The state's Highway 99 tunnel might not be finished until November 2016, a year later than the Department of Transportation earlier planned.

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The state’s Highway 99 tunnel might not be finished until November 2016, a year later than the Department of Transportation earlier planned.

Transportation managers said Thursday they’ve added up to 360 days to the schedule, to take pressure off the tunnel’s three prospective construction teams. The change came after the firms said in closed-door talks that they were squeamish about meeting the state’s aggressive 2015 timeline.

The move should help keep costs down; the companies would have increased their bid prices to account for the risk of missing deadlines, DOT says.

But if any team can still promise to finish the job sooner, that would give them an advantage in bidding competition, for a contract in the vicinity of $1.09 billion.

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For area drivers, the delay means using the Alaskan Way Viaduct, built in 1953, a year longer. The viaduct would continue to be examined quarterly and reinforced if needed.

Thursday’s change underscores how technically challenging this project will be, in a region where a Sound Transit tunnel at Beacon Hill caused voids in the earth, and a drilling machine is stuck at King County’s Brightwater sewage tunnel project.

In addition, it conflicts with a declaration by Gov. Chris Gregoire that the old viaduct, which was damaged in the 2001 Nisqually earthquake, is a safety hazard that must come down by 2015.

“It’s a trade-off. Time is money,” said Transportation Secretary Paula Hammond Thursday, on behalf of the governor. “What’s important is to get the project started now so we can minimize the risk of inflation and cost pressures.” Hammond also said she doesn’t believe the state will lose the entire year.

Seattle Mayor Mike McGinn dislikes the project and has predicted massive cost overruns. He says the project shouldn’t proceed unless state lawmakers take action to shield city taxpayers.

On Thursday, he stayed quiet after DOT’s extra-year announcement, other than issuing this statement later in the day: “This is a very complex project, as the bidders and state are now confirming. We’ll be watching developments closely.”

Nonetheless, the project passed a major checkpoint this week in the release of a huge set of specifications, goals and instructions, known as the request for proposals or RFP.

So far, three teams are still interested in bidding for the job.

The design calls for a hole 56-feet wide beneath downtown. That will require the world’s largest-ever boring machine, said segment manager Linea Laird. DOT has decided to allow a slower pace of drilling, to allow for more deliberate soil removal, and machine maintenance.

An error in handling or measuring the soils may cause ground settlement that threatens utilities or even building foundations.

“You don’t want to put too much pressure on contractors to operate the machine too aggressively; they might not do proper maintenance, proper monitoring,” project Administrator Ron Paananen said. Drilling is expected to take 13 months.

The DOT believes that of 157 buildings over or near the tunnel route, 37 are potentially threatened by soil settlement. Tunnelers are required to inject grout in the soil, add bracing beneath buildings or take other measures.

The documents reflect what the state can demand of tunneling firms, without spooking them away.

The firms are:

• AWV Joint Venture, including Omaha-based Kiewit Pacific Co. and German-based Bilfinger Berger Ingenieurbau.

• Seattle Tunneling Group, made up of S.A. Healy Co., from Lombard, Ill.; Spain’s FCC Construction; S.A. Parsons Transportation Group, which has a Seattle office; and Halcrow, which has an office in Vancouver, B.C.

• Seattle Tunnel Partners, made up of Dragados-USA, from New York, and HNTB Corp., which has a Bellevue office.

A fourth firm, Vinci, Traylor and Skanska, dropped out in March.

The remaining three appear likely to stick with the project, said Laird, though she said it’s always possible in megaprojects that one could still drop out.

Proposals are due in late October. The construction strategies will be reviewed for about a month, before DOT looks at the price bids. Bidders will be given bonus points for their schedules; management plan and experience; and especially their strategy to prevent soil from sinking in unstable zones such as Pioneer Square.

Also, the bidders are required to provide only a 30-foot roadbed each way, with two 11-foot lanes, and shoulders of 2 feet and 6 feet. They’ll get extra credit in bid competition if they can design a safer 32-foot roadbed.

Work will be slow in archaeologically sensitive areas that were Native trade routes or settlements — in 2004, the state abandoned a worksite in Port Angeles, losing $60 million, after disrupting the Klallam village of Tse-Whit-zen and digging up the remains of 335 souls.

In some parts of the tunnel portals, dirt would be removed only 4 inches at a time, or by hand shovels, Laird said.

Mike Lindblom: 206-515-5631 or

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