Subscribe / Renew |
|
Contact Us |
|
► Subscribe to our Free Weekly Newsletter |
home | Welcome, sign in or click here to subscribe. | login |
print email to a friend reprints add to mydjc |
February 5, 2024
Jacobs Engineering Group
Project: I-5 Steilacoom-DuPont Road to Thorn Lane corridor improvements
Client: WSDOT
The Interstate 5 Steilacoom-Dupont Road to Thorne Lane corridor improvements project undertaken by the Jacobs/Atkinson design-build team was a display of technical acumen and teamwork. The project involved widening 4.5 miles of I-5 and reconstructing two diamond interchanges, Berkeley Street and Thorne Lane, with innovative roundabout-controlled interchanges spanning I-5, and a Sound Transit rail line.
The project eliminated potential mainline traffic degradation by introducing a southbound connector roadway between Thorne Lane and Berkeley Street. This eliminated the need for a proposed auxiliary lane and avoided heavy weaving, enhancing traffic safety and flow.
Brain Whitehouse, Olympic Region assistant construction engineer for WSDOT said: “In an effort to save time and money, the team developed several WSDOT-approved alternate technical concepts to enhance the conceptual plan and to simplify any potential future widening in this area. This included redesigning the Thorne Lane interchange from a ‘dog bone’ bridge design (roundabouts at either end of a single bridge) to a two-bridge design. This solution simplified the structural design, eliminated grade-related safety issues, and improved traffic staging and local access during construction.”
The team also redesigned the Berkeley interchange from a similar “dog bone” design to a standard tight-diamond interchange, providing a new southbound barrier-separated connector roadway between Thorne Lane and Berkeley Street that eliminated the need for a proposed auxiliary lane that had the potential to degrade mainline operations.
The new traffic pattern provided a needed connection for the city of Lakewood and Tillicum, and the team coordinated with a multitude of stakeholders to address diverse project interests. Despite several owner-initiated change orders, the team successfully met the substantial completion date. The project has had positive impacts on the environment, local communities, traffic flow, military operations and traveler safety.
Other Stories: