STRENGTHENING OF EXISTING CONCRETE DAMS USING POSTTENSIONED ANCHORS -A STATE-OF-THE-ART REVIEW

Many old dams are in need of strengthening and rehabilitation as a res ult of aging, deterioration, deficiencies in design and construction, and more stringent safety standards. These standards include the proba ble maximum flood and the maximum credible earthquake. Post-tensioned anchors are the most practical and cost-effective method of strengthen ing existing concrete dams subjected to direct tension, sliding, overt urning and seismic loading. In some cases, they are used to stabilize rock abutments and concrete locks and to combat the effects of alkalin e and aggregate reaction. The post-tensioning technique requires minim um demolition, has only a minor impact on the dam, and is relatively i nexpensive using a small number of anchors. This paper reviews about 6 0 case histories of-concrete dams strengthened by post-tensioned ancho rs. The reasons for strengthening existing dams are analyzed. The gene ral design, construction, drilling, grouting, testing, and performance of post-tensioned anchors for strengthening concrete dams are outline d.