PROPOSAL OF NEW FOUNDATION CONSTRUCTION WORKS WITH HIGH DAMPING AND MITIGATION PERFORMANCE; PART 2EARTHQUAKE OBSERVATION OF BLOCKS AND SEISMIC RESPONSE PREDICTION OF FULL-SCALED FOUNDATIONS

摘要

After the forced vibration tests, we have continued seismic observations at the experiment site (two types of foundation blocks, that is CF and IF, and their surrounding grounds) to confirm the effectiveness of the proposed foundation procedure during earthquakes. The CF was constructed by a conventional construction ethod and the IF applied the proposed improved foundation technique. Previously we have obtained many earthquake records, i.e., The Mid Niigata prefecture Earthquake in 2004, The Northwest Chiba prefecture Earthquake in 2005 and so forth. The Northwest Chiba prefecture Earthquake provided the largest acceleration observation record in the last ten years at the experiment site. The evaluation of the spectral intensity of the observation records indicated that the proposed foundation technique would effectively reduce the severe damage of earthquake destructivity. However, the efficient results by the seismic response were not shown in comparison with forced vibration tests because the size of the foundation block was too small. Therefore, the seismic response analysis of a full-scaled structure that installs the damping material into trenches dug along the foundation was carried out, and the effectiveness of the proposed damping material on seismic response mitigation of the structure was demonstrated.