"A national bridge problem"
The Alaskan Way Viaduct and 520 bridge are bad enough, but drivers who brave one of the worst spans in Washington state are flirting with...
Seattle Times staff reporters
The Alaskan Way Viaduct and 520 bridge are bad enough, but drivers who brave one of the worst spans in Washington state are flirting with disaster.
The steel on downtown Tacoma's Murray Morgan Bridge is so corroded, state engineers want the 1911 drawbridge closed. But the city has balked, arguing it needs that link to its industrial tidelands.
"The bridge, in my opinion, is beyond repair," said Jugesh Kapur, chief bridge engineer at the state Department of Transportation. "We really want to shut it down because we are taking a risk every day by keeping that bridge open."
Murray Morgan is among the worst of more than 300 bridges statewide deemed "structurally deficient."
The bridge in Minneapolis that collapsed during rush hour on Wednesday carried the same label. On Thursday, Gov. Christine Gregoire asked transportation officials for a briefing on the condition of Washington state bridges.
And the federal Department of Transportation on Thursday urged inspections of 756 bridges nationwide with designs similar to the one in Minnesota. Two major Seattle spans, the Highway 99 Aurora Bridge and Interstate 5 Ship Canal Bridge, are also steel deck truss bridges.
Today, state Transportation Secretary Paula Hammond directed her engineers to follow the federal transportation request to review inspection reports to determine whether more detailed inspections are needed.
"It's important for people to know that we did not wait until this disaster to inspect and maintain our bridges," she said.
There are 48 steel deck-truss bridges in the state. State crews have inspected 10 state-owned steel-truss bridges within the past six months, including the Aurora Bridge. Crews inspected 13 of the bridges in 2006 and three are scheduled for inspection this summer and fall, including the Ship Canal Bridge.
"We have a national bridge problem," said Rep. Jim Oberstar, D-Minn., chairman of the House Transportation and Infrastructure Committee. He said 79,523 federally funded bridges are rated "functionally obsolete," meaning they need replacing.
The disaster in Minneapolis also heightened attention on bridge-inspection standards, which already had drawn scrutiny. A Transportation Department audit of 43 bridges in Massachusetts, New York and Texas last year found that inspectors routinely miscalculated the load capacity of structurally deficient bridges, posting weight limits that allowed vehicles exceeding the safety threshold or failing to post limits at all.
Inspection of Washington's bridges suggest the state enjoys a relatively low rate of problems — 5 percent of nearly 7,600 bridges were deemed structurally deficient, compared to 12 percent nationwide, according to a Seattle Times analysis of 2006 federal data, the most recent available.
Minnesota was also better than the average, at 8.7 percent.
Washington's bridges generally score well because they are relatively new, and most are made of concrete rather than more corrosion-prone steel, said several bridge engineers. Both the Ship Canal and Aurora Avenue bridges have passed the most recent inspections.
But there remain bridges in the state with unrepaired flaws, from tiny, anonymous one-lane country spans to the heavily used 520 floating bridge.
Some go unfixed for lack of money, others because of squabbling over what to do, such as the Viaduct and Tacoma's Murray Morgan, formerly known as the 11th Street Bridge.
State officials on Thursday couldn't estimate just how much money is needed to complete all the repairs statewide. For example, the Legislature recently committed roughly $90 million over four years to do earthquake work on about 180 bridges around the Puget Sound, said Kapur, the state's chief bridge engineer. But that doesn't cover costly work to buttress the foundations of some bridges against earthquakes, he said.
On the Murray Morgan Bridge, corrosion has eaten holes completely through big steel trusses beneath the bridge deck. The state has posted signs barring vehicles weighing more than 10 tons. But Kapur says he worries that the warning won't always keep heavy trucks from trying to cross.
City spokesman Rob McNair-Huff said the city wants to preserve a historic piece of Tacoma's downtown that's also a quick route for police or firefighters en route to the city's tideflats.
City and state transportation officials met Thursday to discuss the bridge, and they will await the results of an inspection planned in the next three months, he said.
The Tacoma bridge is just one of roughly 3,500 the state owns. All are supposed to undergo scrutiny at least once every two years to catch damage from cars, wind, rain, waves and river currents.
Glen Scroggins, who oversees the state inspectors, cites the Aurora Bridge as one he's concerned with, because it's 75 years old and heavily used.
In June, the bridge got its checkup. Inspectors spent two weeks going over it, using ultrasound to check steel pins for signs of hard-to-see cracks, inspecting concrete for signs of decay. In 2005, divers went into the water to make sure the concrete bases holding up the bridge hadn't corroded.
"It's in pretty good shape, but we keep a close eye on it," Scroggins said.
The state inspection process follow federal standards created after the 1967 collapse of the 2,200-foot Silver Bridge over the Ohio River, which killed 46 people. Four other major bridge collapses between 1983 and 1995 killed 28 more, according to the Federal Highway Administration. All were due, in some part, to catastrophic structural failures.
The inspections don't always find problems, particularly when it comes to relying on visual checks. One study for the Federal Highway Administration issued in 2001 found that just seven of 44 bridge inspectors discovered a weld crack in a bridge.
The consequences of not spotting structural weaknesses can be devastating.
Scroggins said he watched footage of the Minnesota bridge collapse, trying to figure out what might have gone wrong.
"Our goal is to have that never happen under our watch, and we work very hard to make sure that doesn't," he said. "I would hope the Minnesota people had a similar level of care with that thing. It's hard for me to imagine somebody not."
McClatchy Newspapers and Seattle Times reporter Susan Gilmore contributed to this report.
Warren Cornwall: 206-464-2311 or email@example.com
Copyright © 2007 The Seattle Times Company
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