By Keith Benman, Times of Northwest Indiana
keith.benman@nwi.com
Spurred by problems spotted at the now-closed Cline Avenue bridge, the state is having inspectors take a closer look at nine similar ramps and bridges around the state.
They include the Cline Avenue ramps to the eastbound and westbound Borman Expressway, as well as major interstate ramps in Indianapolis and key bridges connecting Lafayette and West Lafayette, according to a list provided by the Indiana Department of Transportation
"Those ones they are looking at a little more in depth," INDOT spokeswoman Angie Fegaras said. "It doesn't mean anything is wrong. But they are just looking at them a little more closely."
The 1 1/4-mile Cline Avenue bridge over the Indiana Harbor and Ship Canal closed Nov. 13 after an engineering firm inspecting the bridge warned INDOT that heavy truck loads on the bridge could cause a "structural failure" of the massive span.
The Cline Avenue bridge is what is known as a post-tensioned, concrete box girder bridge. It's poured-in-place girders are supported by thick cables stretched through ductwork within the concrete.
Concerns about such bridges was raised nine years ago when it was discovered cables had come apart in three major bridges in Florida due to corrosion, according to Michael Sprinkel, associate director of the Virginia Transportation Research Council.
A similar cable failure was found in 2007 in Virginia's Varina-Enon bridge. In response, the Virginia Department of Transportation stepped up inspections of all such bridges, Sprinkel said.
"It's clear now the potential for this problem exists in almost every one of these bridges," Sprinkel said last week.
He will be presenting a paper on the subject at a Washington, D.C., transportation forum in two weeks.
The problem is that water and corrosive materials in the ductwork can eat away at the cables, which are shielded from view by the surrounding concrete and hardened grout, Sprinkel said.
The inspections now going on around Indiana include visual reviews of both the interior and exterior of the bridges, Fegaras said. Core and grout samples are also being collected to check for chloride, which can cause corrosion.
The bridge inspections have been going on for some time because of issues that first came to light at the Cline Avenue bridge, Fegaras said. The "aggressive recommendations" that led to closure of the Cline Avenue bridge have heightened the focus on those bridges, she added.
The inspections will continue through March as weather allows, Fegaras said.
Inspection of the Cline Avenue bridge continues as INDOT formulates options for fixing or replacing it, Fegaras said.
Mayors of some of the cities where post-tensioned, concrete bridges are now being inspected said they had not been told about the situation when contacted by The Times last week.
Lafayette Mayor Tony Roswarksi asked his public works department Thursday and was told the city had not been notified of the inspections of the South Street and Columbia Street bridges over the Wabash River.
Mayor John Hall of North Vernon, a small city about 75 miles southeast of Indianapolis, also said he had not been apprised of the inspection of the U.S. 50 bridge east of the city.
The inspection of the Cline Avenue bridge by INDOT consultant URS Corp. found deficiencies in virtually every section of the bridge and three of its four ramps.
Sprinkel, the Virginia researcher, said the bridges where cables have failed had been in service for relatively short periods. One in Florida had been built just six years prior. The Varina-Enon bridge was completed in 1990.
Engineers inspecting the Cline Avenue bridge would have been aware of the history of failure at other bridges, Sprinkel said.
"Knowing the potential for problems in these bridges and the potential for sudden collapse, that's probably why they closed it," Sprinkel said. "Just to be safe."