• Structural Engineering and Mechanics
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• 제27권2호
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• pp.149-172
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• 2007

An experimental study of five full-scale coupling beam specimens has been conducted to investigate the seismic behavior of strengthened RC coupling beams by bolted side steel plates using a reversed cyclic loading procedure. The strengthened coupling beams are fabricated with different plate thicknesses and shear connector arrangements to study their respective effects on load-carrying capacity, strength retention, stiffness degradation, deformation capacity, and energy dissipation ability. The study revealed that putting shear connectors along the span of coupling beams produces no significant improvement to the structural performance of the strengthened beams. Translational and rotational partial interactions of the shear connectors that would weaken the load-carrying capacity of the steel plates were observed and measured. The hierarchy of failure of concrete, steel plates, and shear connectors was identified. Furthermore, detailed effects of plate buckling and various arrangements of shear connectors on the post-peak behavior of the strengthened beams are discussed.

• 국제강구조저널
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• 제18권5호
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• pp.1772-1783
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• 2018

Nowadays, the researches about composite structure system are being implemented in various fields, and many steel structures are designed based on that. In this study, the bending and seismic performance of the newly developed high-performance cold forming composite beam are evaluated by several experiments. As a result of the bending performance test, the bending moment of beam was increased stably depending on the depth and plate thickness of beam, and it is considered that the bending moment can be evaluated by the equation of a composite beam design. As a result of the seismic performance test, it was verified that sufficient seismic performance was obtained despite the increase of a negative moment rebar and depth of beam. In addition, the nominal bending moment has obtained the strength above the plastic bending moment, and also the plastic rotation angle has satisfied the requirement of composite intermediate moment frame.

• Earthquakes and Structures
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• 제23권1호
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• pp.59-73
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• 2022

In this study, the seismic behavior of an all-steel buckling-restrained (AB) steel plate shear wall (SPSW) with incline slits under fire and cyclic loading was investigated. ABSPSW was composed of two thin steel infill plates with a narrow distance from each other, which were embedded with incline slits on each plate. These slits were in opposite directions to each other. The finite element (FE) numerical model was validated with three test specimens and after ensuring the modeling strategy, the parametric study was performed by considering variables such as wall plate thickness, slit width, strip width between two slits, and degree of temperature. A total of 256 FE numerical models were subjected to coupled temperature-displacement analysis. The results of the analysis showed that the high temperature reduced the seismic performance of the ABSPSW so that at 917℃, the load-bearing capacity was reduced by 92%. In addition, with the increase in the temperature, the yield point of the infill plate and frame occurred in a small displacement. The average decrease in shear strength at 458℃, 642℃, and 917℃ was 18%, 46%, and 92%, respectively, compared to the shear strength at 20℃. Also, with increasing the temperature to 917℃, ductility increased by an average of 75%

• 한국공간구조학회논문집
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• 제22권4호
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• pp.23-30
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• 2022

It is effective to apply hybrid damping device that combine separate damping device to cope with various seismic load. In this study, HRS hybrid damper(hybrid rubber slit damper) in which high damping rubber and steel slit plate are combined in parallel was proposed and structural performance tests were performed to review the suitability for seismic performance. Cyclic Loading tests were performed in accordance with criteria presented in KDS 41 17 00 and MOE 2019. As a result of the test, the criteria of KDS 41 17 00 and MOE2019 was satisfied, and the amount of energy dissipation increased due to the shear deformation of the high-damping rubber at low displacement. Result of performing the RC frame test, the allowable story drift ratio was satisfied, and the amount of energy dissipation increased in the reinforced specimen compared to the non-reinforced specimen.

• Steel and Composite Structures
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• 제27권3호
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• pp.337-353
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• 2018

In previous weak-axis moment connection tests, brittle fracture always initiated near the edge of the beam flange groove weld due to force flow towards the stiffer column flanges, which is the opposite pattern as strong-axis moment connections. As part of the China NSFC (51278061) study, this paper tested two full-scale novel weak-axis reduced beam section moment connections, including one exterior frame connection specimen SJ-1 under beam end monotonic loading and one interior frame joint specimen SJ-2 under column top cyclic loading. Test results showed that these two specimens were able to satisfy the demands of FEMA-267 (1995) or ANSI/AISC 341-10 (2010) without experiencing brittle fracture. A parametric analysis using the finite element software ABAQUS was carried out to better understand the cyclic performance of the novel weak-axis reduced beam section moment connections, and the influence of the distance between skin plate and reduced beam section, a, the length of the reduced beam section, b, and the cutting depth of the reduced beam section, c, on the cyclic performance was analyzed. It was found that increasing three parametric values reasonably is beneficial to forming beam plastic hinges, and increasing the parameter a is conducive to reducing stress concentration of beam flange groove welds while increasing the parameters b and c can only reduce the peak stress of beam flange groove welds. The rules recommended by FEMA350 (2000) are suitable for designing the proposed weak-axis RBS moment connection, and a proven calculation formulation is given to determine the thickness of skin plate, the key components in the proposed weak-axis connections. Based on the experimental and numerical results, a design procedure for the proposed weak-axis RBS moment connections was developed.

• 한국강구조학회 논문집
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• 제29권2호
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• pp.181-192
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• 2017

최근 경사단부강판과 고장력 볼트를 이용한 보 이음(Inclined end-plate beam splice) 공법이 개발되었다. 단부강판은 브래킷 단부에 용접되고 연결보는 고장력 볼트를 통해 이음시킨다. 기둥면에는 브래킷이 용접되고, 브래킷과 연결보 단부에 각각 경사단부강판과 고장력 볼트를 이용하여 이음 시킨다. 이 연구에서는 총 6개의 외부 보-기둥 모멘트접합부의 반복가력실험을 수행하였다. 실험변수는 단부강판 상세와 볼트 배열 상세이다. 모든 실험체는 AISC Design Guide 4에 따라 단부강판 및 볼트에 의한 모멘트 저항성능이 보 이음부 요구모멘트보다 크도록 설계되었다. 실험결과, 확장된 단부강판(Extended end-plate)을 사용한 보이음부의 경우 이음부 단부강판의 지레작용 및 볼트의 취성 파단 없이 중앙 보 모멘트가 단부 브래킷으로 효과적으로 전달되었다. 하지만, 보-기둥 접합부의 변형능력은 기둥면 보 플랜지 용접부의 취성파단으로 제한적이었다. 실험결과를 바탕으로, 기울어진 단부강판 이음부를 갖는 보-기둥 모멘트접합부의 내진설계를 위한 개선사항을 제안하였다.

• Structural Engineering and Mechanics
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• 제87권4호
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• pp.391-403
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• 2023

In this study, a new type of self-centering beam-column joint with tapered steel plate links is proposed. Firstly, mechanical property of the basic joint (with the prestressed steel strands only, to provide the self-centering ability) and the combined joint (with both the prestressed steel strands and tapered steel plate links, to provide self-centering and energy dissipation simultaneously) is theoretically analyzed. Then, three joints with different dimensions and combinations of tapered plate links are designed and tested through a series of quasi-static cyclic loading tests. Test results show that a nearly bilinear elastic moment-rotation relationship for the basic joint is obtained. With the addition of tapered steel plate links, typical flag-shape hysteretic curves are obtained, which indicates good self-centering and energy dissipating ability of the combined joint. By installing multiple tapered plate links, stiffness and bearing capacity of the beam-column joint can be enhanced. The theoretical moment-rotation relationships agree well with the test results. A simplified macro model of the proposed joint is developed using OpenSees, which simulates reasonably well its hysteretic behavior.

• Steel and Composite Structures
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• 제9권1호
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• pp.39-58
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• 2009

Composite joints, considering the composite action of steel and concrete, exhibit, in general, high strength and high ductility. As a consequence, the use of this type of joint has been increasing in many countries, especially in those that are located in earthquake-prone regions. In this paper, a hysteretic model with pinching is presented that is able to reproduce the cyclic response of steel and composite joints. Secondly, the computer implementation and adaptation of the model in a spring element within the computer code Seismosoft is described. The model is subsequently calibrated using a series of experimental test results for composite joints subjected to cyclic loading. Finally, typical parameters for the various joint configurations are proposed.

• 한국가구학회지
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• 제25권4호
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• pp.331-337
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• 2014

The purpose of this paper is to evaluate the moment resistance of glulam post-to-base connections by applying quasi-static cyclic loads. The connectors consisted of inserted plates and drifted pins according to the load direction. The connection types employed in this study were total three including two unidirectional types (H, V) and the multi-directional type (M). The moment resistance of 8 mm-plate M-type is compared to 6 mm plate. Total four types of Post-to-base connection are prepared and tested under pseudo-static reversed cyclic loading. Test results showed that the yield moment of multi-directional connection is about 2 times higher than that uni-directional connections. The ductility ratio of multi-directional connection determined by EEEP was higher that that of uni-directional connection. It was becoming higher as the thickness of plate is increased. The Finite Element Analysis was conducted to estimate the stress distribution behavior of tested connections. Results showed the failure of multi-directional type were caused by the split of pined hole and the shear failure of lifted part of post.

• 한국지반환경공학회 논문집
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• 제13권6호
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• pp.5-17
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• 2012

초연약 지반의 개량을 위한 중장비의 안전한 주행성 확보를 위해 제일 우선적으로 검토되어야 하는 표층처리공법에 대한 연구는 아직 미진하며 표층처리공법 설계 시 건설기계의 반복적인 주행으로 인한 소성침하를 고려하지 못하고 있다. 따라서 본 연구에서는 표층처리공법에서 가장 많이 사용하고 있는 보강재인 지오텍스타일, 인장강도가 200kN/m와 100kN/m인 지오그리드와 대나무망으로 보강한 후 1.0m의 모래로 복토한 지반에서 현장 평판재하시험과 반복 평판재하시험을 실시하여 각 보강재별 지지력과 거동양상을 비교 평가하고자 한다. 평판재하시험 결과 대나무망을 사용하였을 경우 다른 보강재를 사용하였을 때보다 BCR값이 최대 1.5배 증가하였다.