Mating fish, three hurricanes and inadequate clearance at the existing span have made replacing a half-century-old bridge on AL 193 in south Mobile County quite a challenge for L&A Contracting Co. of Hattiesburg, MS.
Work started on the $10 million project — including construction of a new 1,600-ft. bridge over the Fowl River and removal of the existing 1,137-ft. bridge — in February 2005, according to Jay Palmer, district engineer in Mobile for the Alabama Department of Transportation.
Wider and much higher than the 1954 structure, the new two-lane bridge was supposed to be finished in December 2006, but due to disruptions to what had to be a very precise schedule, they’re now looking at March 2007 for completion, said Lynn Cox, area manager for L&A and superintendent on the job.
According to the job contract, there could be no piling driven in February, March, September or October, Cox said.
“It’s been rather tricky to work around that,” he said. “That’s the first time I’ve ever had to deal with (that type of restriction).”
The stipulation was meant to protect the Alabama sturgeon, which lives in the river and mates during those months, explained Palmer.
Going into the job with those limitations laid out, L&A devised its work schedule to get around having to drive piles during the banned months, Cox said.
The plan was to have the piles driven before September came, he said. But the plan didn’t foresee battening down for three hurricanes, including the devastating Katrina, and dealing with Katrina’s aftermath.
“The hurricane hit ... and got us off schedule,” said Cox, who said a lack of workers after Katrina closed down the job for some time.
The company was also involved in hauling off debris and other hurricane relief in Mississippi, he said.
They had to shut down the job three times last season for hurricanes, Cox said. That involves buckling down everything, moving the cranes away from the existing bridge, and then moving everything back after the storm passed, he said.
The old bridge itself posed a challenge for L&A, which couldn’t take the easy way in to the job site from Mobile Bay because of inadequate clearance — just 45 ft. across and 25 ft. high, Cox said.
Because the bridge was too narrow for the barges to pass through, they had to come in from the west on the Fowl River, he said.
“It was quite tricky because the river’s about the same width as the barges,” Cox said. “It’s only 1 to 3 feet deep; the barges draw more water than that.”
So they had to make the barges as light as possible and wait for high tide to be able to move them along, he said.
It took two boats approximately two weeks to get all the way to the site, Cox said, and the slow trek became a spectacle for local residents, who viewed the progress from lawn chairs in their yards.
The barges were brought by tugboats from St. Louis Bay in Mississippi to the Fowl River in just two days, then it took two weeks to go just a few miles down the river, he said.
Fortunately, once the new bridge — with approximately 60 ft. of horizontal clearance and 46 ft. of vertical clearance — is built and the old one torn down, they’ll be able to go home by way of Mobile Bay, Cox said.
Approximately 15 workers are on the job now, putting in 48 hours working a single shift five days a week, Cox said.
At this point, half of the piledriving and substructure is finished, he said.
The job involves driving 332 piles, ranging from 14- to 24-in., to depths ranging from 45 to 101 ft., Cox said.
While still only two lanes, the bridge will feature usable shoulders, unlike the current bridge, he said.
Construction will involve a little more than 5,000 cu. yds. (3,800 cu m) of concrete, not counting all of the prestress, Cox said.
It will feature 9,500 ft. (2,900 m) of type III girders and a little more than 1 million lbs. (454,000 kg) of rebar, he said.
L&A has four barges and four cranes — American Crane models 9299, 7260 and two 5299s — on the job, Cox said. All are owned by the company.
For piledriving, it is using two Delmag piledriving hammers and two vibratory hammers, an International Construction Equipment 4410 and an American Piledriving Equipment 150, he said.
A good portion of the dirt work is also finished, Cox said.
Grady Ralls & Sons of Evergreen, AL, is doing all of the excavation, fill and concrete pipe work for the drainage structure as well as the grassing, Cox said.
The job doesn’t involve a significant amount of earthmoving, he said. Grady is bringing in approximately 24,000 cu. yds. (18,000 cu m) of dirt using borrowed excavation from a nearby dirt pit.
To change the approach to the bridge from the current roadway involves building approximately 500 ft. (152 m) of new roadway at each end of the new bridge, Cox said.
Mobile Asphalt of Mobile, AL, is laying the asphalt — a total of 4,500 tons (4,000 t) of it — at each end of the new bridge, he said.
The job is causing very little disruption to the existing bridge traffic, Cox said.
For a couple of weeks last year, the crew needed to shift traffic 2 ft. to drive some sheet pile to contain dirt work, he said.
The old bridge will be taken down after the new one is in use, Cox said.
While deemed at the end of its lifespan as a bridge by the state DOT, it will still be useful in its retirement, becoming an artificial reef in the Gulf of Mexico south of Dauphin Island, AL. CEG