KAERI has planned to carry out a series of dynamic tests using a shaking table and time-history analyses for a channel-type concrete shear wall to investigate its seismic performance because of the recently frequent occurrence of earthquakes in the south-eastern parts of Korea. The overall size of a test specimen is ×× 2500 mm×3500 mm×4500 mm, and it consists of three stories having slabs and walls with thicknesses of 140 mm and 150 mm, respectively. The system identification, FE model updating, and time-history analysis results for a test shear wall are presented herein. By applying the advanced system identification, so-called pLSCF, the improved modal parameters are extracted in the lower modes. Using three FE in-house packages, such as FEMtools, Ruaumoko, and VecTor4, the eigenanalyses are made for an initial FE model, resulting in consistency in eigenvalues. However, they exhibit relatively stiffer behavior, as much as 30 to 50% compared with those extracted from the test in the 1st and 2nd modes. The FE model updating is carried out to consider the 6-dofs spring stiffnesses at the wall base as major parameters by adopting a Bayesian type automatic updating algorithm to minimize the residuals in modal parameters. The updating results indicate that the highest sensitivity is apparent in the vertical translational springs at few locations ranging from 300 to 500% in variation. However, their changes seem to have no physical meaning because of the numerical values. Finally, using the updated FE model, the time-history responses are predicted by Ruaumoko at each floor where accelerometers are located. The accelerograms between test and analysis show an acceptable match in terms of maximum and minimum values. However, the magnitudes and patterns of floor response spectra seem somewhat different because of the slightly different input accelerograms and damping ratios involved.

In this study, the seismic safety of nuclear power plant structures is evaluated and verified by performing a vibration test on a relatively simple shear wall structure. The shear walls are the prominent members of nuclear power plants and resist the seismic load. The shear wall structure is designed and manufactured to perform shaking table tests and is used to increase the accuracy of the analytical method by comparing them with the numerical analysis results. Different results will be checked and more efficient application methods will be studied depending on the method of designing reinforced concrete structures.

After the manual shutdown of the Wolseong nuclear power plant due to an earthquake in Gyeongju in 2016, anxiety about the earthquake safety of nuclear power plants has become a major social issue. The shear wall structure used as a major structural element in nuclear power plants is widely used as a major structural member because of its high resistance to horizontal loads such as earthquakes. However, due to the complexity of the structure, it is challenging to predict the dynamic characteristics of the structure. In this study, a three-story shear wall structure is fabricated, and the in-structure response characteristics of the shear wall structure are evaluated through shaking table tests. The test is performed using the Gyeongju earthquake that occurred in 2016, and the response characteristics due to the domestic earthquake are evaluated.

Structures of domestic nuclear power plants are designed to perform elastic behavior against beyond design earthquakes, but studies on the nonlinear behavior of structures have been insufficient since the beyond design earthquake. Accordingly, it is judged that it will be necessary to develop an evaluation method that considers the nonlinear behavioral characteristics to check the safety margin for a standard nuclear power plant structure. It is confirmed that the restoring force characteristics for each member level can be identified through the calculation formula, and the lateral stiffness for each story can also be easily calculated by JEAC 4601. In addition, as a result of applying the evaluation method of JEAC 4601 as a nonlinear restoring force model of the nuclear power plant, a certain degree of safety margin can be identified.

A shear wall is a structural member designed to effectively resist in-plane lateral forces, such as strong winds and earthquakes. Due to its efficiency and stability, shear walls are often installed in residential buildings and essential facilities such as nuclear power plants. In this research, to predict the results of the shaking table test of the three-story shear wall RC structure hosted by the Korea Atomic Energy Research Institute, three types of numerical modeling techniques are proposed: Preliminary, Calibrated 1, and Calibrated 2 models, in order of improvement. For the proposed models, an earthquake of the 2016 Gyeongju, South Korea (peak ground acceleration of 0.28 g) and its amplified earthquake (peak ground acceleration of 0.50 g) are input. The response spectra of the measuring points are obtained by numerical analysis. Good agreement is observed in the comparisons between the experiment results and the simulation conducted on the finally adopted numerical model, Calibrated 2. In the process of improving the model, this paper investigates the influences of the mode shape, material properties, and boundary conditions on the structure's seismic behavior.

The dynamic characterization of a three-story auxiliary building in a nuclear power plant (NPP) constructed with a monolithic reinforced concrete shear wall is investigated in this study. The shear wall is subjected to a joint-research, round-robin analysis organized by the Korea Atomic Energy Research Institute, South Korea, to predict seismic responses of that auxiliary building in NPP through a shake table test. Five different intensity measures of the base excitation are applied to the shaking table test to get the acceleration responses from the different building locations for one horizontal direction (front-back). Simultaneously to understand the global damage scenario of the structure, a frequency search test is conducted after each excitation. The primary motivation of this study is to develop a nonlinear numerical model considering the multi-layered shell element and compare it with the test result to validate through the modal parameter identification and floor responses. In addition, the acceleration amplification factor is evaluated to judge the dynamic behavior of the shear wall with the existing standard, thus providing theoretical support for engineering practice.

이 연구의 목적은 전승4국에 의해 각각 4분할된 전범국 독일의 동서독 분단과 베를린 분할, 소련과 동독 당국에 의한 베를린 장벽의 구축, 그리 고 동독 주민들의 여행 자유 개방에 따른 베를린 장벽 해체 등을 통해 동 서독의 통일을 고찰하는 데 있다. 연구방법으로는 전승4국과 양독2국 간 쟁점이 되어 온 베를린 장벽의 구축과 해체에 관하여 헤겔의 정(正, These)→반(反, Antithese)→합(合, Synthese) 변증법을 적용하였다. ⓛ 전승4국이 전전(戰前) 회담의 산물인 전범국 독일을 동서독 분단과 동서 베를린 분할을 해 놓은 국제질서하에서 패권을 장악하려는 의미에서의 정 (正), ② 그중에서 소련과 동독 당국이 기존 국제질서를 깨고 공산주의 패 권을 유지하고자 베를린 장벽을 구축한 의미에서의 반(反), 그리고 ③ 베 를린 장벽 해체가 의도되지는 않았지만 동독 주민들의 이주와 이탈을 넘 어서 동유럽의 민주화 일환으로 나타난 촛불시위, 동독 SED 대변인 샤보 브스키(G. Schabowski)의 기자회견에서의 ‘즉시, 지체 없이’ 국경개방 허 용 발언의 말실수 등이 ‘부정의 부정’으로 지양(止揚, Aufheben)되면서 베 를린 장벽이 해체되는 수순을 밟게 되는 의미에서의 합(合)인 것이다. 요 컨대 미국과 소련 중심의 전승4국은 전범국 독일을 분할하여 패권이란 국 제질서를 지속하고자 했으나, 오히려 소련과 동독이 베를린 장벽 구축에 나서면서 그들만의 공산권 체제유지를 강화하고자 했다. 그러나 동서독 여 행 자유와 국경개방 시위에 나선 동독 주민들의 자유화와 동독 당국의 개 방에 대한 모호한 태도 등이 중첩되면서 베를린 장벽이 해체되기에 이르 렀다. 따라서 베를린 장벽의 해체는 독일 통일을 앞당기는 단초가 되었고, 정상적인 통일 독일로 자리매김한 것은 더이상 분단 독일이 지속될 수 없 다는 변증법적 논리를 깨우쳐준 사실이 아닌가 한다.

현재 우리나라에서 설계 및 시공되는 대부분의 철근콘크리트 벽식구조 공동주택은 상부벽체-하부골조 시스템으로 구성되어 있으며 서로 다른 상하부 구조시스템의 결합을 위해 전이보를 이용한다. 상부의 하중을 하부의 기둥 부재에 효율적으로 전달하기 위해 전 이보가 큰 강성을 지녀야하고 이로 인해 부재의 춤이 커져 많은 물량의 투입되고 전반적인 경제성이 떨어지게 된다. 이러한 문제점을 해결하기 위해 기둥을 벽체요소로 대체하고 일반적인 콘크리트 전이보에 비해 규모가 작은 경계보를 수평 구조요소로 활용한 새로운 경계보-벽체 시스템을 제안한다. 제안된 시스템의 축하중에 대한 성능 평가를 위해 3차원 비선형 유한요소해석을 수행하였다. 주요 설계변수로 상하부벽체 길이비, 경계보 부재의 전단보강근 간격, 하부벽체로 연속되는 상부벽체 수직근의 꺾임 비율, 슬래브 길이를 설정하고 제안된 시스템의 성능에 얼마나 기여하는지 분석하였다.

The purpose of this study is to research about the construction of Chiseong around the Heunginjimun Gate area in the 18th century. the conclusions derived from the historical evidence of the number, location, size, and form, and construction method of Chiseong was as follows. First, the Chiseong(Square-shaped lookout) of Hanyangdoseong was built in the 29th year of King Yeongjo(1753) and can be found in the national record. Five sites of the Chiseong are currently identified. It is assumed that the Foru was installed on top of some of the Chiseongs. Second, Chiseong was destroyed sequentially in the first half of the 20th century. Third, Chiseong is a rectangular in shape and six are constructed. Fourth, Sixth Chiseong could figure out through Hengryeopungsokdo, the drawing of Jeong Seon.

최근 국내 지진 발생 빈도 및 강도가 증가함에 따라 지진 발생시 건물 주요 구조부에 대해서는 내진설계 및 내진 구조기술이 적용되어 지진에 대비하고 있으나, 비구조 요소인 커튼월과 창호에 대해서는 내진에 대비한 충분한 고려가 이루어지지 못하고 있다. 본 연구에서는 동적 내진성능 기준을 만족할 수 있는 커튼월을 개발하기 위해 동적 지진파 인가 시 커튼월이 파손 없이 대응 가능한 지진 변위 대응 패스너를 적용하여 동적 내진성능실험을 통해 이를 규명하고자 한다. 동적 내진성능실험을 수행한 결과, 본 연구에서 제시한 3축 이동형 패스너를 활용한 커튼월이 실제 지진파에 대응 가능하다는 것을 확인할 수 있었다.

Most commercial buildings among existing RC buildings in Korea have a multi-story wall-frame structure where RC shear wall is commonly used as its core at stairways or elevators. The members of the existing middle and low-rise wall-frame buildings are likely arranged in ordinary details considering building occupancy, and the importance and difficulty of member design. This is because there are few limitations, considerations, and financial burdens on the code for designing members with ordinary details. Compared with the intermediate or unique details, the ductility and overstrength are insufficient. Furthermore, the behavior of the member can be shear-dominated. Since shear failure in vertical members can cause a collapse of the entire structure, nonlinear characteristics such as shear strength and stiffness deterioration should be adequately reflected in the analysis model. With this background, an 8-story RC wall-frame building was designed as a building frame system with ordinary shear walls, and the effect of reflecting the shear failure mode of columns and walls on the collapse mechanism was investigated. As a result, the shear failure mode effect on the collapse mechanism was evident in walls, not columns. Consequently, it is recommended that the shear behavior characteristics of walls are explicitly considered in the analysis of wall-frame buildings with ordinary details.

The paper studied the climbing structure and magnet selection method of exploration platform utilized for large-scale steel structures such as vessel surface. With respect to wall climbing robots, the study proposed a stable operation structure even in rapid incline change of vessel surface. Since the wheel-based operating method is hard to work flexibly in inclination changes, we employed joints and designed the robot to have a rotation joint in the center. The arrangement of wheels is an important aspect of this structure. Viewed from the side, the robot wheels should overlap with each other to have intersection points. The wheels here are ring-type permanent magnets and serve as a tool of attachment on walls. Based on the conditions identified through formula modeling, we proposed the required magnetic force. Important factors needed for magnetic force setup include platform weight, angle between ground and inclined plane, and friction coefficient. We considered only the required magnetic force for the stable adhesion of circular magnet while making not a separate mention about the necessary force for directional locomotion. The analysis results of ANSYS Maxwell are applied to magnetic attachment. Based on the final analysis results, we built a platform and found it did not slip and stayed attached on steel plate.

이 연구의 목적은 독일 통일에 있어 동서 베를린 분단의 종료, 특히 베를린 장벽 붕괴에 영향을 끼친 인과관계에 대해 규명하는 것이다. 여기서 논의될 핵심 요소는 베를린 장벽 붕괴가 독일 통일의 도화선이 되었다는 사실이다. 이 과정은 '동독과 서독의 분단→ 동베를린의 분단→ 베를린 장벽 건설→ 베를린 장벽 붕괴→ 동독과 서독의 통일'의 순서로 전개되었다. 여하튼 베를린 장벽 붕괴 이전에 동서독은 정상회담을 수차례 가져왔지만 베를린 장벽 붕괴 전에는 날카로운 대립만이 팽배해 있었다. 그러나 베를린 장벽이 붕괴된 이후에는 일사천리로 정상회담이 진척된 것만 보아도 베를린 장벽의 붕괴는 동서독 통일에 중차대한 역할을 했다는 것을 알 수 있다. 그래서 동서독 주민들, 특히 동독주민들의 통일 여망은 베를린 장벽을 붕괴시키는데 제일 큰 공헌을 한 셈이었다. 결국 베를린 장벽의 붕괴는 분단 독일과 분할 베를린 영토에 펼쳐진 장막과 철조망을 뚫고 하나된 독일을 발원시키는 단초가 되었다. 즉 독일 통일은 독일이 민족적으로 밑으로부터의 통일 과정이 뭉쳐서 정상적인 통일 독일과 독일인으로 합쳐짐으로써 가능했던 것이다.

본 연구는 서울시에 조성되어 있는 수직정원공간의 경관적 이미지를 파악하고 향후 수직정원 을 효과적으로 유지하기 위해서 어떠한 변수 들이 중요한 역할을 하는지를 확인하기 위한 목적 으로 수행되었다. 대상은 네이처리퍼블릭 명동유네스코점과 돈의문박물관마을 외벽의 수직정 원이고 네이버 설문조사 툴을 이용하여 조사를 시행하였다. 분석기법은 기술통계분석과 인자 분석 및 다중회귀분석을 실시하였다. 네이처리퍼블릭 명동점 전면부 수직정원에 대한 시각적 이미지 평가는 깨끗하고 아름다우며 흥미로운 공간이미지를 구축하고 있는 것으로 파악되었 다 ‘신비로운-신비롭지 않은’, ‘연속적인-단절된’ 등의 변인은 상대적으로 낮은 평가치를 보이 고 있는 바 이는 명동 한복판의 독립된 사각형 건물로 인한 영향으로 생각된다. 돈의문박물관 마을 수직정원은 특이하고 아름다운 경관으로 인지됨을 볼 수 있다. 반면 ‘높은-낮은’, ‘넓은- 좁은’, ‘정돈된-정돈되지 않은’ 등의 변인은 다소 부정적 의미의 평가를 받았다. 모두 4개의 인 자군으로 공간이미지가 함축되어 분석되었고 전체 변량 중 이들 인자군의 설명력은 69.88%였 으며 30.20%는 오차변량과 특수변량이라 볼 수 있다. 인자분석 결과를 토대로 수직정원의 시각 적 이미지를 설명하는 인자를 ‘특이성인자’, ‘자연성인자’, ‘정연성인자’, ‘개방성인자’ 등 4개로 분류하였다. 수직정원 경관에 대한 시각선호에 가장 영향을 높게 미치는 변인은 자연성인자 및 정연성인자로 나타나 수직정원의 전반적인 경관이미지가 자연적 아름다움에 의해 좌우되고 있 음을 보여주고 있다.

The domestic of modern architectural remodeling method emphasizes simple aesthetic elements, and the correct design and construction methods are not established based on quantitative grounds, thus damaging the value of cultural properties. This study attempts to re-examine the value of modern buildings recognized as old buildings. It is a basic step to present the correct remodeling of the building. The design criteria for exterior wall remodeling of modern buildings were presented. These research results are suitable for energy conservation design standards and can prevent defects in buildings. In the future, more accurate analysis will be required by securing physical property values for various domestic materials through subsequent research.

In this study, the effect of improving indoor air quality according to the installation of plants was evaluated in classrooms where students spend much time. The purpose was to prepare sustainable and eco-friendly measures to improve the indoor air quality of school classrooms. A middle school in Bucheon was selected as an experiment subject, and IAQ monitoring equipment based on IoT was installed to monitor indoor air quality. After measuring the basic background concentration, plants and air purifiers were installed and the effects of improving indoor air quality using plants and air purifiers were evaluated based on the collected big data. As a result of evaluating the effects of indoor air quality improvement on the installation of plants and air purifiers, the reduction rates of PM10 and PM2.5 in descending order were plant- and air purifier- installed classes, air purifier-installed classes, and plant-installed classes. CO2 levels were reduced in the classrooms with only plants, and increased in two classrooms with air purifiers. The increase in CO2 concentration in the classrooms with plants and air purifiers was lower than in those with only air purifiers.