• 한국강구조학회 논문집
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• 제9권2호통권31호
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• pp.277-285
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• 1997

접합부 패널존의 거동에 영향을 줄 수 있는 변수를 고려하여 SRC 기둥-H형강보 접합부의 역학적 특성에 대해 실험적 연구를 하였다. 7개의 시험체를 제작하여 실험을 수행하였으며 실험으로부터 접합부의 전단강도와 이력거동을 조사하였고 파괴형태에 대하여 분석하였다. 접합부의 이력거동은 약간의 핀칭을 보이는 안정된 거동을 보였다. 이력거동은 최대하중에 도달한 후 변위를 증가할 때 내력이 감소하는 거동을 보였다. 접합부 패널존의 전단강도는 접합부내의 콘크리트 유효면적이 증가함에 따라 증가함을 보였다. 접합부 패널존의 전단강조는 철골기둥 웨브의 항복강도, 패널존내의 철골기둥 플랜지의 소성휨강도 그리고 유효콘크리트의 전단강도의 합으로 표현되며 실험결과는 이러한 접합부의 전단강도와 근사한 값을 보였다.

• Structural Engineering and Mechanics
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• 제41권1호
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• pp.43-65
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• 2012

The primary objective of this study was to identify concrete contribution to the initial shear strength of reinforced concrete (RC) hollow columns under lateral loading. Seven large-scale RC rectangular hollow column specimens were tested under monotonic or cyclic lateral loads. The most important design parameter was column length-to-depth aspect ratio ranging between 1.5 and 3.0, and the other test variables included web area ratio, hollow section ratio, and loading history. The tests showed that the initial shear strength reduced in a linear pattern as the column aspect ratio increased, and one specimen tested under cyclic loading achieved approximately 83% of the shear strength of the companion specimen under monotonic loading. Also, several pioneering shear models proposed around the world, all of which were mainly based on tests for columns with solid sections, were reviewed and compared with the test results of this study, for their possible applications to columns with hollow sections. After all, an empirical equation was proposed for concrete contribution to the initial shear strength of RC hollow columns based on fundamental mechanics and the test results.

• Structural Monitoring and Maintenance
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• 제9권4호
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• pp.337-357
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• 2022

The objective of this study is to present a data-driven machine learning (ML) framework for predicting ultimate shear strength and failure modes of reinforced concrete ledge beams. Experimental tests were collected on these beams with different loading, geometric and material properties. The database was analyzed using different ML algorithms including decision trees, discriminant analysis, support vector machine, logistic regression, nearest neighbors, naïve bayes, ensemble and artificial neural networks to identify the governing and critical parameters of reinforced concrete ledge beams. The results showed that ML framework can effectively identify the failure mode of these beams either web shear failure, flexural failure or ledge failure. ML framework can also derive equations for predicting the ultimate shear strength for each failure mode. A comparison of the ultimate shear strength of ledge failure was conducted between the experimental results and the results from the proposed equations and the design equations used by international codes. These comparisons indicated that the proposed ML equations predict the ultimate shear strength of reinforced concrete ledge beams better than the design equations of AASHTO LRFD-2020 or PCI-2020.

• Steel and Composite Structures
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• 제47권3호
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• pp.423-436
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• 2023

In this research, we tested 10 simply supported concrete-encased composite columns under monotonic eccentric loads and investigated their shear behaviour. The specimens tested were two reinforced concrete specimens, three steel-reinforced concrete (SRC) specimens with an H-shaped steel section (also called a beam section), and five SRC specimens with a cruciform-shaped steel section (also called a column section). The experimental variables included the transverse steel shape's depth and the longitudinal steel flange's width. Experimental observations indicated the following. (1) The ultimate load-carrying capacity was controlled by web compression failure, defined as a situation where the concrete within the diagonal strut's upper end was crushed. (2) The composite effect was strong before the crushing of the concrete outside the steel shape. (3) We adjusted the softened strut-and-tie SRC (SST-SRC) model to yield more accurate strength predictions than those obtained using the strength superposition method. (4) The MSST-SRC model can more reasonably predict shear strength at an initial concrete softening load point. The rationality of the MSST-SRC model was inferred by experimentally observing shear behaviour, including concrete crushing and the point of sharp variation in the shear strain.

• 대한토목학회논문집
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• 제26권2A호
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• pp.391-399
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• 2006

정 부모멘트 사이의 효과적인 휨강성분배를 통한 경제적인 단면을 설계하고 하부플랜지의 교축방향 곡선화를 통한 교량의 미를 도모하기 위해, 강플레이트거더 교각부에서 높이가 변하는 복부판을 설계에 종종 반영하고 있다. 이 같은 높이가 변하는 플레이트거더의 전단거동은 일반적인 플레이트거더에 비해 복잡하다. 그러나 관련연구의 부족으로 현행 하중-저항계 수설계규정은 명확한 전단설계기준을 제시하고 있지 못하다. 본 연구에서는 전단력을 받는 높이가 변하는 복부판의 탄성좌굴 및 극한전단거동을 조사하기 위해 다양한 매개변수가 고려된 3차원 유한요소해석이 수행되었으며, 해석결과로부터 높이가 변하는 복부판의 전단강도를 간단하며 합리적으로 산정할 수 있는 전단설계식을 제안하였다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1999년도 학회창립 10주년 기념 1999년도 가을 학술발표회 논문집
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• pp.381-384
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• 1999

The present paper describe the result obtai ed from 11 beam specimens to explore the influence of stirrups on shear failure process. Each beam specimen was reinforced with one or two stirrup. Then the experimental results were analyzed and compared with the results obtained from truss model analyzsis.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1992년도 봄 학술발표회 논문집
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• pp.131-136
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• 1992

Eight singly reinforced high strength concrete beams without web reinforcement were tested to investigate their behavior and to determine their ultimate shear capacities. In this study, the main variable was the ration of longitudinal reinforcement. Test results were compared with strength predicted by using ACI code, Zsutty's dquation and Bazant & Kim's equation. As the result, for the beams of low steel ratio, the margin of safety in ACI code may be disappeared. It was shown that Zsutty.s equation well predict the trend of the test data.

• 전산구조공학
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• 제1권2호
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• pp.111-120
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• 1988

이 연구는 철근콘크리트보의 전단파괴 매카니즘에 대한 근본적인 성질을 밝히기 위해서 전단균열의 생성 및 진행과정을 해석적으로 연구하였다. 유한요소법에 파괴역학(fracture mechanics)을 결합시킨 program을 이용하여서, 철근 콘크리트 보에서 균열이 진행함에 따라 바꿔지는 내부응력상태와 균열정점에서의 stress intensity factors 등을 조사하여서, 전단균열의 생성 및 진행의 근본적인 이유를 밝히고자 하였다. 해석결과로 밝혀진 사실들을 간단한 실험으로 비교 검증하였다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1996년도 가을 학술발표회 논문집
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• pp.337-344
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• 1996

Reinforced concrete deep beams with conpressive strengths in the range of 500kg/$\textrm{cm}^3$~750kg/$\textrm{cm}^3$ were tested under two-point loding. All the beams were singly reinforced with main steel percent $\rho$=1.29% and with nominal percentage of vertical shear reinflrcements $\rho_v$=0.26%. According to shear-span to depth ratio a/d. The beams were tested for four horizontal shear reinforcement ratio $\rho_h$, ranging from$\rho_h$=0.0 to $\rho_h$=0.53. The results indicate that the horizontal shear reinforcements of beams have an effect on failure load and on ductile behavior of deep beams. The test results are compared with predictions based on the current ACI Building Code. The computated reports in the paper will have designers assured for design of high strength concrete deep beam. Though ACI Code is relatively conservative and tend to non-economical, ACI Code has the merit that is easy to use.

• Earthquakes and Structures
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• 제7권5호
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• pp.877-890
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• 2014

The purpose of this study is to present adequate modeling solutions for squat and slender RC walls. ASCE41-13 (American Society of Civil Engineers) specifies that the aspect ratios of height to width for the RC walls affect the hysteresis response. Thus, this study performed non-linear analysis subjected to cyclic loading using two different macroscopic models: one of macroscopic models represents flexural failure of RC walls (Shear Wall Element model) and the other (General Wall Element model) reflects diagonal shear failure occurring in the web of RC walls. These analytical results were compared to previous experimental studies for a slender wall (> aspect ratio of 3.0) and a squat wall (= aspect ratio of 1.0). For the slender wall, the difference between the two macroscopic models was negligible, but the squat wall was significantly affected by parameters for shear behavior in the modeling method. For accurate performance evaluation of RC buildings with squat walls, it would be reasonable to use macroscopic models that give consideration to diagonal shear.