WASHINGTON — Ohio has 187 steel deck truss bridges similar in design to the one that collapsed into the Mississippi River in Minneapolis on Wednesday, by far the most of any state, according to a Transportation Department inventory released Friday.
Ohio's truss bridges account for more than a fourth of the 756 bridges that Transportation Secretary Mary Peters has designated for immediate inspection.
The truss bridges are described as non-redundant, meaning that if one component fails, the bridge will likely collapse. They were commonly built more than 40 years ago to span distances of 300 to 800 feet, said Shankar Nair, a Chicago-based structural engineer specializing in bridge design.
California has 59 of the bridges, followed by Oregon (38), Pennsylvania (37), New York (33), Washington (32), West Virginia (31), Texas (25), Massachusetts (19), Alabama (18), and Kansas and Wisconsin with 15 each.
Based on the inventory, most of the bridges appear to be spans on roads and highways that are unlikely to experience a heavy weight load from bumper-to-bumper traffic, as occurred in the rush-hour disaster in Minneapolis, but a couple of dozen are along interstate highways, with some near major cities.
Peters sent out an advisory Thursday urging state officials to immediately inspect, ``out of an abundance of caution,'' all truss bridges to look for signs of stress, corrosion, fatigue or other weaknesses that might make them vulnerable to collapse.
A department spokesman said the agency couldn't say how many of the truss bridges are among the more than 150,000 bridges nationally that have been rated as structurally deficient or functionally obsolete, the latter rating signaling that they've been designated for replacement.
But Nair said that many of the steel deck truss bridges are rated deficient only because of cracks in the concrete deck, which wouldn't cause a collapse.
"For a bridge like this to fall all the way down, not just a partial failure, but a complete failure,'' he said, would normally require a buckling of the steel superstructure or concrete support piers.
The locations of some of Ohio's bridges weren't fully identified. Of those listed, only two are on an interstate highway, along I-90 spanning the Cuyahoga and Grand rivers.
Ten of Oregon's truss bridges span the Columbia, Umpqua and Willamette rivers. West Virginia has five that are on interstate highways.
Other bridges on heavily traveled highways include:
Minnesota had only six of the truss bridges. The one that failed was the only one on an interstate highway.
FOR MORE INFORMATION
Download an Excel spreadsheet with a complete list of the truss bridges.
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