Fiber-reinforced polymer (FRP) exhibits superior tensile strength and corrosion resistance compared to steel but has a lower elasticity. Recently, researchers have addressed this by proposing composite sections of FRP and concrete. To ensure the intended composite behavior, these FRP–concrete sections should exhibit sufficient stress transfer between the two elements through a shear connection. Herein, various shear connection methods were proposed to improve the composite behavior of glass fiber–reinforced polymer (GFRP) plates and concrete. Through push-out tests, the behavior characteristics of the prepared specimens were analyzed. The findings confirm that an FRP shear key (FSK) with a small cross-section resists high shear stresses, making it suitable for sections vulnerable to damage from bolt drilling. Additionally, combining an FSK with bolts as shear connectors on a GFRP plate proves beneficial in preventing the fracture of the plate and improving the shear resistance.

In this study, considering the expansion/contraction behavior of the upper structure at all times and the abnormal behavior of the receiving friction elements that allow horizontal movement during earthquakes, a port receiving test body simulating the protrusion of the friction elements was created and the modulus performance was evaluated. In order to confirm the influence of the friction element's projection, the friction element's degree of separation was divided into four stages, and the shear behavior of the test specimen and the friction coefficient were confirmed. As a result of the experiment, it was found that the friction load increases as the protrusion degree of the friction element increases. On the other hand, as the degree of protrusion of the coefficient of friction increases, the coefficient of friction also increases. It was confirmed that damage to the friction elements during use increases the coefficient of friction, hinders smooth expansion and contraction of the upper structure, and causes stress concentration at the fixed-end support.

콘크리트 바닥판의 파손 등으로 인하여 강합성 거더 교량의 생애주기가 짧아짐에 따라 프리캐스트 바닥판을 사용한 모듈화 공법에 대한 연구가 활발히 진행되고 있으나, 바닥판의 해체 시 발생하는 분진 및 소음으로 인한 환경적 측면에 대한 연구는 미흡한 실정이다. 본 연구는 기존 용접 스터드 볼트를 대체할 수 있는 볼트 접합 전단연결재의 성능을 검증하기 위하여 정적강도 실험 및 피로강도 실험을 수행하였다. 실험결과 200만 회 피로하중에 대하여 실험체의 균열 및 파괴 양상은 관측되지 않았으며, 이후 실시한 잔류강도 실험 또한 정적강도 실험과 동일한 것으로 확인되었다.

본 논문은 철계형상기억합금(Fe-SMA) stirrup으로 전단보강된 철근콘크리트 보의 전단거동을 예측하기 위한 해석적 연구이다. 전단거동 예측을 위해 변형률 적합조건 및 하중 평형조건을 만족하는 휨해석이 수행되었으며, 이후 수정압축장이론 (MCFT)에 기반한 전단해석이 수행되었다. 부재의 처짐을 계산하기 위해 휨 및 전단에 의해 발생된 처짐이 모두 고려되었다. 제 안된 해석모델의 검증은 Ji et al.(2022)의 실험결과를 비교하여 수행되었다. 비교결과 제안된 해석모델과 실험결과의 극한하중, 극한하중 시 처짐의 오차는 평균 4.77%, 6.62%로 Fe-SMA Stirrup으로 전단보강된 철근콘크리트 보의 전단 거동을 비교적 정확 하게 예측하는 것으로 나타났다.

본 연구는 초고강도 콘크리트판, 그라우팅 및 모체 콘크리트 내에 후크와 스터드로 연결한 합성접합부의 전단 실험 을 수행하고 그 거동을 파악하고자 한다. 압축강도 35 MPa, 50 MPa 및 90 MPa 그라우팅의 강도, 4종류의 전단연결재 배치를 실험변수로 총 12개의 시험체를 제작하였다. 합성접합부의 전단력은 그라우팅 콘크리트의 압축강도에 따라 비례적 관계를 가지 고 있다. 휨모멘트가 지배적인 힘이 아니고 면적이 크며 서로 다른 시기에 콘크리트를 친 경계면 합성체에서 콘크리트 전단력 은 무시할 정도 크기가 아니다. 콘크리트 모체 압축강도보다 그라우팅의 압축강도가 크다면 접합부에서 콘크리트 전단력이 유 의미하게 크며 전단연결재를 병용하면 더 큰 전단력을 얻을 수 있다.

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.

Recently, the use of transfer slab system has increased greatly. However, several construction problems are being encountered owing to its excessive thickness. Therefore, in this study, a transfer slab system that uses a reverse drop panel, which can utilize the facility space of the pit floor by reducing the transfer slab thickness, was considered. To investigate the shear behavior of transfer slab system that uses the reverse drop panel, the two-way shear strength of transfer slab-column connection with the reverse drop panel was analyzed using nonlinear FE analysis. In addition, the two-way shear strength evaluations of transfer slab with the reverse drop panel conducted using the existing evaluation methods were verified by comparing the strengths predicted by those methods with the results of nonlinear FE analysis.

본 연구는 FRP-콘크리트 합성구조의 휨/전단에 대한 구조적 성능 및 거동 특성을 해석적으로 규명하고자 휨/전단 저항성능에 대해 외연적 유한요소해석을 이용하여 FRP 합성보의 휨/전단파괴거동 해석을 실시하여 기 수행한 실험과 비교분석 하고, 적용된 콘크리트손상소성모델의 각각의 인자들의 영향에 대해 매개분석하고 최적화된 안을 제시하고자 하였다. 기하학적 및 재료적 비선형성 큰 경우 유한요소해석 중 내연적 해석의 경우 수렴에 많은 문제점을 내포함으로 외연적 유한요소 접근법이 보다 합리적임을 수치해석을 통해 보였다. 본 연구의 경우 콘크리트손상소성모델의 여러 인자들에 대한 매개변수 해석을 수행한 결과, 다이레이션각의 경우는 26°, 파괴에너지 값으로 100Nm/m2, 인자 Kc의 값으로는 0.667 그리고 손상계수는 감안하는 것이 합리적이다.

본 논문에서는 프리스트레스트 콘크리트 깊은 보의 전단 강도를 유한요소법을 이용한 수치해석으로 예측해 보았다. 프리스트레스의 정도를 주요 변수로 하여 전단 강도의 변화를 살펴보았다. 유한요소해석 프로그램인 Abaqus를 사용하여 CDP재료 모델과 초기조건을 설정함으로 프리스트레스트 콘크리트 깊은 보의 전단 강도를 비교적 정확하게 예측할 수 있으며 오차는 5%이하였다. 또한 깊은 보의 strut-and-tie 모델과 동일한 형태를 나타냈으며, 해석이 타당하다고 본다. 프리스트레스트 콘크리트 깊은 보의 전단 강도를 예측하기 위해 제안된 수식으로 전단 강도를 계산하였을 때 실제 전단 강도보다 큰 수치를 얻었다. 텐던에 가해진 프리스트레스의 크기가 커질수록 깊은 보의 전단 강도는 선형적으로 증가하는 현상을 보였다. 깊은 보의 전단 강도를 효과적으로 증가시키기 위해 프리스트레스트 콘크리트 깊은 보를 활용할 수 있다.

Structural insulated panels, structurally performed panels consisting of a plastic insulation bonded between two structural panel facings, are one of emerging products with a viewpoint of its energy and construction efficiencies. Of the SIPs, Cyclic test was conducted by two kinds of specimens: single panel and double panels. Cyclic test results, which were equivalent to static test results, showed that maximum load was 45.42kN, allowable shear load was 6.3kN/m. Furthermore the accumulated energy dissipation capability for double panels was as 2.3 times as that for single panel. From performance of structural tests, the allowable shear load for panels was suggested to be at least 6.1kN/m.

본 논문에서는 국부좌굴 현상을 고려하여 강판 콘크리트 패널(SCP)의 유한요소 해석을 수행하고 설계지침과 비교하여 전 단 스터드의 효율적인 스터드 배치 간격을 연구하였다. 강판 콘크리트 구조의 설계 및 기술기준은 전단 균열의 전개와 국부 좌굴 현상을 방지하기 위하여 스터드의 최대 간격을 제한하고 있으나 이는 기존 강재-콘크리트 합성 구조의 설계기준을 토대로 산정되었다. 이에 유한요소 해석 프로그램을 이용한 강판 및 SCP의 국부좌굴 부재 해석을 통하여 스터드 최대 배치 간격을 구하고 설계지침에서 제시한 값과 비교하였다. 먼저, 단일 강판에 대하여 국부좌굴 해석을 수행하여 판좌굴 이론과 비교 검증하였고, 연속적인 스터드 배치에 따른 영향을 확인하기 위하여 다수의 강판이 연결된 경우에 대하여 해석을 수행하였다. 또한 강판 콘크리트 구조에서 콘크리트의 영향 및 합성 거동에 따른 영향을 확인하기 위하여 강판 콘크리트 구조를 모델링하고, 국부좌굴이 발생하지 않는 스터드 배치 최대 간격을 구하여 설계지침과 비교하였다.

The concrete wall panels are composed of various members such as studs, brackets, bolts and nuts, etc. Embedded studs in the concrete wall resist transferred lateral and horizontal load in the structure. The thickness of the concrete wall influences shear behavior of embedded studs. The finite element analysis was carried out with respect to the thickness of the concrete wall to investigate shear behavior of embedded studs. The numerical analysis results were compared with the experimental results and confirmed that The deformation of the stud anchor is reduced with an increase of the thickness of the concrete wall.

Columns in existing reinforced concrete structures that are designed and constructed without considering seismic loads generally exhibit widely spaced transverse reinforcements without using seismic hooks. Due to the insufficient reinforcement details in columns compared to the reinforcement requirements specified in modern seismic codes, brittle shear failure is likely to occur. This may lead to sudden collapse of entire structure during earthquakes. Adequate retrofit strategy is required for these columns to avoid such catastrophic event. In order to do so, behavior of columns in existing reinforced concrete structures should be accurately predicted through computational analysis. In this study, an analytical model is proposed for accurately simulating the cyclic behavior of shear critical columns. The parameters for backbone, as well as pinching and cyclic deterioration in strength and stiffness are calibrated using test data of column specimens failed by shear.

The purpose of this study is to develop a new seismic resistant method by using precast concrete wall panels for existing low-rise, reinforced concrete beam-column buildings such as school buildings. Three quasi-static hysteresis loading tests were experimentally performed on one unreinforced beam-column specimen and two reinforced specimens with L-type precast wall panels. The results were analyzed to find that the specimen with anchored connection experienced shear failure, while the other specimen with steel plate connection principally manifested flexural failure. The ultimate strength of the specimens was determined to be the weaker of the shear strength of top connection and flexural strength at the critical section of precast panel. In this setup of L-type panel specimens, if a push loading is applied to the reinforced concrete column on one side and push the precast concrete panel, a pull loading from upper shear connection is to be applied to the other side of the top shear connection of precast panel. Since the composite flexural behavior of the two members govern the total behavior during the push loading process, the ultimate horizontal resistance of this specimen was not directly influenced by shear strength at the top connection of precast panel. However, the RC column and PC wall panel member mainly exhibited non-composite behavior during the pull loading process. The ultimate horizontal resistance was directly influenced by the shear strength of top connection because the pull loading from the beam applied directly to the upper shear connection. The analytical result for the internal shear resistance at the connection pursuant to the anchor shear design of ACI 318M-11 Appendix-D except for the equation to predict the concrete breakout failure strength at the concrete side, principally agreed with the experimental result based on the elastic analysis of Midas-Zen by using the largest loading from experiment.

The curved bridges shows very complicate behaviors compare to straight girders due to its initial curvature. Usually, the shear strength is investigated due to the aspect ratio(transverse stiffeners spacing/height of girder) and many researches have been conducted for the web shear strength for I-shaped curved girders with high aspect ratios(larger than 3). In this study, numerical studies are carried out and the results are compared with the current design practices. By the analyses, the maximum aspect ratio of a transversely stiffened web panel are suggested to revisits the validity of a limited imposed by Basler.