In Disaster's Wake, An Expert Warns of America's Aging Bridges: Cross at Your Own Risk
How dangerous are America's bridges?
One of every five highway bridges is hazardous—a total of more than 100,000. According to TRIP—The Road Information Program, a nonprofit research organization based in Washington, D.C.—every other day a bridge either collapses or sags seriously. TRIP, by the way, is a good source of information on which bridges in your area maybe unsafe.
How long should bridges last?
Generally the life of a bridge is 50 years. We have more than 90,000 bridges that were built 50 years ago or more, and 25,719 built before the turn of the century. Trucks are bigger now and beating the hell out of bridges. Even those built more recently are carrying traffic loads far larger than anticipated. The elevated Santa Monica Freeway, for example, was designed to carry 100,000 cars a day. It was carrying 160,000 within 30 days of its completion in 1966.
But what causes relatively new bridges to collapse so readily?
Poor design. Some bridges have been designed to take vertical stress and not horizontal stress. A most dramatic example is the bridge over the Tacoma Narrows in Washington State, which buckled and collapsed in 1940 because of high winds. Fortunately, traffic had been stopped, so no one was killed. Other bridges have gone down because they've been rammed by ships. Sections of the world's longest bridge, the 23.8-mile Lake Ponchartrain Causeway in Louisiana, have been knocked down twice by barges. The tugboat pilots had either blacked out or fallen asleep at the wheel. Nine people were killed in the two accidents.
What are the chief maintenance problems with bridges?
Rust and crumbling concrete—due in part to deicing salt attacking the steel in bridges and in part to less than top quality concrete. Water seeps through and begins to rust steel reinforcing bars in the concrete and other steel parts. It's like the cartoon of the two astronauts being launched into orbit. One says, "Did it ever occur to you that it was the low bidder who built this?" It's the low bidder who builds bridges.
Aren't these bridges inspected?
Most bridges are inspected inadequately and infrequently. Bridge inspector is normally the lowest job in the state departments of transportation. Most inspectors are not well trained and are reluctant to "climb the steel" to make up-close, careful inspection. The Silver Bridge over the Ohio River at Point Pleasant, W.Va. collapsed in 1967, killing 46 people. It was the worst U.S. bridge disaster in this century. Officials were able to prove only three inspections in 30 years.
Are safety warnings heeded?
Not always. In the case of the Sunshine Skyway Bridge, the span had been built with pilings only seven and a half feet deep, as opposed to 30 to 50 feet for the pilings supporting an earlier span. The structure began sagging even before the roadway was completed. An inspection two years before the accident revealed that thousands of bolts holding the bridge together had rusted out. The safety report was ignored. The Yadkin River Bridge near Siloam, N.C. was declared unsafe by state authorities in 1972, but was kept open anyway. Three years later a car struck a support pillar and six cars were catapulted off the collapsed span. Four people were killed and 16 were injured.
Who is to blame?
Politicians. Money for bridge inspection and maintenance is something that today's politician can put off to let the next administration worry about. If the bridge has a lot of potholes on the surface, then voters driving over it complain, so they put two inches of asphalt on top of the decaying bridge.
What can be done to make bridges safe?
We have to make the job of inspection and maintenance of bridges important. Then we have to put people in jail who are responsible for unsafe bridges. With all the people killed on bridges, no one has served a day in jail. One barge boat operator was fined $500 and given five years suspended sentence for negligence which resulted in the death of three people on the Lake Ponchartrain Causeway.
What must we pay to repair the bridges?
It will take about $60 billion to correct existing bridge problems. Under the Highway Bridge Replacement and Rehabilitation Program last year, about $850 million was spent. But at the present rate of expenditure, it will take 71 years to repair them all. The program is part of the Federal Aid to Highways Act, which is due for a complete congressional reappraisal this spring.
Why won't existing taxes pay for repairs?
Federal gasoline taxes are used to finance road and bridge repairs. But ever since the push for economical cars, people are buying fewer and fewer gallons of gasoline. Because gasoline taxes are collected on gallons sold, there's less money available to repair bridges.
Besides human lives, what are the costs if we don't make these repairs?
Public safety is a great concern. Fires have not been answered, and police haven't been able to respond to calls because they're not allowed to go over some unsafe bridges. In 1977 the Pittsburgh Chamber of Commerce estimated that area manufacturers had to pay $45 million a year more in transportation costs because of the detours they have to make around unsafe bridges.
What should you do if you're on a bridge when it collapses?
Hope your seat belt is fastened, because the impact of hitting the water is like driving into a stone wall, but the car will absorb some of it. There may be an air bubble over the back seat if the car goes in nose first. Take a deep breath, roll down the window or kick it out, and get to the surface as quickly as possible.
How frightened are you by bridges?
Very. I cross the Potomac several times a day. I will not go over the Key Bridge at all. I prefer the Memorial or Teddy Roosevelt bridges because they are better built. And if the Memorial collapses, it's about 40 feet to the water; the Key Bridge is 84 feet. If it collapsed, you'd be dead as soon as you hit the water.
Should motorists not cross some bridges when they come to them?
If you have a choice, use a low bridge as opposed to a high one. If you have to get on the bridge, stay in the center lanes. They are usually the strongest. Often after the bridge has been built and the traffic has increased, a lane will be added on each side. It's more likely that the outer lanes will go down first should the bridge collapse. If a bridge is posted with a light weight limit and it's loaded with trucks and cars, I would pull off and wait until it had lighter traffic. Avoid rush hour. Kill 20 minutes or an hour and save your life.