Clarkson Construction Company of Kansas City, Mo., is the general contractor for two related Kansas Department of Transportation (KDOT) projects along Interstate 435 in Overland Park totaling $127.5 million.

The larger of the two projects is, at $91.7 million, the largest project ever let by KDOT and calls for the construction of a new interchange at Antioch Road and related improvements to Interstate 435. The project is about two miles east and west along I-435 by one mile north to south along US Highway 69 and includes the construction of 13 new bridges and the redecking of four others. One of the 13 bridges to be constructed is a "flyover" bridge connecting Highway 69 and I-435. Because of the high traffic volume in the area, the project includes $23 million for noise and retaining walls.

Clarkson also has a $35.8-million contract to reconstruct I-435 from the east junction of Highway 169 to 0.4 miles west of Highway 69 in Overland Park. That 2.4-mile project involves grading and surfacing to add two new lanes, widening the existing roadway to eight lanes. Ramp reconstruction and bridge widening work are also included in that project. Both projects are scheduled to be completed by the fall of 2008.

One of the first pieces of the work to be completed is the relocation of sanitary sewer to make way for the widening along I-435 just west of Antioch Road. Subcontractor Redford Construction, Inc. of Raymore, Mo., began its work in early November and planned to have the 12-inch and 21-inch lines installed by the end of the year.

"This is the biggest project KDOT has ever let and ours is just a very small portion of the work but it's important because Clarkson Construction can't build the new bridge over Indian Creek until we relocate the sewer," said Redford Construction Project Manager Kevin Waddell, P.E.

The Redford crew is installing about 250 feet of 12-inch pipe and 150 feet of 21-inch, all encased in flowable fill with gravel backfill on top. But despite the relatively short installation, the crew has had to overcome challenges.

"We had rock in the ditch that we couldn't drill and shoot because of the proximity to the existing sewer, so we had to use a hammer to get that rock," Waddell said. "That requires more time and effort but it's working out.

"It was also a challenge to bypass the sewer from one side of the highway to the other. We had to plug it off and set up a pumping system, so we ran hose and piping underneath the interstate using the open space where the bridge crosses Indian Creek."

According to Waddell, Redford worked with Thompson Pump to rent the pumping system which includes a 6-inch pump and 800 feet to 1,000 feet of pipe. Redford's equipment on the job includes a John Deere 230C LC excavator with the hammer attached to get through the rock, a Caterpillar 330C L excavator and 963B track loader, and a John Deere 444J wheel loader. The 330 is ideal for the project, Waddell said, because of the deeper excavation (14 feet to 15 feet). The crew uses the 963 to quickly move spoils away from the ditches and the 444J for moving materials and dumping gravel into the ditches.