RCC and rock 'back-up' berm enhances seismic safety of Saluda dam, USA

摘要

A reassessment of the seismic safety of Saluda dam in South Carolina, USA, has led to a major remedial project, now under way, to construct a berm of RCC and rock. This paper describes the design criteria and studies conducted to assess the response of the RCC section to various magnitudes of earthquake. The construction challenges ahead are also outlined. In 1886, the worst earthquake to strike the East Coast of the USA shook Charleston, South Carolina. Sixty people were killed and almost every structure in the city suffered some form of damage. In investigating the seismic design bases for critical facilities in South Carolina, engineers now assume that an earthquake with a similar magnitude, estimated to have been between 7.1 and 7.3 on the Richter scale, could occur in the area again sometime in the next 1000 years. In the late 1980s, while carrying out a seismic evaluation for Saluda dam, a typical embankment structure to impound the Saluda river just upstream of Columbia, South Carolina, geotechnical engineers realized that an earthquake similar to the one in 1886 could cause the dam to liquefy. The liqeufaction of the dam would cause substantial damage to the nearby communities and their economies.