Arch bridge closure delayed by ODOT
The arch bridge between Oregon City and West Linn could still be open at this time next year.
The Oregon Department of Transportation announced last week that it is suspending the bridge closure while engineers review suggestions from the Federal Highway Administration (FHWA) on how to make the bridge project faster and smoother for area residents and businesses. ODOT originally planned to close the bridge this month, but pushed the date back until after the holiday season to accommodate downtown businesses. They now plan to submit bids in the spring, with the closure coming later in 2010 or possibly being pushed back into 2011, according to Susan Hanson, ODOT Community Affairs Coordinator.
“We asked the Federal Highway Administration to do a review of the construction as well as the schedule on the bridge project, and now we’re going to take a little more time to study the results,” Hanson said.
The FHWA report makes several recommendations, including:
* Tweaking ODOT’s contracting method to further encourage contractors to finish their work early. With most public projects, the lowest bidder gets the work. ODOT is allowing the timeline to be a factor for the bridge repair project. FHWA suggests they provide more incentives for finishing early. The report also suggests looking into extended work shifts.
* Revisiting the construction schedule so that all of the “above deck” work on the bridge takes place during the first part of the repair project, allowing for intermittent bridge closures later on. FHWA indicates this might not be feasible, but if it is, estimates it could reduce the length of the bridge closure by “several months.”
* Performing further tests on the bridge to try to eliminate some of the “unknowns” associated with the project, and to develop detailed mitigation strategies for worst-case scenarios. The arch bridge is a steel structure wrapped in concrete, so engineers aren’t completely sure of what they’ll find when they strip all of the concrete off the structure.
The FHWA report also confirms something ODOT representatives have been saying for years: this is one unique bridge. It scanned the nation and found 195 steel arch bridges, but none encased in concrete. While the concrete complicates bridge repair, it likely staved off a major renovation project for decades. Most steel bridges are painted to protect against corrosion, and paint typically provides protection for 20 to 25 years. The arch bridge has had no major renovations since it was built in 1922.
The Arch Bridge carries Highway 43 between Oregon City and West Linn. Last year, ODOT put a weight limit on the bridge that prevents TriMet busses and large trucks from crossing, engineers say the structure is still suitable for normal vehicle traffic. While the steel skeleton is thought to be in reasonably good condition, the concrete encasing the bridge is literally falling off in several locations, and needs to be replaced. ODOT is planning on hiring contractors to use a high-powered pressure washer of sorts to strip the concrete off of the bridge and onto a barge. They will make any necessary repairs to the steel and then encase the bridge in a new layer of concrete. The bridge is on the National Register of Historic Places, and will remain largely the same after repairs.
Hanson said that ODOT plans to lift the weight limit on the bridge after repairs are complete, allowing TriMet busses back on the bridge. While ODOT has agreed to run a shuttle for bikes and pedestrians during the closure, the frequency of that shuttle and other details are still being worked out.
To view a copy of the FHWA report, visit www.archrehab.com.