Shani Wallis, TunnelTalk
- A determined step forward for the Alaskan Way tunnel project was taken yesterday when a $1.35 billion design-build contract for its construction was signed with Seattle Tunnel Partners (STP).
- After emerging with the best value proposal in December, Washington State Transportation Secretary Paula Hammond was on hand yesterday (6 Jan, 2011) to sign the contract with STP representatives Fernando González Alcañiz for Dragados and Jack Frost of Tutor Perini Corp.
- In addition to the proposal price of just under $1.09 billion, the total $1.35 billion contract includes allowances for inflation, bonding and insurance requirements as well as utility works reimbursed by the City of Seattle and up to $70 million in incentives. Total cost of the bored tunnel is estimated at $1.96 billion, which includes design, right-of-way acquisition, construction management, more than $200 million set aside for risk and allowances and separate contracts for connection to existing highway routes at the north and south ends of the tunnel.
The mighty 17.5m or 58ft diameter tunnel will replace the double-decked waterfront viaduct
- Under the contract STP is committed to design and build the mega-TBM bored highway tunnel under the streets of Seattle to replace the seismically unsafe Alaskan Way Viaduct along city's downtown waterfront. Specified as a closed-face pressurised operation, the slurry or EPBM machine needed to excavate the double-deck highway tunnel will be the world's largest to date at more than 17.6m in diameter (58ft high and wide). At 2.7km long (1.7 miles) the TBM bored tunnel will provide underground space for a double-deck four-lane highway with an emergency lane in each direction for all types of highway traffic including 16-wheeler trucks.
- STP submitted the higher of two financial proposals in October 2010 but the series of technical credits earned during bid evaluation gave it a final total below that of its one rival. The offer of a large internal diameter tunnel to include an 8ft-wide safety shoulder on each two-lane deck and a commitment to finish the tunnel a year earlier than the official due date, saw the Dragados/Tutor Perini bid of $1,089,700,002 reduced by $71,577,000 in technical credits for a best-value score of $1,018,123,002. This outflanked the lower priced proposal by Impregilo with its S A Healy company of the USA and FCC Construccion of Spain as leaders of the Seattle Tunneling Group with designers Parsons Transportation Group and Halcrow. Its bid price of $1,088,302,002 was reduced by $38,152,000 technical credits for a final bid score of $1,050,150,002. Along with JV partners Spanish-owned Dragados-USA and Tutor Perini of California, the STP group includes several local firms, including Frank Coluccio Construction, Mowat Construction and design engineer HNTB Corp.
The huge closed-face TBM will advance beneath the high-rise city centre of Seattle
- At the construction contract signing ceremony yesterday, Transportation Secretary Hammond said: "With this contract, we are confident that the tunnel will be built within budget and delivered on time. More than 90% of the design-build work will be performed for a fixed price and the committed completion date by Seattle Tunnel Partners is December 2015, a year earlier than the official end 2016 project due date."
- Manuel Pardo, Project Executive for Seattle Tunnel Partners, said: "We are pleased to sign this contract with WSDOT. We have worked hard to win this project and we are ready to go to work. Our team is composed of international, national, and local contractors and provides the people of Seattle and the State of Washington the best value to build the bored tunnel. We look forward to a close collaboration with construction unions, minority business advocates, and the local community right up to the ribbon-cutting ceremony of this incredible transportation asset."
- There are however a few hurdles yet to clear before work can begin in earnest. A Supplemental Draft Environmental Impact Statement (EIS) that analyzes the bored tunnel over alternative schemes for replacing the elevated viaduct is currently with the Federal where its work and the necessary record-of-decision is not expected until August this year (2011). Procurement of the design-build contract ahead of this legal requirement has given the project a valuable head start but only design and 'project neutral' work can progress before then. Once approved, a second notice to proceed will initiate committed tunnel construction work.
- The project must also survive effective opposition by Seattle's City Mayor who objects particularly strongly to legal language in the project's approval legislations that makes the City responsible for any project cost overruns. Standing alone against most of the eight City Councillors, a compromised was reached back in July when the Council passed a resolution to delay its commitment agreements to the project until after the bids were in and the contractors' prices for design and construction of the project were revealed. With that now achieved and the project still on the stakeholders' agreed budget, work is likely start this month on passing an ordinance that will allow the City Council to sign the agreements.
- With these two issues pending, the next significant announcement for the project will be selection and placement of an order for the design, fabrication and supply of the giant 17.6m (58ft) diameter tunnel boring machine. The type of closed-faced boring system and the manufacturer are yet to be confirmed.
Best value proposal for Alaskan Way - TunnelTalk, Dec 2010
Alaskan Way mega-project procurement - TunnelTalk, Oct 2010
Alaskan Way Construction Management RFQ - TunnelTalk, Procurement
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