Before Gov. Janet Napolitano ordered the records of all the bridges in Arizona reviewed, the Yavapai County Board of Supervisors had its own annual list of bridge inspections ready to go.

Before Gov. Janet Napolitano ordered the records of all the bridges in Arizona reviewed, the Yavapai County Board of Supervisors had its own annual list of bridge inspections ready to go.

The review is in response to a busy interstate bridge that collapsed Aug. 1 in Minneapolis.

On the board’s Aug. 6 agenda, HDR Engineering of Phoenix got the contract for $154,000 to look at 15 bridges located in all three county districts.

The board awards a contract to a bridge engineering firm to inspect the bridges in the county on two-year cycles.

Yavapai County’s go-to man for bridges is Tim Stotler, assistant county engineer.

According to Phil Bourdon, public works director, Stotler “knows more about bridges than any human should.”

Stotler relishes his responsibility for the 58 spanned bridges in the county.

“Twenty-six of them are 70 years old or more,” he said.

The process begins with the Arizona Department of Transportation’s inspection of the state’s bridges. ADOT engineers recommend to the counties those that need further evaluation.

The county then hires experts to make further recommendations about its bridges.

A county method of insuring bridge safety is to lower their load limits as they age.

During the last inspection cycle in 2005, the consulting firm tested 13 bridges.

Twelve of them were then posted with lowered load limits, Stotler said.

Sedona’s pet bridge

Midgely Bridge, also known as the Wilson Canyon Bridge, is Sedona’s most well-known bridge. It is located north of the city in Oak Creek Canyon in Coconino County. ADOT is responsible for ensuring the bridge is safe.

Built in 1938, Midgely is a redundant, single-spanned steel arch bridge, according to Bill Pederson, public involvement officer for ADOT.

The bridge that had the recent deadly failure in Minnesota was a non-redundant, multi-spanned steel truss bridge.

“Midgely Bridge is considered ‘functionally obsolete’ but is not ‘structurally deficient,’” Pederson said.

The “functionally obsolete” tag stems from the fact that the roadway is wider than the bridge, Pederson said.

Hwy. 89A is 33 feet wide and the bridge is only 24 feet wide.

Midgely is 374 feet long.

Pederson said ADOT engineers have no plans of refurbishing the historic bridge.

There are also no restrictions on loads allowed over the bridge.

“It is significant that it is not structurally deficient,” Pederson added. That term can be applied to a bridge for several reasons, including a pothole in the deck.

Testing bridges

Stotler said that most of the older bridges in Yavapai County are lightly traveled and in rural areas.

“Some of these bridges do not see 50 cars a day,” Stotler said. “The firms we hire to inspect and test them will do everything from X-ray supports to checking the spacing and size of the steel beams.”

A full concrete truck can weigh 20 to 30 tons and a full bridge load limit is usually 80,000 pounds or 40 tons, according to Stotler.

Stotler admits that, eventually, the bridges will have to be updated to handle current loads.

“We have three or four in the county that are steel truss bridges like the one in Minnesota,” Stotler said.