• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2018년도 추계 학술논문 발표대회
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• pp.136-137
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• 2018

The domestic seismic retrofit guide was primally enacted in 1988, then the mandatory target have been consistently. As a result, the rate of earthquake-resistant is achieved 58.3% in public facilities. On the other hand, the rate of earthquake-resistant is low as 24.8% in education facilities. As education facilities damaged from Gyeong-ju, Po-hang earthquake occurred in South-Korea and the rate of earthquake-resistant is low, the seismic retrofit of existing education facilities got to be ordinary people's interest. Therefore, domestic researchers have been developed seismic retrofit methods which can apply to existing educational facilities, It is expected to become more active in the future. However, it is insufficient to consideration that how far domestic technology has been developed. Therefore, the objective of this study is to measure the level of domestic research through comparative analysis between domestic and foreign researches that seismic retrofit methods which can apply to existing educational facilities.

• Structural Engineering and Mechanics
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• 제59권1호
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• pp.15-36
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• 2016

The components of the seismic behavior factor of RC frames are expected to change as structural redundancy increases. Most researches indicate that increasing redundancy is desirable in response to stochastic events such as earthquake loading. The present paper investigated the effect of redundancy on a fixed plan for seismic behavior factor components and the nonlinear behavior of RC frames. The 3D RC moment resistant frames with equal lateral resistance were designed to examine the role of redundancy in earthquake-resistant design and to distinguish it from total overstrength capacity. The seismic behavior factor and dynamic behavior of structures under natural strong ground motions were numerically evaluated as the judging criteria for structural seismic behavior. The results indicate that increasing redundancy alone in a fixed plan cannot be defined as a criterion for improving the structural seismic behavior.

• 한국전산구조공학회논문집
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• 제22권2호
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• pp.181-187
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• 2009

내진 설계기준이 도입된 이후, 신설교량에 대한 내진 설계의 시행은 물론 기존교량의 내진 성능 검토에 의한 내진 성능 확보가 요구되고 있다. 기존교량의 내진 성능 확보 또한 내진 설계의 기본개념에 따라 붕괴방지수준을 만족하여야 하며, 확보방안으로는 교량의 중요도와 형식에 따라 보강규모가 다른 여러 가지 방안이 제시되어야 한다. 현재 일반교량의 경우 받침의 교체, 교각의 보강 및 전단키 설치 등의 보강방안이 내진 성능 향상 및 확보 방안으로 가장 많이 연구, 적용되고 있는 상황이다. 이 연구에서는 내진 설계가 수행되지 않은 일반적인 기존 교량은 해석대상교량으로 선정하고, 붕괴방지 수준을 만족하기 위해 연성파괴메카니즘을 확보하도록 기존교량의 설계변경을 수행하고 내진 성능을 검토하였다. 기존교량의 경우, 하부구조 교각기둥의 설계단면 결정 및 상/하부구조 연결부 받침의 기능변경 등 교량시스템의 재 설계에 의해 내진 성능을 확보할 수 있다는 것을 제시하였다.

• 한국재료학회지
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• 제27권9호
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• pp.477-483
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• 2017

This present study deals with the microstructure and tensile properties of 600 MPa-grade high strength and seismic resistant reinforcing steels. The high strength reinforcing steel (SD 600) was fabricated by Tempcore processing, while the seismic resistant reinforcing steel (SD 600S) was air-cooled after hot-rolling treatment. The microstructure analysis results showed that the SD 600 steel specimen consisted of a tempered martensite and ferrite-pearlite structure after Tempcore processing, while the SD 600S steel specimen had a fully ferrite-pearlite structure. The room-temperature tensile test results indicate that, because of the enhanced solid solution and precipitation strengthening caused by relatively higher contents of C, Mn, Si and V in the SD 600S steel specimen, this specimen, with fully ferrite-pearlite structure, had yield and tensile strengths higher than those of the SD 600 specimen. On the other hand, the hardness of the SD 600 and SD 600S steel specimens changed in different ways according to location, dependent on the microstructure, ferrite grain size, and volume fraction.

• 한국방재학회 논문집
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• 제5권1호
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• pp.23-32
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• 2005

1995년 일본 고베 대지진 발생 이후 한국정부는 국내 시설물에 대한 내진설계분야 및 지진피해 최소화 방안에 대한 연구를 지속적으로 진행해왔으며, 현재까지 괄목할 만한 많은 성과를 내고 있다. 그렇지만, 국내비탈면과 같은 구조물들은 여전히 내진설계가 적용되지 않고 있으며, 일부 기관에서만 설계자의 판단에 의해 비탈면 내진설계가 적용되고 있는 실정이다. 본 연구에서는 국내외 비탈면 내진설계에 대한 연구 결과를 소개하고 국내비탈면에 적용할 수 있는 내진설계 방안을 제시하였다. 비탈면 내진설계 적용범위는 경제성, 비탈면의 중요도 및 복구의 용이성 등을 고려하여 공학자가 내진설계 여부를 판단하도록 하는 것이 바람직하며, 우리나라 비탈면의 내진설계 적용 범위 및 관련 기준도 지진관련 자료를 축적하여 향후 단계적으로 정립하는 것이 바람직 할 것으로 판단된다.

• Structural Engineering and Mechanics
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• 제15권5호
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• pp.513-534
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• 2003

Using fluid dampers to connect adjacent buildings for enhancing their seismic resistant performance has been recently investigated but limited to linear elastic adjacent buildings only. This paper presents a study of inelastic seismic response of adjacent buildings linked by fluid dampers. A nonlinear finite element planar model using plastic beam element is first constructed to simulate two steel frames connected by fluid dampers. Computed linear elastic seismic responses of the two steel frames with and without fluid dampers under moderate seismic events are then compared with the experimental results obtained from shaking table tests. Finally, elastic-plastic seismic responses of the two steel frames with and without fluid dampers are extensively computed, and the fluid damper performance on controlling inelastic seismic response of the two steel frames is assessed. The effects of the fundamental frequency ratio and structural damping ratio of the two steel frames on the damper performance are also examined. The results show that not only in linear elastic stage but also in inelastic stage, the seismic resistant performance of the two steel frames of different fundamental frequencies can be significantly enhanced if they are properly linked by fluid dampers of appropriate parameters.

• Computers and Concrete
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• 제30권2호
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• pp.113-126
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• 2022

Reinforced concrete bearing walls (RCBWs) are one of the most applicable structural systems. Therefore, vulnerability analysis and rehabilitation of the RCBW system are of great importance. In the present study, in order to the more precise investigation of the performance of this structural resistant system, pushover and nonlinear time history analyses based on several assumptions drawing upon experimental research were performed on several models with different stories. To validate the nonlinear analysis method, the analytical and experimental results are compared. Vulnerability evaluation was carried out on two seismic hazard levels and three performance levels. Eventually, the need for seismic rehabilitation with the basic safety objective (BSO) was investigated. The obtained results showed that the studied structures satisfied the BSO of the seismic rehabilitation guidelines. Consequently, according to the results of analyses and the desired performance, this structural system, despite its high structural weight and rigid connections and low flexibility, has integrated performance, and it can be a good option for earthquake-resistant constructions.

• Structural Engineering and Mechanics
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• 제71권4호
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• pp.417-432
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• 2019

Seismic performance analysis of steel-brace reinforced concrete (RC) frame using topology optimization in highly seismic region was discussed in this research. Topology optimization based on truss-like material model was used, which was to minimum volume in full-stress method. Optimized bracing systems of low-rise, mid-rise and high-rise RC frames were established, and optimized bracing systems of substructure were also gained under different constraint conditions. Thereafter, different structure models based on optimized bracing systems were proposed and applied. Last, structural strength, structural stiffness, structural ductility, collapse resistant capacity, collapse probability and demolition probability were studied. Moreover, the brace buckling was discussed. The results show that bracing system of RC frame could be derived using topology optimization, and bracing system based on truss-like model could help to resolve numerical instabilities. Bracing system of topology optimization was more effective to enhance structural stiffness and strength, especially in mid-rise and high-rise frames. Moreover, bracing system of topology optimization contributes to increase collapse resistant capacity, as well as reduces collapse probability and accumulated demolition probability. However, brace buckling might weaken beneficial effects.

• 소성∙가공
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• 제30권2호
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• pp.91-98
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• 2021

The present study deals with the microstructure and mechanical properties of 700 MPa-grade high-strength seismic resistant reinforced steel bars fabricated by various TempCore process conditions. For the steel bars, in the surface region tempered martensite was formed by water cooling and subsequent self-tempering during TempCore process, while in the center region there was ferrite-pearlite or bainite microstructure. The steel bar fabricated by the highest water flow and the lowest equalizing temperature had the highest hardness in all regions due to the relatively fine microstructure of tempered martensite and bainite. In addition, the steel bar having finer microstructures as well as the high fraction of tempered martensite in the surface region showed the highest yield and tensile strengths. The presence of vanadium precipitates and the high fraction of ferrite contributed to the improvement of seismic resistance such as high tensile-to-yield strength ratio and high uniform elongation.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1991년도 봄 학술발표회 논문집
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• pp.72-78
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• 1991

An improved procedure for earthquake resistant design of multistory building structures is proposed in this study. The effect of gravity load on seismic response of structures is evaluated through nonlinear dynamic analyses of a single story example structure. The presence of gravity load tends to initiate plastic hinge formation in earlier stage of a strong earthquake. However, the effect of gravity load seems to disapper as ground motion is getting stronger. And one of shortcomings in current earthquake resistant codes is overestimation of gravity load effects when earthquake load is applied at the same time so that it may leads to less inelastic deformation or structural damage in upper stories, and inelastic deformation is increased in lower stories. Based on these observation, an improved procedure for earthquake resistant design is derived by reducing the factor for gravity load and inceasing that for seismic load. Structures designed by the proposed design procedure turned out to have increased safety and stability against strong earthquakes.