• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1997년도 가을 학술발표회 논문집
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• pp.665-672
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• 1997

In this paper, sixteen column specimens were tested under the concentrated and excentric load condition to examine the structural behavior of strengthened columns. 16 column specimens were divided into four groups. One group is not strengthened, the other three groups are strengthened by the materials : 1) steel plate, 2) carbon fiber sheet, and 3) glass fiber sheet, each group is composed of four specimens. As a result, strengthened columns have larger bearing capacity and energy absorption after ultimate load than unstrengthened columns. The column group strengthened with steel plate has the best bearing capacity among the strengthened column groups. Also, the columns strengthened with the carbon fiber sheet are similar to glass fiber sheet in bearing capacity. If necessary to strengthen columns in trouble, car should be taken to treat the joint between beam and column because of crack propagation in tension side.

• 한국구조물진단유지관리공학회 논문집
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• 제4권3호
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• pp.205-210
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• 2000

The objective of this study is to investigate the structural behavior of steel beam-high strength concrete column joints subjected to reversed cyclic loadings. The variables of the experimental study is amount of steel plates at the beam-to-column joint panel zone. Three specimens were prepared and tested under constant uniaxial load($0.2f_{ck}A_g$) to reinforced high strength concrete column, and the reversed cyclic loads were applied to end of steel beams, The failure modes, hysteresis loop, stiffness degradations and energy dissipation capacities were analyzed and compared for test variables.

• Earthquakes and Structures
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• 제20권3호
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• pp.309-323
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• 2021

Architectural design decisions and structural systems arrangements affect their earthquake behaviors significantly of reinforced concrete building in Turkey. Because the performances as safe and economical against earthquake loads of reinforced concrete buildings can be provided with especially design decisions in the architectural design stage. This matter reveals the importance of design decisions in the architectural design phase and the right structural system arrangement. The purpose of this study, the short-column situation frequently observed in reinforced concrete buildings after the earthquakes occurred in Turkey are to examine comparatively the effects on behavior and the rough construction cost of the building. The obtained results show that the short column circumstance composed due to different reasons negatively affects the earthquake performance of the reinforced concrete buildings and increases the rough construction cost. This matter shows that the measures to be taken against short column formation should be foreseen especially at the architectural design stage.

• 콘크리트학회논문집
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• 제24권6호
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• pp.633-641
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• 2012

이 논문에서는 비탄성 시간이력해석을 통해 보-기둥 접합부 비탄성 전단거동이 구조물 거동에 미치는 영향을 알아보기 위해 지반조건 $S_B$ 내진설계범주 C에 대해서 5층 철근콘크리트 보통모멘트골조를 KBC2009에 맞게 구조설계 하였다. 보 및 기둥 부재의 휨모멘트-곡률 관계는 fiber model로 확인하였으며 보-기둥 접합부 모멘트-회전각 관계는 simple and unified joint shear behavior model과 보-기둥 접합부 모멘트 평형관계를 이용하여 확인하였다. 이력거동은 IDARC 프로그램의 three-parameter model을 활용하여 나타내었다. 2400년 재현주기 수준의 최대지반가속도에 대한 비탄성 시간이력해석 결과 비탄성 보-기둥 접합부를 고려하는 경우 최대밑면전단력은 감소하나 최대지붕층변위, 최대층간변위는 차이가 없었으며 발생한 최대층간변위도 KBC2009의 허용층간변위를 만족하여 구조설계 과정에서 보-기둥 접합부의 비탄성 전단거동을 고려하지 않아도 문제가 없을 것으로 판단된다.

• Steel and Composite Structures
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• 제28권1호
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• pp.73-82
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• 2018

This paper experimentally and analytically elucidates the shear behavior and shear bearing capacity of partially prefabricated steel reinforced concrete (PPSRC) columns and hollow partially prefabricated steel reinforced concrete (HPSRC) columns. Seven specimens including five PPSRC column specimens and two HPSRC column specimens were tested under static monotonic loading. In the test, the influences of shear span aspect ratio and difference of cast-in-place concrete strength on the shear behavior of PPSRC and HPSRC columns were investigated. Based on the test results, the failure pattern, the load-displacement behavior and the shear capacity were focused and analyzed. The test results demonstrated that all the column specimens failed in shear failure mode with high bearing capacity and good deformability. Smaller shear span aspect ratio and higher strength of inner concrete resulted in higher shear bearing capacity, with more ductile and better deformability. Furthermore, calculation formula for predicting the ultimate shear capacity of the PPSRC and HPSRC columns were proposed on the basis of the experimental results.

• Advances in concrete construction
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• 제9권3호
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• pp.313-326
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• 2020

Glass fiber-reinforced polymer (GFRP) bars have been introduced as an effective alternative for the conventional steel reinforcement in concrete structures to mitigate the costly consequences of steel corrosion. However, despite the superior performance of these composite materials in terms of corrosion, the effect of replacing steel reinforcement with GFRP on the seismic performance of concrete structures is not fully covered yet. To address some of the key parameters in the seismic behavior of GFRP-reinforced concrete (RC) structures, two full-scale beam-column joints reinforced with GFRP bars and stirrups were constructed and tested under two phases of loading, each simulating a severe ground motion. The objective was to investigate the effect of damage due to earthquakes on the service and ultimate behavior of GFRP-RC moment-resisting frames. The main parameters under investigation were geometrical configuration (interior or exterior beam-column joint) and joint shear stress. The performance of the specimens was measured in terms of lateral load-drift response, energy dissipation, mode of failure and stress distribution. Moreover, the effect of concrete damage due to earthquake loading on the performance of beam-column joints under service loading was investigated and a modified damage index was proposed to quantify the magnitude of damage in GFRP-RC beam-column joints under dynamic loading. Test results indicated that the geometrical configuration significantly affects the level of concrete damage and energy dissipation. Moreover, the level of residual damage in GFRP-RC beam-column joints after undergoing lateral displacements was related to reinforcement ratio of the main beams.

• 한국강구조학회 논문집
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• 제22권3호
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• pp.253-260
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• 2010

콘크리트충전 강관구조는 구조성능이 우수하고 내화성능 등이 우수하여 점진적으로 현장 적용이 확대되고 있다. 그러나 지금까지 이러한 구조형식에 있어서는 구조부재의 저항능력에 대해 연구가 활발하게 진행되어 왔으나, 기둥의 주각부에 대한 연구가 활발하지 못하여 아직까지 주각부에 대한 응력의 흐름이나 이력 특성에 대해 명확히 규명되어 있지 못하며, 따라서 주각부에 대한 구조설계 시에는 순수 철골구조에서 적용하는 설계방법을 원용하여 설계되고 있다. 본 연구에서는 충전강관 기둥의 주각부에 있어서의 구조적 거동을 규명하기 위하여 실험을 수행하였다. 실험의 주된 변수로는 강관의 주각부 형식과 매립깊이를 변수로 하였으며, 비교를 위하여 순수강관 기둥에 대한 주각부의 실험도 병행하였다. 실험결과 순수강관과 충전강관의 주각부에 있어 구조적 거동의 차이점은 크게 나타나지 않고 있으나, 주각부의 형식에 따른 거동의 차이는 크게 나타나고 있다.

• 한국방재학회 논문집
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• 제9권6호
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• pp.1-9
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• 2009

콘크리트의 구속효과 및 재료 비선형성, 강재의 변형 경화, 초기작용 축력을 고려하여 원형 콘크리트 충전 강관(Concrete Filled Steel Tube : CFT) 기둥의 해석을 위한 프로그램을 작성하고 검증 및 해석을 수행하였다. 축력-모멘트 상관관계 해석, 모멘트-곡률 해석, 모멘트-횡변위에 대한 해석을 수행하고, 선행연구자의 실험결과와 비교하여 검증하였다. 검증결과, 작성된 프로그램은 실제 CFT 기둥의 거동에 근접하였으며, 콘크리트의 구속효과를 고려한 경우 그렇지 않은 경우보다 더 큰 강도와 연성능력을 나타내었다. 콘크리트의 강도와 강관의 두께 변화에 따른 간단한 매개변수 해석을 수행하였으며, 콘크리트의 강도 증가 시 CFT 기둥의 강도는 증가하나 연성은 저하되는 결과를 보여주었다. 반면에 강관 두께를 증가시키는 경우에는, CFT 기둥의 강도와 연성 모두 증가하는 결과를 보여주었다.

• Steel and Composite Structures
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• 제31권1호
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• pp.69-83
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• 2019

This paper investigates the structural behavior of very high strength concrete encased steel composite columns via combined experimental and analytical study. The experimental programme examines stub composite columns under pure compression and eccentric compression. The experimental results show that the high strength encased concrete composite column exhibits brittle post peak behavior and low ductility but has acceptable compressive resistance. The high strength concrete encased composite column subjected to early spalling and initial flexural cracking due to its brittle nature that may degrade the stiffness and ultimate resistance. The analytical study compares the current code methods (ACI 318, Eurocode 4, AISC 360 and Chinese JGJ 138) in predicting the compressive resistance of the high strength concrete encased composite columns to verify the accuracy. The plastic design resistance may not be fully achieved. A database including the concrete encased composite column under concentered and eccentric compression is established to verify the predictions using the proposed elastic, elastoplastic and plastic methods. Image-oriented intelligent recognition tool-based fiber element method is programmed to predict the load resistances. It is found that the plastic method can give an accurate prediction of the load resistance for the encased composite column using normal strength concrete (20-60 MPa) while the elastoplastic method provides reasonably conservative predictions for the encased composite column using high strength concrete (60-120 MPa).

• Steel and Composite Structures
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• 제16권2호
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• pp.221-231
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• 2014

The purpose of this study was to evaluate the cyclic behavior of steel column-tree moment connections used in steel moment resisting frames. These connections are composed of shop-welded stub beam-to-column connection and field bolted beam-to-beam splice. In this study, the effects of beam splice length on the seismic performance of column-tree connections were experimentally investigated. The change of the beam splice location alters the bending moment and shear force at the splice, and this may affect the seismic performance of column-tree connections. Three full-scale test specimens of column-tree connections with the splice lengths of 900 mm, 1,100 mm, and 1,300 mm were fabricated and tested. The splice lengths were roughly 1/6, 1/7, 1/8 of the beam span length of 7,500 mm, respectively. The test results showed that all the specimens successfully developed ductile behavior without brittle fracture until 5% radians story drift angle. The maximum moment resisting capacity of the specimens showed little differences. The specimen with the splice length of 1,300 mm showed better bolt slip resistance than the other specimens due to the smallest bending moment at the beam splice.