Brighton Dam Rehabilitation

The Brighton Dam is a concrete slab and buttress dam that has been in continual service for over 75 years.  Over those years, the dam developed a number of deficiencies that resulted in a reduction of the safety of the dam and increased difficulties in operation of the dam to its full capacity. These deficiencies included significant deterioration of the shotcrete overlay on the spillway apron slabs, corroded and misaligned radial arm (Tainter) gate wallplates and sill plates, corrosion of Tainter gate components and wear of Tainter gate coatings, deteriorated intake tower sluice gates and trash rack, and other miscellaneous items. The rehabilitation of the dam consisted of removing these deteriorated components and replacing them with new or upgraded components or repairing the existing components to extend the service life of the dam. Throughout construction, several issues were discovered in the field that lead to impactful change to the project. Even with a thorough inspection and design, some elements of the project cannot be known until the construction activities uncover aspects of the work. For the rehabilitation of Brighton Dam, these issues included unexpected asbestos containing materials in the construction joints of the spillway apron slabs, deterioration and section loss of the lower girder of the spillway Tainter gates that were hidden by the existing heater cable enclosure, and issues with hydrodemolition of the spillway slabs due to a strength differential between a previous shotcrete overlay repair and the underlying concrete slab, as well as unexpected flooding, due to a wetter than normal construction period.