Interstate 10 bridges get ready for future hurricanes

Boh Bros. lands $379 million Lake Pontchartrain Bridge

By Debra Wood

During back-to-back killer hurricane seasons, Interstate 10 bridges from Florida to Louisiana suffered serious damage, forcing states to cobble together rapid repairs to reopen the spans and to embark on constructing replacement bridges.

One of only three transcontinental highways reaching from coast-to-coast, I-10 is one of the longest interstate routes in the country, totaling 2,460 mi. from Jacksonville, Fla., to Los Angeles and traversing eight states. The Gulf Coast region considers it a lifeline for commerce and visitors.

"I-10 is a major east-west thoroughfare through Florida," said Tommie Speights, spokesman for the Florida Department of Transportation, district three. "It's the main artery from Alabama across to Jacksonville and connects with I-75 and I-95."

Louisiana. Hurricane Katrina's storm surge plunged the I-10 bridges across Lake Pontchartrain, east of New Orleans, under water. Air trapped under the spans lifted them up and allowed wave action to drop about 60 sections of the 5.4-mi.-long bridges into the water and to misalign more than 400 additional spans.

Soon after the storm passed, FDOT engineers headed to Louisiana to share their expertise and experiences.

"They certainly did go out of their way," said Artur D'Andrea, project manager and assistant bridge design administrator for the Louisiana Department of Transportation and Development (DOTD), in an emailed statement. "William Nickas (Florida state structures design engineer) was aware of trouble they had with Escambia and the Florida coast, so he knew we'd need their help."

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The DOTD decided to cannibalize intact deck on one span to more quickly repair and open at least one structure. Crews then filled in missing segments with prefabricated, modular-steel Acrow panels. DOTD hired Volkert & Associates Inc. of Mobile, Ala., for inspection and consulting. John Horn served as project manager on both jobs.

"There were a lot of lessons he learned that he was able to help us with," said Al Flettrich, bridge division manager for Boh Bros. Construction Co. LLC of New Orleans, which began repairs two weeks after Katrina hit. "There were some [things] we came up with on our own, but we got some tips on what not to do and that certainly helped."

HNTB Corp. of Baton Rouge, La., served as consulting engineer to Boh Bros. Dennis Gowins, department manager for structures at HNTB, said the general scheme of repairs was patterned after a similar project on the I-10 bridge across Escambia Bay in Florida, but the actual repairs and retrofits were different, including the type of Acrow used.

Gowins said most engineering was done onsite after determining what materials were available in the Boh Bros. yard. The team purchased jacks off the Internet.

"The people you're [normally] getting your materials from were no longer in business or operational," Gowins said. "You were left to your own imagination."

Boh Bros. used the jacks to slide shifted spans back into place. Those sections more than half off required a hydraulic trailer on a barge to move them back into the proper position. The team repaired holes in some of the hollow cylinder piles and left some structurally sound damaged piles.

Boh Bros. finished the eastbound lanes in October and completed the westbound span in January, eight days ahead of schedule. Boh's $35 million contract includes annual maintenance and repair or replacement of the temporary elements.

DOTD will replace the existing twin spans with two new, higher bridges, estimated to cost $630 million and take five years. Rather than members as low as 8.5 ft., the new bridge will be at least 30-ft. above sea level.

"Even though we are building the bridges at higher elevations, we are taking additional storm precautions," D'Andrea said. "A positive anchor system, including keeper walls, should prevent the girders for falling off the caps."

The new design also calls for the substructure to withstand forces determined by a post-Katrina storm surge analysis and sheer keys on the bent caps to catch and hold the deck in place, said Amy Kohls Buehler, vice president and director of the Texas office of Figg Engineering Group of Tallahassee, Fla., designer of one of two possible replacement options.

DOTD divided the project into two parts, a 1-mi. section above the navigational channel at the north end and the balance of the bridge, which will be constructed first.

The department designed an I-beam girder bridge and hired Figg to design a post-tension segmental bridge.

"The options allow for a better competitive bid and contractor flexibility," D'Andrea said. "This gives the contractor real choices and tries to keep costs within our budgets."

Both options have incorporated repetition in the design to speed construction, Buehler said.

"We implemented the option of precast elements, which enable the contractor to prefabricate most of the parts of the bridge and erect on site, as opposed to having a lot of cast-in-place work on the water," Buehler said.

Louisiana opened contractor bids for the first section in mid-April and Boh Bros. was the low bidder at $379 million to build the DOTD designed girder bridge.

No bids were submitted for the segmental design, said Cheryl Maze, spokesperson for Figg. The navigational channel section will not open for bidding until summer.

Mississippi. Storm surge from Hurricane Katrina pushed barges holding cranes and tugboats into the eastbound I-10 bridge at Pascagoula, Miss., damaging two fascia girders and six span units.

T.L. Wallace Construction Inc. of Columbia, Miss., received the $5.2 million Mississippi DOT repair contract and completed the work within 20 days, earning a $1 million bonus for early completion. Crews removed damaged unit, broke off pilings, drove new precast concrete piles, poured new caps, set new beams, and repoured the deck.

"We started casting piles right after the storm hit, so they wouldn't have to wait for the piles to cure," said Steve Twedt, a spokesman with the MDOT. "By the time they had a contract, they were able to get the beams cast."

Florida. In September 2004, Hurricane Ivan plowed into Pensacola, Fla. Air trapped under the bridges during the category three storm's 20-ft. high surge lifted segments of the 1960s-era Escambia Bay Bridge's deck off its piers and dropped 58 spans, more than 3,400-ft. of decking, into the water and misaligned another 66 spans.

A joint venture team of Gilbert Southern Corp. of Atlanta, and Massman Construction Co. of Kansas City, Mo., completed the $26 million repair ahead of schedule, allowing the state to open two lanes on the westbound bridge within 17 days and one lane of the eastbound span 66 days post-storm. Volkert & Associates Inc. of Mobile, Ala., consulted.

The team moved salvageable sections from the more severely damaged eastbound bridge to the westbound bridge, straightened misaligned spans, and replaced bents and pilings as needed. To compensate for the missing segments on the eastbound bridge, contractors placed prefabricated, modular-steel Acrow panels, which the FDOT had in inventory.

In April 2005, FDOT awarded a design-build team led by Tidewater Skanska Inc. of Virginia Beach, Va. and including Flatiron Construction Corp. of Longmont, Colo., and Parsons Brinckerhoff Quade & Douglas Inc. of Tampa a $243 million contract to build higher and wider replacement structures.

"Design-build is an excellent way to deliver an emergency project," said David Bogan, PE, I-10 project manager for the FDOT. "It streamlines the process and allows you to get the product you need."

The new 3-mi.-long bridges combine Florida Bulb-T 78-in. beam construction with a post-tensioned girder segment over the navigational channel. About 1,300 36-in. square, voided concrete piles, driven up to 147-ft., support the bridges. As of mid-April, Tidewater/Flatiron had driven 560 piles. The design-built team selected the larger than typical piles due to their lateral stability.

"Not only do you drive less of them, the 36-in. piles are just more stout," Bogan explained.

After starting construction, the design-build team modified the plan to use precast pile caps and footings, rather than cast-in-place to speed construction.

Low-member elements on the new bridges will be more than twice as high as the existing structures' 12-ft. clearance. Height in the navigational channel will increase from 45-ft. to 65-ft. In addition to the added height, the new bridges include deck venting to release trapped air and are more robustly secured, tying together four spans.

"If you get any lift on the girder caused by a storm surge, they are designed to vent themselves out," said Bill Eskins, project manager for Tidewater/Flatiron. "[A surge] would have to lift a continuous four-span unit, which is much longer, much heavier, and get it off place. It would be more difficult for a storm surge to pick up a four-span unit and move it."

The replacement bridges will have three lanes of traffic in each direction, as well as inside and outside emergency shoulders and a bicycle lane. The joint venture team stands to earn a $10 million bonus if it gets the first, eastbound bridge open before December 29, 2006 and a $133,000 per day penalty, up to $10 million if it does not.