On the verification of superposition method of kinematic interaction and inertial interaction in dynamic response analysis of soil-pile-structure systems. Issue 113 (October 2018)

• Record Type: Journal Article
• Authors: Ullah, Md. Shajib; Yamamoto, Hiroki; Goit, Chandra Shekhar; Saitoh, Masato
• Is Part Of: Soil dynamics and earthquake engineering. Issue 113(2018)
• Page Start: 522
• Page End: 533
• Publication Date: 2018-10
• Subjects: Kf* pile head impedance functions (IFs) -- kf real part of pile head IFs -- Cf imaginary part of pile head IFs -- ωm circular loading frequency on model -- ωp circular loading frequency on prototype -- η density scaling ratio -- λ geometric scaling ratio -- ρm density of the model -- ρp density of the prototype -- lm linear dimension of the model -- lp linear dimension of the prototype -- d pile diameter -- s pile-to-pile spacing -- s/d spacing to diameter ratio -- fns natural frequency of superstructure -- ζs superstructure damping ratio -- ms mass of superstructure -- mf mass of footing -- Ks stiffness of superstructure -- üg input ground excitation -- u̇eff effective foundation input motion in terms of velocity -- u̇f footing response in terms of velocity -- u̇s superstructure response in terms of velocity -- qk generalized coordinate -- T kinetic energy -- U strain energy -- D dissipation function -- Cs damping coefficient of superstructure -- Ts total response of superstructure with respect to the base excitation -- ϕs phase corresponding to the total response of superstructure -- Tf total response of footing with respect to the base excitation -- ϕf phase corresponding to the total response of footing -- u̇r relative acceleration response at footing; Superposition -- Kinematic interaction -- Inertial interaction -- Dynamic response -- Shaking table tests; Soil dynamics -- Periodicals; Earthquake engineering -- Periodicals; Sols -- Dynamique -- Périodiques; Génie parasismique -- Périodiques; 624.176205
• DOI: 10.1016/j.soildyn.2018.06.023
• Languages: English
• ISSNs: 0267-7261

Abstract

Abstract: A simplified analytical formulation has been used to verify the superposition method of two components of soil-structure interactions (SSI), namely-the kinematic interaction and the inertial interaction for estimating the dynamic response of soil-pile-structure systems (SPSS). The dynamic response analysis is conducted in the frequency domain and the soil behavior ranging from elastic-to-inelastic state is covered. The effective foundation input motion (EFIM) is obtained from shaking table model testing under 1 g conditions for the kinematic interaction and the pile head impedance functions (IFs) are estimated from pile-head loading test for the inertial interaction, respectively. The EFIM and pile head IFs both have frequency and loading amplitude dependent characteristics. These experimentally recorded EFIM and pile head IFs are used as inputs in the analytical formulations to compute the dynamic response of the SPSS by superimposing the kinematic and inertial interaction. Superimposing adopts a linear interpolation method for appropriate use of the pile head IFs. The analytical (superimposed) dynamic response is then compared with experimentally measured dynamic response for verification purpose of superposition method and the comparison shows good agreement indicating that with appropriate use of EFIM and IFs, superposition method is reasonably good to produce the frequency and amplitude dependent dynamic response characteristics of SPSS. Certain discrepancies in amplification ratio and in resonant frequency particularly around the dominant vibrating modes have been observed in the comparison. The reason for such observed disagreements is possibly the difference between soil damping (hysteretic and radiation) and the difference between soil-pile stiffness. Highlights: Effective foundation input motion (EFIM) i.e. the kinematic interaction effects are measured experimentally. Impedance functions (IFs) i.e. the inertial interaction effects are measured experimentally. Total dynamic response of soil-pile-structure systems (SPSS) are measured experimentally. Total dynamic response of SPSS are estimated analytically by superposition of experimental EFIM and IFs. Superposition method results accuracy are verified by comparing with experimental total responses.