• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2001년도 봄 학술발표회 논문집
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• pp.69-74
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• 2001

Steel plate or fiber composite plate are mainly used in externally bonding method. Shear strengthening by externally bonding method is to confirm shear safety and to avoid brittle failure. In case of strengthening by externally bonding method, a failure of structure occurs frequently due to delamination between strengthening plate and concrete. Therefore, it is important to consider the delamination in the strengthening design. The objective of this study is to propose a modified shear strength evaluation by considering the delamination. The delamination criteria of strengthening plate is established by the ultimate strain and shear stress. And shear strength of RC beams is proposed in terms of the delamination criteria. The proposed shear strength is compared with test results and verified through the comparison.

• 콘크리트학회논문집
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• 제12권5호
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• pp.101-110
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• 2000

A practical approach of calculating the ultimate strength of composite beams with unreinforced web opning is proposed through shear behavioral tests. In this method, the slab shear contribution at the opening is calculated as the smaller value of the pullout capacity of shear connector at the high moment end and the one way shear capacity of slab. A simple interaction equation is used to predict the ultimate strength under simultaneous bending moment and shear force. Strength prediction by the proposed method is compared with previous test results and the predictions by other analytical methods. The comparison shows that the proposed method predicts the ultimate capacity with resonable accuracy.

• Structural Engineering and Mechanics
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• 제27권4호
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• pp.501-521
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• 2007

This study presents a model to better understand the shear behavior of reinforced concrete walls subjected to lateral load. The scope of the study is limited to squat walls with height to length ratios not exceeding two, deformed in a double-curvature shape. This study is based on limited knowledge of the shear behavior of low-rise shear walls subjected to double-curvature bending. In this study, the wall ultimate strength is defined as the smaller of flexural and shear strengths. The flexural strength is calculated using a strength-of-material analysis, and the shear strength is predicted according to the softened strut-and-tie model. The corresponding lateral deflection of the walls is estimated by superposition of its flexibility sources of bending, shear and slip. The calculated results of the proposed procedure correlate reasonably well with previously reported experimental results.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2007년도 정기 학술대회 논문집
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• pp.663-668
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• 2007

An enhanced first shear deformation theory for composite plate is developed. The detailed process is as follows. Firstly, the theory is formulated by modifying higher order zigzag theory. That is, the higher order theory is separated into the warping function representing the higher order terms and lower order terms. Secondly, the relationships between higher order zig-zag field and averaged first shear deformation field based on the Reissner-Mindlin's plate theory are derived. Lastly, the effective shear modulus is calculated by minimizing error between higher order energy and first order energy. Then the governing equation of FSDT is solved by substituting shear modulus into effective shear modulus. The recovery processing with the nodal unknown obtained from governing equation is performed. The accuracy of the present proposed theory is demonstrated through numerical examples. The proposed method will serve as a powerful tool in the prediction of laminated composite plate.

• Steel and Composite Structures
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• 제17권5호
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• pp.623-639
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• 2014

Due to recent advancements in the area of Artificial Intelligence (AI) and computational intelligence, the application of these technologies in the construction industry and structural analysis has been made feasible. With the use of the Adaptive-Network-based Fuzzy Inference System (ANFIS) as a modelling tool, this study aims at predicting the shear strength of channel shear connectors in steel concrete composite beam. A total of 1200 experimental data was collected, with the input data being achieved based on the results of the push-out test and the output data being the corresponding shear strength which were recorded at all loading stages. The results derived from the use of ANFIS and the classical linear regressions (LR) were then compared. The outcome shows that the use of ANFIS produces highly accurate, precise and satisfactory results as opposed to the LR.

• Structural Engineering and Mechanics
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• 제30권2호
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• pp.211-223
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• 2008

A number of studies have suggested that the use of high ductile and high shear materials, such as Engineered Cementitious Composites (ECC) and High Performance Fiber Reinforced Cementitious Composites (HPFRCC), significantly enhances the shear capacity of structural elements, even with/without shear reinforcements. The present study emphasizes the development of a nonlinear model of shear behaviour of a HPFRCC panel for application to the seismic retrofit of reinforced concrete buildings. To model the shear behaviour of HPFRCC panels, the original Modified Compression Field Theory (MCFT) for conventional reinforced concrete panels has been newly revised for reinforced HPFRCC panels, and is referred to here as the HPFRCC-MCFT model. A series of experiments was conducted to assess the shear behaviour of HPFRCC panels subjected to pure shear, and the proposed shear model has been verified through an experiment involving panel elements under pure shear. The proposed shear model of a HPFRCC panel has been applied to the prediction of seismic retrofitted reinforced concrete buildings with in-filled HPFRCC panels. In retrofitted structures, the in-filled HPFRCC element is regarded as a shear spring element of a low-rise shear wall ignoring the flexural response, and reinforced concrete elements for beam or beam-column member are modelled by a finite plastic hinge zone model. An experimental study of reinforced concrete frames with in-filled HPFRCC panels was also carried out and the analysis model was verified with correlation studies of experimental results.

• International Journal of Naval Architecture and Ocean Engineering
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• 제8권2호
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• pp.177-187
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• 2016

To evaluate the tractive performance of tracked trencher on seafloor surface, a new shear stress-displacement empirical model was proposed for saturated soft-plastic soil (SSP model). To validate the SSP model, a test platform, where track segment shear test can be performed in seafloor soil simulacrum (bentonite water mixture), was built. Series shear tests were carried out. Test results indicate that the SSP model can describe the mechanical behavior of track segment with good approximation in seafloor soil simulacrum. Through analyzing the main external forces applied to seafloor tracked trencher during the uniform linear trenching process, a drawbar pull prediction model was deduced with the SSP model. A tracked walking mechanism of the seafloor tracked trencher prototype was built, and verification tests were carried out. Test results indicate that this prediction model was feasible and effective; moreover, from another side, this conclusion also proved that the SSP model was effective.

• Structural Engineering and Mechanics
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• 제30권2호
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• pp.247-261
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• 2008

Performance of shear-deficient reinforced concrete (RC) beams strengthened with carbon fiber-reinforced polymer (CFRP) strips/sheets is analyzed through numerical simulations on four-point bending tests. The numerical simulations are carried out using the finite element (FE) program ABAQUS. A micromechanics-based constitutive model (Liang et al. 2006) is implemented into the FE program ABAQUS to model CFRP strips/sheets. The predicted results are compared with experiment data (Khalifa and Nanni 2002) to assess the accuracy of the proposed FE analysis approach. A series of numerical tests are conducted to investigate the influence of stirrup lay-ups on the shear strengthening performance of the CFRP strips/sheets, to illustrate the influence of the damage parameters on the microcrack density evolution in concrete, and to investigate the shear and flexural strengthening performance of CFRP strips/ sheets. It has been shown that the proposed FE analysis approach is suitable for the performance prediction of RC beams strengthened with CFRP strips/sheets.

• Nuclear Engineering and Technology
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• 제27권2호
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• pp.189-202
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• 1995

계면 전단응력이 있을 때와 없을 때 가열 또는 응축되면서 하강하는 난류액막의 열전달 계수를 예측하기 위한 개선된 방법을 제시하였다. 특히 큰 계면 전단응력이 있을 때 하강하는 난류액막에 적용할 수 있도록 Mudawwar와 El-Masri의 준 실험적 난류모델을 수정하여 Yih와 Liu가 제안한 통합적 접근방법에 사용한 와류점성모델대신에 사용하였다. 광범위한 크기의 계면전단응력에 대해 액막 레이놀즈 수 대액체막 두께 및 접근적 열전달 계수를 개선된 방법과 다른 여러 기존 방법으로 예측하여 실험값들과 비교하였다. 그 결과 일반적으로 수정한 모델과 예측한 값이 다른 기존 모델로 예측한 값보다 실험 치와 더밀접하게 일치하는 것을 보여주었다.

• 한국구조물진단유지관리공학회 논문집
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• 제23권7호
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• pp.33-39
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• 2019

이 연구에서는 지반의 개량에 따른 전단파속도 및 지반등급 향상 여부를 알아보기 위하여 지반개량체의 형상을 변수로 실험적 연구를 수행하였다. 실험은 지반개량체의 형상을 변수로 크로스홀(Cross hole) 기법을 이용하여 전단파속도를 측정하였다. 또한, 이 연구에서 측정된 결과와 기존 전단파속도 측정결과를 이용하여 국내 지반조건에 맞는 N-Value에 대한 전단파속도 예측식을 제안하였다. 실험결과, 지반개량을 수행하는 경우 원지반의 전단파속도는 소폭 상승하였다. 또한, 이 연구에서 제안한 예측식은 지층조건에 관계없이 기존실험결과를 합리적으로 예측하였다.