State engineers in Louisiana, Alabama and Mississippi began assessing damages and preparing emergency repair bids last week and plans for long-term rebuilding just began to emerge. Some facilities survived better than engineers worst fears but two Mississippi bridges washed away.
|Crush. Ports await emergency generators.|
Two of four lanes of Alabamas Cochrane-Africatown U.S.A. Bridge over Mobile Bay remained closed last week as engineers assessed damage to suspension cables. They were hit by a 13,000-ton oil platform cut loose from its moorings (ENR 9/5 p. 13). The impact knocked the center span 4 in. to the north and into a main pier. "The impact opened a substantial spall in the pier and numerous smaller spalls, exposing the rebar on the underside of the decks overhang," says Nick Amberger, a maintenance engineer for the Alabama Dept. of Transportation.
Several spans of a ramp connecting U.S. 98 to Interstate 10the two main roads into Mobilewere knocked out of alignment. Alabama DOT officials estimate it will take 90 days to fix. Katrina also dropped a 700-ft-long section of the eastbound U.S. 98 causeway over Mobile Bay by 10 ft and sucked soil from under westbound lanes. Mobile-based H.O. Weaver & Sons Inc. rebuilt the westbound lane and filled the eastbound void with concrete, reopening the lanes last week.
In Louisiana, a request for bids was to go out Sept. 9, after a meeting for prequalified contractors, to begin emergency repairs to the 5.4-mile I-10 twin span bridge across Lake Pontchartrain. Some 40% of the bridge is destroyed. Mark Lambert, a spokesman for the Louisiana Dept. of Transportation and Development, says the agency plans to restore one of the twin spans by taking precast segments off its counterpart. Thats what the Florida Dept. of Transportation did a year ago for I-10 across Escambia Bay after Hurricane Ivan (ENR 9/27/04 p. 12).
FDOT engineers flew to Louisiana a few days after Katrina to offer advice borne of experience. One piece of advice was to document everything during assessment and repairs, with federal funding requests in mind. Another is to repair bridges from a strength standpoint "not from the durability standpoint," says William Nickas, FDOT structures design engineer. "You wont be repairing it back to pre-event status." FDOT also has offered to lend some of its stored Acrow temporary bridges.
"Part of our visit was to encourage bringing in coastal engineers to review hydraulic requirements, wave attacks and storm surge," Nickas adds. "Theyll need that information so they can establish the new bridge criteria."
|Katrinas Trip. Major highways in three states suffered damage to varying degrees.|
In Mississippi, the Bay St. Louis bridge and another bridge along U.S. 90 were both lifted up by the surge and destroyed, officials say. Structural details of the crossings were not available. Other major state routes are passable.
Repairing transport facilities is crucial for relief efforts. Last week, the Mississippi River reopened to ships in one direction with 35-ft drafts during daylight. That will allow the Port of New Orleanswhich suffered transit shed and wharf damage due to Katrina and subsequent propane explosionsto begin preparing for military relief vessels, says port chief operating officer Gary LaGrange. The port is "in fairly decent shape," he said in a report.
Two of four gantry cranes at the port are expected to work once they regain electric power. The U.S. Dept. of Transportation is to supply generators and several ships with the capacity to house 1,000 port work crews. Katrina also filled channels along the northern Gulf Coast and the Intracoastal Waterway with debris, prompting the U.S. Coast Guard to close shipping lanes. The Port of Mobile suffered minimal damage and is now open, but the ports of Biloxi and Gulfport in Mississippi and Bayou La Batre in Alabama remained closed last week. The Port of Pascagoula reopened to daytime vessels with 14-ft drafts.
|Ports. Katrina closed most Gulf Coast ports.|
Emergency operations continued at New Orleans Louis Armstrong Airport last week, where 70 evacuee flights used two 10,000-ft runways Sept. 4. Officials were literally finishing an $83-million airfield reconstruction program when Katrina hit, says Mario Rodriguez, airport deputy director of planning and development.
Crews had installed polystyrene sections, poured new concrete and elevated the runways by 18 in. "It made the difference," in getting the runways operational for relief efforts, Rodriguez says. The Federal Aviation Administration is "working feverishly" to repair navigational runway aids, he says.
Terminal damage was mostly wind-related and will cost at least $40 million to fix, Rodriguez says. But the building still housed hundreds of refugees.
(Photos by Michael Goodman for ENR )