Saturday, October 24, 2020
Oct. 24, 2020

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Swap-out part of I-5 Bridge work mostly done

Test lifts with new trunnions, sheaves likely to begin Thursday

By , Columbian business reporter
Published:

Wednesday marked the halfway point in the nine-day Interstate 5 Bridge trunnion replacement project, and Oregon Department of Transportation officials say the work is on track to wrap up on Sunday as scheduled.

The primary goal of the project is to replace a cracked trunnion at the top of the northbound bridge’s south tower. The trunnions are the axles for the sheaves — a pair of 20-foot-diameter pulley wheels at the top of each tower that move the cables that connect the lift span to the counterweights.

Only one of the trunnions was cracked, but all of the pieces were more than a century old, so ODOT opted to replace both trunnions and their sheaves, as well as the south tower’s cables. The north tower’s components were replaced in a similar operation in 1997.

Most of the swap-out work is finished; crews began removing the old trunnions and sheaves on Monday using a barge-mounted crane, and both sets of parts were gone by Tuesday afternoon. As of Wednesday afternoon, the new trunnions and sheaves were all in place and crews were in the process of installing the new cables, ODOT spokesman Don Hamilton said. Test lifts of the bridge will likely begin Thursday.

Crews have also been taking advantage of the bridge closure to perform smaller routine tasks such as patching potholes, striping asphalt and upgrading the bridge lighting, according to a Wednesday press release from ODOT.

Heavy rain Wednesday afternoon prompted officials at the Washington State Department of Transportation to close the ramp from northbound I-5 to downtown Vancouver due to pooling water on the freeway median.

The median barrier normally guides rainwater to flow along the shoulder of the freeway, according to Washington State Department of Transportation spokeswoman Celeste Dimichina, but the median was temporarily removed for the bridge project so that northbound drivers would be able to cut across and reach the downtown Vancouver exit ramp.

The ramp will likely remain closed through Saturday, she said, because there is more rain in the forecast for the next few days.

Wednesday’s rainstorm caused more problems for drivers on the roads than workers up on the bridge towers, Hamilton said. The main hazard for the workers is wind — the tops of the towers are 239 feet above the river — but the wind on Wednesday wasn’t strong enough to be an issue, and the forecast so far hasn’t predicted any dangerous wind in the coming days either.

The closure is scheduled to end at 11:59 p.m. Sunday. Immediately following the reopening of the northbound span, crews will close the left lane of the southbound span for seven days to perform wrap-up work and maintenance.

Photo

Trunnion replacement

Read more about the Interstate 5 trunnion replacement project at columbian.com/bridgeclosure

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