5/22/2013 9:14:00 AM Hell Canyon bridge gets 'heavier fix'
Matt Hinshaw/Daily Courier/Courtesy
Vehicles drive over Hell Canyon bridge March 21 north of Paulden.
An effort to "bolster" the recent repairs on the Hell Canyon bridge on north Highway 89 got under way this past weekend.
The Arizona Department of Transportation (ADOT) reported this past week that construction would resume on the bridge on Sunday morning, and would continue for the next several days.
ADOT District Engineer Alvin Stump said the work is necessary to strengthen the repairs that occurred on the bridge in March. "This is basically a heavier fix," Stump said.
The earlier repairs 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 contract that included removing and replacing the deteriorating concrete on 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 project wrapped up in late March with the application of epoxy and aggregate to the bridge deck.
The fix apparently was not enough, however.
Stump explained that the March job involved placing a steel plate over the 12-by-9-foot section where the original hole had developed, and covering that with epoxy.
But in the weeks after the completion of the job, the stresses on the welding became too great, causing the welds to break and the plate to flex. "The issue with the fix the first time is the welds didn't hold (the plate) in place," Stump said.
That led ADOT to report in late April that design work was under way on a new fix for the steel plate.
Stump said the new fix would bolster the previous job. "They're taking that same plate, bolting it down, and putting concrete on it," he said.
The new repair will cost an additional $49,000. Stump said the original contractor, Lawrence Construction of Phoenix, would do the job.
Stump maintains that the contractor's work was not to blame for the failed welding.
"Sometimes you put it out and realize that you have to go in and make adjustments," he said.
ADOT currently faces a situation of doing enough to get the 59-year-old bridge through the next several years, without doing a major fix.
Stump pointed out that a full bridge replacement is in ADOT's schedule for fiscal year 2015. A project assessment is currently under way, and design should begin this summer.
ADOT has estimated the cost of the new bridge at $18.5 million. Meanwhile, Stump said the fixes are being done as interim measures.
"Obviously, we don't want to get into a situation where we spend a large amount of money on a fix that's going to be a throw-away," he said.
An ADOT news release reported that traffic at the bridge will be narrowed to one lane, beginning at 6 a.m. Sunday, and continuing until 9 p.m., Wednesday.
"Crews will work a 24-hour schedule in an effort to expedite the project and minimize the impact to drivers," the release stated.
A temporary traffic signal will be in place at both ends of the bridge, and the speed limit will be reduced to 25 miles per hour to allow drivers to safely travel through the work zone.
ADOT is advising drivers to expect possible delays of as long as 30 minutes, and is asking drivers to use extreme caution when workers are present on the bridge.
The 600-foot-long Hell Canyon bridge is located about 13 miles north of Chino Valley on Highway 89. The highway carries approximately 3,400 vehicles per day, and is the only north-south corridor linking the Prescott area with Interstate 40 at Ash Fork.