CEDAR BLUFF — In a few weeks, campers and boaters at Cedar Bluff Reservoir will no longer see the familiar silhouette of the overhead steel truss arch bridge over the spillway.
Completed in 1950, the old bridge and its arches are coming down.
That’s to make way for a new $2.2 million steel girder bridge, now under construction.
What’s the biggest challenge building the new one on K-147 highway over the dam on the Smoky Hill River at Cedar Bluff?
“Setting the existing structure down to the ground,” said J.R. Katz, supervisor for the contractor Wildcat Construction Co. Inc., the bridge division of Wichita-based Sherwood Cos.
“The structure sits 70 feet in the air, and we’re going to split it in half and pick it up with a 600-ton crane, one half at a time,” said Katz, who stood Friday at the base of the spillway with his crew, their trucks, and a crane, with the iron bridge skeleton suspended high above them.
The bridge was closed suddenly almost a year ago, June 26, 2019, shutting down the fastest route around the popular lake 45 miles west of Hays. Public safety concerns from structural deficiencies found during inspections forced the Kansas Department of Transportation to close it.
For now, people are taking familiar back-road shortcuts to reach beaches, boat ramps, fishing spots and Sport Haven marina on either side of the north and south shores. The new bridge could open by late August.
Katz’s bridge construction crew of three to five people already has removed the concrete deck of the old bridge, as well as the rail, by cutting the parts into slabs and picking them off with a crane stationed down below on the spillway. Standing on the spillway Friday and pointing up at the arches, Katz described the process for removing what’s left.
“We have to take out all the cross braces on the top and the bottom, and then we’ll have a crane supporting this,” he said, of the arch on the west side. “And to support the other arch we’ll have bracing coming down on both sides that will support the far arch while we pick this one down.”
Once that’s done, they’ll go back up and pick the other one.
The removal will be done with a massive 600-ton crane, arriving in a few weeks from Colorado. It will be situated on the spillway and extended up to the bridge, going about 20-30 feet above the arches.
The process is not a typical one, said Charles Scott, bridge inspector for Kirkham Michael, the engineering firm contracted for the project by KDOT.
“The length of the bridge is reasonably typical, but the complexity is much, much more detailed,” said Scott, who was at the job site Friday. “We can’t damage the spillway; it’s a surgical removal. Typically in the country you just knock it over and haul it off.”
The crane will remove each 50-ton arch one at a time, Scott said.
“This morning we had seven loads of counterweights come in for the crane,” he said. “You hang those off the back of the crane to keep it from tipping over.”
Four more loads of counterweights are on their way, he said, along with a second crane, 125-ton capacity, which is needed to set up the big crane. The old bridge will go to salvage.
Apart from technical challenges, the Cedar Bluff bridge project is different in other ways too.
“This is a pretty good task,” Scott said, “a state bridge over a federal spillway, so there are lots of obstacles.”
The new bridge will have a deck comprised of 12 iron beams: four 95-footers, each weighing 30,000 pounds, and eight 29-footers, each weighting 7,500 pounds. Some of those arrived Thursday and Friday from the manufacturer in Jefferson City, Mo., and more are scheduled for this week. Mike and Paula Wibberg, co-owners of Brush Creek Trucking LLC, Linn, Mo., on Friday delivered two loads on semi-tractor flat beds. Hauling them from the asphalt highway down a steep chalk road to the spillway construction zone was a trick.
It took a steerable flatbed trailer to haul the 95-foot beam down the curving road, which has a 10-degree slope at its steepest point, said Paula.
“So it’s in two parts,” she said of the trailer. “The front of the beam was on one piece of the trailer and the back was on another piece.”
Katz and his crew Friday morning used a 55-ton crane to lift the beams off the flatbeds, placing each one level to prepare for bolting a short one to each end of the long ones, creating four 153-foot girders to support the new bridge deck.
“I think there’s a little over 2,000 bolts go into it,” said Katz, who lives in Kinsley. “We gotta get all these beams assembled and ready to set up. We’ll get them bolted together, and then when the big crane comes in we’ll set that structure down and set these up there the same couple days.”
Getting in all those 7/8-inch bolts will take the next few weeks, he said.
“Once we get all this steel up in the air, it’s all normal bridge,” Scott said.
Thankfully, there hasn’t been any water in the spillway since the project began, Katz said, since the lake is always maintained pretty level.
“But if it happened to rain 8 or 9 inches, we could be in trouble,” he said. “If we don’t have a flood in the next four weeks and we get this done and the new beams up, then we’re done down below pretty much, and we’ll work from up above.”
Katz explained the rest of the process.
“After you get the beams up, then you gotta deck it. Once it’s decked, you put on the overhangs. Once the overhangs are on, then you tie the steel. After you get the steel all tied, then you pour the concrete on it, and after the concrete sets awhile, you gotta build the walls, the corral rails. After that you’re about ready to open it,” he said. “That simple.”