Cities, counties try to keep up with structurally deficient bridges

Maggie Mears's vehicle is one of about 127 each day that use the Second Avenue Bridge over Ralston Creek on the east side of Iowa City. Cyclists and pedestrians using a new bike path along the creek also cross the approach to the bridge.

The bridge deck looks beat up with cracks and potholes, but the posts and under-structure, at a glance, don't appear to be rusting or crumbling.

The only other clue of potential problems is a posted 10-ton weight limit to deter heavy vehicles.

That's why Mears, who lives nearby, was surprised to hear the Second Avenue Bridge is one of 40 in Johnson County deemed structurally deficient, according to an inventory of bridges from the Federal Highway Administration.

'It's kind of shocking,' Mears said. 'You wouldn't think it had problems because there's not a high volume of traffic, so maybe it's just been forgotten about and fallen into disarray.'

Iowa ranks second worst in the nation for the number of 'structurally deficient' bridges. More than 1.6 million motorists a day travel over 5,043 such bridges in Iowa, which is 21 percent of all of Iowa's 24,398 bridges.

In the Corridor, Linn and Johnson County have kept up with bridge repairs and replacements more effectively than many parts of the state. Those counties have 6 percent and 11 percent, respectively, of bridges on the structurally deficient list, while at the other end counties such as Davis and Ringgold have more than 40 percent deficient bridges.

Still, every day, there are 48,297 vehicles traveling over 40 structurally deficient bridges in Johnson County, and 30,744 motorists crossing 28 similarly classified bridges in Linn County, according to the federal bridge inventory.

Public officials at the federal, state and local level, as well as explanatory documents about the bridge inventory, caution that structurally deficient does not mean a bridge is not safe, but rather that it 'needs repair, closer monitoring or weight restrictions so that it does not become unsafe.'

'It is a little misleading to the public,' said Ron Knoche, Iowa City city engineer. 'Don't get me wrong, clearly we have structures out there that are beyond their useful life, but they are not dangerous structures. They are not putting travelers at risk.'

The federal bridge inventory rates components of each bridge.

Generally, the lower score signifies poorer condition, and scoring below 5 on the deck, superstructure or substructure generally can trigger a bridge's inclusion on the structurally deficient list, according to an explanatory sheet of the inventory.

The ratings are based on how the current condition compared to its original condition and design, according to the federal information sheet. So a bridge may rate poorly compared to when it was first built, but it may remain functional and safe for current use, state and local officials said.

For the Second Avenue Bridge, the post-evaluation scores a 1 out of 9, the superstructure — which includes rails, the deck and other components that span Ralston Creek — scores a 3 out of 9, and the deck also rates a 3 of 9.

The bridge has an overall sufficiency rating of 30.4 out of 100, which is a measure that previously was used to determine federal funding eligibility and is still used to guide priorities by many communities.

The Second Avenue Bridge, which is the only one in the city with a weight limit, was submitted for funding assistance, Knoche said, but the need to replace was deemed less than 46 other projects for fiscal 2014.

The Second Avenue Bridge's condition was as bad as many that were offered funding, but many of the 46 saw much more daily traffic or required vehicles to take long detours because the bridge couldn't handle the weight.

In Cedar Rapids, there are no bridges with weight limits, and only the McCloud Run bridge over McCloud Place NE is slated for replacement, said Doug Wilson, capital improvement project manager.

McCloud Run bridge has a sufficiency rating of 2, with deterioration of the steel beams in the superstructure and cracks and seepage through the deck, Wilson said. Backed by $617,000 in federal aid covering 80 percent of the project, that bridge will be replaced in 2015, he said.

While in many cases sufficiency ratings can guide prioritization, it doesn't in all cases.

Take the Burlington Street Bridge in Iowa City.

That bridge, which is on the structurally deficient list, has some swelling and voids in the substructure. But a consultant who reviewed the city's bridges in 2013 determined it had another eight years of useful life, Knoche said.

And it was not one of four bridges the consultant recommended for replacement. That list included the Second Avenue Bridge, the Prentiss Street bridge, and the North Gilbert Street bridge, as well as the Rochester Avenue bridge, which was replaced last year.

Critics of the state of bridge conditions, such as Andrew Herrmann, past president of the American Society of Civil Engineers and principal of Hardesty & Hanover LLP in New York City, said the number of bridges on the structurally deficient list is a sign that leaders aren't paying close enough attention to bridge conditions.

'It comes down to dollars and sense,' Herrmann said. 'We are just not paying attention to the bridges. Unfortunately we don't find out about these things until they are closed or have weight limits.

'It comes down to funding.'

According to the Congressional Research Service, which provides non-partisan research for Congress, an additional $8 billion dollars a year, or $20.5 billion annually would be needed to clear a backlog of structurally deficient bridges by 2028.

In Iowa, there's been some progress.

The state Department of Transportation has made clearing structurally deficient bridges a priority, and structurally deficient bridges under state control have declined from 240 to 117 in six years, said Norm McDonald, director of the Iowa DOT Office of Bridges and Structures.

'That is the good news,' McDonald said. 'The bad news is the number on the local system has stayed about same the last couple years.

'The problem is the funding. They'd like to replace more of those, but they don't have the money.'

Just last month an Adair man pulling anhydrous ammonia tanks across a Guthrie County bridge with his tractor was injured when the bridge collapsed. McDonald said the weight was well above the limit for that bridge over Brushy Creek.

Rep. Brian Moore, R-Bellevue, serves as vice chairman on the House transportation committee, and also owns Elwood Feed and Livestock, a livestock transportation business.

Weight limits on insufficient bridges are a big problem for his business, in which semis need access to remote areas, he said. A bridge with a weight limit can force drivers to detour miles out of the way.

Moore has been pushing a gas tax increase to help improve roads and bridges in Iowa. Structurally deficient bridges are among the $215 million backlog in critical transportation needs, according to the state transportation department.

'As a trucker, if I have to go around, it creates a series of problems,' Moore said. 'We need to get something done.'

l Comments: (319) 339-3177; brian.morelli@sourcemedia.net