Fairfield County has the largest percentage of structurally deficient bridges in the state, according to a new analysis by a Washington, D.C., transportation group, highlighting the need for more funding for replacement and upkeep of spans nationwide.

In Fairfield County, 107 of the 827 spans included in the analysis, or 13 percent, were categorized as structurally deficient, or in need of significant "maintenance, rehabilitation, or replacement," according to the report. Overall, the analysis showed of 4,182 state and local maintained bridges, 383 of them were structurally deficient in some way, a little over 9 percent of spans compared to a national average of 11.5 percent.

The report, "The Fix We're In: The State of the Nation's Bridges," ranked Connecticut 20th among 50 states and Puerto Rico. The report was released last week by Transportation for America, a coalition of more than 350 transportation, pedestrian, housing, and other advocacy groups nationwide.

"We are making the point that we are facing a backlog of maintenance, rehabilitation, and replacement in some of our critical infrastructure and that means the age of major highway construction is over," Daniel Goldberg, communications director for Transportation for America said.

"The typical bridge is designed for a 50-year life span so many of them will be due for some sort of critical repair or maintenance in coming years."

Kevin Nursick, a spokesman for the Connecticut Department of Transportation, said bridges termed "structurally deficient" in engineering terms doesn't signify they are unsafe for travel, but that some type of repair need that reduces the load capacity called for in their initial design.

Connecticut bridge engineers conduct more than 5,000 inspections of state and local bridges on a biannual basis, Nursick said.

"It doesn't mean the bridge is weak or prone to some kind of failure," Nursick said. "All the structures open to the public are 100 percent safe, and we're adamant about that. Nobody should panic at the term structurally deficient, though it is not the best term to use and it doesn't resonate well with the public." The DOT maintains approximately 2,795 bridges that are 20 feet or longer, 178 of which are rated structurally deficient, while municipalities own about 1,240 bridges of 20 feet or longer, 200 of which are considered structurally deficient.

In addition, the DOT maintains about 1,007 bridges that are shorter than 20 feet, of which 119 are structurally deficient in some way, according to Nursick.

The average age of Connecticut's bridges is 47.2 years, Nursick noted, significantly older than many states with higher rates of structurally deficient bridges.

"If you look at all the factors including the level of traffic here and the age of the bridges, you see that we are doing better than a majority of the states," Nursick said. "You would have a hard time finding an unsafe bridge in Connecticut because it would be closed." Pennsylvania was ranked as having the highest percentage, 26.6 percent of rundown spans, and Nevada the lowest, at 2.2 percent.

Two of the top 10 of the busiest spans in Connecticut that were rated structurally deficient were on Interstate 95 near Exit 17, and near Exit 8 northbound.

"Yes, structures continue to need attention and will need them in perpetuity, but they are not dangerous and drivers are not being put at risk," Nursick said.