In this paper, a twisted shape structure with an elevation form favorable to the resistance of vibration caused by wind loads is selected from among the forms of high-rise buildings. The analytical model is a square, triangular, and hexagonal plane with a plane rotation angle of one degree from 0 to 3 degrees per each story. As a result of the analysis, as the twist angle increased, story drift ratio is increased. Responses with different eccentricity rates were shown by analytical models. Therefore planar shapes designed symmetrically to the horizontal axis of X and Y are considered advantageous for eccentricity and torsion deformation. In the case of the bending moment of the column, the response was amplified in the column supporting the base floor, the roof floor, the floor in which the cross-section of the vertical member changes, and the floor having the same number of nodes as the base floor. Finally, the axial force response of the column is determined to be absolutely affected by the gravity load compared to the lateral load.

본 논문에서는 풍력터빈과 하부구조물을 연결하는 L형 플랜지 볼트 접합부의 거동 특성에 대한 연구를 수행하였다. L형 플랜지 볼 트 접합부는 링(Ring) 형태의 L형 단면 플랜지가 볼트에 의해 상하 체결되는 방식으로서 국내 풍력터빈에서 주로 적용되고 있는 연결 방식이다. 특히 풍력타워 구조물은 이들 연결부의 손상이 전체 구조시스템의 붕괴로 이어질 수 있으므로 중요한 구조 요소 중 하나이 다. 따라서 L형 플랜지 볼트 접합부에 대한 정확한 거동 특성의 이해가 필요하다. 본 연구에서는 FE 해석을 통하여 L형 플랜지에 작용 하는 외력과 볼트장력의 관계, 그리고 L형 플랜지의 응력분포 변화를 외력 작용 단계별로 분석하였다. 여기서 FE 해석모델은 실제 링 형태의 L형 플랜지를 단일볼트의 L형 플랜지로 이상화하였다. 또한 볼트장력과 작용외력의 관계를 이론적으로 제안한 Petersen, Schmidt와 Neuper 그리고 VDI 2230의 볼트-외력 곡선모델에서 언급되는 접합부의 거동 불연속점과 FE 해석결과를 비교함으로써 FE 해석조건의 적절성을 검증하고, 각 볼트-외력 곡선모델의 특징과 L형 플랜지 볼트 접합부 거동 특성을 분석하였다. 그리고 L형 플랜 지 단면 제원을 일부 변화시켜 볼트-외력 곡선의 변화를 분석하였다.

본 연구에서는 환경, 재료 물성 및 제작 등에서의 불확실성을 고려하여 130m급 고정식 해양구조물의 신뢰성 기반 최적설계를 수행 하였다. 구조물의 구조건전성을 엄밀하게 반영하기 위해 작용 및 허용 응력의 비인 UC 값을 신뢰성 해석 및 신뢰성 기반 최적설계의 제약조건으로 고려하였다. 해양구조물의 제작비용을 저감하기 위해 자켓형 지지구조물의 중량을 최소화하였다. 불확실성의 통계적 특성은 문헌 등을 참고하여 관측되거나 측정된 데이터를 기반으로 정의하였다. 자켓형 해양구조물의 신뢰성 해석과 신뢰 기반 최적 설계는 부재 수가 많아 계산 부담이 큼으로 문제의 차원을 축소하기 위해 응답의 중요성을 기준으로 설계변수를 선별할 수 있는 방법 을 제안한다. 또한 효율적인 계산을 위해 신뢰성 기반 최적설계를 수행하기 전 결정론적 최적설계를 먼저 수행하였다. 마지막으로, 도 출된 최적설계(안)을 기존 각 급 규정 기반 설계와 안전성 및 경제성 측면에서 비교 분석하였다.

Combat vehicles were developed in two types depending on the purpose of operation. The body of the vehicle is relatively large welded structure, and there is a quality problem in that welding deformation occurs in a certain area. Welding deformation is a problem that is inevitably generated during the welding process, and additional corrective work is performed. However, due to the structural characteristics of the welded structure of combat vehicl, there are many limitations in the correction method, which lowered the productivity. To improve this problem, we intend to establish improvement measures through analysis of the areas where welding deformation occurs and apply corrective measures suitable for welding structures of combat vehicles. For the design improvement plans, the finite element analysis were used and the correction method were applied to simulated structure to confirm the possibility. Finally, the improvement effect was confirmed by manufacturing the actual welded structure. Based on the results of this study, it is expected that the productivity of related similar welding structures as well as structures of wheeled armored vehicles, can be improved.

The prospect of the new railway construction has led to resistance from residents, partly based on noise and vibration issues. Particularly, as tracks often pass closely to residential dwellings, constructors are then required to take account of noise and vibration. So the prediction of noise and vibration for train is very important thing. The train noise and vibration nearby the elevated railway make one specific issue. For the elevated railway, this paper concerns the rolling noise by the wheel/rail and the structure-borne noise by the bridge. Based on the results, this paper proposes the source model of elevated structure-borne noise and the calculation model for elevated railway noise. Also prediction model is presented with rolling noise and elevated structure noise which are calculated by considering the power level of a source for one-third octave band, ground absorption and barrier deflection. A lot of empirical data is needed to predict the noise and vibration. And one of the best ways to control the wayside noise is to analyze the noise level.

가거초 해양과학기지 자켓 구조물 내 콘크리트를 배제하고 강재로만 이루어진 최적설계를 제시한다. 50년 재현주기 극한하중조건에서 허용응력 및 허용응력비 조건을 모두 만족하는 안전한 경량 설계를 목표하였다. 역할에 따라 부재를 세 그룹으로 나눈 설계 조건 (Case-1)과 보다 세분화한 설계 조건(Case-2)에 대해 각 부재그룹별 현재 단면 두께 대비 두께 변화율을 설계변수로 설정한 유전 알고 리즘을 통해 최적설계를 탐색하였다. 그 결과 Case-1의 결과로 현재 가거초 해양과학기지보다 약 217톤 더 가벼운 설계(OPT-1)를 찾았고, Case-2에서는 추가적으로 약 84톤을 경량화하여 현재 대비 약 45%의 무게를 절감한 설계(OPT-2)를 얻을 수 있었다. 결론적으로 레그 내 콘크리트 보강 없이도 극한조건에서 허용응력 및 허용응력비를 모두 만족시킬 수 있는 경량화된 가거초 해양과학기지 설계를 제시하였다.

구조물에 장기적으로 발생하는 노후화를 정량적으로 파악하기 위해 상시진동 데이터를 활용한 일반화된 모니터링 시스템에 관한 연구가 세계적으로 활발히 수행중이다. 본 연구에서는 구조물에서 장기적으로 취득되는 동특성을 앙상블 학습에 활용하여 구조물의 이상을 감지하기 위한 보급형 엣지 컴퓨팅 시스템을 구축하였다. 시스템의 하드웨어는 라즈베리파이와 보급형 가속도계, 기울기센서, GPS RTK 모듈, 로라 모듈로 구성됐다. 실험실 규모의 구조물 모형 진동실험을 통해 동특성을 활용한 앙상블 학습의 구조물 이상 감지를 검증하였으며, 실험을 기반으로 한 실시간 동특성 추출 분산처리 알고리즘을 라즈베리파이에 탑재하였다. 구축된 시스템을 하우징하고 포항시 행정복지센터에 설치하여 데이터를 취득함으로써 개발된 시스템의 현장 적용성을 검증하였다.

In this paper, horizontal seismic responses of a structure built on a sunken mat foundation were compared with those built on a solid embedded mat foundation to investigate the effect of a sunken mat foundation on the horizontal response of a structure. Seismic analyses of a structure laid on the embedded mat foundation were performed by utilizing a pseudo-3D finite element software of P3DASS. Three bedrock earthquake records downloaded from the Pacific Earthquake Engineering Research Center database were scaled to reproduce weak-moderate earthquakes. Weak, medium, and stiff soil layers were considered for the seismic analyses of the structure-foundation-soil system. Parametric studies were performed for foundation radius, foundation embedment depth, and shear wave velocity of a soil layer to investigate their effect on the seismic response spectrum. The study result showed that the design spectrum of a structure built on a sunken mat foundation was similar to that with a solid embedded mat foundation showing a slight difference due to almost the same seismic base motion beneath both embedded foundations.

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.

A shake table test is conducted for the three-story reinforced concrete building structure using 0.28 g, 0.5 g, 0.75 g, and 1.0 g of seismic input motions based on the Gyeongju earthquake. Computational efforts are made in parallel to explore the mechanical details in the structure. For engineering practice, the elastic modulus of concrete and rebar in the dynamic analysis is reduced to 38% and 50%, respectively, to calibrate the structure's natural frequencies. The engineering approach to the reduced modulus of elasticity is believed to be due to the inability to specify the flexibility of the actual boundary conditions. This aspect may lead to disadvantages of nonlinear dynamic analysis that can distort local stress and strain relationships. The initial elastic modulus can be applied directly without the so-called engineering adjustment with infinite element models with spring and spring-dashpot boundary conditions. This has the advantage of imposing the system flexibility of the structure on the sub-boundary conditions of springs and damping devices to control its sensitivity in a serial arrangement. This can reflect the flexibility of realistic boundary conditions and the effects of system damping (such as the gap between a concrete footing and shake table, loosening of steel anchors, etc.) in scalar quantities. However, these spring and dashpot coefficients can only be coordinated based on experimental results, making it challenging to select the coefficients in-prior to perform an experimental test.

신재생에너지 신규설비 보급이 매년 꾸준히 증가하고 있으며, 그중 개발 확장성이 풍부하고 생산유발계수가 큰 해상풍력 시장이 급성장하고 있다. 특히 서남해 권역은 최고 수준의 해상풍력 잠재량을 보유하고 있으며, 관련 프로젝트들이 추진 중이다. 본 연구는 점토층 지반에 효과적인 해상풍력 하부구조물의 개발에 있어 EUROCODE에 의한 구조물의 설계 절차를 제시하고 구조 안전성을 고찰하여 관련 기술 분야에 이바지함을 목표로 한다. 선행연구에서는 풍력발전기 용량이 5MW급을 주요 대상으로 하였으나, 서남해 해상 풍력발전기 시장의 기술 추세에 부합하는 발전 용량 8MW급을 연구 모델로 선정하였다. 이에 본 연구에서는 서남해 지질 조건에 부합하는 하부구조물을 개발하고, 구조 안전성을 유한요소법을 활용하여 검증하였다. 초기 설계안에서 일부 구간을 보강하여 구조 안전성을 확보하였다. 본 연구 결과를 기반으로 하여, 향후 다양한 형태의 하부구조물에 대한 구조 안전성 평가가 가능하며, 전문화된 구조 설계 및 평가 기준을 확립하였다.