• 한국지진공학회:학술대회논문집
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• 한국지진공학회 1997년도 춘계 학술발표회 논문집 Proceedings of EESK Conference-Fall 1997
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• pp.199-206
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• 1997

Under sever earthquake, structural elements or structures may sustain a large number of inelastic excursions. To predict seismic damage of the structures with accuracy, much research for general definition of structural collapse and seismic damage analysis is required. The ductility method, the energy method and Park and Ang method for seismic damage analysis of structural elements and structures are compared in this paper. Also, the seismic damage analysis for system-level of structure is carried out using the ESDOF-system method and Powell method. To compare tendency of the seismic damage analysis using each methods, example analysis is accomplished for several cases of different structures and different earthquake excitation.

• 한국지진공학회논문집
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• 제24권2호
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• pp.67-76
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• 2020

This study aims to optimize the cochlea-inspired artificial filter bank (CAFB) using El-Centro seismic waveforms and test its performance through a shaking table test on a two-span bridge model. In the process of optimizing the CAFB, El-Centro seismic waveforms were used for the purpose of evaluating how they would affect the optimizing process. Next, the optimized CAFB was embedded in the developed wireless-based intelligent data acquisition (IDAQ) system to enable response measurement in real-time. For its performance evaluation to obtain a seismic response in real-time using the optimized CAFB, a two-span bridge (model structures) was installed in a large shaking table, and a seismic response experiment was carried out on it with El-Centro seismic waveforms. The CAFB optimized in this experiment was able to obtain the seismic response in real-time by compressing it using the embedded wireless-based IDAQ system while the obtained compressed signals were compared with the original signal (un-compressed signal). The results of the experiment showed that the compressed signals were superior to the raw signal in response performance, as well as in data compression effect. They also proved that the CAFB was able to compress response signals effectively in real-time even under seismic conditions. Therefore, this paper established that the CAFB optimized by being embedded in the wireless-based IDAQ system was an economical and efficient data compression sensing technology for measuring and monitoring the seismic response in real-time from structures based on the wireless sensor networks (WSNs).

• Structural Engineering and Mechanics
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• 제58권2호
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• pp.243-257
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• 2016

The aim of this study is to investigate the seismic resistance of dry stone arches under in-plane seismic loading. For that purpose, several numerical analyses were performed using the combined finite-discrete element method (FDEM). Twelve types of arches with different ratios of a rise at the mid-span to the span, different thicknesses of stone blocks and different numbers of stone blocks in the arch were subjected to an incremental dynamic analysis based on excitation from three real horizontal and vertical ground motions. The minimum value of the failure peak ground acceleration that caused the collapse of the arch was adopted as a measure of the seismic resistance. In this study, the collapse mechanisms of each type of stone arch, as well as the influence of the geometry of stone blocks and stone arches on the seismic resistance of structures were observed. The conclusions obtained on the basis of the performed numerical analyses can be used as guidelines for the design of dry stone arches.

• 한국지진공학회논문집
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• 제17권1호
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• pp.33-41
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• 2013

Due to a high level of system ductility, steel moment resisting frames have been widely used for lateral force resisting structural systems in high seismic zones. Earthquake field investigations after Northridge earthquake in 1994 and Kobe earthquake in 1995 have reported that many steel moment resisting frames designed before 1990's had suffered significant damages and structural collapse. In this research, seismic performance assessment of steel moment resisting frames designed in accordance with the previous seismic provisions before 1990's was performed. Buckling-restrained braces and shear walls are considered for seismic retrofit of the reference buildings. Increasing stiffness and strength of the buildings using buckling-restrained braces and shear walls are considered as options to rehabilitate the damaged buildings. Probabilistic seismic performance assessment using fragility analysis results is used for the criteria for determining an appropriate seismic retrofit strategy. The fragility contour method can be used to provide an intial guideline to structural engineers when various structural retrofit options for the damaged buildings are available.

• Nuclear Engineering and Technology
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• 제50권8호
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• pp.1387-1401
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• 2018

An aircraft impact (AI) on a nuclear power plant (NPP) is considered to be a beyond-design-basis event that draws considerable attention in the nuclear field. As some NPPs have already adopted the seismic isolation technology, and there are relevant standards to guide the application of this technology in future NPPs, a new challenge is that nuclear power engineers have to determine a reasonable method for performing AI analysis of base-isolated NPPs. Hence, dynamic influences of the seismic isolation on the vibration and structural damage characteristics of the base-isolated CPR1000 containment are studied under various aircraft loads. Unlike the seismic case, the impact energy of AI is directly impacting on the superstructure. Under the coupled influence of the seismic isolation and the various AI load, the flexible isolation layer weakens the constraint function of the foundation on the superstructure, the results show that the seismic isolation bearings will produce a large horizontal deformation if the AI load is large enough, the acceleration response at the base-mat will also be significantly affected by the different horizontal stiffness of the isolation bearing. These concerns require consideration during the design of the seismic isolation system.

• 한국지진공학회논문집
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• 제25권1호
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• pp.11-20
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• 2021

The seismic deformation method is conventionally used as a seismic design for a multi-utility tunnel in Korea. In the seismic deformation method, the soil ground's natural period is one of the most critical factors for calculating the ground displacement using cosine functions. Correction factors for the natural period and shear wave velocity have been used to consider the non-linearity of dynamic soil properties. However, the correction factors have been issued because the correction factors have not been sufficiently studied to consider Korea's regional conditions. This paper aims to evaluate the natural periods for the seismic deformation method considering Korea's ground conditions. Ground response analysis was performed using seven real earthquake records on twelve sites with different soil conditions where actual multi-utility tunnels are installed. As a result, natural periods of the sites were analyzed and new correction factors were proposed according to seismic performance and Korea's regional conditions.

• Structural Engineering and Mechanics
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• 제82권1호
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• pp.55-67
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• 2022

The precast reinforced concrete frame system is a method for industrialization of construction. However, the seismic performance factor of this structural system is not explicitly clarified in some existing building codes. In this paper, the seismic performance factor for the existing precast concrete building frame systems with cast-in-situ reinforced shear walls were evaluated. Nonlinear behavior of the precast beam-column joints and cast-in-situ reinforced shear walls were considered in the modeling of the structures. The ATC-19's coefficient method was used for calculating the seismic performance factor and the FEMA P-695's approach was adopted for evaluating the accuracy of the computed seismic performance factor. The results showed that the over-strength factor varies from 2 to 2.63 and the seismic performance factor (R factor) varies from 5.1 to 8.95 concerning the height of the structure. Also, it was proved that all of the examined buildings have adequate safety against the collapse at the MCE level of earthquake, so the validity of R factors was confirmed. The obtained incremental dynamic analysis (IDA) results indicated that the minimum adjusted collapse margin ratio (ACMR) of the precast buildings representing the seismic vulnerability of the structures approximately equaled to 2.7, and pass the requirements of FEMA P-695.

• Earthquakes and Structures
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• 제24권5호
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• pp.345-352
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• 2023

This paper studied the effect of soil-structure interaction (SSI) on the seismic response and retrofit of a reinforced concrete structure with a soft-first story for different soil types. A 5-story structure built on a 30m deep homogeneous soil mass was considered as a case study structure, and steel column jacketing and steel bracing were chosen as seismic retrofit methods. Seismic responses of a fixed-base and a flexible base structure subjected to seven scaled earthquake records were obtained using the software OpenSees to investigate the effect of soil on seismic response and retrofit. The nonlinearBeamColumn elements with the fiber sections were used to simulate the nonlinear behavior of the beams and columns. Soil properties were defined based on shear wave velocity according to categorized site classes defined in ASCE-7. The finite element model of the soil was made using isoparametric four-noded quadrilateral elements and the nonlinear dynamic responses of the combined system of soil and structure were calculated in the OpenSees. The analysis results indicate that the soil-structure interaction plays an important role in the seismic performance and retrofit of a structure with a soft-first story. It was observed that column steel jacketing was effective in the retrofit of the model structure on a fixed base, whereas stronger retrofit measures such as steel bracing were needed when soil-structure interaction was considered.

• 한국지진공학회논문집
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• 제7권5호
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• pp.1-9
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• 2003

국내 콘크리트댐의 경우 내진설계는 관성력을 고려한 진도법을 적용하여 설계를 하고 있으나, 보수적인 설계 방법으로 동적특성을 반영하지 못하는 단점이 있어, 동적특성을 고려한 댐 내진설계가 필요하다. 또한 콘크리트댐 내진성능평가는 동적해석으로 평가해야 하지만, 국내의 경우 대부분 진도법으로 평가를 하고 있어 현행 기준을 적용하기에는 어려운 점이 있다. 이에 본 연구에서는 진도법, 수정진도법, 동적해석 방법을 수행하여 내진설계 및 내진성능평가 결과에 대해서 비교 분석하였다.

• 대한전자공학회논문지SP
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• 제46권1호
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• pp.79-86
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• 2009

본 논문에서는 자연지진음과 인공지진음 특성 분석을 위해 스펙트럼 기울기 파라미터 추출을 위한 알고리즘을 제안하였다. 신뢰성을 높이기 위해 다양한 지역에서 실험을 실시하였고 제안한 알고리즘을 이용하여 실험 데이터로부터 자연지진음과 인공지진음의 기울기 지수를 추출함으로써 특성을 분석하였다. 실험 및 분석결과 자연지진음이 인공지진음보다 스펙트럼에서 고주파 감쇠가 크고 저주파대역에 집중되어 있어 자연지진음의 기울기 지수가 인공지진음의 기울기 지수보다 높은 것으로 나타났다.