Dec. 7 project update
WSDOT and Seattle Tunnel Partners conducted additional survey work early Sunday morning to further assess the amount and extent of settlement that recently occurred on and near the Alaskan Way Viaduct.
Some of the data was inconclusive and analysis is still underway; however, WSDOT observed that a small amount of differential settlement is occurring near the access pit. Differential settlement is when the ground settles unevenly over an area. When the ground settles evenly or uniformly over an area, there is less risk of damage.
The additional survey work did not find that the differential settlement has caused any new damage to the viaduct nor have we observed any damage to buildings or utilities in the surrounding area. On-the-ground surveys will continue this week by historic architects and structural engineers.
Public safety is our top priority and while we have not seen any damage, Seattle Tunnel Partners is taking the prudent step to stop dewatering. The contractor will work with its geostructural designer to stop the dewatering in a deliberate manner in order to ensure worker safety and the structural integrity of the access pit and surrounding structures.
Data analysis, collection and monitoring will continue and we will provide updates as we have new information to share.