Alaskan Way Viaduct and Seawall Replacement Program - Proposed SR 99 Bored Tunnel Underground Simulation

Seattle’s Alaskan Way Viaduct is a critical north/south artery that runs through the heart of downtown, supports the greater regional transportation system plus downtown businesses. After a 2001 earthquake, the Viaduct’s seismic vulnerability was made clear, and it became obvious that it needed to be re-built or replaced. WSDOT needed a way to communicate complex information in a way that various target audiences could understand so Parsons Brinckerhoff's Project Visualization team drew upon CAD and geospatial information to develop digital 3D and Building Information Models (BIM) for all of the major parts, pieces and processes of the project. Multiple virtual models were created, enabling the project team to literally see into the future, to make more informed decisions with multiple stakeholders. This approach was also used to evaluate design alternatives and traffic impacts, study construction sequencing and closures, analyze lighting and shadows, and support a public outreach and communication effort that proved successful in helping the public understand the process and gaining support for the project. Parsons Brinkerhoff’s BIM tools and visualizations contributed greatly to the planning and design process. They helped identify conflicts and optimization early on. They improved internal and external communication, and helped stakeholders “see” what was possible. The visualizations assisted in the selection of a preferred alternative and are now being leveraged to support the preliminary design process, using 3D models to improve communication, collaboration and decision making amongst multiple parties.