The Cumberland River Bridge at Smithland provides a vital link between north and south Livingston County, Ky. Without it, the drive from one end to the other is a good 1.5 hours. But at 93 years of age, the bridge, which is used by about 5,100 vehicles daily, was woefully in need of a replacement. The challenge is the location — a narrow spot on the river with tight turns and heavy river traffic. The question for the Kentucky Transportation Cabinet (KYTC) was: where to build the bridge and then, how to get it where it needed to go? The answers: 15 mi. away and carefully.
"It's been in need of replacement for several years now," said Chris Kuntz, KYTC project development branch manager, District 1. "We've been doing a lot of repair work. The way the geography of Livingston County works, the Cumberland River cuts the county in half between the south and the north. Then, on the other end, you've got Kentucky Lake. This is really the only crossing to get from the north to south. When the bridge had to be closed for repairs it caused extensive delays for school transportation, people going to and from work. It's an important link for the community."
The convenient place to build the new bridge would be the along the riverbank, but the bank is tight and the contractor, Jim Smith Contracting, worried that building it there, which would have meant having a crane barge on the river for at least several days, would impact the barge traffic at the site.
"There's a lot of barges that use the river," said Kuntz. "There are a few rock quarries upstream of here. So, an important consideration in the project was to design something that had minimal impact to the river traffic."
The project team decided on a 700-ft. truss to be built at the Paducah Riverport about 15 mi. from the replacement site, then float it to the replacement site by barge.
"In the end, we ended up with a 700-foot span truss and trusses have a bad reputation of being the clunky outdated type structures that have lots of members, lots of visual clutter and difficult to erect," said Taylor Perkins, principal, senior bridge designer of Stantec. "So, our challenge was to figure out how to trim that down and how to slim down the truss design. We eliminated as many members as we felt we could and still get a nice efficient design. So, for the user, it's nice to have that open visual space, reduced clutter as you're looking out the side of the window."
Last fall, the team successfully floated the truss into place, lifting it about 90 ft. above the river. The float was so impressive, Jim Smith Contracting arranged for a viewing area for the public.
"You never really paid get a sense of the size and the scale of a project until you put a new truss right next to an old one, so to see this yesterday as it started floating down the river," said Austin Hart, KYTC resident engineer. "This is really the last major phase of this project. It was awesome."
Work is now ongoing to build the forms for the concrete deck.
The new $63.6 million bridge, slated to open in May of this year, is taller and wider. The existing bridge is 20-ft. wide, the new will be 42 ft., and including approach spans, 1,912 ft. At its highest point, it will be 95 ft. off the water.
"It's been a long time coming," Kuntz said. "The community local leaders and residents have been asking for this for a long time, pushing for it, trying to get funding for it from the General Assembly. And it feels very good to see that we're one step closer to getting it completed." CEG
