Dam Modifications Checked by Hydraulic Models

Reconsideration of the maximum design flood, and a review of the stability analyses for the 25-year-old Bartlett's Ferry Dam, on the Chattahoochee River near Columbus, Ga., showed that the dam was deficient in freeboard and stability. Furthermore, a review of assumptions made for the original design indicated that, with the reservoir at normal pool level or above, the concrete spillway section was probably subject to tensile stresses. Field measurements also showed that high uplift pressures existed within the dam. Measures undertaken to remedy these conditions are described herein. Structural modifications, which were completed in 1950, included the installation of drains, the raising and strengthening of the non-overflow sections of the dam, and the addition of prestressed, reinforced concrete buttresses to the spillway section. Questions regarding the effect of the latter modification on the hydraulics of spillway operation called for extensive hydraulic model studies. Models were used also to obtain information pertinent to the structural design of the buttresses and certain appurtenances. Results of the uplift measurements, a description of the structural modifications to the dam, and a discussion of the model tests are given in this paper.