The Boh Bros. project manager credits Mobile, Ala.-based Volkert Inc., DOTD project manager for construction services, with helping to improve the process. “We coordinated with DOTD and Volkert to come up with solutions to problems in the field and obtained approvals in a matter of hours,” Schexnayder says. “To play a part in what was, at the time, the biggest project in Louisiana, and the biggest project Boh Bros. has done to date, was very rewarding.”
Weather and Louisiana's wildly variant soil conditions created some of the project's biggest challenges. “Because the lake is so wide open, shallow and close to the Gulf of Mexico, weather comes in quickly, and winds from different directions cause the lake to become rough really quickly,” says TKM's Lee.
TKM's portion of the project was in the middle of the lake, so the contractor barged material and people from a remote staging area to perform most of the work from the water. The contractor used tandem cranes to lift the 650-ft-long steel girder spans across the main navigation channel in 2008 and 2009. The pre-assembled pairs of steel girders that comprise the two 200-ft-length spans on either bridge weigh about 120 tons per pair. TKM used ringer cranes of both 300-ton and 650-ton capacities to make the lifts in order to compensate for the cumbersome length, required reach and water movement.
Variation in Subsurfaces
Pile-driving was a significant project challenge due to the amount of variation in subsurfaces, probably because of two fault lines in the lake, says John Horn, project manager for Volkert. “In some areas the sand was shallow enough to put in end-bearing piles,” he says. “In others, we had to put in skin-friction piles. Sometimes we had both in the same bent.”
Also daunting was having two separate contracts sharing resources and a work area on such a fast-paced project, Horn says. The project includes 63 miles of girders, 78 miles of piles, 38,563 tons of steel and 48,537 truckloads of concrete. “It was challenging making sure we had the right pile lengths at the right time,” he says. “Everybody really had their head in the game and wanted to do what was best for the project.”
Despite the hectic pace, the team remained keenly aware of the project's historical significance and its symbolism. “As a company, Traylor and the joint venture partners certainly have a sense of pride in being part of restoring a major lifeline to the city,” Lee says. Adds Schexnayder: “This will probably go down as the most memorable project of my career.”