Contractors are paving and striping the portion of Stone Drive that passes through a new tunnel beneath the Tacoma Narrows Airport property, prior to opening the road to through traffic at 5 a.m. June 11.
The 530-foot tunnel — technically, it’s a “lid” — was created to protect Stone Drive motorists in the event that the runway safety area above the structure is needed for an aircraft emergency landing.
The Federal Aviation Authority required creation of the runway safety area and associated tunnel, and also provided 95 percent of the project’s $15.5 million cost.
Following the tunnel’s opening, the temporary bypass road will be filled and graded to match the safety area elevation. Graded areas will be seeded with grass, security fencing will be added, and existing runway lighting in the safety area will be restored.
The project is scheduled to be entirely complete by late July or early August, at which time a public celebration will be announced.
The project was initially under jurisdiction of the City of Tacoma, but was transferred to Pierce County when the county purchased the airport in late 2008.
Technically, the Stone Drive structure is considered a “lid.” Lids cover an open trench in the ground with a bridge-type structure that supports the weight of the soil above, and in this case, perhaps an errant airplane. True tunnels are bored or blasted through soil or rock, and rely on the strength of the tunnel lining and surrounding soil for support. The City of Ruston tunnel is the only true tunnel in Pierce County.
Thursday’s anticipated opening of the Stone Drive tunnel beneath the Tacoma Narrows Airport was delayed to address issues associated with the tunnels fire detection system. The tunnel will open when the Pierce County fire marshal, Public Works and Utilities, and the construction contractor resolve several technical and logistical issues.
The tunnels fire suppression system is in place, but the automated monitoring cameras that detect and report a fire are waiting for installation of an Internet connection. Manual pull-station fire alarms also await final testing.
At this time, Pierce County Public Works and Utilities has not authorized that Stone Drive be opened to the traveling public. An announcement will be made when an opening date and time are set.
Issues surrounding the Stone Drive tunnel opening have been addressed, and as of 11 a.m. today, the tunnel opened to traffic.
Security and fire watch personnel will be posted at the tunnel to report a fire or unauthorized activity until the Pierce County fire marshals final inspections are complete.
Pierce County Airport and Ferries administrator Michael Esher apologized for the unexpected delay in opening the tunnel. We are very sorry for any problems encountered by drivers as a result of the delay. If anyone has questions about the delay or any other aspect of this project, please feel free to contact me. As Pierce County assumes responsibility for operating the Tacoma Narrows Airport, I want to assure the public that we are responsive to any concerns they may have.”