From ODOT press release - July 8, 2011

Starting the third week of July, work begins on a new phase of the Arch Bridge rehabilitation project (See the ODOT Arch Bridge Rehabilitation site or Oregon City Arch Bridge Project page for more information). Barges will move into place to prepare the containment system for bridge exterior Gunite removal using high-pressure hydroblasting.

The hydroblasting phase will direct water and removed Gunite into containers to avoid contaminating the Willamette River. It will also produce steamclouds, which ODOT indicates will consist of water vapor only and contains no chemicals.

A unique opportunity to see the steel structure of the bridge will occur once the Gunite covering is removed, a process expected to take about 6 weeks. Two good places to view bridge work are from under the bridge deck on the east side of Hwy 99E, and from the top of the Oregon City Municipal Elevator.

ODOT has more information on their Arch Bridge Rehabilitation website on traffic impacts and recommendations for travel in the area. The Bridge Shuttle will remain in operation until the bridge reopens for vehicular traffic.

In addition to the Gunite removal, bumpers protecting the bridge from floating logs will be replaced. Steel cables and bracket plates will be installed for seismic reinforcement, and corroded steel beams in the sidewalk replaced.