SR 520 project estimated to cost more than $500 million less than expected
Constructing the State Route 520 corridor, including a new floating bridge and six-lane highway, is estimated to cost $522 million less than expected, said the Washington State Department of Transportation.
WSDOT finalized documents for a $300 million federal loan that will fund design and construction of the next portion of the SR 520 project which includes a bridge between the west-end landing of the new floating bridge and Montlake.
In addition, Transportation Secretary Paula Hammond has instituted personnel and organizational changes for the pontoon construction. Hammond has also re-convened an expert review panel to conduct additional analysis of pontoon design, repairs and construction.
The changes come as a result of a review of the first cycle of pontoon construction in Aberdeen to fully understand the cause of concrete spalling and more-than-expected cracking. WSDOT’s pontoon design included an error that is determined to have caused the spalling in one pontoon during tensioning, making repairs necessary.
These issues that occurred during the first cycle will likely lead to additional, yet-to-be-determined costs for repairs and schedule delays under discussion between the state and its pontoon and bridge-replacement contractors. Negotiations will take place over the next few months.
The changes within WSDOT will strengthen the delivery team and construction oversight by adding additional contract management and quality verification staff to the Aberdeen site.
The remaining budget for the SR 520 projects includes funds to address potential risks during construction. No new funds will be requested from the Legislature.