Forced vibration tests of a model foundation on rock ground

The effect of the dynamic soil-structure interaction was investigated experimentally by forced vibration tests of a model foundation resting on rock surface. The experiment was carried out in 1985 at Tomari nuclear power plant site, Hokkaido, Japan. The model foundation was made of reinforced concrete of 14m*14m in plan and 5m thick and the total weight was 2352 ton. The ground was made of two layers whose interface was inclined by certain degree from north-west to south-east. The forced vibration tests were carried out mainly by an exciter of maximum 4 ton force. Micro-tremor and micro-earthquake were also observed. In this experiment such special attention was paid for obtaining good traction data beneath the foundation as accurate calibration of pressure gauges at the site and the use of auxiliary exciter with larger capacity. Simulations are carried out by wave propagation theory and FEM. Simulated results can reasonably explain the experimental results and the dynamic soil-structure interaction effects in various aspects. Resultant forces and moments evaluated by experimentally obtained tractions with approximated polynomial distribution are in good agreement with those evaluated by displacements