Arkansas DOT Replaces Little River Bridge Near Lockesburg
A Much-Needed Upgrade: Arkansas DOT Combats Alligators and Flooding to Replace Little River Bridge
Infrastructure ages. Populations grow. Infrastructure needs to be replaced or expanded. The story seems to be never ending. However, every project comes with its own set of complications and wrinkles. Such is the case with the replacement of the Highway 41/Little River Bridge in Lockesburg, Arkansas. The complications in this project included alligators, mussels, and flooding.
The project includes replacing the existing bridge that was built in 1960. The existing bridge was considered “structurally deficient” and had reached the end of its expected service life. In addition to constructing a new 1,993-foot bridge down-stream of the old bridge, the approaching roadways are being re-aligned to join the new bridge. The new approaches have wider lanes and shoulders. In addition, the approaching lanes have three county roads intersecting, all of which are being re-aligned.
While the 2016 average daily traffic was 2,600 vehicles per day, the new bridge was designed in anticipation of 3,100 vehicles per day. Located on Highway Route 41 that connects to Texas and eventually I-30, the Little River Bridge sees a mix of local and commercial transport traffic. Approximately, 20 percent of the average daily traffic is commercial trucks.
A Wider, Safer Passage
The new Little River Bridge represents an upgrade over the previous one. The previous bridge was much narrower as the shoulders were not wide enough for a disabled vehicle to pull over. The new bridge is significantly wider, having two 12-foot wide lanes with 8-foot wide shoulders, for a total useable roadway width of 40 feet.
“The increased width along with the new guardrail at each approach makes the new structure safer for the traveling public,” says Danny Straessle, a Public Information Officer with the Arkansas Department of Transportation (ARDOT). He adds, “The new bridge is very smooth, so the public will notice a big improvement from the old structure.”
The unevenness along the old bridge came about because of the way it was constructed. Much of its length was constructed with concrete slab spans which tend to deflect in the middle over time, causing a slight galloping effect on the vehicles. There was a joint between each of the 24 spans, and each joint is a potential for a bump. The old bridge also had many patches.
“The new bridge only has seven deck units ranging from 237 to 490 feet in length and eight total joints,” says Straessle. “It also has beams under the concrete deck for its full length, so there should be no resulting gallop over time.”
The clear opening under the bridge varies depending upon the river water level, but it is normally around 37 feet. It’s approximately 44 feet from the bridge deck down to the water during normal summer flows. The Little River, which originates in the Kiamichi Mountains just west of the Ouachita National Forest in Oklahoma, is an ecologically sensitive waterbody that is surrounded by ponds and sloughs. Environmental protection has been both a goal and a challenge of the project.
The ecological sensitivity came primarily from over a thousand Ouachita Rock Pocketbook Mussels and Rabbits Food Mussels bedded near one of the river piers. Before the work could be performed in the river, the mussels had to be relocated. ARDOT divers combed the riverbed for the mussels and brought them slightly upstream to a very similar water depth, and channel type. Straessle says, “It’s expected that over time some of the mussels will migrate back to their original bed.” The relocation process took hours and was made complicated by the murky water and by the alligators.
The Little River is home to a significant population of American Alligators. According to National Geographic, these alligators, which are carnivores, range from 10 to 15 feet long and weigh about 1,000 pounds. They were once endangered but are now thriving. Despite their preference for meat, Straessle says, “The alligators typically shy away from people and construction equipment.” Fortunately, for the divers, they did not encounter an alligator.
Construction workers on the banks adjacent to the job often saw alligators in the water and on the banks themselves. Ultimately there were no direct encounters between the crew and the alligators, though workers had to tread carefully and be leery.
A Good Construction Pace Despite Water Issues
The contract for this project was awarded in 2016 to Jensen Construction. Work began in June 2016 and was expected to be complete spring 2019. The new Little River Bridge opened to traffic on February 26, 2019. However, major work such as constructing county road connections, removal of the old bridge structure, and placing the final layer of asphalt pavement on the bridge approaches remained to be completed. The entire project is expected to be complete this summer.
Delays in completing the project can be attributed to rain. Greater than normal rainfall over the past two years has caused the river rise out of the banks and has slowed production at times. “The contractor has progressed the work at a very good pace when they were able to work which has minimized delays,” says Straessle.
Because of the flooding, the contractor had an equipment problem. While Jenson was able to secure the barge and equipment in the swelled river, the column reinforcing steel on the center pier was damaged by the high water. This interruption required the shaft to be re-drilled and poured, which added to the delay in the project. Straessle notes the contractor was able to complete other work during the delay, so the total impact on the project is difficult to determine.
The Little River Bridge project was slated to run just under $14 million. It’s being funded by a combination of state and federal funds. Upon completion, ARDOT expects the project will be close to the bid cost.
To complete the project, the contractor utilized a variety of equipment. Items used include several large cranes, pile driving hammers, vibratory hammers, drill rigs with 10-foot diameter augers, barges and tugboats, and several slurry tanks and mixers for the drilling fluid. Jensen utilized explosives to remove the underwater portions of the old bridge.
Those commuting along Highway 41 and over the Little River can feel secure that the new bridge will provide a safe and smooth ride. With the expanded width of the bridge, traffic and back-ups will be minimized. Plus, the Pocketbook Mussels and Rabbits Foot Mussels have a new home upriver while the American Alligators continue to enjoy their place in the ecosystem. The replacement of the Little River Bridge was more than an infrastructure project – it was an ecological one too.