Prepare for delays during Bandaret Bridge overhaul

March 2, 2009

By Warren Kagarise

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Bandaret Bridge (above) crosses Issaquah Creek where it intersects with Southeast May Valley Road, about halfway between 230th Avenue Southeast and 231st Place Southeast, near Issaquah-Hobart Road. File

Crews are expected to begin working March 16 on a replacement for the aging Bandaret Bridge, a narrow timber span that carries May Valley Road over Issaquah Creek. 

Motorists should expect delays while the bridge is reduced to a single traffic lane during construction. A new bridge with wider traffic lanes is expected to open in November, according to the King County Department of Transportation. The department is overseeing the $5.5 million project.

The existing bridge, near Issaquah-Hobart Road between 230th Avenue Southeast and 231st Place Southeast, carries about 5,100 vehicles daily — too many for an aging, deteriorating structure, transportation officials said.Larry Jaramillo, a supervising engineer with the department’s Road Services Division, said the bridge is “functionally obsolete,” because traffic lanes are 11 feet wide and road shoulders are too narrow. The new bridge will include lanes that are 12 feet wide and bracketed by shoulders that are 8 feet wide.

Linda Thielke, a transportation department spokeswoman, said motorists should expect traffic delays until the new bridge opens in November. Crews will construct the new bridge in stages. The option carries the lowest construction cost of those considered by the transportation agency.

During the first phase of construction, the old bridge will be open to traffic while the new span is built. In the second stage, traffic will be shifted to the single open lane on the new bridge. A temporary traffic signal will be installed at each end of the bridge; county traffic engineers will monitor the signals. The old bridge will be demolished and the second lane of the new bridge will be built during the second phase. 

The traffic signal should be activated by March 16, Thielke said. An electronic sign to alert motorists to oncoming one-lane traffic should be installed early next week.

Plans also call for a traffic camera to be installed at the site. Jaramillo said the camera would allow commuters to observe traffic patterns and potential backups via the transportation department’s Web site.

King County transportation planners considered a handful of options for the construction, including a full closure of the bridge, which would have allowed for the shortest construction schedule. However, a full closure would have also required a nine-mile detour.

Officials chose to construct the new bridge in phases, because it will preserve the existing roadway alignment. They also said it will lessen traffic disruptions and reduce the impact of construction on the environment. If a new bridge were to be built upstream or downstream of the existing span, crews would have likely had to disturb wetlands during construction.

 

On the Web

Check out traffic patterns   and potential backups  during  construction at www.metrokc.gov/kcdot/mycommute.

 

Reach Reporter Warren Kagarise at 392-6434, ext. 234, or wkagarise@isspress.com. Comment on this story at www.issaquahpress.com.

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