Pile-Loading Tests, Morganza Floodway Control Structure

A comprehensive pile-testing program was performed at the site of the Morganza Floodway control structure to determine the size of pile required to support the design loads-both compression and tension-without any significant movement. As an 80-ft layer of very compressible clay overlies sand at the site of the structure, an attempt was made to determine the bearing capacity of only that part of the piles penetrating the sand. This capacity was determined by testing various sizes of compression piles in pairs. One pile of each pair was stopped above the top of the sand and was loaded to obtain the resistance developed by skin friction in the clay. A test on a second pile driven into the sand indicated the total supporting capacity of both the clay and sand. The difference in the capacities of these two piles was then assumed to be the tip capacity of the pile driven into sand. Tension tests were also made on a third pile of the same size which was driven into the sand. The sizes of the piles tested ranged from a tapered pile with an 8-in. tip to a 30-in. pipe pile. Details of the loading arrangement and test procedures are described.