The Arkansas Department of Transportation will use an accelerated construction method for the first time on a $12.6 million project to replace two small bridges on Interstate 30 crossing De Roche Creek, which marks the boundary between Hot Spring and Clark counties.
Under the method, the new bridges will be constructed next to the existing bridges, one for eastbound traffic and one for westbound traffic. Once work is completed, the existing bridges will be dismantled and the new bridges will slide into place.
The project was one of 31 projects on which the department awarded contracts totaling $31 million and released Monday.
The low bidder was Manhattan Road & Bridge Co. of Tulsa, which said its proposal would limit "head to head traffic" in which motorists in both directions would have to share one bridge to no more than 10 days for each bridge.
The traditional method of bridge replacement required motorists in both directions using just the eastbound lanes or the westbound lanes for up to a year and a half on an important segment of the state highway system that carries 29,000 vehicles daily between Little Rock and Texarkana and beyond.
"We would have to turn the traffic head to head from beginning to end" if traditional bridge building was employed, said Mike Fugett, the department's chief engineer for design. "It was a substantial savings versus what we would have normally had to do."
Another method, in which the bridges are built a third at a time, also would have required motorists sharing one bridge for a considerable period of time. That method has been employed on bridges on Interstate 40 between North Little Rock and Conway and in the West Memphis area.
"That was an option," Fugett said. "But from a standpoint of impacts to the traveling public, [the impact] still would've been substantial."
The project also marks the first time the department will widen bridges on I-30 between Little Rock and Texarkana to accommodate three lanes of traffic in each direction. The route now is largely two lanes. The bridge work on I-40 between North Little Rock and West Memphis has replaced bridges to accommodate six lanes of traffic even though the route remains four lanes.
"We're planning for the future," Fugett said.
The Federal Highway Administration has been promoting slide-in bridge construction and other accelerated construction methods to shorten project delivery, reduce impacts to motorists and enhance roadway safety.
Rick Ellis, head of the department's bridge division, estimates that nationwide about 100 bridge projects have used the slide-in method, which was first developed by the railroads.
"Railroad companies, they can't keep their tracks closed for very long," he said. "The first time I saw it was in Echo, Utah. That was probably six or seven years ago."
The two bridges at De Roche Creek are each about 170 feet long, which isn't long by bridge standards.
Employing the slide-in method "would've been more difficult" on longer bridges, Ellis said. "This [site] is a pretty good first trial in the state of Arkansas."
He said the new bridges will be constructed on the outside shoulders on temporary foundations. New foundations, meanwhile, will be built under the existing bridges while they still carry traffic.
Once the bridge and foundation work are completed, a crossover lane will be built that will allow, for example, eastbound traffic to cross over to the westbound bridge, which traffic in both directions will have to share for 10 days while the existing bridge is removed and crews slide the new bridge into place and complete the approaches.
The project had one other bidder, Mobley Contractors Inc. of Morrilton. The company said it would have required a total of eight days to limit traffic "head to head," but its bid price, $18.8 million, was significantly higher.
Metro on 06/25/2019