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| Sholeh Patrick |
That tall Portland bridge over the river does it to me every time. I feel this twinge of apprehension and then reason with myself, "Of course it's stable; think of all the cars that cross it every day without incident."
And then the unthinkable happens in Minneapolis Wednesday -- a bridge collapses and people die. The July/August 2000 issue of the Federal Highway Administration's "Public Roads" warned that one in seven bridges is functionally obsolete. That doesn't mean they're about to fall down; functionally obsolete bridges are those which do not have adequate lane widths, shoulder widths, or vertical clearances to serve the traffic demand or those that may be occasionally flooded.
The Press and other news services nationwide, indeed worldwide, have been fast to interview bridge engineers, state and national officials, and consultants to answer the questions why. Not just why did this tragedy happen, but why should we feel safe on the thousands of other highway bridges in the U.S.?
Not to sound alarmist, but we're all thinking it.
So as a non-expert, I read in search of a primer on bridge safety (a little knowledge always helps quench my fears). Here's what I learned from the Federal Highway Administration, as well as various state departments of transportation -- who are the ones responsible for maintenance:
• Life: Bridges are typically designed to last 30 years, but actual length could be shorter or (more often) longer, depending upon the amount of physical stress on the bridge. Hence, varying height and weight restrictions for different bridges/locations, and over time.
• Age: Of course it varies and some are much newer, but a whole host of them were built around the 1950s and sixties, so in the nineties Congress funneled a lot of money into highways and states began a maintenance and replacement schedule to fix, replace, and make them safer. It's still under way, with biannual reporting back to the feds.
• Maintenance: Rules vary by state, but generally full inspection is every two years.
Maintenance includes a check for deck smoothness (and resurfacing when needed), painting the supporting steel with weather-proof seal, replacing joints, sealing the deck to prevent moisture infiltration, and replacing the pins and hangers that connect the parts.
• Best and worst: In general (always exceptions) "poor pavement" ratings -- are worst where there is the most congestion and physical stress (urban areas). But in some of the rural areas, things aren't so hot either (fewer resources, perhaps?). In general, rural is still better, with less traffic on the roads and fewer bridges anyway. We who live in the in-between tend to have a decent pavement rating (5 percent or less).
• Fatalities: Measured in deaths per 100 million miles, fatality rates have dropped (cut in half or less) over the last decade-plus since the highway funds went up.
So overall the news is good and the tragedy is already leading to increased vigilance, but much like the occasional plane crash, that's not always immediately comforting.
Still, the open road beckons and life's adventure is worth the ride.
Sholeh Patrick is a columnist for the Hagadone News Network. Send e-mail to sholehjo@hotmail.com.
