- The Washington Times - Sunday, June 2, 2002

The Interstate 40 bridge across the Arkansas River in eastern Oklahoma that collapsed last week was considered safe by state and federal engineering standards.
Nevertheless, tugboat operators and state transportation officials are debating the reasons why a portion of the bridge fell when hit by a barge and whether faulty design contributed to the collapse that killed at least 14 people.
"Let's keep things in perspective," said Terri Angier, a spokeswoman for the Oklahoma Department of Transportation, the agency that oversees the I-40 bridge. "That bridge was knocked down. It did not fall down."
Oklahoma highway officials say they will rebuild the bridge using the same engineering design. "It wasn't a bridge failure," said the state's chief highway engineer last week. "You're talking about something that can happen anywhere."
Several towboat captains argue, however, that better construction would have prevented the impact from collapsing a 500-foot section of the four-lane interstate, one of the busiest such highways in the nation. I-40 is a major east-west route, crossing North Carolina, Tennessee, Arkansas, Oklahoma, part of Texas, New Mexico and Arizona before it ends in Barstow, Calif.
"Those piers should have been anchored in the river better than that," said David Greer of Baton Rouge, La., founder of the American Inland Mariners Association for pilots and captains on the lower Mississippi River. "When he hit that pier, that barge should have crunched like an empty beer can."
A 98-foot towboat, owned by Magnolia Marine Transport Co, of Vicksburg, Miss., was moving upstream and pushing two empty barges, connected to each other and each weighing 400 to 500 tons, transportation officials said.
No bridge in the country is built to absorb that kind of impact, Oklahoma transportation officials say. "You don't anticipate people slamming into piers," Ms. Angier says.
Barges and bridges make a troublesome mix on the nation's busy inland waterways. Early in the nation's history rivermen often tried to prevent construction of bridges, arguing that they interfered with river traffic. Abraham Lincoln, as a young lawyer representing the railroads, clinched a memorable case with the argument: "This case is about whether people traveling north and south have more rights than people traveling east and west."
Some bridges take hits better than others. Only last week a bridge across the Mississippi River at Greenville, Miss., took two towboat hits. Damage was slight. The river was closed to commercial traffic briefly while the 1,967-foot span connecting Greenville and Lake Village, Ark., built in 1940, was inspected. "It's a massive bridge," said a spokesman for the Arkansas Highway and Transportation Department. "It's well-constructed." Over the past 30 years, officials have documented 49 hits by barges.
And it's not just highway bridges. Barges have damaged railway bridges, too. In one of Amtrak's worst accidents, 47 persons died when a barge hit a railway bridge across a bayou near Mobile, Ala., in 1993, and the Sunset Limited, a crack Amtrak passenger train, fell into the bayou.
The I-40 bridge that collapsed in Oklahoma scored high on its last annual inspection in June 2001. Completed in 1968, the bridge was supplemented in 1983 by installation of barriers that protect bridge supports on the north side. Those "protective cells" are not in place on the south side, where the barges hit the bridge.
It is common practice across the country for such bridges to have protective cells placed around main piers only on the upstream side along the navigation channel because loaded barges coming down the river veer off course more easily due to currents than can those moving up the river, officials said.
"The majority of fixed bridges across the inland navigation system do not have pier protection cells," said Bridge Administrator Roger Wiebusch of the Coast Guard's 8th District. "The bridges that do have cells usually only have the cells on the upstream side in front of the channel piers."
What happened May 26 near Webbers Falls is still under investigation, but officials believe that towboat captain Joe Dedmon may have blacked out and steered the two barges off the main navigation channel a couple of minutes before the accident. Preliminary tests showed he was not under the influence of alcohol or drugs, but investigators do believe his lack of sleep, less than 10 hours in two days, may have been a factor.
Investigators know that Mr. Dedmon, "all of sudden," made a sharp left turn, steering the barges 250 to 300 feet from the navigation channel between Piers 4 and 5, which are guarded by the 40-feet-wide, cement barriers.
Mr. Dedmon's 98-foot boat headed toward Piers 2 and 3, knocking them down and slicing off a part of Pier 1. All the piers are on the west side of the bridge. Piers 1, 2 and 3 are not protected by barriers.
Representatives of the American Waterways Operators, the national trade association for tugboat owners and pilots, declined to comment on the Oklahoma incident. "We're leaving it up to the National Transportation Safety Board investigators. They're the experts," spokeswoman Anne Burns said.
National Transportation Safety Board officials who are investigating said other possible causes include mechanical failure of the boat, its steering mechanisms and severe weather that limited visibility.

A matter of physics
It all comes down to physics, several engineers say.
Officials estimate that the tugboat and barges were moving upstream at about 5 mph, fast enough to hit the support pilings with a force of 100 semitrailers. The effect was the equivalent of 60 cars, each weighing 2,000 pounds, slamming into the structure simultaneously at 60 mph, physics professors say.
"It would look deceivingly slow, like you might be able to reach out and stop it yourself," a University of Tulsa professor said. "But it actually would have had a tremendous amount of power to it."
Coast Guard records do not document any past incidents in which boats hit the I-40 bridge, even though barge traffic on the Arkansas River has increased 19 percent in the past decade. A total of 10,733 short tons were carried on the river in 2000, compared with 9,014 in 1991, according to statistics compiled by the Army Corps of Engineers.
Dry cargo barges and towboats or tugboats are the main vessels that travel the 445-mile length of the navigation channel. The Arkansas, which rises in Lake County, Colo., where it is little more than a shallow brook a few feet wide, is a major waterway when it flows into the Mississippi River below Helena, Ark. Not navigable along much of its journey of 1,459 miles to the Mississippi, it is a busy stream once past Tulsa. A total of 15,723 cargo barges and 8,299 tow or tugboats traveled the river in 2000 alone.

'Unfortunate accident'
Several transportation researchers who periodically conduct surveys on bridges say that what happened was an "unfortunate accident."
"Design considerations don't include upriver barges in the direction that particular one in Oklahoma went in," said John Durrant, executive director of the Structural Engineering Institute of the American Society of Civil Engineers (ASCE). "It's way too premature to make any conclusions on whose fault it was."
Bridge collapses are rare, and incidents of runaway barges or tugboats slamming into unprotected piers even more so, officials said.
The last time a runaway barge hit a bridge was Sept. 15, when a barge slammed into a pillar of the Queen Isabella Causeway off the Texas coast, killing eight. The bridge connects South Padre Island and Port Isabel.
In July, a barge carrying flammable, hazardous chemicals struck a bridge near Cypremort, La. Hundreds of residents living close to the site were evacuated from their homes. No one was injured.
"The number of tragic accidents are really very rare. There's only been a few in the last 20 years. The rest of the time, we're an invisible entity," Ms. Burns said. "But any accident is too many, and any loss of life is totally unacceptable."
Increased traffic along the nation's waterways will inevitably lead to more such accidents, officials predict. Barge traffic climbed 8 percent in the last decade, according to the latest statistics compiled in the Army Corps of Engineers' "Waterborne Commerce of the United States." A total of 808 short tons were carried on waterways in 2000, compared with 746 in 1991.

Failing bridges
Although transportation researchers don't believe the collapse of the I-40 span was due to faulty construction or disrepair, they do fear that failing bridges will prove harmful to motorists. The problem with the bridges is that most are aging and there isn't enough money to pay for much-needed repairs, they say.
"We're doing a good job in managing bridges, but the problem is we're not spending enough money on repairing them," said Frank Moretti, director of policy and research at the Road Information Program (TRIP), a national nonprofit transportation research group based in Washington.
Studies show that nearly half of the nation's bridges 48 percent were built between 1950 and 1980. The busiest bridge-building era in America was the 1960s, when 19 percent of the bridges still open to traffic were constructed. "We're asking for trouble here because we're not spending the type of money required to get all of these bridges back into shape," Mr. Moretti said. "These bridges aren't going to get any better."
Researchers say the government understandably spends more money on transportation problems that cause more frequent harm to commuters. Such projects include widening lanes and adding median strips or "rumble strips," indentations that cause a vibration when a car begins to veer off a road.
As for bridges, the government will build protective barriers around piers that run along navigation channels, but not around those support columns considered well out of the path of traffic, Mr. Moretti said. "Money is finite, and it's spent on the most productive safety improvements."

Passed inspection
The I-40 bridge in Oklahoma was in good standing before last week's accident, state officials say. It scored 67 out of a maximum 100 points in the June 2001 inspection. Many of Oklahoma's bridges score about 30 points on inspections, Ms. Angier said. During inspections, officials check for structural damage.
The I-40 bridge has a capacity posting of 49 tons, which equals the weight of 16 school buses. And, Ms. Angier noted, it was not among the top 100 worst bridges in the country identified in a recent study. "This bridge is one of the best we have," she said.
Oklahoma has the highest percentage of deficient bridges; 33 percent of its 22,799 bridges are structurally deficient, and 7 percent are functionally obsolete, according to a study released last month by TRIP. A study by ASCE estimated that four out of 10 of Oklahoma's bridges are rated as structurally deficient or functionally obsolete because they have deteriorated or do not meet design standards to improve safety.
Ms. Angier said the conclusion came as no surprise to state officials. "Funding is extremely unequal with the needs we have here," she said.
Some 80 percent of the most dangerous bridges cited in the TRIP study were already scheduled to undergo repairs within five years, she said. But Ms. Angier said these bridges are at no point unsafe to drive on.
"We post them at what we have determined [is the] weight that particular bridge can hold," she said. "We're not ever going to take a chance and put people's lives in danger."
Nationally, one in four major, heavily traveled bridges is deficient and in need of repair or replacement, according to the TRIP study. The study "Showing Their Age: The Nation's Bridges at 40" found that 14 percent of the country's bridges show significant deterioration to decks and other major components.
Another 14 percent of bridges are functionally obsolete, which means the structures no longer meet design standards for safety features such as lane widths or alignment with connecting roads, or no longer are adequate for the volume of traffic being carried, the study concluded. "Our bridges are a visible sign of an aging and overburdened roadway system," said William M. Wilkins, TRIP's executive director.

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