Project Location: Arlington, WA
Construction Cost: $7.5 million

Wilder’s Role: Prime

Construction Period: 3/98 - 9/99

   The project involved the realignment of SR9 and SR530 in Snohomish County.  Early work included the removal and demolition of existing structures, clearing and grubbing and the installation of settlement indicating devices.  A vertical fill of approximately 35 feet was constructed in three stages, in order to provide for adequate settlement of in situ materials.

   The substructure of the steel bridge was constructed during the summer of 1998, as mandated by the Hydraulic Project Approval permit.  Construction of the steel girders and cement concrete bridge deck proceeded throughout the winter, during one of the region’s wettest winters in recorded history.

   The bridge deck was formed and poured in the spring of 1999.  Simultaneous work included the construction of traffic barrier, guardrail, traffic signals and lights. Traffic was rerouted over the new bridge in June of 1999.

     Notable components of the project included the construction of a mechanically stabilized earth wall, consisting of over 200 precast cement concrete panels.  The wall was approximately 300 feet in length and 30 feet tall at its highest point.  An additional earth retaining structure was completed on the west side of new SR9, consisting of geotextile and geogrid reinforcing fabric.

     Final work activities included the removal of the existing bridge (circa 1923), which consisted of lead abatement work; 500,000 pounds of steel; and three large bridge piers.