Influence of frequency-dependent dynamic soil stiffness and interacting parameters on elastic and inelastic response of soil-structure systems

Document Type : Original Article

Authors

1 Department of Civil Engineering, University of Mazandaran, Babolsar, Iran

2 Department of civil engineering. University of Mazandaran, Babolsar, Iran

Abstract

In seismic analysis and design of structures, it is generally assumed that the soil beneath the foundation is rigid and, thus, its flexibility is not taken into account. Soil flexibility can affect the response of structures through complex phenomenon of dynamics soil-structure interaction effect. It is believed that effective soil and structural parameters could in some case significantly influence seismic response of structures in different manners and conditions. In this study, through an intensive parametric study, the effect of key parameters of soil-structures for both constant-strength and constant-ductility conditions are examined. In this regard, the effect of foundation mass, structure and foundation mass moment of inertia, structure-to-soil stiffness ratio, structural aspect ratio, the ratio of structural mass to soil mass, and, more importantly, the effect of frequency-dependent soil dynamic stiffness on the elastic and inelastic response of superstructures are investigated. The results of this study indicate that excitation frequency dependence, foundation mass and mass moment of inertia have insignificant effects on the base shear coefficient, displacement amplification factor of soil-shallow foundation systems. Nevertheless, other parameters such as soil foundation-to-structure mass ratio and dimensionless frequency and aspect ratio could have considerable effects on the response of the soil-shallow foundation SDOF systems.

Keywords

Main Subjects

References

[1] FEMA, Prestandard And Commentary For the Seismic Rehabilitation Of Buildings., (2000)., Washington, D.C.: Report FEMA 356, Federal Emergency Management Agency, 519.
[2] FEMA, NEHRP Recommended Provisions For Seismic Regulations For New Buildings And Other Structures., (2003)., Washington, D.C.: Report FEMA 450, Federal Emergency Management Agency, 356.
[3] Ganjavi, B., And Hao, H. (2014). Strength Reduction Factor for MDOF Soil-Structure Systems. The structural Design of Tall and Special Buildings, 23 (3), 163-180.
[4] Ahmadi, E., And Khoshnoudian, F. (2015). Near-fault effects on strength reduction factors of soil-MDOF structure systems. Soils and Foundations, 55(4), 841-856.
[5] Muller FP, And Keintzel E. (1982) Ductility requirements for flexibly supported anti-seismic structures. Proceedings of the Seventh European Conference on Earthquake Engineering, , 3, 27–34.
[6] Ganjavi, B., And Hao, H. (2012). A parametric study on the evaluation of ductility demand distribution in multi-degree-of freedom systems considering soil–structure interaction effects. Engineering Structures, 43, 88–104.
[7] Khoshnoudian, F., Ahmadi, E., & Nik, F. A. (2013). Inelastic displacement ratios for soil-structure systems. Engineering Structures, 57, 453-464.
[8] Eser, M., Aydemir, C., And Ekiz, I. (2012). Inelastic displacement ratios for structures with foundation flexibility. KSCE Journal of Civil Engineering, 16(1), 155-162.
[9] Ahmadi, E. And Khoshnoudian, F. (2013). Evaluation of maximum displacement factor for soil-structure systems, CSCE 2013 General Conference. Montreal, Québec, Canada: 95, 1.
[10] Ganjavi, B. Hajirasouliha, I. And Bolourchi, A. (2016). Optimum lateral load distribution for seismic design of nonlinear shear-buildings considering soil-structure interaction. Soil Dynamics and Earthquake Engineering, 88, 356-368.
[11] Cruz, C. And Miranda, E. (2017). Evaluation of soil-structure interaction effects on the damping ratios of buildings subjected to earthquakes. Soil Dynamics and Earthquake Engineering, 100, 183-195.
[1] FEMA, Prestandard And Commentary For the Seismic Rehabilitation Of Buildings., (2000)., Washington, D.C.: Report FEMA 356, Federal Emergency Management Agency, 519.
[2] FEMA, NEHRP Recommended Provisions For Seismic Regulations For New Buildings And Other Structures., (2003)., Washington, D.C.: Report FEMA 450, Federal Emergency Management Agency, 356.
[3] Ganjavi, B., And Hao, H. (2014). Strength Reduction Factor for MDOF Soil-Structure Systems. The structural Design of Tall and Special Buildings, 23 (3), 163-180.
[4] Ahmadi, E., And Khoshnoudian, F. (2015). Near-fault effects on strength reduction factors of soil-MDOF structure systems. Soils and Foundations, 55(4), 841-856.
[5] Muller FP, And Keintzel E. (1982) Ductility requirements for flexibly supported anti-seismic structures. Proceedings of the Seventh European Conference on Earthquake Engineering, , 3, 27–34.
[6] Ganjavi, B., And Hao, H. (2012). A parametric study on the evaluation of ductility demand distribution in multi-degree-of freedom systems considering soil–structure interaction effects. Engineering Structures, 43, 88–104.
[7] Khoshnoudian, F., Ahmadi, E., & Nik, F. A. (2013). Inelastic displacement ratios for soil-structure systems. Engineering Structures, 57, 453-464.
[8] Eser, M., Aydemir, C., And Ekiz, I. (2012). Inelastic displacement ratios for structures with foundation flexibility. KSCE Journal of Civil Engineering, 16(1), 155-162.
[9] Ahmadi, E. And Khoshnoudian, F. (2013). Evaluation of maximum displacement factor for soil-structure systems, CSCE 2013 General Conference. Montreal, Québec, Canada: 95, 1.
[10] Ganjavi, B. Hajirasouliha, I. And Bolourchi, A. (2016). Optimum lateral load distribution for seismic design of nonlinear shear-buildings considering soil-structure interaction. Soil Dynamics and Earthquake Engineering, 88, 356-368.
[11] Cruz, C. And Miranda, E. (2017). Evaluation of soil-structure interaction effects on the damping ratios of buildings subjected to earthquakes. Soil Dynamics and Earthquake Engineering, 100, 183-195.

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History

  • Receive Date: 14 July 2017
  • Revise Date: 28 October 2017
  • Accept Date: 05 November 2017

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