This section of the scenic Natchez Trace Parkway in Natchez Mississippi crosses Catherine’s Creek and Melvin’s Bayou. Anelevated bridge structure 1720 feet in length was designed to span both streams. The design also had to assume that the future convergence of these two streams would be under the bridge, so up to 60 feet of scour in some areas, had to be factored into the foundation design. Due to this large depth of scour, the original foundation design consisted of clusters of H piles along with drilled shafts, which resulted in a very expensive design.
A. H. Beck Foundation Co., Inc. and Applied Foundation Testing offered an alternate foundation design utilizing A. H. Beck’s patented post grouting process, “Post Stressed Pier” US Patent No. 6,371,698, which significantly reduced the depths of the drilled shafts to the minimum tip elevation for lateral design limits and helped to bring the project back into budget. The final design called for the installation of 26 post grouted shafts 72” in diameter ranging from 75 to 100 feet deep. One full scale test shaft was also installed and tested using AFT’s 2000 ton Statnamic testing device.
ENGINEER: Wilbur Smith and Associates