water conveyance. With a capacity of 130 million gallons per day, it provides enough water to maintain lifeline service to customers following a magnitude-7.0 earthquake. The pipe rests on sliding cradles that enable it to shift within the vault as an earthquake moves the tunnel.

AMEC Geomatrix characterized the geologic conditions along the bypass tunnel alignment and provided the design team with the geotechnical and earthquake parameters needed to design the bypass tunnel. Jacobs Associates, a leader in underground engineering, was responsible for the overall design and construction management support. The contractor was Guy F. Atkinson Construction.

The Claremont Tunnel project pioneered innovative seismic features that will help many other engineers and owners address severe seismic hazards in tunnels. In September 2006, the San Francisco Section of ASCE recognized the project for its innovative design and creative use of materials.

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UCA Hosts Regional Conference in Seattle

The Underground Construction Association of SME on May 4 held a regional conference covering tunneling in Seattle. The area is rich in tunneling history with notable past, present and upcoming projects. The event, held at the Seattle Sheraton, attracted about 250 attendees.

The conference started with a presentation from Seattle resident and past ITA president Harvey Parker, Harvey Parker Associates, who discussed the history of tunneling in Seattle. Joe Gildner, Sound Transit, and Judy Cochran, King County, followed with updates on their agencies’ projects, which include a new transit tunnel through downtown and the ongoing Brightwater wastewater program.

Much of the agenda focused on the $4.2 billion Alaskan Way Viaduct Replacement Tunnel Project, which was approved in March as the preferred method for replacing the aging viaduct. The 54-ft diameter bored tunnel will be about 2 miles long and carry four lanes of traffic.

One of the highlights of the program was the participation of local stakeholders, including representatives of Seattle City Council, Chamber of Commerce, and groups representing area businesses. A panel on worldwide large-bore projects was also included.

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