This project built new multi-level, “braided” ramps to separate vehicles entering and exiting northbound I-405 between NE 8th Street and SR 520 in Bellevue. The project also adds a bypass lane for I-405 traffic heading eastbound to SR 520. A new ramp from the NE 10th Street overpass will give drivers direct access to SR 520 from downtown Bellevue.
Additional project elements included new storm water management facilities and a substantial upgrade of the existing drainage systems. Other improvements incorporate wetland and stream mitigation areas to compensate for the loss of these resources within the project area. SDA was the Stormwater Design Lead, Utility Lead, TESC Lead, and Stream Mitigation Lead for this complex design-build project and was responsible for the design and coordination associated with approximately $8 million of the $106 million project budget.