Abstract
The existing Tsengwen Dam is located in a seismically active region in the southwest part of Taiwan. The dam is a 133-meter-high zoned earthfill and rock embankment with total volume of over 9 million m3. Crest length is 400m. The gross capacity of the reservoir is 700 million m3. During 1974-75, the Bureau of Reclamation, United States Department of the Interior carried out a special dynamic analysis using the newly developed technology to reconfirm the safety of the dam for normal reservior water elevation of 225. In 1986, 13 years after the completion of the dam construction, the authors had an opportunity to reassess the safety of the dam against the maximum credible earthquake, of which ground peak acceleration at the dam site was 0.45g, under a revised new normal reservior water elevation of 230. For the purpose of reaching more sophisticated and accurate results on the assessment of the Tsengwen Dam during earthquakes than the USBR's previous study, the authors conducted earthquake risk analyses, field investigations, dynamic laboratory tests, dynamic response analyses and safety evaluation of the dam embankment using state-of-the-art technical methods and evaluation procedures at that time. In this paper, the authors shows significant topics and results obtained from the safety assessment of the existing Tsengwen dam.
