Contents tagged with sr99
Most freight will be able to use the SR 99 tunnel. Vehicles hauling hazardous or combustible materials will be prohibited from the tunnel, similar to current restrictions in the Battery Street Tunnel and on the viaduct during peak hours. These vehicles will take I-5 or Alaskan Way along the waterfront, as they do today.
The SR 99 tunnel will maintain freight routes through Seattle and preserve I-5 for regional and state freight trips. It will also provide a route through the city for vehicles that would otherwise use city streets.
Some freight trips destined for Ballard and the Interbay industrial area will likely use the new Alaskan Way street along the waterfront, with its crossing over the railroad tracks to Elliott and Western avenues. Traffic signals along the waterfront will be operated to ensure through trips move efficiently.
Freight trips leaving Port of Seattle terminals will also have improved access to I-5 and I-90 as a result of SR 519 and Spokane Street improvements and a new overpass at South Atlantic Street, which is included in our south-end viaduct replacement project.
Drivers heading north on SR 99 will have access to downtown Seattle via an off-ramp to a new Alaskan Way street. The new Alaskan Way will provide several east-west connections to downtown. West Seattle residents can also reach downtown using the Spokane Street Viaduct off-ramp to Fourth Avenue South.
Residents from northwest Seattle will have two options to get to or through downtown Seattle. They could travel along Elliott Avenue, as they do today, and drive down a new bridge over the railroad tracks near Pike Place Market to a new Alaskan Way street along the waterfront. Alaskan Way will connect directly to SR 99 near South Royal Brougham Way.
If northwest Seattle residents want to use the SR 99 tunnel, they could take the new two-way Mercer Street to Sixth Avenue North and enter the tunnel at Republican Street. They could also use any of the existing connections to Aurora Avenue north of Mercer Street.
We signed a design-build contract with Seattle Tunnel Partners in January 2011. Design-build combines project design and construction in a single contract.
More than 90 percent of the design-build work will be performed for a fixed price. The remaining amount includes work such as building repairs along the tunnel route, unplanned repairs to the tunneling machine and work stoppages due to differing site conditions. For these items, we established risk sharing with the design-builder.
We have set aside $205 million for known and unknown risks during tunnel construction. This amounts to 15 percent of the design-build contract, which falls well within industry standards.
Structural engineers agree that tunnels can be one of the safest places to be during an earthquake. The SR 99 tunnel is being designed to withstand an earthquake that only happens every 2,500 years on average (in the range of 9.0 on the Richter scale) without collapsing.
The tunnel will have emergency passages to safe refuge areas, and state-of-the-art ventilation, fire detection and suppression, security and lighting systems. It will be monitored 24 hours a day by WSDOT, similar to the I-90 tunnel today.