Reconstruction of Rio Cobre Dam

The Rio Cobre Dam in Jamaica experienced a major failure due to excessive flooding in May of 1991. Investigations revealed that the dam also failed during its construction in 1876, and that the overflow section was extended, but to a lesser design standard. It was this extended overflow section of the dam that failed. The reconstruction project consisted principally of replacing the failed portion with a concrete gravity ogee section constructed on an extended pile foundation. Steel sheet piling and H-piling was driven into the alluvial foundation to confine disturbed material and to serve as a seepage barrier. The project also rehabilitated the remaining portion of the diversion structure to current design standards and to essentially its same configuration and size prior to failure. A new stilling basin provided improved scour protection. This paper describes the design and construction challenges of reconstructing a concrete gravity dam on a disturbed alluvial foundation. 10 pp.