The Contribution of Shaking Tables to Early Developments in Earthquake Engineering

Using examples, the thesis developed here is that shaking tables were essential to the progress made in earthquake engineering during the period 1900–1980. This period covers that from the very first shaking tables at the beginning of the twentieth century and ends just before the rapid advances in computing and control engineering made such major changes in shaking table performance capabilities that a separate paper would be required to record them. Not surprisingly, progress was linked to major earthquakes, but corroboration of existing theories or new design methods based on theoretical advances also played a part, as did the specific practical needs of the construction industry. Examples of the first of these spurs to activity are foundation issues highlighted by the 1906 Californian earthquake and similar events in 1964 in Alaska and Niigata in Japan in the same year; also, elevated water tanks by the 1933 event in California, and the general range of structures by the 1923 Tokyo (Kanto)earthquake which devastated the city. Relating to shaking table developments due to theoretical advances, the 1933 “added-mass” analysis by Westergaard for the effect of a rigid wall vibrating against a body of water (as in a dam), prompted several shaking table studies to test the validity of practical design issues, as did Biot’s 1943 introduction of spectral curves to represent earthquake input in a simplified way.