In Seattle, some striking finishing works are being carried out to Sound Transit’s Beacon Hill Tunnel Station, with the installation of an unusual blue color scheme.
The décor will be augmented by Dan Corson sculptures, named ‘Space Forms’, which are to be suspended from the ceilings of the Northbound and Southbound platforms. Internally illuminated with LEDs, the sculptures are said to reflect imagery of microscopic plant and animal forms.
As the Beacon Hill project moves into its final phases, Sound Transit’s 3.15-mile (5km) long University Link light rail extension continues to move towards construction. In September last year, the Sound Transit Board unanimously approved University Link’s capital Baseline Cost Estimate of $1.61 billion and established a schedule that has the project completed in fall 2016.
On July 10, funding approval was received from the US Senate Appropriations Committee, $128.8 million, of which $100 million is for the University Link project. The bored tunnel components of the project will be separated into two contracts, U220 and U230.
Potential bid documents have since been issued for industry review. T&TNA was told by a Sound Transit spokesman: “It’s a way to make the actual bidding as competitive and comprehensive as possible. On U220 we got more than 100 different comments on everything from the general conditions of the contract, to questions about various specifications. We heard from primes, major subs and one TBM manufacturer.”
Running entirely underground, the extension will connect downtown Seattle with the University of Washington via Capitol Hill. The scheme is likely to utilize three TBMs. Two of which will start at the University site and simultaneously bore south to Capitol Hill. The third will start at the Capitol Hill station site and bore south to the end of the initial construction segment. That TBM will then be disassembled, returned to Capitol Hill and reassembled to bore a second tube south.
As the design progressed, Sound Transit, with the Seattle Fire Department’s concurrence, determined that the Montlake emergency ventilation facility originally proposed will not be required, as emergency ventilation functions can be fully met at the Capitol Hill and University stations.
U220, the tunnel contract from the University of Washington to Capitol Hill, is on the critical path of the scheme. Bidding and award is due to take place from mid-December this year through to mid-July 2009. With time allocated for various approvals, construction could begin by the end of 2009.
Beacon Hill’s southbound platform tunnel Artist’s impression of the platform tunnels once the sculptures have been installed
