The people on the Interstate 5 bridge that abruptly collapsed Thursday evening north of Seattle got lucky. They survived because their vehicles were entangled in the heartless embrace of twisted steel girders, which saved them from drowning in the cold waters of the Skagit River.
We all drive on bridges, overpasses, and viaducts that we assume must be safe because, surely, somebody inspected them and determined that they are safe. We pay taxes so somebody makes sure the bridges and roads are safe, right?
That trust is badly misplaced. For decades, we have been using up our infrastructure faster than we have been replacing it.
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Every day, cars and trucks carrying more than 200 million people cross over bridges in urban areas that remain in use even though they have exceeded their design life or are in such serious need of major repairs that engineers rate them as structurally deficient.
More than three-quarters of the 239 heavily used bridges in the nation’s capital are rated structurally deficient or obsolete, the American Society of Civil Engineers estimates.
The society gives America’s highway bridges an overall grade of C+.
Six years ago, the I-35 bridge near Minneapolis fell into the Mississippi River, killing 13 people. An Amtrak train clipped another train going the other way in 1996, sending passenger cars into the Hackensack River in New Jersey, because a swivel bridge in use long past its intended life did not align the tracks properly after swinging open to let a ship pass. Luckily, no one died in that entirely avoidable incident.
And it is not just outdated bridges that put lives at risk, as we saw three years ago when a natural-gas pipeline blew up an entire block in a San Francisco, killing eight residents, including a state employee who was investigating whether such aging equipment was safe.
Unless we rebuild and replace our aging infrastructure, it is just a matter of time until we have more such disasters, including another Johnstown Flood.
It is not like we have not been warned. Two days before the Skagit collapse, the American Society of Civil Engineers detailed the decrepit condition of Evergreen State bridges. More than a third had exceeded their design life. Overall, the society gave the state’s bridges a grade of C-.
Already thousands of bridges have weight restrictions or speed limits because of their weakened condition. Like highways with potholes and ports filling in with silt, using up infrastructure instead of maintaining and replacing it also damages the economy.
“We cannot hope to have an A+ economy with a C-level infrastructure,” said James Chae, president of the engineering society’s Seattle section.
A bridge may hold up for decades after its design life is reached. Despite rust, shorn connecting bolts, spalling concrete foundations, and the erosion of its base by flowing water, it may bear the loads from vehicles, winds, and rivers. But as shown by the collapse of the Skagit bridge, which carries 67,000 vehicles each day, a bridge can fail without warning. And that instant may not always be at 7 in the evening when traffic is light. It could be at rush hour.
Close to one in three American highway bridges has surpassed its designed life. One in nine is rated structurally deficient, meaning major repairs or replacement are needed—yesterday.
Newer bridges are designed so one broken part does not mean catastrophic loss. Instead of just falling into a waterway like the Skagit bridge, newer bridges shift the load to backup structures—what engineers call redundancy. This principle is used in jetliners, where multiple systems allow a plane to land safely after one or even two or three systems fail.
Experts estimate bridge spending at $10 billion to $13 billion, far short of the $17 billion to $21 billion needed to replace outdated and dangerous bridges within two decades.
State and local governments spent $156 billion on highways in 2010, roughly a penny out of each dollar of America’s gross domestic product.
Right now, governments can borrow at the lowest interest rates in 700 years. Roughly 25 million people are involuntarily forced into part-time work, are looking for work, or have given up because they cannot find a job.
We must either update our infrastructure or face a future that is both more dangerous and poorer, as more bridges collapse, pipelines leak and explode, and the movement of goods and people becomes less efficient. We could increase our spending and reap big dividends in jobs and the taxes they generate, improved safety, and a more efficient economy.
Why put off until tomorrow what is cheaper to do today?
