By CHELSEA DAVIS
Courier staff writer
---- — OTTUMWA — A 77-year-old Ottumwa structure needs some work done on its joints.
The Jefferson Street Viaduct will be closed for maintenance on its expansion joints beginning shortly after 8 a.m. Thursday. Crews expect work to be finished by sometime in the early afternoon.
Once a year the public works department cleans the expansion joints of the bridge, which is on the National Register of Historic Places.
"It's a spring deal we do every year because the salt and sand get in there during the winter time," said Public Works Superintendent Steve Edgington. "We get whatever salt and sand that's built up in there out so the rollers can expand and contract at the joints.
"A lot of people don't realize that the bridge does actually move. It isn't just sitting there."
The bridge, which expands when temperatures rise, needs its joints to be in good shape, otherwise it "could put the bridge in a bind," he said.
Crews will be doing the exact same work on Market Street Bridge on Thursday, though that bridge won't be closed to traffic.
The rollers on Market Street Bridge are at both ends of the bridge, whereas due to the Jefferson Street Viaduct's height and number of joints, it will have to be shut down for a few hours.
If crews were not to clean the joints every year, "they would deteriorate, freeze up and not be able to move," Edgington said.
"That bridge would be under a lot of stress if it was not allowed to move," he said.
The problem crews sometimes encounter while cleaning the expansion joints is tearing the bladders, the rubber coverings on the joints and rollers, due to the force of the water pressure and the general wear and tear and movement of the bridge, which leads to their eventual deterioration.
Motorists will need to seek alternate routes across the river during this work.
To follow reporter Chelsea Davis on Twitter, head to @ChelseaLeeDavis.