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Bridge Collapse: Here Comes the Alarmism
(WCCO) Minneapolis The major wound on the face of Minneapolis will not heal anytime soon. "Bridges in America should not fall down, so we need to get to the bottom of this," said Mary Peters, the U.S. Secretary of Transportation.I am not an engineer, but I reject "life-span theory" of bridge collapses. Most bridges - as with railway lines and unmanned electrical sub station - are given daily inspections at at least the work crew level. Workers eyeball structural steel and concrete sections of structures, and deliver a simple checklist report to engineering departments, who may chose in depth analysis. There are work-around means to replace cracked metal, often without closing down facilities. The auto companies spend millions of dollars during Summer shutdown, to undo "plant erosion." Why not re-vive the dying? When the I-35W bridge was built 40 years ago, it was state of the art -- a massive steel arch spanning the mighty Mississippi. However, several inspection reports from the past few years, and a quick glance at the bridge's rusting metal, reveal it was showing its age. In 2001, researchers at the University of Minnesota determined the bridge had "not experienced fatigue cracking but has many poor fatigue details." Likely that referred to stressed metal on the bridge supports, according to Dick Stehley with American Engineering Testing. The report concluded the bridge did not need to be replaced. "There was no call by anyone we're aware of that it should be immediately closed or immediately replaced," said Gov. Tim Pawlenty. By 2005, the federal government called the bridge "structurally deficient" in its National Bridge Inventory. On a scale of zero to nine, with nine being excellent, the bridge was a four. That means it may have had "advanced deterioration" and "connection failure may have been imminent." "None of those ratings indicated there was any kind of danger here. It simply says we need to schedule this bridge for rehabilitation," said Peters. So they have intervention standards. These should be fixed at some level where repair is a must. In fact, more than 1,000 bridges in Minnesota are considered deficient. More than 70,000 bridges across the country are rated structurally deficient like the span that collapsed in Minneapolis, and engineers estimate repairing them all would take at least a generation and cost more than $188 billion. That works out to at least $9.4 billion a year over 20 years, according to the American Society of Civil Engineers. Okay, there's the first benchmark. Separately, the Federal Highway Administration has said addressing the backlog of needed bridge repairs would cost at least $55 billion. That was five years ago, with expectations of more deficiencies to come. Len Levine, former Minnesota Transportation Commissioner says, "It was a disaster waiting to happen." Levine doesn't blame the inspectors, but rather a lack of funding that has delayed repairs on bridges across the country. "You can't put a Band-aid on cancer," he said. "The whole lifeline of our communities depend on transportation." That's a lifeline now severed for the nearly 140,000 drivers that used to bridge the river each day. Drivers and voters. Posted by: McZoid 2007-08-03 |
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