By JOSEPH S. PETE
Staff writer
Aug 3, 2007
The bridges in Johnson County, most of which span creeks, are inspected regularly and were deemed safe after the most recent inspection last year, officials said.
The 155 bridges in the county, most of which span 20 feet to 40 feet, receive 93-point inspections every two years that pinpoint any problems and any spot repairs needed, county highway director Gary Vandegriff said.
Only three of the county's bridges are in such a condition that they require a posted weight limit.
Most county bridges, a majority of which are of the simple continuous concrete beam design, rank at least 80 or 90 on of a scale of 100 in Indiana's sufficiency test, which is based on federal engineering guidelines, Vandegriff said.
The test assesses the deck or pavement part, supporting beams and the structure beneath, highway department engineer Mike Pelham said.
Inspectors gauge such things as structural integrity, fatigue and soundness of foundation.
"We're not like some other Indiana counties, with over a hundred covered wooden bridges built over a century ago," Vandegriff said. "We take care of our bridges, the way you would with your car."
The county highway department is responsible for all the bridges in cities, towns and unincorporated areas except those on state-managed roads.
About 90 percent of the county's bridges are in rural areas, spanning Sugar, Youngs, Pleasant Run and other creeks, Pelham said.
A catastrophe like the collapsed bridge in Minneapolis would be unlikely in Johnson County, he said. Most of the bridges here are too short and wouldn't have to bear the weight of stalled rush hour traffic, which investigators believe may have contributed to the Minneapolis collapse.
The county's two most heavily trafficked bridges are in Greenwood on Smith Valley Road, which was widened last year, and Main Street, which was replaced last summer. The county's longest bridge stretches 378 feet over Big Blue River on County Road 800E at the Shelby County line.
That bridge is one of the five bridges in the county that must have underwater foundations inspected every five years, Pelham said. Divers inspect the submerged parts of the piers for cracks and other signs of fatigue.
The county hires a private engineering firm to inspect all the bridges in the county every two years. The Indiana Department of Transportation reviews all the findings, and INDOT spokesman Marvin Jenkins said the state would never allow the public to drive on a bridge considered to be unsafe.
The county highway department, which has a budget of $1.1 million for bridges this year, makes spot repairs to bridges based on the inspection's findings. Repairs most commonly are made to guard rails, the road surface and approach slabs, which often need to be resealed because construction crews dig too deep when installing them, Vandegriff said.
Inspections determine when bridges need to be replaced, which can be anticipated years in advance, Vandegriff said. The highway department is replacing a bridge on Nineveh Road near County Road 100E this year at a cost of $600,000.
Nine bridges are slated be replaced through 2015. Next year, the county will replace bridges at the intersection of Morgantown and Olive Branch roads and on County Road 200N, just west of the new Franklin high school.
That bridge is structurally sound but needs to be replaced because of the expected increase in traffic, Vandegriff said.