By Kirk Johannesen, The Republic
johannesen@therepublic.com
The collapse of the Interstate 35W bridge in Minneapolis on Aug. 1 sent a chill through many motorists across the country. Twelve people died, and about 100 suffered injuries. Subsequent investigations showed that the steel arch deck truss bridge, built in 1967, showed structural problems as early as 1990.
The tragedy left people across the country wondering about the safety of the bridges in their communities.
People in Columbus still remember the closing of the old Second Street Bridge on Sept. 15, 1949.
State officials prevented disaster when they shut it down after an inspection, which revealed structural problems and little in the way of maintenance or repair since the bridge was built in 1884.
Associated Press studied Federal Highway Administration statistics from 2006 and found that 2,066 of Indiana's 18,361 bridges were deemed structurally deficient.
That means the capacity of the bridge to support heavy loads might be insufficient because of problems, or the bridge has suffered significant deterioration. While the bridge might not have structural problems, posted weight limits are needed.
The AP study said 35 of Bartholomew County's 265 bridges are structurally deficient. Those include smaller bridges for which the county is responsible and bridges maintained by the state and federal governments. The numbers in local and state reports do not exactly match numbers in AP's report.
Eight bridges in Bartholomew County are truss bridges, an older design. Two are structurally deficient and five functionally obsolete.
A functionally obsolete bridge is inadequate to accommodate traffic.
AP's study also said 27 percent of the bridges in Jennings County, 22 percent in Brown, 15 percent in Decatur and 11 percent in Jackson were structurally deficient.
According to Indiana Department of Transportation's Seymour District, none of the 62 state-owned bridges in Bartholomew County are structurally deficient. Surveys of the bridges in 2006 or 2007 showed that 10 are functionally obsolete.
Inspections required
Bartholomew County Commissioners, with the aid of County Engineer Danny Hollander, try to replace, through property taxes and federal funds, at least four or five bridges each year.
Federal Highway Administration requires that every bridge be inspected at least every 24 months to ensure that problems are spotted.
Some state-owned bridges are inspected annually by Indiana Department of Transportation because of their design.
United Consulting of Indianapolis prepared a bridge inventory for Bartholomew County in 2006 and has had a contract with this county the last eight years.
The federal government pays for 80 percent of this bridge inventory project and the county 20 percent.
Dave Richter, United Consulting vice president, said the company spent six weeks inspecting 204 bridges and documenting their conditions.
When United presented the inventory to Bartholomew County Commissioners in December, it listed 22 bridges as structurally deficient and 26 as functionally obsolete. United also recommended 25 be replaced.
The commissioners and Hollander studied the bridge inventory report so they could create a priority list.
Commissioner President Paul Franke said officials first look at the bridges that need posted weight limits.
"That's a major indication that a bridge is defective and can't carry the load," he said.
Hollander said a bridge with a posted weight limit of 12 tons or less is a concern, because a school bus is not supposed to use it. He said an empty school bus weighs 15 tons.
Officials also consider the bridge location and whether it supports a heavy traffic volume.
Bridges that are too narrow to accommodate traffic or have an estimated life of less than 10 years are a concern, too.
County Highway Department's Cumulative Capital Fund is used to repair and replace bridges annually.
The county receives 4.86 cents per $1 on property taxes, which generates approximately $1.9 million for the bridge fund.
"We have a process where we always have some in design and try to build them the following year," Hollander said.
DOT's Seymour District takes a different approach, because the federal projects take seven to 10 years to complete.
The district's annual budget is $30 million, but that covers road projects and culverts also.
John McCrary, systems assessment manager of the Seymour District, said he looks at replacing or repairing the worst bridges first, but projects are planned through 2012.
He has to consider the economical and feasible way to build at a location, using current design standards.
A bridge receiving federal funds takes more time to replace, about five years, because of requirements and procedures, Hollander said.