The St. Johns Blvd Interchange project replaced the signalized intersection at SR 500 and St. Johns Blvd located in Vancouver, Wash., with a freeway-style interchange. The Tapani team raised the St. Johns Blvd roadway by 25 feet, built a new bridge to take the traffic up and over SR 500, and connected SR 500 to St. Johns Blvd with interchange ramps. Additionally, 1.13 miles of improvements were installed on SR 500. The project included: clearing and grubbing, excavation and grading, storm drainage system, crushed surfacing, hot mix asphalt (HMA) paving, bridges, pavement, traffic signals, illumination, signing and landscaping.
Because SR 500 and St. Johns Blvd are major roadways, keeping both roads open was extremely important. Tight workspaces were also challenging at times. Many small walls had to be installed around existing traffic. Other challenges included traffic control, in-water work, existing utilities, and a creek crossing, culvert cap, and mitigation work. The final product allows traffic to flow freely on SR 500 and reduces the wait time for drivers at the St. Johns Blvd signal.