• 한국재난정보학회 논문집
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• 제19권4호
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• pp.882-896
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• 2023

연구목적: 국가산업단지 공장시설물이 보유한 내진설계의 잠재적 위험과 안전지도 및 점검의 미비점을 효과적으로 향상시킬 수 있는 안전관리 및 내진보강대책 마련을 목적으로 한다. 연구방법: 본 연구에서는 국가산업단지의 지진재난 대비 안전관리 현황 및 관리체계 등 지진재난 안전관리 전반에 관한 조사·분석을 통해 문제점 및 개선방안을 도출하였고, 국가산업단지 내 입주기업체 내진설계 실태조사를 실시하여 시설유형과 구조적 특성에 기반한 개선방안을 제시하였다. 연구결과: 결론적으로 국가산업단지 지진재난 대비 안전관리 및 내진보강에 대한 문제점을 정리하여 4가지 유형별(내진성능 평가 및 관련 제도 보완, 입주기업 및 지자체 권한, 내진보강 및 안전관리 지원대책, 조직의 역량강화)로 개선방안을 도출하였다. 결론: 이를 기반으로 국가산업단지 입주기업이 지진재난을 대비하여 추진해야 하는 내진보강 대책을 마련하였으며, 각 대책별 세부적인 방안을 제시하였다.

• Structural Engineering and Mechanics
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• 제63권2호
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• pp.259-268
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• 2017

In this paper, the incremental nonlinear dynamic analysis is used to evaluate the seismic performance of steel moment frame structures. To this purpose, three special moment frame structure with 5, 10 and 15 stories are designed according to the Iran's national building code for steel structures and the provisions for design of earthquake resistant buildings (2800 code). Incremental Nonlinear Analysis (IDA) is performed for 15 different ground motions, and responses of the structures are evaluated. For the immediate occupancy and the collapse prevention performance levels, the probability that seismic demand exceeds the seismic capacity of the structures is computed based on FEMA350. Also, fragility curves are plotted for three high-code damage levels using HASUS provisions. Based on the obtained results, it is evident that increase in the height of the frame structures reduces the reliability level. In addition, it is concluded that for the design earthquake the probability of exceeding average collapse prevention level is considerably larger than high and full collapse prevention levels.9.

• Steel and Composite Structures
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• 제44권3호
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• pp.325-337
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• 2022

In this research, an earthquake-resistant structural system consisting of a pin-connected steel frame and a bracing with metallic fuses is proposed. Contrary to the conventional braced frames, the main structural elements are deemed to remain elastic under earthquakes and the seismic energy is efficiently dissipated by the damper-braces with an amplification mechanism. The superiority of the proposed damping system lies in easy manufacture, high yield capacity and energy dissipation, and an effortless replacement of damaged fuses after earthquake events. Furthermore, the stiffness and the yield capacity are almost decoupled in the proposed damper-brace which makes it highly versatile for performance-based seismic design compared to most other dampers. A special attention is paid to derive the theoretical formulation for nonlinear behavior of the proposed damper-brace, which is verified using analytical results. Next, a direct displacement-based design procedure is provided for the proposed system and an example structure is designed and analyzed thoroughly to check its seismic performance. The results show that the proposed system designed with the provided procedure satisfies the given performance objective and can be used for developing highly efficient low-damage structures.

• 한국지반환경공학회 논문집
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• 제23권5호
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• pp.25-32
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• 2022

최근 우리나라에 리히터 규모 5.0 이상의 지진발생 2건과 규모가 낮은 지진발생이 많아짐에 따라 지진피해가 늘어나면서 내진설계에 대한 많은 연구와 관심이 높아지고 있으며, 그 중 최근 발생한 포항지진으로 인해 항만시설물에 대한 내진설계에도 관심이 높아졌다. 본 연구에서는 1g 진동대시험을 통하여 항만구조물 중 직립식, 경사식 방파제에 대한 지진 시 발생하는 동적거동에 대해서 실험 및 분석을 하였다. 이를 위해 사상법칙을 적용한 모델에 장주기(Hachinohe), 단주기(Ofunato), 인공지진파 총 세가지 지진파를 적용하고, 연약지반의 DCM 공법 보강 여부를 고려하여 실험하였다. 진동대시험결과를 기초로 지진 시 DCM 공법 보강 여부에 따라 직립식과 경사식 방파제의 동적거동에 대하여 가속도 및 수평·수직 변위를 분석하였다. 검토 결과 직립식 및 경사식 방파제 동적거동은 DCM 공법 보강을 한 경우에 지지력 및 강성이 높아짐에 따라 가속도의 증폭이 억제되는 경향을 나타내었다.

• 한국지진공학회논문집
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• 제5권6호
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• pp.11-19
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• 2001

일정한 축하중과 반복적인 횡하중을 받는 콘크리트충전 강합성 기둥의 내진성능에 관한 실험적인 연구가 수행되었다. 강합성 기둥은 충전콘크리트가 강판의 국부좌굴로 인한 내측방향의 변형을 억제하고, 강판의 콘크리트 측압에 대한 구속효과와 같은 상호작용에 의해서 콘크리트와 강재의 단순누가강도 이상의 강도증진효과를 가지며, 강재 및 콘크리트기둥에 비해 우수한 연성 및 에너지 흡수능력을 나타내었다. 단면분할법을 이용하여 콘크리트충전 강합성 기둥의 비선형 모멘트-곡률 관계를 예측해 보았으며, 이는 실험결과와 비교적 잘 일치하는 것으로 나타났다. 또한, 구조물의 내진설계의 중요한 요소인 강합성 기둥의 연성 및 응답수정계수를 평가해 보았다. 실험결과 강합성 기둥은 효과적인 내진구조 부재로 판단되었다.

• Steel and Composite Structures
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• 제43권2호
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• pp.201-219
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• 2022

This paper firstly proposed high performance composite columns for cold-region infrastructures using ultra-high performance concrete (UHPC) and ultra-high strength steel (UHSS) Q960E. Then, 24 square UHPC-filled UHSS tubes (UHSTCs) at low temperatures of -80, -60, -30, and 30℃ were performed under axial loads. The key influencing parameters on axial compression performance of UHSS were studied, i.e., temperature level and UHSS-tube wall thickness (t). In addition, mechanical properties of Q960E at low temperatures were also studied. Test results revealed low temperatures improved the yield/ultimate strength of Q960E. Axial compression tests on UHSTCs revealed that the dropping environmental temperature increased the compression strength and stiffness, but compromised the ductility of UHSTCs; increasing t significantly increased the strength, stiffness, and ductility of UHSTCs. This study developed numerical and theoretical models to reproduce axial compression performances of UHSTCs at low temperatures. Validations against 24 tests proved that both two methods provided reasonable simulations on axial compression performance of UHSTCs. Finally, simplified theoretical models (STMs) and modified prediction equations in AISC 360, ACI 318, and Eurocode 4 were developed to estimate the axial load capacity of UHSTCs at low temperatures.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 춘계 학술발표회 제16권1호
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• pp.724-729
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• 2004

The purpose of this study is to investigate the strength and ductility improvement of columns retrofitted with Fiber-Steel Composite Plate, compared with Steel Plate, and Carbon Fiber Sheet. Test specimens strengthened with 3 different materials--- carbon fiber sheet, steel plate and fiber-steel composite plate --- were tested under cyclic lateral force and a constant axial load equal to $20\%$ of the column's axial load capacity. The hypothetical equivalent value of the strengthening among three materials is introduced to evaluate.

• 공학기술논문지
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• 제5권1호
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• pp.11-18
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• 2012

Large scale earthquake was occurred in different parts of the world like Japan (in 1995), Republic of Pakistan (2005), in China (2008) etc and enormous structures were damaged. As a result of collapse of school buildings structures numerous students are died and it had a big impact on the international community. Therefore, the interest of preparing the seismic resistant school building structures in our country is increases as school building are used as emergency shelter for local residents. But the current standard of seismic design ratio of 3.7% is applied for school building in Korea which is only significant earthquake damage is expected. In order to overcome the current situation, seismic performance evaluation is carried out for the existing school building and an accurate and appropriate seismic retrofit is required based on performance evaluation to upgrade the existing school buildings. In this paper, nonlinear analysis on existing school buildings for ATC-40(Applied Technology Council, ATC) and FEMA-356(Federal Emergency Management Agency, FEMA) are carried out using the capacity spectrum method to evaluate seismic performance and to determine the need for retrofitting. In addition, after reinforcement to enhance the seismic performance is applied the seismic performance evaluation is carried out to verify the effectiveness of seismic retrofit.

• Earthquakes and Structures
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• 제7권5호
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• pp.779-796
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• 2014

This experimental investigation was conducted to examine the behavior and response of high-strength material (HSM) reinforced concrete (RC) columns under combined high-axial and cyclic-increasing lateral loads. All the columns use high-strength concrete ($f_c{^{\prime}}$=100MPa) and high-yield strength steel ($f_y$=685MPa and $f_y$=785MPa) for both longitudinal and transverse reinforcements. A total of four full-scale HSM columns with amount of transverse reinforcement equal to 100% more than that required by earthquake resistant design provisions of ACI-318 were tested. The key differences among those four columns are the spacing and configuration of transverse reinforcements. Two different constant axial loads, i.e. 60% and 30% of column axial load capacity, were combined with cyclically-increasing lateral loads to impose reversed curvatures in the columns. Test results show that columns under 30% of axial load capacity behaved much more ductile and had higher lateral deformational capacity compared to columns under the 60% of axial load capacity. The columns using closer transverse reinforcement spacing have slightly higher ductility than columns with larger spacing.

• 한국안전학회지
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• 제31권3호
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• pp.68-74
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• 2016

This paper presents a new strengthening method of underground box structures against seismic loads for anti-seismic capacity improvement. A threaded steel member with pressure devices(so called 'Pre-flexed member system') is used to improve seismic capacity of the RC box structure. The pre-flexed member system is fixed the corner of opening after chemical anchor was installed by drilling hole on the box structure. The structural performance was evaluated analytically. Two bracing types of strengthening methods were used; conventional bracing method and I-bracing pressure system. For the performance evaluation, seismic analyses were performed on moment and shear resisting structures with and without strength member system. Numerical results confirmed that the proposed pre-flexed member system can enhance the seismic capacity of the underground RC box structures.