I-26 Mars Hill - Madison County, N.C.
The $121 million Mars Hill project involved extending 6 miles of Interstate 26 through the Appalachian Mountains in North Carolina. The new I-26 replaces U.S. 23 as the major artery in Madison County between North Carolina and Tennessee, and represents the first interstate highway in North Carolina to be designated as a scenic byway.
At the time of its completion in April 2002, this 64-month project was the largest ever undertaken by the North Carolina Department of Transportation. Crews worked in steep, mountainous terrain at elevations near 4,000 feet with variable and unpredictable soil conditions.
The major scope of work featured 25 million cubic yards of roadway excavation, which included 18 million cubic yards of rock excavation. Additional work involved 2 million cubic yards of under-cut excavation, 60,000 feet of pipe ranging from 6-inch to 112-inch diameter, 14,000 feet of 60-inch diameter structural-plate pipe, six box culverts, four bridges totaling more than 40,000 square feet and 6,200 feet of fence to control rock fall.
To control erosion and protect the environment, crews installed 20,000 feet of temporary slope drains, 13,000 feet of temporary silt fence, 129,000 cubic yards of silt and 75,000 tons of riprap.