Regional transit builder SoundTransit adopted a two-part strategy when it went to bid on tunneling work for University Link, a 3.15-mi underground extension of light rail from downtown Seattle to the University of Washington. The project includes construction of two twin-bore tunnels and two stations.
SoundTransit, the regional transit builder and operator in Central Puget Sound, divided the tunneling work into two separate contracts. A $153.5-million contract—$20.7 million less than the engineer’s estimate of $174.3 million—for 1 mi of tunneling from a new Capitol Hill station to downtown Seattle was awarded in August to JCM U-Link, a joint venture of Jay Dee Contractors of Livonia, Mich.; Frank Collucio Construction Co. of Seattle; and Michaels Corp. of Brownsville, Wis.
Five months earlier, the agency awarded a $309.2-million contract to a joint venture of Traylor Bros. Inc. and Frontier-Kemper Constructors Inc., both of Evansville, Ind., for the 2.1 mi of tunnel between the University of Washington and Capitol Hill stations. The engineer’s estimate on this project was $395.4 million.
“We were hoping that we would get more competition if we divided the contracts,” SoundTransit spokesperson Bruce Gray says. “It seemed to have worked.”
Four joint ventures bid on the two projects, and the millions of dollars in savings will be used for a healthy contingency budget.
Michael DiPonio, JCM project manager, says the division of tunneling and station-building is a good way to break the project up. His joint venture is made up of companies that specialize in heavy-construction tunneling and the contract specifications allow them to focus on what they do best, he says.
Because the University of Washington to Capitol Hill stretch is more than twice as long as the Capitol Hill to downtown leg of the tunnel, plans call for using two earth pressure balance tunnel-boring machines for the first one and one for the second so both crews finish work at about the same time.
Both contractors started work in January, excavating the sites and relocating utilities. Boring could begin in 2011 and be complete in 2013.
“We learned a lot when we built the Beacon Hill tunnel,” Gray says. Workers on the 160-ft-underground station ran into sand issues, and the station box had to be moved 80 ft west. That project was completed in late 2008 and went into service in July, 2009. Tokyo-based Obayashi Corp. was the contractor on the tunneling, station mining and finishes of the complex project.
Geotechnical work on the new tunneling project indicates the presence of glacial till, hard-packed clay and sandy soil. “You never know what you will be faced with on a tunneling project,” Gray says.
DiPonio says working in the dense urban setting won’t be easy. His team of 30-50 construction workers will have to minimize impact by operating the equipment with as few ground movements as possible. When the work is complete, the mechanical equipment will be removed from the tunnel-boring machine and the shell will be filled with concrete and abandoned in place. “This is done quite a bit in Japan, but it’s the first time I have done it on a project,” DiPonio says.
Meanwhile, SoundTransit administrators are testing out another new contracting method for construction of the University of Washington station, one of the two stations required for the new line. Instead of awarding separate construction management and general contractor contracts, the agency plans to compile a short list of qualified bidders by March for a single general contractor/contract manager role.
“We are hoping that one GC/CM can find creative solutions to value engineer the $115-million project,” Gray says.
The U-Link, which is funded in part by an $813-million federal grant, is projected to add 70,000 daily riders to the Link system, bringing total daily ridership to 114,000 in 2030.
Lead Design: Northlink Transit Partners (Jacobs Associates; HNTB Corp.; AECOM)
Other Design: LMN Architects; Hewitt Architects; PFF Consulting Engineers; Earth Tech
General Contractors: JCM U-Link; Traylor Frontier-Kemper JV
Construction Manager: Seattle Tunnel and Rail Team JV