A problem that developed this past week with the recent repair work on the Hell Canyon Bridge has led to a new round of repairs, as well as a temporary reduction in the speed limit.
Arizona Department of Transportation (ADOT) Public Information Officer Dustin Krugel reported Tuesday that design work is under way for the repair of a steel plate that was a part of the early-2013 repairs on the Highway 89 bridge.
Krugel explained that ADOT discovered last week that the welding on the corner of a recently installed steel plate had broken, causing the plate to flex.
In response, maintenance crews did an interim repair on April 29, Krugel said, and ADOT bridge engineers began work on a design to repair the steel plate. In addition, ADOT is meeting with the previous contractor to come up with a repair solution.
As a precaution, Krugel said ADOT temporarily reduced the speed limit on the bridge to 45 miles per hour. The new speed limit will remain in effect until the construction is completed.
The construction is expected to start soon, Krugel said, and all of the work should be complete next month. Meanwhile, "The bridge is safe for motorists, and ADOT staff will check on the bridge every 12 hours," he added.
The earlier repair became necessary after the deck of the bridge developed a hole on Jan. 19. ADOT crews patched the area with steel plates, but determined that a more permanent fix was needed.
That led to a $288,000 repair job that occurred during the first three weeks of March. Those repairs included removing and replacing deteriorating concrete from the bridge deck, installing support beams, removing and replacing the deck-joint assembly at the north end, sealing the entire bridge deck, and re-striping the road.
The bridge, which is located 13 miles north of Chino Valley, carries about 3,400 vehicles per day and is the only north-south corridor linking the Prescott area with Interstate 40 at Ash Fork.
In 2011, bridge inspectors classified the Hell Canyon bridge as structurally deficient, which ADOT defined as "safe but some repairs or improvements have been identified."
ADOT currently is doing a "project assessment" on a complete bridge replacement, and expects to begin the design this summer for a new bridge that would feature wider travel lanes and would meet current bridge-design standards.
The design will cost about $1.1 million, and the bridge replacement is estimated at $18.5 million. ADOT's tentative five-year plan recommends replacing the bridge in fiscal year 2015.