Contract summary
This project will replace the existing Portage Bay Bridge 520/3, with two new parallel variable depth segmental box girder bridges across Portage Bay, the existing SR 520 eastbound off-ramp structure to Montlake Boulevard East, the existing 10th Ave E and Delmar E under-crossings with a new Roanoke Lid Bridge, and provide approximately 75 retaining walls. This project will also extend the SR 520’s transit/HOV system from Montlake to I-5 and the cross-lake bicycle and pedestrian trail over Portage Bay to a new lid between Delmar Drive East and 10th Avenue East.
Other major work includes providing stormwater conveyance, stormwater treatment, maintaining existing WPA drainage system, utility relocation, protect sewer outflow, relocate existing lumen duct bank, replace trolly poles, landscaping, paving, mechanical ventilation fire life safety system, and reversible ramp gate system.