• Journal of the Society of Disaster Information
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• v.11 no.3
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• pp.406-412
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• 2015

Recently, frequent earthquakes can cause serious damage to the bridge. So newly constructed bridge is considered earthquake resistant design, and for the existing old bridge evaluation of damage state is needed. In this paper, replacement of US-artificial earthquakes which are used for the construction of fragility curve for evaluating damage state to Korean artificial earthquakes to meet the Korean specifications is studied. For the generation of artificial earthquakes, the fragility curves are constructed for the PGA, for the cases of having isolated bearing and not having that.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2002.04a
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• pp.214-221
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• 2002

This study introduces a method to generate artificial earthquakes in Korean Peninsular using historical earthquake catalogues and point source model. For this purpose, three earthquake catalogues compiled by different researchers are compared to each other. And epicenters and magnitudes of future earthquakes are generated based on those catalogues. In generating ground motion accelertation, point source model proposed by Boore and Atkinson was adopted. Parameters of the model for South-Eastern part of Korean Peninsular was proposed by Noh and kn. From the epicenters, magnitudes, and ground motion models, possible earthquakes for 50,000 years are generated. Using these generated earthquakes ground accelrations and uniform hazard response spectra (UHRS) having 2%, 5%, and 10% exceedance probability in 50 years are proposed.

• Journal of the Earthquake Engineering Society of Korea
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• v.21 no.6
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• pp.295-301
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• 2017

This paper relates to the study of load characteristics applicable to wind turbine generators induced by earthquakes. An artificial design earthquake wave generated through the target spectrum and the envelope function of Richter Magnitude Scale (ML) 7.0 as in ASCE4-98 was created. A simulation of earthquake loads were performed according to the design load cases (DLC) 9.5~9.7 of GL guidelines. Additionally, simulation of seismic loads experienced by Wind Turbines installed in the Gyeongju region were carried out utilizing artificial earthquakes of ML 5.8 simulating the real earthquakes during the Gyeongju Earthquakes of Sept. 2016.

• Structural Engineering and Mechanics
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• v.24 no.4
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• pp.429-446
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• 2006

Experimental investigation was conducted to evaluate the seismic ductility of earthquake-experienced concrete columns with an aspect ratio of 2.5. Eight circular concrete columns with a diameter of 600 mm were constructed with three test parameters: confinement ratio, lap-splice of longitudinal bars, and retrofitting with Fiber Reinforced Polymer (FRP) materials. The objective of this research is to examine the seismic performance of RC bridge piers subjected to a Quasi static test (QST), which were preliminary tested under a series of artificial earthquake motions referred to as a Pseudo dynamic test (PDT). The seismic enhancement effect of FRP wrap was also investigated on these RC bridge piers. Six specimens were loaded to induce probable damage by four series of artificial earthquakes, which were developed to be compatible with earthquakes in the Korean peninsula by the Korea Highway Corporation (KHC). Directly after the PDT, six earthquake-experienced columns were subjected to inelastic cyclic loading under a constant axial load of $0.1{f_c}^{\prime}A_g$. Two other reference specimens without the PDT were also subjected to similar quasi-static loads. Test results showed that specimens pre-damaged by moderate artificial earthquakes generally demonstrated good residual seismic performance, which was similar to the corresponding reference specimen. Moreover, RC bridge specimens retrofitted with wrapping fiber composites in the potential plastic hinge region exhibited enhanced flexural ductility.

• Earthquakes and Structures
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• v.4 no.5
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• pp.509-525
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• 2013

In this paper, learning capabilities of two types of Arterial Neural Networks, namely hierarchical neural networks and Generalized Regression Neural Network were used in a two-stage approach to develop a method for generating spatial varying accelerograms from acceleration response spectra and a distance parameter in which generated accelerogram is desired. Data collected from closely spaced arrays of seismographs in SMART-1 array were used to train neural networks. The generated accelerograms from the proposed method can be used for multiple support excitations analysis of structures that their supports undergo different motions during an earthquake.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.11a
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• pp.608-612
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• 2003

In the seismic response analysis, the artificial earthquake time history is generated to do the exact seismic analysis for the complex structural system like as containment building. In the present study the several simulated earthquakes are generated by use of SIMQKE program and the time history dynamic analysis of containment building is performed. Also, the seismic responses are statistically analyzed. The seismic response uncertainty arisen from the simulation of earthquakes is one of major uncertainties and the statistical description is needed to account for the random nature of earthquake.

• Proceedings of the Korean Society for Rock Mechanics Conference
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• 1995.03a
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• pp.108-108
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• 1995

There are always some difficulties to discriminate artificial exlposions from micro-earthquakes, furthermore more difficulties to identify and determine decoupled explosions and/or multiple explosions from micro-earthquakes. In this study we use the synthetic seismogram of the in homogeneous models between the source and the observation station in order to find the source effect of the geological environment. We have found some source characteristics of the air-filled and/or water-filled cavity that we can hardly see P-n and S- waves arrivals and that the high frequency coda waves are well observed compared to the coupled explosions or earthquakes.

• Earthquakes and Structures
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• v.14 no.2
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• pp.129-142
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• 2018

The current paper introduces a new approach for development of damage index to obtain the maximum damage in the reinforced concrete frames caused by as-recorded single and consecutive earthquakes. To do so, two sets of strong ground motions are selected based on maximum and approximately maximum peak ground acceleration (PGA) from "PEER" and "USGS" centers. Consecutive earthquakes in the first and second groups, not only occurred in similar directions and same stations, but also their real time gaps between successive shocks are less than 10 minutes and 10 days, respectively. In the following, a suite of six concrete moment resisting frames, including 3, 5, 7, 10, 12 and 15 stories, are designed in OpenSees software and analyzed for more than 850 times under two groups of as-recorded strong ground motion records with/without seismic sequences phenomena. The idealized multilayer artificial neural networks, with the least value of Mean Square Error (MSE) and maximum value of regression (R) between outputs and targets were then employed to generate the empirical charts and several correction equations for design utilization. To investigate the effectiveness of the proposed damage index, calibration of the new approach to existing real data (the result of Park-Ang damage index 1985), were conducted. The obtained results show good precision of the developed ANNs-based model in predicting the maximum damage of regular reinforced concrete frames.

• Journal of the Earthquake Engineering Society of Korea
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• v.23 no.2
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• pp.89-99
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• 2019

In order to increase the seismic safety of nuclear power plant (NPP) structures, a technique to reduce the seismic load transmitted to the NPP structure by using a seismic isolation device such as a lead-rubber bearing has recently been actively researched. In seismic design of NPP structures, three directional (two horizontal and one vertical directions) artificial synthetic earthquakes (G0 group) corresponding to the standard design spectrum are generally used. In this study, seismic analysis was performed by using three directional artificial synthetic earthquakes (M0 group) corresponding to the maximum-minimum spectrum reflecting uncertainty of incident direction of earthquake load. The design basis earthquake (DBE) and the beyond design basis earthquakes (BDBEs are equal to 150%, 167%, and 200% DBE) of G0 and M0 earthquake groups were respectively generated for 30 sets and used for the seismic analysis. The purpose of this study is to compare seismic responses and seismic fragility curves of seismically isolated NPP structures subjected to DBE and BDBE. From the seismic fragility curves, the probability of failure of the seismic isolation system when the peak ground acceleration (PGA) is 0.5 g is about 5% for the M0 earthquake group and about 3% for the G0 earthquake group.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1998.10a
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• pp.497-504
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• 1998

In the nonlinear dynamic structural analysis, the given ground excitation as an input should be well defined. Because of the lack of recorded accelerograms in Korea, it is required to generate an artificial earthquake by a stochastic model of ground excitation with various dynamic properties rather than recorded accelerograms. It is well own that earthquake motions are generally non-stationary with time-varying intensity and frequency content. Many researchers have proposed non-stationary random process models. Yeh and Wen (1990) proposed a non-stationary stochastic process model which can be modeled as components with an intensity function, a frequency modulation function and a power spectral density function to describe such non-stationary characteristics. This model is based on the simulation for the strong-motion earthquakes with magnitude greater than approximately 5.0~6.0, because it will be not only expected to cause structural damage but also involved the characteristics of earthquake motions. Also, the recorded earthquake motion within this range are still very scarce in Korea. Thus, it is necessary to verify the model by the application of it to the mid-magnitude (approximately 4.0~6.0) earthquakes actually recorded in domestic or foreign area. The purpose of the paper is to generate an artificial earthquake using the model of Yeh and Wen in the area with low seismicity.