Seismic Evaluation of Gatun Dam - Panama Canal

For many dams, the behavior of cohesionless and cohesive soils under cyclic loading plays a key role in their seismic stability. Such is the case of Gatun Dam, which retains Gatun Lake, the main waterway of the Panama Canal. The dam was built by hydraulic filling between 1907 and 1914 and is founded on deep, geologically young deposits of granular and fine-grained soils. This paper presents a case history on the seismic evaluation of the dam. The study involved recently developed procedures for evaluating the susceptibility and potential for liquefaction of soils, for characterizing the residual strength of liquefied soils, and for evaluating the potential for cyclic softening of clayey soils. The paper describes the dam and foundation characterization; the analyses of liquefaction potential, cyclic softening, and seismic deformations; and the assessment of expected dam performance. Key issues in the implementation of the analysis procedures and considerations involved in assessing the seismic stability of the dam are also discussed.