New Mt. Si Bridge Kicks Off County's 2007 Road Construction Season
Seattle, WA - The summer construction season for the King County Road Services Division kicks off this month with a $21.5M project to replace the 93-year-old Mt. Si Bridge. It is just one of several projects to improve the transportation network throughout unincorporated King County.
In the past decade, the county has placed primary importance on preserving infrastructure and supporting traffic and pedestrian safety to keep the road network safe and useable. The collection of projects the division will work on in 2007 centers on replacing aging infrastructure and upgrading safety for motorists, bicyclists and pedestrians.
One long-term need has been replacing the Mt. Si Bridge over the Middle Fork of the Snoqualmie River.
"The county has been patching and repairing the Mt. Si Bridge for more than 90 years," said Division Director Linda Dougherty. "Not only is the bridge old, but it is also not original to its location on Mt. Si Road near North Bend. The narrow, rusting bridge was built over the White River near Buckley and moved to North Bend in the 1950s. Today, it requires a great deal of ongoing maintenance and special inspections to keep it open and safe for public use – plus, it does not meet modern standards."
The new bridge will be built next to the existing one, and its alignment will improve visibility for drivers approaching and leaving the bridge. It will also be wider than the existing bridge, with an eight-foot-wide shoulder on the west side and a four-foot shoulder and six-foot sidewalk on the east side. These features will make the bridge safer for vehicles, bicyclists, and pedestrians. It will also be longer than the existing bridge to avoid interfering with the river's natural width.
Work begins this month, and will not be complete until the summer of 2009. During the two-year construction period, the old bridge will remain open – although there could be periodic closures to accommodate moving equipment in and out of the work site. The project includes significant environmental work in and around the river, not just to improve fish habitat but also for the osprey and elk that roam the area.
Other Road Services Division projects that will get underway or continue this year include:
Vashon Highway – Both short and long-term projects are in the works to ensure the preservation of vital infrastructure on Vashon Island. This summer, repairs will be made to the aging seawalls along Southwest Quartermaster Drive and the Vashon Highway. Work was completed on the Dockton Road seawall in December. These seawalls either support or protect the county's road system on the island. The estimated cost is $598,000.
In the long term, a more permanent solution will be developed for two large sections of failing seawall. One is the seawall that supports more than three-quarters of a mile of the Vashon Highway along Quartermaster Harbor. The other is along Dockton Road on both sides of Tramp Harbor. The goal is to design and construct solutions to preserve the roads for the next 80 to 100 years. The project could cost as much as $44M.
Wagners Bridge – This one-lane timber bridge carries North Fork Road Southeast over the Snoqualmie River about 10 miles northeast of North Bend. Work will begin this summer and stretch into the fall to replace it with a concrete girder bridge using the same alignment as the old bridge. This $3M project will reduce seismic vulnerability and load limitations, and remove sight-distance problems.
Simonds Road Northeast – Work should begin this summer to stabilize the slope supporting Simonds Road Northeast north of Kirkland. After two years of rough winter weather, the hillside on Simonds Road north of 100th Avenue Northeast is showing signs of movement. This $350,000 project will reinforce the slope embankment and the restore roadway surface.
Tolt Bridge – The $27M Tolt Bridge replacement project continues, and is scheduled to be complete next summer. The new bridge over the Snoqualmie River on Northeast Tolt Hill Road will be a 970-foot-long span made up of two 300-foot-long trusses over the west side of the river and the river itself, and a concrete girder section on the east side. The twin trusses will be reminiscent of the existing 85-year-old bridge.
Short span bridges – The Roads Division is beginning an ambitious project to replace up to 60 short span bridges throughout the county. Most of these old bridges are supported by decaying timbers or shallow concrete footings. Two bridges near Fall City will be replaced this summer – the Rutherford Slough Bridge on Southeast 39th Place and the Neal Road Bridge. The cost is approximately $944,000 for both.
Culvert replacements – The division has several culvert replacement projects that are in the preliminary design phase. The first project to actually get underway this summer will be on 396th Drive Southeast at 60th Street near Snoqualmie. Replacing aging culverts under county roads helps preserve the roadway, often reduces local flooding, and enhances fish habitat. More than $1M is planned for these projects in 2007.
Pedestrian safety – There are several pedestrian-safety projects planned that involve adding sidewalks or walking paths alongside busy roads. Projects that will start in late summer and fall include: Military Road South in Boulevard Park, 28th Avenue Southwest in White Center, South 128th Street in Skyway, 124th Avenue Southeast near Kent, and South 133rd Street in Skyway.
For more information about most of these projects, visit the Roads Division's Capital Improvement Program website.
SOURCE: King County Road Services