• 한국전산구조공학회논문집
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• 제34권5호
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• pp.309-317
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• 2021

이 논문에서는 박스형 전력구의 지진응답해석에 사용되는 응답진도법의 보수성을 평가하였다. 이를 위해 25가지 전력구 단면과 각 전력구에 대한 2개의 지반조건을 고려한 총 50개 예제를 선정하였다. 응답진도법의 보수성을 평가하기 위해 동적 지반-구조물 상호작용을 고려한 정밀해석법에 의한 응답과 비교하였다. 비교결과, 정밀해석 응답에 대한 응답진도법에 의한 응답의 비로 정의한 응답비의 평균이 1.0에 근접하며, 응답비의 표준편차도 5% 이내로 매우 작아서, 응답진도법에 의한 해석이 정밀해석법과 일관됨을 알 수 있었다. 마지막으로 응답진도법에 의한 응답에 하중계수 1.1을 적용하면 전력구의 보수적인 내진설계가 가능할 것으로 나타났다.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1996년도 가을 학술발표회 논문집
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• pp.70-77
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• 1996

In this study, sliding response analysis of free standing structure such as multi-purpose nuclear spent fuel storage cask is peformed. The governing factors of sliding response are aspect ratio of structure and ground acceleration. The vertical acceleration component is very important factor in the sliding response of the structure. Based on the mathematical model, computer program is developed using direct forward integration method to predict the sliding response. Using the program, several parametric studies were made for sinusodial ground motion and for El Centre 1940 earthquake and Mexico 1973 earthquake. From the results, it is known that the frequency content and duration of strong motion affect the sliding of the structure.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2002년도 봄 학술발표회 논문집
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• pp.767-772
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• 2002

Free-field ground motion during earthquake is significantly affected by the local site conditions and it is essential in the seismic design to perform the accurate site-specific ground response analysis. In this paper, one-dimensional seismic characteristics of waste landfill are studied based on the vertical propagation of horizontal shear waves through the column of soil/waste. Seismic response analysis is peformed for short-period, long-period and artificial earthquake ground motions using a computer program for seismic response analysis of horizontally layered soil deposits. The computed peak ground accelerations are compared with the values calculated according to Korean seismic design guidelines. The analysis result shows that the long-period earthquake causes the largest peak ground acceleration while the artificial earthquake results in the smallest one.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2006년도 학술발표회 논문집
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• pp.637-644
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• 2006

Acceleration time history used in the seismic analysis of nuclear porter plant structure should envelop a target power spectral density (PSD) function in addition to design response spectrum. Current regulation guide defines the target PSD function only for the U.S. URC RG 1.60 Design Response Spectrum. This paper proposes a technical scheme to obtain the target PSD function compatible with generally defined design response spectrum. The scheme includes the methodology for design-spectrum compatible motion history in order to minimize the variation of the derived target PSD function. The PSD calculation procedure follows simple and practical methods allowed within regulation. Effectiveness of the proposed scheme is identified through an example problem. The design response spectrum In the example is based on U.S. NRC RG 1.60 but amplifies the spectral acceleration amplitudes above 9Hz. The target PSD function with little variation can be constructed with the reduced time history ensemble.

• Geomechanics and Engineering
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• 제15권3호
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• pp.833-839
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• 2018

Dynamic behaviour of a tunnel is one of the most important issues for the safety and it is generally subjected to the seismic response of the surrounding soil. Relative displacement occurred in tunnel lining during earthquake produces severe damage. Generally, it concentrates at the connecting area when two tunnels are connected in the ground. A flexible segment is a useful device for the mitigation of seismic loads on tunnel lining. In this study, 1-g shaking table tests are performed to investigate the acceleration response for the verification of the effect of flexible segment and to determine the optimum location of the flexible segment for connected tunnels. Four different seismic waves are considered; as a result, peak acceleration is reduced to 49% in case that flexible segment is implemented adjacent to connecting area. It also exhibited that the mitigation of acceleration response is verified in all seismic waves. Additionally, 3-dimensional numerical analysis is performed to compare and verify the results. And the numerical results show good agreement to those of the experimental study.

• 한국해양공학회지
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• 제23권1호
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• pp.114-121
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• 2009

In this study, acceleration responses of caisson structures under various environmental conditions are experimentally examined as a basic study to develop the health assessment technique for harbor structures. To achieve the objective, three approaches are implemented. Firstly, a target caisson structure is selected and its small-scaled caisson is constructed in the laboratory. Secondly, a finite element model of the caisson is generated to identify dynamic responses of the baseline structure. Thirdly, experimental tests are performed on the caisson model to examine dynamic responses under various boundary conditions and impact locations. Four different boundary conditions, 'standing on concrete floor', 'standing on styrofoam block', 'standing on sand-mat' and 'hanging by crane', are considered and correlation coefficients of frequency response functions between four states are analyzed.

• 한국안전학회지
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• 제33권1호
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• pp.81-87
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• 2018

The seismic response, the natural frequencies and the mode shapes of an offshore wind turbine with twisted tripod substructure subject to various pile-ground interactions are discussed in this paper. The acceleration responses of the tower head by four historical earthquakes are presented as the seismic response, while the other loads are assumed as ambient loads. For the pile-ground interactions, the fixed, linear and nonlinear models are employed to simulate the interactions and the p-y, t-z and Q-z curves are utilized for the linear and nonlinear models. The curves are designed for stiff, medium and soft clays, and thus, the seven types of the pile-ground interactions are used to compare the seismic response, the acceleration of the tower head. The mode shapes are similar to each other for all types of pile-ground interactions. The natural frequencies, however, are almost same for the three clay types of the linear model, while the natural frequency of the fixed support model is quite different from that of the linear interaction model. The wind turbine with the fixed support model has the biggest magnitude of acceleration. In addition, the nonlinear model is more sensitive to the stiffness of clay than the linear pile-ground interaction model.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 추계학술대회논문집
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• pp.465-470
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• 2003

In this study, the state-space Newmark method based on average velocity is presented to analyse the transient dynamic response for general dynamic system. The conventional Newmark method based on average acceleration cannot he directly to the first-order state-space differential equations introducing the state-space vector. To overcome this problem, the time-step integration algorithm, based on average velocity concept, suitable for the first-order state-space differential equations is proposed In results, the proposed method has %he numerical stability and order of accuracy, which is proved analytically, equal to those of the conventional Newmark method based on average acceleration. Also, the formulation for numerical solution is very simple and the calculation time Is nearly equal to that of the conventional Newmark method based on average acceleration in spite of an increase of two times over matrix size. This method will be look forward to applying the general dynamic system to calculate the transient dynamic response.

• 한국지진공학회논문집
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• 제20권7_spc호
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• pp.425-434
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• 2016

This study investigates important parameters used to determine an effective peak ground acceleration (EPGA) based on the characteristics of response spectra of historical earthquakes occurred at Korean peninsula. EPGAs are very important since they are implemented in the Korean Building Code for the seismic design of new structures. Recently, the Gyeongju earthquakes with the largest magnitude in earthquakes measured at Korea took place and resulted in non-structural and structural damage, which their EPGAs should need to be evaluated. This paper first describes the basic concepts on EPGAs and the EPGAs of the Gyeongju earthquakes are then evaluated and compared according to epicentral distances, site classes and directions of seismic waves. The EPGAs are dependant on normalizing factors and ranges of period on response spectrum constructed with the Gyeongju earthquake records. Using the normalizing factors and the ranges of period determined based on the characteristics of domestic response spectra, this paper draw a conclusion that the EPGAs are estimated to be about 30 % of the measured peak ground accelerations (PGA).

• Geomechanics and Engineering
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• 제21권1호
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• pp.35-51
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• 2020

In this study, the seismic response analysis of embankment dams was investigated through numerical modeling. The seismic behavior of dams under main earthquake records and wavelet-based records were studied. Earthquake records were decomposed using de-noising method (DNM) and down-sampling method (DSM) up to five levels. In decomposition process, low and high frequencies of the main earthquake record were separated into two signals. Acceleration response, spectral acceleration, and Fourier amplitude spectrum at the crest of embankment dams under different decomposition levels were evaluated. The seismic behavior under main and decomposed earthquake records was compared. The results indicate an acceptable agreement between the seismic responses of embankment dams under wavelet-based decomposed records and main earthquake motions. Dynamic analyses show that the DNM-based decomposed earthquake records have a better performance compared to DSM-based records. DNM-based records up to level 4 and DSM-based records up to level 2 have a high accuracy in assessment of seismic behavior of embankment dams. The periods corresponding to the maximum values of acceleration spectra and the frequencies corresponding to the maximum values of Fourier amplitude spectra of embankment dam crest under main and decomposed records are in good agreement. The results demonstrate that the main earthquake records can be replaced by wavelet-based decomposed records in seismic analysis of embankment dams.