Stabilizing steep hillsides along busy U.S. 27 while enlarging the width to eight lanes has been a major challenge, Jim Floyd of Volkert and Associates told members of the North Chattanooga Chamber Council on Tuesday.
He said 23 walls were initially planned, but it has been necessary to erect 32 retaining walls to safely stabilize hillsides with large residential complexes at the tops.
Mr. Floyd also said some "sinkhole-type" problems have been encountered near the existing roadway and those also had to be dealt with. There has also been some "pyrite" (Chattanooga shale) located that has to be disposed of in specialized landfills.
Ten bridges are being replaced by six bridges.
He said, "This project has been a tremendous challenge. It's the second largest TDOT project ever. It was projected at $75 million to $80 million and came in at $102.6 million."
Mr. Floyd said, "It's a huge project. It's a big deal for Chattanooga."
He said it is being carried out in four phases and is due to be complete at the end of 2014.
The speaker noted that the 1.6-mile section from the Olgiati Bridge to Signal Mountain Boulevard was built in the late 1950s for speeds of 55 miles per hour and 33,000 vehicles per day.
He said there currently are 27,000 vehicles per day before Signal Mountain Boulevard, 63,000 after Signal Mountain Boulevard, and 72,000 after Dayton Boulevard.
Mr. Floyd said motorists will notice that the grade on the roadway is changing. He said that will take place in order to avoid dips and rises and to improve visibility. It will be as much as five feet higher.
Club members were shown a coloring rendering by photographer Lawson Whitaker of how the project will look when completed. Mr. Whitaker attended the meeting.