Replacing the Temporary Bridge

From ODOT- With all the construction work under way on the new Interstate 5 Willamette River bridges, it’s easy to forget the bridge carrying I-5 traffic since 2004 is temporary.

This fall, when the new southbound bridge is complete, we’ll shift all I-5 traffic onto it, which will allow us to dismantle the temporary bridge clearing the way for construction of the new northbound bridge.

As we closely watch construction of the new arch bridges, I think it’s important to remember why we’re building them.

When ODOT inspected the original I-5 Willamette River bridges in 2002, we discovered structural problems in the aging girders. We quickly put load limits in place that forced heavy haul truck traffic to detour on U.S. 97 through Central Oregon. The long detour increased the cost and time of moving goods in and through Oregon.

While we immediately started planning for new bridges to replace the old, we knew it would take significant amount of time to design and construct a bridge to meet the environmental and seismic standards for permanent bridges with a lifespan of 100 years. That was too long to wait to return heavy truck traffic to I-5 through Eugene-Springfield. Building a temporary bridge became the best interim solution.

We quickly designed a temporary bridge and acquired needed right of way and permits. Our contractor, Hamilton Construction, started work on the temporary bridge in 2003, and it opened to traffic in 2004. The temporary bridge was built using materials and methods that could be quickly installed, but it does not meet all standards required for a permanent bridge with 100-year lifespan.

The temporary bridge has carried traffic for more than six years. During that time heavy freight has moved easily on I-5. Truckers, and the consumers of the goods they transport, have avoided the economic impacts of a costly detour.

We expect the new bridges to be complete in 2013, almost a decade after the temporary bridge opened. By the time both new bridges are open to traffic, Oregonians will see a good return on their investment in the temporary bridge. In addition, material from the temporary bridge will be reused or recycled, and the right of way used for the temporary bridge will be returned to its natural state.

When the work is done, our goal is to leave the project area in far better shape than we found it.