Study on earthquake response of slightly damaged RC school building during the 2008 Iwate-Miyagi Nairiku Earthquake: Examination considering influence of lateral soil spring caused by embedded footing beam

The earthquake response analyses of the Iwagasaki High School, the RC building of which was slightly damaged during the 2008 Iwate-Miyagi Nairiku Earthquake, are performed to examine the correspondence relation of the analysis result and the actual damage. In the analyses, the soil structure is estimated by performing the simulation analyses of the aftershock records obtained at this site, and the soil response during the main shock is analyzed using both the estimated soil model and the main shock record obtained at the JMA Kurikoma site near this building.The earthquake response analyses of the structure on the pile foundation considering the nonlinear interaction of the soil-pile-structure system are performed by continuously inputting the soil response during the main shock and the aftershocks to the 3-D model. For the model installed the lateral soil spring showing the resistance caused by the embedded footing beam, the maximum story drift angle of the structure in the part of main shock is in agreement with the value estimated on the basis of the actual damage. The predominant frequency of the model in the part of aftershocks is also in agreement with that estimated using the records. From these results, it is shown that the lateral soil spring influences the actual behavior of this building.