• Journal of the Korean GEO-environmental Society
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• v.24 no.10
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• pp.41-49
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• 2023

Structures such as bridge columns installed on the asymmetric ground such as mountain areas and sloping ground are subject to various loads such as wind, temperature, earthquake, and etc. The pile foundation is generally applied to bridge columns on the asymmetric ground in order to stably support structures. The behavior of the pile foundation supporting bridge columns changes due to various load conditions. In particular, ground-pile-structure interactions should be studied to analyze the behavior of the pile foundation that supports bridge columns effected by dynamic loads such as earthquakes. The pile foundation installed on the asymmetric ground effected by the earthquake has the complicated dynamic interaction between the foundation and the ground due to the ground slope, the difference in soil resistance according to the shaking direction, and the ground movements. In this study, the 1g shaking table tests were conducted to confirm the effect of the slope of the sloping ground on the dynamic behavior of group piles supporting the superstructure installed at the berm of the sloping sandy soil which is the asymmetric ground. The result shows that the acceleration of the pile cap and the superstructure decrease as the slope of the sloping ground increase, and the slope of the dynamic p-y curve of the pile decrease.

• Journal of the Earthquake Engineering Society of Korea
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• v.1 no.3
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• pp.1-10
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• 1997

It is recognized that the dynamic of a structure is affected by the characteristics of the soil layer and foundation. However the design codes for the seismic design of structures are partially reflecting the caharcteristics of the soil layers due to the inherent complexity of them and the lack of systematic study results for the foundation-soil system, and leading to unconservative or too conservative results. In this study, the kinematic interaction effects of foundation-soil system was investigated for the seismic analyses of structures estimating the effects of the shear wave velocity, the depth of the soil layer, the embedment of a foundation and pile foundation, and the modified classification criteria of soil layers are proposed for the reasonable seismic analyses of structures considering the characteristics of soil layers and foundations. For the embedded medium or large foundations (including pile foundations), at least 60m soil layer below the foundation should be considered for the seismic analyses of structures to tate into account the kinematic interaction effects of the foundation-soil system, and also the rocking motion of foundation-soil system with or without piles should be included in the seismic analyses of structures.

• Journal of the Earthquake Engineering Society of Korea
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• v.16 no.3
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• pp.13-22
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• 2012

Even with its significant influence on the dynamic analysis and foundation design of structures, sometimes the soil-structure interaction has been ignored during the design process. One of the reasons is due to the fact that the modeling procedures are too complicated to meet the requirements in practice. In this study, using the Cali(IT)2 building in California with high and frequent seismic activities, the analysis differences for different boundary conditions are reviewed. The Beam on Nonlinear Winkler Foundation Model, one of the foundation modeling methods, is modified for easy use by the Linear Matrix Inequalities Model Reduction Technique. The product of the proposed process is applied to create the Finite Element Model. The results show fairly good agreement with the real data acquired from the Cal(IT)2 building.

• Journal of the Korean Geotechnical Society
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• v.38 no.6
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• pp.17-28
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• 2022

The effect of the soil-structure interaction (SSI) on has been recently evaluated in shaking table tests. However, most of these tests were conducted on single-degree-of-freedom (SDOF) superstructures and a single-pile. This study investigates the inertial interaction effect of a multi-degree-of-freedom (MDOF) superstructure system with a group piles on a large-scale shaking table test. Whereas the SDOF superstructure system shows a single-frequency amplification tendency, the MDOF superstructure system exhibited amplification tendencies of the acceleration phase and frequency responses for multiple frequencies. In addition, the amplification phenomenon between the footing and the column-type superstructure exceeded that between the footing and the wall-type superstructure, indicating a greater inertial interaction effect of the column-type superstructure. The relationship between shear force and inertial force, the relative vertical and horizontal displacements on the footing was figured out. Also, the ananlysis of dynamic p-y curve at each depth was conducted. In summary, the MDOF and SDOP superstructure systems exhibited different behaviors and the column-type superstructure exerted a higher interaction effect than the wall-type superstructure.

• Geotechnical Engineering
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• v.5 no.2
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• pp.33-44
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• 1989

In this paper, uncertainties in dynamic soil structure interaction (SSI) of nuclear poi.or plants subjected to seismic loading are studied considering the random characteristics of soils surround- ing the structure. Firstly sensitivity analysis is performed to study the effect of uncertain dynamic soil properties on the response of the structure. Secondly, to take into account the non-neterministic characteristics in analysis caused by random characteristics of the soil properties, Perturbation method and Rosenblueth's Two point estimates were used for this studu. The procedure is based on the comptex response method which is constituted by a combined usage of conventional finite elements for the near field and infinite elements for the far field. Results of the sensitivity analysis show that dynamic soil properties greatly affect the response of the sol.uc- lure. Results of the probabilistic analysis show that the Two-point estimate method produces good agreements with the Perturbation method.

• Journal of the Korean Geotechnical Society
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• v.38 no.4
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• pp.47-58
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• 2022

Many 1g shaking table tests with an SDOF structure supported by a single pile were performed to evaluate the soil-structure interaction (SSI) effect. Since most structures supported by group piles are MDOF structures with columns, the SSI effect is simulated using a large 1g shaking table test and numerical analysis. According to the results, the movement in the piles tends to increase with input acceleration and when the input frequency is similar to the natural frequency. Furthermore, the slope of the dynamic p-y curve remains constant regardless of the variation of acceleration and input frequency. According to the results of the dynamic p-y backbone curve and the moment of group piles, a center pile with a leading pile has more soil resistance than side piles with a trailing pile, and the effect of group piles is observed above the 7D center to center pile distance.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.10 no.2
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• pp.103-112
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• 1990

This study examines the characteristics of soil behavior which includes many uncertainties in seismic design, evaluates the dynamic soil properties and studies the soil-structure interaction to generalize the applicability and economy of the available sites. An example analysis is performed for soil-structure system response assuming a containment structure built on site which includes soil layers using both elastic halfspace analysis and FEM analysis against the seismic loads from the actual design. This exercise is performed as a part of the safety analysis and economic assessment of the nuclear power plant built on soils. It includes the preparation of computer program capable of incorporating large nonlinearity in the analysis, resonable evaluation procedures to determine input soil data. Nonlinear FEM analysis of Seed and Idriss model is found suitable for the accurate analysis of dynamic response of soils. Linear FEM analysis using dynamic soil properties at strain level obtained by one-dimensional seismic response, and elastic half-space analysis using dynamic soil properties at strain level under static loads are recommended to evaluate the dynamic soil properties.

• Journal of the Earthquake Engineering Society of Korea
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• v.2 no.1
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• pp.23-34
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• 1998

A dynamic fluid-structure-soil interaction analysis method is developed to investigate the effects of translational and/or rocking motions on the seismic response of flexible rectangular liquid storage tanks founded on the deformable ground. The governing equation for the dynamics of 3-D rectangular tanks subjected to the translational and/or rocking motion is abtained by applying Rayleigh-Ritz method. The dynamic stiffness matrices of a rigid rectangular foundation resting on the surface of a stratum overlaid bedrock are calculated by hyperelement method. The seismic responses of 3-D flexible tank model founded on the deformable ground is calculated by combining the governing equation for the fluid-tank system with the dynamic stiffness matrix of th rigid surface foundation.

• Journal of Korean Tunnelling and Underground Space Association
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• v.7 no.3
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• pp.249-257
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• 2005

There are basically two methods for the seismic design of underground structures ; analytical or pseudo-static, and dynamical method. In pseudo-static analysis approach, the ground deformations are imposed as a static load and soil-structure interaction does not include dynamic or wave propagation effects. However the behavior of soil structure interaction is nonlinear, it needs to consider nonlinear soil-structure interaction effects. In this study simplified seismic analysis method to consider soil-structure interaction by iterative procedure is proposed and the results are compared and analyzed by a finite difference computer program.

• Journal of Korean Tunnelling and Underground Space Association
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• v.20 no.5
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• pp.757-772
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• 2018

Recently, earthquakes have occurred in large cities such as Gyeongju and Pohang, and seismic analysis studies have been actively conducted in various fields. However, since most of the previous seismic analyses have dealt with ground structures and the ground separately, there is a lack of a study on the complete soil-structure dynamic interaction. Therefore, in this study, a sensitivity analysis is conducted with MIDAS GEN and MIDAS GTS NX to apply the underground structure fixed-end model considering only the building and the complete system model considering both the building and the ground, respectively and the validity of dynamic analysis considering SSI is examined. As a result of the study, in most conditions it is found that the maximum horizontal displacement of the tall building in case of the underground structure fixed-end model is estimated to be smaller, the bending stress is larger, and the range of the weak part is smaller than that of the complete system model. Therefore, it is expected to be more reasonable to use the complete system model considering soil-structure interaction in seismic analysis.