By . Daily Mail Reporter . PUBLISHED: . 09:26 EST, 26 May 2013 . | . UPDATED: . 09:33 EST, 26 May 2013 . Thousands of heavily-trafficked bridges around the U.S. may be one accident or mistake away from collapse, even if the spans are deemed structurally sound, officials warned today. The crossings are kept standing by engineering design, not supported with brute strength or redundant protections like their more modern counterparts. Bridge regulators call the more risky spans 'fracture critical' meaning that if a single, vital component of the bridge is compromised, it can crumple. Those vulnerable crossings carry millions of drivers every day. In Boston, a six-lane highway 1A near Logan airport includes a 'fracture critical' bridge over Bennington Street. In northern Chicago, an I-90 pass that goes over Ashland Avenue is in the same category, as is an I-880 bridge over 5th Avenue in Oakland, California. Also on that list is the Interstate 5 bridge over the Skagit River north of Seattle, which collapsed into the water days ago after officials say an over-sized truck load clipped the steel truss. Wreckage: The section of the Skagit River bridge that collapsed, sending cars and passengers plunging into the river below . Public officials have focused in recent years on the desperate need for money to repair thousands of bridges deemed structurally deficient, which typically means a major portion of the bridge is in poor condition or worse. But the bridge that collapsed Thursday is not in that deficient category, highlighting another major problem with the nation's infrastructure: although it's rare, some bridges deemed to be fine structurally can still be crippled if they are struck hard enough in the wrong spot. 'It probably is a bit of a fluke in that sense,' said Charles Roeder, a professor of civil and environmental engineering at the University of Washington. While the I-5 truck's cargo suffered only minimal damage, it left chaos in its wake, with two vehicles catapulting off the edge of the broken bridge into the river below. Three people involved escaped with non-life threatening injuries. Officials asked people to plan for an . extra hour to make their way through detours around the collapsed . bridge. There are three detour options northbound and two options . southbound. About 71,000 vehicles use that . stretch of highway every day. Late Saturday morning, traffic was moving . freely through the detours. Officials were looking for a . temporary, pre-fabricated bridge to replace the 160-foot section that . failed, Governor Jay Inslee said Friday. That option could be in place . in weeks. Otherwise, it could be months before a replacement can be . built, the governor said. Survivor: Motorist Bryce Kenning sits on the roof of his car after it fell into the Skagit River when the Interstate 5 bridge collapsed minutes earlier on Thursday . Inslee said it will cost $15 million . to repair the bridge. The federal government has promised $1 million in . emergency dollars and more money could come later, according to . Washington's congressional delegation. The Chairman of the National Transportation Safety Board Debbie Hersman and her team . will spend a week to 10 days looking at the bridge, talking to the . truck driver whose vehicle hit it, and examining maintenance documents . and previous accident reports. They'll be watching for safety issues that could affect other bridges. Washington . state officials said Saturday that it will take time to find both . short- and long-term fixes for the bridge that collapsed on Interstate . 5. The most famous failure of a fracture . critical bridge was the collapse of the I-35W bridge in Minneapolis . during rush hour on Aug. 1, 2007, killing 13 people and injuring more . than 100 others. The National Transportation Safety Board concluded that . the cause of the collapse was an error by the bridge's designers — a . gusset plate, a key component of the bridge, was too thin. The plate was . only half of the required one-inch thickness . Because . the bridge's key structures lacked redundancy, where if one piece . fails, there is another piece to prevent the bridge from falling, when . the gusset plate broke, much of the bridge collapsed. Mark . Rosenker, who was chairman of the NTSB during the I-35W bridge . investigation, said the board looked into whether other fracture . critical bridges were collapsing. They found a few cases, but not many, . he said. 'Today, they're still building fracture critical bridges with the belief that they're not going break,' Rosenker said. Fracture critical bridges, like the . I-5 span in Washington, are the result of Congress trying to cut corners . to save money rather than a lack of engineering know-how, said Barry B. LePatner, a New York real estate attorney and author of 'Too Big to . Fall: America's Failing Infrastructure and the Way Forward.' Collapse: The I5 bridge in Seattle, Washington, had been deemed 'functionally obsolete' by state authorities before it collapsed after being clipped by a truck . About 18,000 fracture . critical bridges were built from the mid-1950s through the late 1970s in . an effort to complete the nation's interstate highway system, which was . launched under President Dwight Eisenhower, LePatner said in an . interview. The fracture critical bridge designs were cheaper than . bridges designed with redundancy, he said. Thousands of those bridges remain in use, according to an AP analysis. 'They . have been left hanging with little maintenance for four decades now,' he said. 'There is little political will and less political leadership . to commit the tens of billions of dollars needed' to fix them. There . has been little focus or urgency in specifically replacing the older . 'fracture critical' crossings, in part because there is a massive . backlog of bridge repair work for thousands of bridges deemed to be . structurally problematic. Washington state Rep. Judy Clibborn, a . Democrat who leads the House transportation committee, has been trying . to build support for a tax package to pay for major transportation . projects in the state. But her plan wouldn't have done anything to . revamp the bridge that collapsed. National bridge records say the I-5 . crossing over the Skagit River had a sufficiency rating of 57.4 out of . 100 — a score designed to gauge the ability of the bridge to remain in . service. To qualify for federal replacement funds, a bridge must have a . rating of 50 or below. A bridge must have a sufficiency rating of 80 or . below to qualify for federal rehabilitation funding. Hundreds . of bridges in Washington state have worse ratings than the one that . collapsed, and many around the country have single-digit ratings. Human chain: Rescue workers pulled three people from the water after the Skagit River bridge collapse, none were critically injured . Clibborn . said the Skagit River crossing wasn't even on the radar of lawmakers . because state officials have to prioritize by focusing on bridges with . serious structural problems that are at higher risk of imminent danger. Along . with being at risk of a fatal impact, the I-5 bridge was deemed to be . 'functionally obsolete,' which essentially means it wasn't built to . today's standards. Its shoulders were narrow, and it had low clearance. There . are 66,749 structurally deficient bridges and 84,748 functionally . obsolete bridges in the U.S., including Puerto Rico, according to the . Federal Highway Administration. That's about a quarter of the 607,000 . total bridges nationally. States and cities have been whittling down . that backlog, but slowly. In 2002, about 30 percent of bridges fell into . one of those two categories . There is wide recognition at all levels of government that the failure to address aging infrastructure will likely undermine safety and hinder economic growth. But there is no consensus on how to pay for improvements. The federal Highway Trust Fund, which provides construction aid to states, is forecast to go broke next year. The fund gets its revenue primarily from federal gas and diesel taxes. But revenues aren't keeping up because people are driving less and there are more fuel-efficient cars on the road. Delay: The collapsed bridge in Skagit, Washington, carried 71,000 vehicles daily. Drivers are being asked to factor in an extra hour travel time to detour the bridge . Neither Congress nor the White House has shown any willingness to raise federal gas taxes, which haven't been increased since 1993. Many transportation thinkers believe a shift to taxes based on miles traveled by a vehicle is inevitable, but there are privacy concerns and other difficulties that would preclude widespread use of such a system for at least a decade. Transportation spending got a temporary boost with the economic stimulus funds approved by Congress after President Barack Obama was elected. Of the $27 billion designated for highway projects under the stimulus program, about $3 billion went to bridge projects, Black said. States are looking for other means to raise money for highway and bridge improvements, including more road tolls, dedicating a portion of sales taxes to transportation and raising state gas taxes. Clibborn, the Washington state lawmaker, has proposed a 10-cent gas hike to help pay for projects, though the effort has been held up by a dispute over how to rebuild the Columbia River bridge connecting Vancouver, Washington, and Portland, Oregon. 'We can't possibly do it all in the next 10 years,' Clibborn said. 'But we're going to do the first bite of the apple.'
Thousands of bridges in use across the country 'functionally obsolete'
Bridges vulnerable to collapse carry millions of drivers every day .
Many bridges in Washington State alone have worse sufficiency ratings than the Interstate 5 that collapsed .
By . Daily Mail Reporter . PUBLISHED: . 09:26 EST, 26 May 2013 . | . UPDATED: . 09:33 EST, 26 May 2013 . Thousands of heavily-trafficked bridges around the U.S. may be one accident or mistake away from collapse, even if the spans are deemed structurally sound, officials warned today. The crossings are kept standing by engineering design, not supported with brute strength or redundant protections like their more modern counterparts. Bridge regulators call the more risky spans 'fracture critical' meaning that if a single, vital component of the bridge is compromised, it can crumple. Those vulnerable crossings carry millions of drivers every day. In Boston, a six-lane highway 1A near Logan airport includes a 'fracture critical' bridge over Bennington Street. In northern Chicago, an I-90 pass that goes over Ashland Avenue is in the same category, as is an I-880 bridge over 5th Avenue in Oakland, California. Also on that list is the Interstate 5 bridge over the Skagit River north of Seattle, which collapsed into the water days ago after officials say an over-sized truck load clipped the steel truss. Wreckage: The section of the Skagit River bridge that collapsed, sending cars and passengers plunging into the river below . Public officials have focused in recent years on the desperate need for money to repair thousands of bridges deemed structurally deficient, which typically means a major portion of the bridge is in poor condition or worse. But the bridge that collapsed Thursday is not in that deficient category, highlighting another major problem with the nation's infrastructure: although it's rare, some bridges deemed to be fine structurally can still be crippled if they are struck hard enough in the wrong spot. 'It probably is a bit of a fluke in that sense,' said Charles Roeder, a professor of civil and environmental engineering at the University of Washington. While the I-5 truck's cargo suffered only minimal damage, it left chaos in its wake, with two vehicles catapulting off the edge of the broken bridge into the river below. Three people involved escaped with non-life threatening injuries. Officials asked people to plan for an . extra hour to make their way through detours around the collapsed . bridge. There are three detour options northbound and two options . southbound. About 71,000 vehicles use that . stretch of highway every day. Late Saturday morning, traffic was moving . freely through the detours. Officials were looking for a . temporary, pre-fabricated bridge to replace the 160-foot section that . failed, Governor Jay Inslee said Friday. That option could be in place . in weeks. Otherwise, it could be months before a replacement can be . built, the governor said. Survivor: Motorist Bryce Kenning sits on the roof of his car after it fell into the Skagit River when the Interstate 5 bridge collapsed minutes earlier on Thursday . Inslee said it will cost $15 million . to repair the bridge. The federal government has promised $1 million in . emergency dollars and more money could come later, according to . Washington's congressional delegation. The Chairman of the National Transportation Safety Board Debbie Hersman and her team . will spend a week to 10 days looking at the bridge, talking to the . truck driver whose vehicle hit it, and examining maintenance documents . and previous accident reports. They'll be watching for safety issues that could affect other bridges. Washington . state officials said Saturday that it will take time to find both . short- and long-term fixes for the bridge that collapsed on Interstate . 5. The most famous failure of a fracture . critical bridge was the collapse of the I-35W bridge in Minneapolis . during rush hour on Aug. 1, 2007, killing 13 people and injuring more . than 100 others. The National Transportation Safety Board concluded that . the cause of the collapse was an error by the bridge's designers — a . gusset plate, a key component of the bridge, was too thin. The plate was . only half of the required one-inch thickness . Because . the bridge's key structures lacked redundancy, where if one piece . fails, there is another piece to prevent the bridge from falling, when . the gusset plate broke, much of the bridge collapsed. Mark . Rosenker, who was chairman of the NTSB during the I-35W bridge . investigation, said the board looked into whether other fracture . critical bridges were collapsing. They found a few cases, but not many, . he said. 'Today, they're still building fracture critical bridges with the belief that they're not going break,' Rosenker said. Fracture critical bridges, like the . I-5 span in Washington, are the result of Congress trying to cut corners . to save money rather than a lack of engineering know-how, said Barry B. LePatner, a New York real estate attorney and author of 'Too Big to . Fall: America's Failing Infrastructure and the Way Forward.' Collapse: The I5 bridge in Seattle, Washington, had been deemed 'functionally obsolete' by state authorities before it collapsed after being clipped by a truck . About 18,000 fracture . critical bridges were built from the mid-1950s through the late 1970s in . an effort to complete the nation's interstate highway system, which was . launched under President Dwight Eisenhower, LePatner said in an . interview. The fracture critical bridge designs were cheaper than . bridges designed with redundancy, he said. Thousands of those bridges remain in use, according to an AP analysis. 'They . have been left hanging with little maintenance for four decades now,' he said. 'There is little political will and less political leadership . to commit the tens of billions of dollars needed' to fix them. There . has been little focus or urgency in specifically replacing the older . 'fracture critical' crossings, in part because there is a massive . backlog of bridge repair work for thousands of bridges deemed to be . structurally problematic. Washington state Rep. Judy Clibborn, a . Democrat who leads the House transportation committee, has been trying . to build support for a tax package to pay for major transportation . projects in the state. But her plan wouldn't have done anything to . revamp the bridge that collapsed. National bridge records say the I-5 . crossing over the Skagit River had a sufficiency rating of 57.4 out of . 100 — a score designed to gauge the ability of the bridge to remain in . service. To qualify for federal replacement funds, a bridge must have a . rating of 50 or below. A bridge must have a sufficiency rating of 80 or . below to qualify for federal rehabilitation funding. Hundreds . of bridges in Washington state have worse ratings than the one that . collapsed, and many around the country have single-digit ratings. Human chain: Rescue workers pulled three people from the water after the Skagit River bridge collapse, none were critically injured . Clibborn . said the Skagit River crossing wasn't even on the radar of lawmakers . because state officials have to prioritize by focusing on bridges with . serious structural problems that are at higher risk of imminent danger. Along . with being at risk of a fatal impact, the I-5 bridge was deemed to be . 'functionally obsolete,' which essentially means it wasn't built to . today's standards. Its shoulders were narrow, and it had low clearance. There . are 66,749 structurally deficient bridges and 84,748 functionally . obsolete bridges in the U.S., including Puerto Rico, according to the . Federal Highway Administration. That's about a quarter of the 607,000 . total bridges nationally. States and cities have been whittling down . that backlog, but slowly. In 2002, about 30 percent of bridges fell into . one of those two categories . There is wide recognition at all levels of government that the failure to address aging infrastructure will likely undermine safety and hinder economic growth. But there is no consensus on how to pay for improvements. The federal Highway Trust Fund, which provides construction aid to states, is forecast to go broke next year. The fund gets its revenue primarily from federal gas and diesel taxes. But revenues aren't keeping up because people are driving less and there are more fuel-efficient cars on the road. Delay: The collapsed bridge in Skagit, Washington, carried 71,000 vehicles daily. Drivers are being asked to factor in an extra hour travel time to detour the bridge . Neither Congress nor the White House has shown any willingness to raise federal gas taxes, which haven't been increased since 1993. Many transportation thinkers believe a shift to taxes based on miles traveled by a vehicle is inevitable, but there are privacy concerns and other difficulties that would preclude widespread use of such a system for at least a decade. Transportation spending got a temporary boost with the economic stimulus funds approved by Congress after President Barack Obama was elected. Of the $27 billion designated for highway projects under the stimulus program, about $3 billion went to bridge projects, Black said. States are looking for other means to raise money for highway and bridge improvements, including more road tolls, dedicating a portion of sales taxes to transportation and raising state gas taxes. Clibborn, the Washington state lawmaker, has proposed a 10-cent gas hike to help pay for projects, though the effort has been held up by a dispute over how to rebuild the Columbia River bridge connecting Vancouver, Washington, and Portland, Oregon. 'We can't possibly do it all in the next 10 years,' Clibborn said. 'But we're going to do the first bite of the apple.'
crossings carry millions of drivers every day. In when the Interstate 5 bridge collapsed minutes Thousands of those bridges remain in use, Washington state have worse ratings than the one that . collapsed, and many around the country and 84,748 functionally . obsolete bridges in the