OC/West Linn bridge work more visible this week
The most visible part of the Oregon City/West Linn bridge rehabilitation work starts soon as the Gunite (concrete) coating on the steel is removed using a very high-pressure water process called hydroblasting. You can view the work under the bridge deck from the east side of the sidewalk of Hwy. 99E or go to the top of the Municipal Elevator for a good view of the other work going on above the deck.
With the arrival of the barges, the contractor is preparing the containment system for the hydroblasting. Big curtains will direct and capture the water and debris into containers so none of it enters the river. After treatment it is sent through the sanitary sewer system, you will see clouds of steam from this hydroblasting rising over the tops of the curtains. The steam is only water vapor and contains no chemicals.
The Gunite removal starts this week on the arches under the bridge deck on the Oregon City side and later moves to the West Linn side. When the Gunite is gone, you will be able to see the steel of the arch ribs. The workers will use 'Manlift' access platforms, stationed on the barges to remove the Gunite below the bridge deck. The curtains will be moved along as the work progresses along the span. The whole process continues for about six weeks. Windy days can affect this schedule, so the contractor will work longer days during the hydroblasting. The work on the arches above the deck will start at a later date.
To address traffic backups during afternoon commute time in West Linn at Willamette Falls Drive,the Oregon Department of Transportation recently installed signs to indicate that the right lane on Willamette Falls Drive approaching Hwy. 43 is local access to the paper mill and police station only. ODOT officials are asking motorists to not use Mill Street or the West Linn Paper Mill parking lot (private property) to turn around or make U-turns because it interferes with mill operations.
ODOT officials say the agency is continuing to look at additional measures to reduce congestion in this area and proactively working with the West Linn police on these issues.
With the nice weather, Bridge Shuttle ridership is growing. After 23 weeks of service, the number of shuttle riders is 13,459, including 1,969 bicyclists.
The average number of pedestrians riding on weekdays is currently 81 and the daily average for bicyclists is 12. Overall, pedestrians ride more on weekdays and bicyclists ride more on weekends.
The bridge has 'bumpers' attached to the arch on the upstream side of the bridge protecting it from damage caused by logs floating down the river in high water. The current wooden bumpers will be replaced with timber-type lumber made from reclaimed plastic and wood waste.
The installation of seismic restraints continues throughout the length of the bridge for the next few weeks. These restraints consist of steel cables and bracket plates connected under the bridge to keep the roadway from falling in case of an earthquake.
The contractor is replacing the beams in the sidewalk that have corroded over time where the arch goes through the deck. Other ongoing work includes replacement of areas of corroded steel.