• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2001.09a
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• pp.139-146
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• 2001

The seismic safety analysis were performed for the center-core rockfill dam(CCRD) The static and pseudo-static FEM analysis using seismic coefficient Method, and dynamic FEM analysis using Hachinohe earthquake wave(0.12g) were used for the seismic safety of CCRD. The results of seismic analysis were that the factor of safety of down slope was 1.5, horizontal displacement is about 14.3cm, and vertical displacement is 3.3cm at dam creast. The model dam did not show any seismic stability problems for 0.12g. And much more research is still necessary in seismic safety of CCRD.

• Journal of the Earthquake Engineering Society of Korea
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• v.9 no.4 s.44
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• pp.1-10
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• 2005

The purpose ol this study Is to suggest a proper analysis model that can evaluate seismic stability for local rock foundation of nuclear power plant. Sliding Analysis, Pseudo-static Analysis and Dynamic Analysis methods are used for analysing NPP rock foundation with the conditions like acting directions of input earthquake, boundary conditions, width and depth of analysing model, and modeling methods of weakness fault zones. As the results of study, Pseudo-static Analysis for lateral roller and dynamic analysis for transfer boundary condition showed good results, and analysing ranges of width and depth were 5 times of structure width and over 2 times ol structure depth.

• Journal of Korean Association for Spatial Structures
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• v.14 no.4
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• pp.89-96
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• 2014

Spatial structures as like dome structure have the different dynamic characteristics from general rahmen structures. Therefore, it is necessary to accurately analyze dynamic characteristics and effectively control of seismic response of spatial structure subjected to multi-supported excitation. In this study, star dome structure that is subjected to multi-supported excitation was used as an example spatial structure. The response of the star dome structure under multiple support excitation are analyzed by means of the pseudo excitation method. Pseudo excitation method shows that the structural response is divided into two parts, ground displacement and structural dynamic response due to ground motion excitation. And the application of passive tuned mass damper(TMD) to seismic response control of star dome structures has been investigated. From this numerical analysis, it is shown that the seismic response of spatial structure under multiple support seismic excitation are different from those of spatial structure under unique excitation. And it is reasonable to install TMD to the dominant points of each mode. And it is found that the passive TMD could effectively reduce the seismic responses of dome structure subjected to multi-supported excitation.

• Geomechanics and Engineering
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• v.5 no.1
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• pp.37-55
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• 2013

An important issue in the design of soil-nailing systems, as long-term retaining walls, is to assess their stability during seismic events. As such, this study is aimed at simulating the dynamic behavior and failure pattern of nailed structures using two series of numerical analyses, namely dynamic time history and pseudo-static. These numerical simulations are performed using the Finite Difference Method (FDM). In order to consider the actual response of a soil-nailed structure, nonlinear soil behaviour, soil-structure interaction effects, bending resistance of structural elements and construction sequences have been considered in the analyses. The obtained results revealed the efficiency of both analysis methods in simulating the seismic failure mechanism. The predicted failure pattern consists of two sliding blocks enclosed by three slip surfaces, whereby the bottom nails act as anchors and the other nails hold a semi-rigid soil mass. Moreover, it was realized that an increase in the length of the lowest nails is the most effective method to improve seismic stability of soil-nailed structures. Therefore, it is recommended to first estimate the nails pattern for static condition with the minimum required static safety factor. Then, the required seismic stability can be obtained through an increase in the length of the lowest nails. Moreover, placement of additional long nails among lowest nails in existing nailed structures can be considered as a simple retrofitting technique in seismic prone areas.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2001.09a
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• pp.147-154
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• 2001

In this study, comprehensive seismic performance analysis were performed for the concrete face rockfill dam(CFRD) designed seismic coefficient method(0. 10g). The static and pseudo-static FEM analysis, limited equilibrium method and dynamic FEM analysis were used for the dam safety analysis. The results of the seismic analysis were that the minimum factor of safety of down slope was 1.2 and horizontal displacement increased 8cm and vertical displacement increased 1.2cm at dam crest rather than those of static condition. The model dam did not show any serious tai lure in seismic stabi1ity for 0.13g. And much more research is still necessary in seismic safety of CFRD.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2005.03a
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• pp.74-81
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• 2005

The purpose of this study is to suggest a proper analysis model that can evaluate seismic stability for local rock foundation of nuclear power plant. Sliding Analysis, Pseudo-static Analysis and Danamic Analysis methods are used for analysing NPP rock foundation with the conditions like acting directions of input earthquake, boundary conditions, width and depth of analysing model, and modeling methods of weakness fault zones. As the results of study, Pseudo-static Analysis for lateral roller and dynamic analysis for transfer boundary condition showed good results, and analysing ranges of width and depth were 5 times of structure width and over 2 times of structure depth.

• Journal of the Korean Geotechnical Society
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• v.37 no.9
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• pp.5-12
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• 2021

Pseudo-static slope stability analysis method is widely used in engineering practice to calculate the seismic factor of safety of slope subjected to earthquake ground motions. Although the dynamic analysis method is well recognized to have the primary advantage of simulating the stress-strain response of soils, it is not often used in practice because of the difficult in estimating the factor of safety. In this study, a procedure which utilizes the dynamic analysis method to extract the transient dynamic factor of safety is devleoped. This method overcomes the major limitation of the pseudo-static method, which uses an empirically determined seismic coefficient to derive the factor of safety. The proposed method is applied to a slope model and the result is compared with that of the pseudo-static method. It is shown that minimum dynamic factor of safety calculated by the dynamic analysis is slightly larger than that determined from the pseudo-static method. It is also demonstrated that the dynamic factor of safety becomes minimum when the horizontal seismic coefficient and horizontal average acceleration are maximum.

• Journal of the Earthquake Engineering Society of Korea
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• v.21 no.2
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• pp.77-85
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• 2017

Pseudo-static approach has been conventionally applied for the design of gravity quay walls. In this method, the decision to select an appropriate seismic coefficient ($k_h$) is an important one, since $k_h$ is a key variable for computing an equivalent pseudo-static inertia force. Nonetheless, there is no unified standard for defining $k_h$. Likewise, port structure designers in Korea have a difficulty in choosing an appropriate $k_h$ definition, as there are conflicts in how $k_h$ is defined between the existing seismic code of port structures and the proposed new one. In this research, various seismic design codes for port structures were analyzed to compare the definitions of the seismic coefficient. The results were used for the proposing a unified seismic coefficient definition. Further, two dynamic centrifuge tests were performed with different wall heights (5 m, 15 m) to clarify the reference point of peak acceleration used in determination of $k_h$ according to the wall height. Results from dynamic centrifuge experiments showed that correction factors for the peak ground acceleration considering both the wall height and allowable displacement are needed to calculate $k_h$.

• Journal of the Earthquake Engineering Society of Korea
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• v.11 no.1 s.53
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• pp.21-27
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• 2007

In this study, an approach that installs seismic isolation bearings was proposed for the seismic retrofit of the existing bridges. The method that replaces all existing bearings with seismic isolators was proposed already. However, in this study, we recommend to utilize the existing bearings for the benefit of safety and cost. According to our proposal, the seismic isolators do not support vertical loads but they Just function as the period shifter and the horizontal damper. To verify this approach experimentally, the real scale bearings and lead rubber bearings far the real highway bridges were designed and fabricated. And the responses of this isolated bridges to the assumed earthquakes were determined by the pseudo dynamic test scheme. The test results were also compared to the responses computed by the well known structural analysis software to check the reliability of the test. From the test results, we found that the retrofitted bridges using the proposed method showed stable performances under earthquakes.

• Journal of the Korea Concrete Institute
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• v.14 no.2
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• pp.180-189
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• 2002

The objective of this experimental research is to assess the seismic performance of circular RC bridge pier specimens retrofitted with fibers which were designed as a prototype of Hagal bridge in the city of Suwon, Korea. Pseudo dynamic test has been done for four(4) test specimens which were nonseismically or seismically designed by the related provisions of the Korea roadway bridge design specification, and four nonseisemic test specimens retrofitted with fibers in the plastic hinge region. Glass and carbon fiber sheets were used for the seismic capacity enhancement of circular test specimens. Important test parameters were confinement steel ratio, load pattern, and retrofitting. The seismic behavior has been analyzed through the displacement ductility, energy analysis, and capacity spectrum. Approximate 7.7 ∼8.7 displacement ductility was observed for nonseismic test specimens retrofitted with fibers subjected to Korea Highway Cooperation artificial earthquake motions. It is concluded that these retrofitted test specimens could have sufficient seismic capacity in the region of moderate seismic zone.