A cable-stayed structure, the Downtown Bridge will carry six northbound lanes of Interstate 65 over the Ohio River, while the existing John F. Kennedy Memorial Bridge will be rehabilitated and restriped to carry the interstate’s six southbound lanes. Courtesy of Louisville-Southern Indiana Ohio River Bridges Project
A new bridge across the Ohio River is part of a larger effort to relieve traffic congestion along the Interstate 65 corridor between Indiana and Kentucky.
May 28, 2013—A busy bridge that spans the Ohio River to link Louisville, Kentucky, and Jeffersonville, Indiana, is getting a sister structure. The new bridge is one of two river crossings that are being constructed as part of a single project that is designed to alleviate congestion and improve safety along the corridor, and the work will also involve the reconstruction of an interchange at which three interstates converge in Louisville’s downtown.
The John F. Kennedy Memorial Bridge is a cantilevered Warren through truss structure that opened in 1963. The bridge carries four northbound and three southbound lanes of Interstate 65 over the Ohio, and like the two other existing bridges that cross the river into the Louisville metropolitan area, it is often the scene of major traffic backups. The bridge carries approximately 123,000 vehicles a day, and the proportion of trucks in this total is roughly 20 percent, far higher than the structure was designed to handle, according to Chuck Wolfe, the executive director of public affairs for the Kentucky Transportation Cabinet.
Options for relieving congestion on the Kennedy bridge have been studied since the 1970s, but possible solutions ran up against the fact that lanes cannot be added to the structure. So in the 1990s Kentucky and Indiana officials agreed to pursue plans to construct a new bridge adjacent to the existing structure. Dubbed the Downtown Bridge, the new, cable-stayed crossing will carry six northbound lanes of I-65; the Kennedy bridge will then be rehabilitated and restriped to carry six southbound lanes of the interstate. In addition to the construction of the Downtown Bridge, the project will involve the reconstruction of the connecting Kennedy Interchange, referred to locally as Spaghetti Junction, where the interstates 65, 64, and 71 merge in the city’s downtown. The redesign is intended to eliminate tight weaves and sharp curves on ramps and to add lanes on I-65 to accommodate the revised lanes on the highway as it crosses the river and enters downtown Louisville. The project will also involve the construction of a second new bridge, the East End Bridge, to form a downtown bypass that will help to further reduce congestion on the Kennedy bridge. (See “Cable-Stayed Bridge Joins Ohio River Crossings,” on Civil Engineering online.)
The Downtown Bridge will be constructed adjacent to the existing
John F. Kennedy Memorial Bridge over the Ohio River between
Louisville, Kentucky, and Jeffersonville, Indiana. Courtesy of
Louisville-Southern Indiana Ohio River Bridges Project
The general engineering consultant, which will provide oversight on all aspects of the multifaceted project, is Community Transportation Solutions, a joint venture of the engineering firms HMB Professional Engineers, Inc., headquartered in Frankfort, Kentucky; Beam, Longest and Neff, LLC, based in Indianapolis; and Parsons Corporation, headquartered in Pasadena, California. As team members began designing the Downtown Bridge, they met with community stakeholders to narrow the selection of 31 possible bridge types to 3. The public then provided input, and on the basis of that information state officials and an executive committee ultimately selected a three-tower, cable-stayed bridge. “The fact that the Downtown Bridge [will be] a three-tower, four-span cable stay is unusual,” said John Sacksteder, P.E., a project manager for HMB Professional Engineers, in response to written questions from Civil Engineering online. “Preliminary research indicated that of the more than twelve hundred cable-stayed bridges worldwide to date, only about six of these have more than two towers [and] three spans.” (A video of the design is available here.)
The bridge’s main spans over the river will have lengths of 303, 750, 750, and 303 ft, for a combined length of 2,106 ft. The two longest spans will traverse the river’s main and secondary channels to accommodate the significant amount of barge traffic on the river. The main spans will be 71 ft above the river’s ordinary high-water level. Additional spans will extend north into Indiana 1,058 ft.
The bridge will have three sets of slender towers, each angled at the top. The central set will loom 195 ft above the bridge deck, and the two outer sets will rise 141 ft over the deck. A total of 88 steel cables will extend from the towers to the outer edges of the superstructure.
The bridge will be founded on 12 ft diameter drilled shafts, which will be constructed in the wet by driving steel casing pipes down through the riverbed and into the rock below. Once the casings are secure, the soil and rock inside will be drilled out and the shafts will be embedded in solid rock. The casing and the rock socket will then be cleaned out, reinforcement will be inserted, and concrete will be placed in the shaft to form the drilled shaft foundations.
The bridge is being designed to handle not only high winds and significant seismic events but also barge impacts. “The Ohio River has major commercial barge traffic, the McAlpine Locks and Dam is located only a little over a mile to the west of the Kennedy bridge, [and] considerable recreational boat traffic also exists in the area,” Sacksteder said. “Numerous barge hits have occurred on the existing structures over the years. [So] the [new] bridges must be designed to withstand an impact from a barge.”
The Downtown Bridge and the project’s related works are part of a $2.6-billion infrastructure initiative known as the Ohio River Bridges Project. Construction of the Downtown Bridge is scheduled to begin in July, and completion is anticipated by December 2016. Upon completion of the East End Bridge, which is being constructed on a similar schedule, traffic on the Kennedy bridge and its new sister structure is expected to fall to approximately 104,000 vehicles a day. The completed project “will lessen the congestion that exists in downtown Louisville and improve the safety to the traveling public,” Sacksteder said.