Bridges in Ventura County are not at risk of collapse like the catastrophic failure in Minnesota that took at least four lives, state, county and local transportation officials said Thursday.

"I don't think people of Ventura County should be unduly worried," said Ginger Gherardi, executive director of the Ventura County Transportation Commission.

But the rush-hour collapse of the Interstate 35W bridge, a major Minneapolis artery, has focused extra scrutiny on California's own aging infrastructure.

"We as engineers are concerned about what happened in Minnesota," said Doug Failing, the director of California Department of Transportation District 7, which includes Ventura and Los Angeles counties.

Many of the state's bridges were built in the 1950s and 1960s, and they were not meant to have 60-to-70-year lifespans, Failing said.

Part of the reason for the passage of last year's $20 billion bond measure was to both improve and maintain the state's sometimes battered highways.

The district is responsible for some 2,362 bridges, with 301 of those within Ventura County. Only one of the district's bridges, a span that crosses the San Gabriel River on Highway 39 near Azusa, shares a similar design as the failed bridge in Minnesota, Failing said.

It was inspected last year, but engineers went back out to look at the structure Thursday. Built in 1939, the bridge was in "excellent shape," Failing said.

No backlog in inspections

The state maintains a vigorous bridge inspection and seismic retrofitting program, with engineers doing visual surveys or more detailed looks at structures every two years, said Kwan Lam, chief of structural maintenance for Caltrans' District 7. Although there are only from 130 to 150 engineers charged with inspecting all the state's bridges, meaning that they have to average about two bridges a day to keep up, Lam said there was no backlog in inspections.

California ranks seventh in bridge safety among all states, according to Caltrans officials. Still, state engineers want to know what happened in the Twin Cities to ensure that nothing has been overlooked, Failing said.

Yet drivers "do not need to be concerned about the safety of our bridges in California," Failing said. "If we thought a bridge was unsafe we wouldn't allow people to use it."

A 2005 review by The Star of a federal database found nearly 100 bridges in Ventura County were identified as either "structurally deficient" or "functionally obsolete." Nothing has changed in the two years since the paper reported on those bridges, said Butch Britt, Ventura County director of transportation.

Also, funding for maintenance, repairs or replacement of problem bridges is scarce and continues to move at a glacial pace, he said.

"It's a very slow process," Britt said of the red tape required for funding. "I don't think the average person understands just how much of a maze it is."

The Star's 2005 computer analysis found that 28 of the county's 485 bridges were "structurally deficient." An additional 71 were considered "functionally obsolete." The bridge inventory contained data through 2003.

County has applied for funding

More recent data from county disaster plans now show there are 421 bridges in the unincorporated area and 10 cities. The plans estimate it would cost $786.8 million to replace the county's bridges.

Structurally deficient bridges are not necessarily in danger of imminent collapse but need repairs to prevent major problems that could lead to failure. Functionally obsolete bridges need to be redesigned because they can't adequately handle the traffic that rolls over them. They may be out of alignment with the road, too narrow or too low.

The only bridge to demand a strong response so far in the unincorporated county is South Mountain, which crosses the Santa Clara River to Santa Paula, Britt said.

In the wake of heavy floods in 2005, Britt closed the bridge for several days while a team of structural engineers evaluated it. A form of erosion around its supports — called scouring — had compromised the structure, Britt said.

Britt reopened the bridge but reduced the allowable load for trucks to 10 tons. The county has applied for funding to repair the bridge, but it has not arrived, Britt said.

Officials in Port Hueneme, Santa Paula, Fillmore and Camarillo said there are no problems with their bridges. In Thousand Oaks, there are 10 bridges, many built by developers, and all cross creeks or arroyos, said Jay Spurgin, the city's engineer.

"If there were any problems or suggestions for maintenance by Caltrans inspections, there would not be any question of funding. We would fix it immediately," Spurgin said.

Simi Valley has about 35 small bridges built to handle city traffic, said Assistant Public Works Director Ron Fuchiwaki.

"They're all well-supported; they're not going to fall," he said.

Two bridges in Oxnard made the list of 28 deemed structurally deficient. The city retrofitted one — on Channel Islands Boulevard at Mandalay Bay — to better withstand earthquakes about 10 years ago, City Engineer Lou Balderrama said.

Balderrama could not say why it was still rated structurally deficient and speculated that the federal government had yet to update its status. The other bridge has scouring problems, but it's unclear what is being done to repair it. Neither bridge needs to be closed, Balderrama said.

Flooding is largest threat

Ventura's Main Street bridge spanning the Ventura River needs to be replaced, City Engineer Rick Raives said. The bridge suffered a partial collapse in 1995.

But replacement costs would run from $25 million to $35 million, Raives said. Even though the federal government would pay 80 percent of the costs, the city would have trouble finding the matching funds, Raives said.

"It's not something we're pursuing right now," Raives said, but added the bridge was seismically upgraded about 10 years ago. "It has some resistance to earthquakes, and frankly it's only going to be a concern when we have water running in the river."

Flooding is the largest threat to the county's bridges, because of frequency.

Since 1862, damaging floods have occurred every five years in Ventura County. Traveling at great speeds, these flash floodwaters carry heavy loads of mud, rocks, trees and other debris that slam against the footings of bridges. In 2005, floodwaters destroyed Caltrans equipment, scaffolding and bridge construction at the Santa Clara bridge.

Of the 421 county bridges, 100 bridges are exposed to floods, including the heavily traveled Santa Clara bridge on Highway 101.