Interstate Bridge Trunnion Replacement & Lift Span Closure (2020)


The northbound span of the Interstate Bridge over the Columbia River (River Mile 106.5) requires repairs to prevent failure of the 272-foot high lift span that allows marine traffic through the main river navigation channel.

In the fall of 2020, ODOT will replace bridge components including the two sheave/trunnion/bearing (pulley) assemblies and counterweight cables in the top of the tower at the south end of the bridge lift span.

Routine inspection revealed a half inch deep crack in the trunnion. The bridge is currently safe, but the crack has grown from 4.0 inches long to 6.5 inches long in 2 years and analysis indicates that it could reach critical depth causing catastrophic failure by 2045.

The repair project is expected to take place from August 2020 through October 2020 and will affect river navigation by interrupting operation of the lift span.

Fact Sheet Notice to Mariners


In September 2020, the northbound bridge of the Interstate Bridge will close for up to two weeks as crews replace a cracked trunnion and other parts that help lift and lower the bridge. During the closure, all traffic crossing the bridge will share the three lanes and sidewalk on the southbound bridge.

The Interstate Bridge is located on Interstate 5 where it crosses the Columbia River between Portland, Oregon and Vancouver, WA.

This important maintenance work is necessary to keep the bridge in working order. Because this work takes place overhead, the northbound bridge must close to keep drivers safe and to provide access for construction crews and heavy equipment.

IB Trunnion Fact Sheet

For more information or to sign up for project updates, please visit:



Representatives from the Interstate Bridge Trunnion Replacement Project presented to the LCRHSC at the November 14, 2018 General Membership meeting. All information presented here is from materials presented at the meeting and are also available on the project website.