Elliott Bay Seawall Construction

The City of Seattle engaged Mortenson-Manson, Joint Venture team, as the general contractor and construction manager for the Elliott Bay Seawall reconstruction project. As essential and critical infrastructure, the seawall supports the Alaskan Way roadway fill, utilities, and upland areas while also protecting the tidal waters of Elliott Bay. It provides access to many adjacent pier structures, including the historic Washington Street Boat Landing structure. During the course of the project, the team replaced the original seawall structures built between 1916 and 1934, ranging in width from 15 to 60 feet, and refurbishing the Washington Street Boat Landing Structure. 

The project’s mission focused on construction of a new earthquake-resistant system that supports the street and right-of-way, provides access to the waterfront piers, improves marine habitat, and supports upland uses. Divided into two phases, the reconstruction efforts initial focus and first phase included the central seawall’s most deteriorated section, from South Washington Street to the northern edge of Pier 63 (near Virginia Street), a stretch of over 3,720 feet long. This section of the seawall’s critical deteriorating condition and high risk of failure in the event of an earthquake or other natural disasters prompted priority. The second phase involved replacing the northern seawall, reinforcing it to withstand coastal storm damage and shoreline erosion. 

Throughout construction, the team utilized modern engineering techniques and materials, such as steel-reinforced concrete and composite sheet piles. The seawall features a new stormwater management system that improves water quality and reduces the impact of pollutants on the marine environment.

The improved Elliott Bay Seawall protects the general public and surrounding businesses against catastrophic consequences in the event of seawall failure. The project significantly improves public safety while enhancing the natural beauty of the waterfront area, making it a more attractive place to live, work, and visit for years to come.