A fundamental study on the earthquake response reduction of base‐isolated foundation backfilled using an improved compound geomaterial

• Published in: Japan architectural review 2018-01, Vol.1 (1), p.56-66
• Main Authors: Miyamoto, Yuji, Shimamura, Atsushi, Fujii, Satoru, Hoshizawa, Fumiko, Kashiwa, Hisatoshi
• Format: Article
• Language: English
• Subjects: Aseismic buildings; Backfill; Cement; Deformation; Deformation effects; Earthquakes; Embedded foundations; Embedding; Finite element method; Friction resistance; improved compound geomaterial; Laboratories; Laboratory tests; Material properties; Model testing; nonlinear soil‐structure interaction; Particle size; Physical properties; Recycling; Rubber; Seismic engineering; Seismic response; seismic‐isolated foundation; Shake table tests; shaking table test; Shear tests; Soil improvement; Soil investigations; Soils; Studies; Superstructures; three‐dimensional nonlinear finite element method; Ultrasonic testing
• ISSN: 2475-8876; 2475-8876
• DOI: 10.1002/2475-8876.1013

This study addresses the development of a seismic‐isolated foundation embedded with improved soil to reduce the response of a superstructure. The material properties of the new improved composite soil are investigated by performing laboratory tests. Subsequently, the response behaviors of test model structures are discussed considering various contact conditions at the bottom of the foundation and different improved backfill soils around the foundation by conducting shaking table tests. Furthermore, the results of the analysis are obtained using a three‐dimensional nonlinear finite element method to clarify the effect of contact conditions at the bottom of the foundation and that of the improved compound soil on the seismic response of a building. Based on these results, an effective method to reduce the response of a building is to decrease the frictional resistance of the foundation bottom in order to reduce the input motion and make it non‐resonant. In addition, the response can be reduced by absorbing the seismic vibration energy in the improved composite soil embedded around the foundation. Furthermore, it is expected that the improved composite soil along with its toughness will result in the suppression of the excessive deformation of the foundation due to the effect of embedding.