• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.3
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• pp.1-12
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• 2021

The purpose of this paper is to study of the applicability of the current response spectrum analysis method by grasping the dynamic behavior characteristics of soil-pile and pier-crane in pile mooring facilities. To this end, time history analysis was performed using Abaqus as a design variable for various soil types, pile-ground modeling, and structure specific cycles. The results were compared with the analysis results of the response spectrum. Subsequently, a problem has been found in the current response spectrum analysis and the improvements are needed when considering the dynamic behavior of the ground-pile and pier-crane of the pile mooring facility.

• Journal of the Korea institute for structural maintenance and inspection
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• v.24 no.5
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• pp.27-36
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• 2020

The purpose of this paper is to study on the applicability of the standard design response spectrum from the response spectrum analysis method, mainly applied to pile mooring facilities. To this end, after performing the ProShake 1-dimensional site response considering various geological conditions, the current standard design response spectrum was compared, and the ground-pile model in time history and two-dimensional site response analysis using Abaqus were performed to analyze the dynamic behavior of the ground-pile and to examine the selection method of the reference surface of the response spectrum on the installed slope, respectively. As a result, it was confirmed that no problems were found in the applicability of the current standard design response spectrum and no improvements are needed as well when considering the characteristics of the ground-pile dynamic behavior and the slope of the pile mooring facility.

• Journal of the Korean GEO-environmental Society
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• v.24 no.9
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• pp.33-40
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• 2023

The lateral load which is applied to the pile foundation supporting the superstructure during an earthquake is divided into the inertia force of the upper structure and the kinematic force of the ground. The inertia force and the kinematic force could cause failure to the pile foundation through different complex mechanisms. So it is necessary to predict and evaluate interaction of the ground-pile-structure properly for the seismic design of the foundation. The interaction is affected by the lateral behavior of the structure, the length of the pile, the boundary conditions of the head, and the relative density of the ground. Confining pressure and ground stiffness change accordingly when the relative density changes, and it results that the coefficient of subgrade reaction varies depending on each system. Horizontal bearing behavior and capacity of the pile foundation vary depending on lateral load condition and relative density of the sandy soil. Therefore, the 1g shaking table tests were conducted to confirm the effect of the relative density of the dried sandy soil to dynamic behavior of the group pile supporting the superstructure. The result shows that, as the relative density increases, maximum acceleration of the superstructure and the pile cap increases and decreases respectively, and the slope of the p-y curve of the pile decreases.

• Journal of the Korean Geotechnical Society
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• v.39 no.11
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• pp.41-51
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• 2023

This study employs three-dimensional simulation through FLAC3D to investigate the impact of installation angles on the dynamic characteristics of Triaxial Micropiles. The numerical model is validated against centrifuge test results to ensure accuracy. The findings reveal significant influences of the installation angle on the dynamic behavior of Triaxial Micropiles. Specifically, under seismic conditions such as the Capetown and San Fernando earthquakes, the lowest recorded values for peak bending moment and settlement occurred at an installation angle of 15 degrees. In contrast, when subjected to an artificial earthquake with a frequency of 2 Hz (Sine 2 Hz), Micropiles installed at 0 degrees exhibited the lowest peak bending moment, maximum axial load, and settlement values.

• Journal of the Korean Geotechnical Society
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• v.23 no.4
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• pp.79-90
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• 2007

Behaviors of instrumented steel sheet piles which are installed in sand ground by vibratory hammer were investigated. Especially, stresses acting on the pile during vibratory driving, efficiency factor which reflects differences between theoretical driving force and actually delivered acting force, justifiability of rigidity of steel sheet pile, dynamic resistance characteristics of soil and penetration characteristics of sheet pile were analysed. According to the field test results it is justifiable that steel sheet pile behaves as a rigid body during vibratory driving. And it can be seen that maximum stress acting on sheet pile section is far less than tensile strength of the material. Value of the maximum section force at sheet pile head was 72% of that estimated from theoretical equation. Magnitudes of displacement amplitudes computed from displacement-time history curve corresponding to four penetration depths were in the range of 16 $\sim$ 75% of that specified by manufacturer.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.3B
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• pp.281-287
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• 2009

In this study, the behavior of breasting dolphin caused by the maximum wave height in the coastal area of Incheon has been investigated. The dynamic deflection, shear stress and moment of pile are analyzed using the coefficient of horizontal subgrade reaction resulted from loading tests for different DWT (Dead Weight Tonnage). The dynamic characteristics of pile in accumulated and dredged soils show almost the same pattern. It is shown that the resistance of dolphin to external load increases as the diameter of pile increases. The bettered pile dolphin is more than 10 times stable than the vertical pile type based on the study of dynamic characteristics of dolphin.

• Geotechnical Engineering
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• v.12 no.2
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• pp.19-32
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• 1996

Based on Trifuilac's empirical model to transform earthquake acceleration time history in the time domain into Fourier amplitude spectrum in the frequency domail an earthquake scaling technique for simulating the earthquake record of certain magnitude as the required magnitude earthquake was suggested. Also, using the earthquake record of magni dude(M) 5.8, the simulated earthquake of magnitude(M) 8.0 was established and its application to dynamic testing system was proposed. The earthquake scaling technique could be considered by several terms : earthquake magnitude(M), earthquake intensity(MMI), epicentral distance, recording site conditions, component direction and confidence level required by the analysis. Albo, it had an application to the various earthquake records. The simulated earthquake in this study was established by two orthogonal horizontal components of earthquake acceleration-time history. The simulated earthquake shaking could be applied to the dynamic pile load test for the model tension pile and the model compressive open -ended piles driven into the pressure chamber. In the static pile load test, behavior of two piles was very different and after model tension pile experienced 2 or 3 successive slips of the pile relative to the soil, it was failed completely. During the simulated earthquake shaking, dynamic behavior and pile capacity degradation of two piles were very different.

• Journal of the Korean Geotechnical Society
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• v.38 no.5
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• pp.5-17
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• 2022

A pile is a type of medium for constructing superstructures in weak geotechnical conditions. A pretensioned spun high-strength concrete (PHC) pile is composed of high-strength concrete with a specified strength greater than 80 MPa. Therefore, it has advantages in resistance to axial and bending moments and quality control and management since it is manufactured in a factory. However, the skin friction of a pile, which accounts for a large portion of the pile bearing capacity, is only approximated using empirical equations or standard penetration test (SPT) N-values. Particularly, there are some poor research results on the pile-soil interface under the seismic loads in Korea. Additionally, some studies do not consider geoenvironmental elements, such as groundwater pH values. This study performs sets of cyclic simple shear tests using submerged concrete specimens for 1 month to consider pH values of groundwater and clay specimens composed of kaolinite to generate a pile-soil interface. 0.2 and 0.4 MPa of normal stress conditions are considered in the case of pH values. The disturbed state concept is employed to express the dynamic behavior of the interface, and the disturbed function parameters are newly suggested. Consequently, the largest disturbance increase under basic conditions is observed, and an early approach to the failure under low normal stress conditions is presented. The disturbance function parameters are also suggested to express this disposition quantitatively.

• 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 Korean Geotechnical Society
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• v.36 no.11
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• pp.7-20
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• 2020

In this study, the dynamic behavior of a single pile foundation was investigated by using an analytical and numerical studies. The emphasis was given on quantifying a function about the coefficient of dynamic horizontal subgrade reaction from 3D analysis. Based on the numerical analysis, a modified correction factor (α), which is used to obtain the coefficient dynamic horizontal subgrade reaction, was proposed by considering shear wave velocity of soil and confining stress. It was found that the prediction by pseudo-static analysis using the proposed coefficient is in good agreement with the general trends observed by dynamic analysis, and it represents a practical improvement in the prediction of behavior for pile foundations subjected to dynamic loads.