• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2008년도 추계 학술발표회 제20권2호
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• pp.5-8
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• 2008

본 연구에서는 고강도철근콘크리트 보-기둥 접합부의 고성능화 기술 즉 콘크리트의 고강도화, 접합부 영역의 손상을 최소화하고 보의 소성힌지를 보의 내측으로 완전히 이동함과 동시에 내진성능을 향상시키는 고성능 설계상세 기술 및 고인성섬유 복합모르타르을 도입한 시험체를 제작하고 실험을 수행하여 이력거동을 평가하였다. ${\blacksquare}$ 철근콘크리트 보-기둥 접합부의 내진성능을 향상시키고, 보-기둥 접합면에 인접하여 발생하는 소성힌지를 보의 내측으로 이동시킬 목적으로 새로운 접합부 설계상세를 도입한 정착형 중간철근(1.5d)과 이중폐쇄스터럽 보강 시험체(HJCI)는 소성힌지의 이동은 물론 내진성능이 현저히 개선 되었다. ${\blacksquare}$ 철근콘크리트 보-기둥 접합부의 철근배근 및 콘크리트 밀실타설의 문제점을 해소하고 기둥의 띠철근 및 보의 스터럽을 고인성섬유 복합모르타르(HDFRM)로 대체한 실험체 (HJRP)의 경우 안정적인 이력거동, 충분한 내력확보 및 만족스런 파괴형태를 나타내었다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2008년도 춘계 학술발표회 제20권1호
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• pp.301-304
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• 2008

선시공 조립식 거푸집 공법을 사용한 계단의 접합부는 힌지로 처리하여 구조설계를 하는 것이 일반적인 방법이다. 계단참과 경사계단이 만나는 접합부를 힌지로 간주하게 되면 접합부의 모멘트 성능이 전혀 없으므로 계단부분의 휨모멘트가 증가하게 되어 철근 배근량이 늘어난다. 또한 진동 및 피로하중에 의한 접합부 손실이 증가하여 사용성이 저하된다. 그럼에도 불구하고 계단 접합부를 핀접합하는 이유는 현장에서의 시공성이 용이하기 때문이다. 최근들어 시공성을 고려하면서 접합부의 휨성능을 향상시킬 수 있는 반강접에 대한 상세가 제시되고 있으나, 이러한 상세를 구조설계에 전혀 반영하지는 못하고 있다. 따라서 본 연구에서는 계단의 반강접 접합부를 설계에 반영할 수 있는 방법을 제시하고자 하였다. 강접합, 반강접합, 핀접합으로 설계된 계단 접합부에 대해 모멘트 성능을 비교하고, 부정정 구조물인 계단 코아부분의 비선형 해석을 통해 항복 이후의 변화를 비교하였다. 연구결과 반강접합 성능을 반영하기 위한 휨강성계수를 도입하였고, 이를 적용한 비선형 해석결과 핀접합보다는 안정적인 결과를 보였고, 강접합에 비해 연성이 뛰어나 내진 및 진동에 대해 유리한 시스템으로 판단된다.

• Steel and Composite Structures
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• 제39권3호
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• pp.337-352
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• 2021

The study presented experimental and numerical investigation on the seismic performance of steel reinforced concrete (SRC) L-shaped column- reinforced concrete (RC) beam joints. Various parameters described as steel configuration form, axial compressive ratio, loading angle, and the existence of slab were examined through 4 planar joints and 7 spatial joints. The characteristics of the load-displacement response included the bearing capacity, ductility, story drift ratio, energy-dissipating capacity, and stiffness degradation were analyzed. The results showed that shear failure and flexural failure in the beam tip were observed for planar joints and spatial joint, respectively. And RC joint with slab failed with the plastic hinge in the slab and bottom of the beam. The results indicated that hysteretic curves of spatial joints with solid-web steel were plumper than those with hollow-web specimens. The capacity of planar joints was higher than that of space joints, while the opposite was true for energy-dissipation capacity and ductility. The high compression ratio contributed to the increase in capacity and initial stiffness of the joint. The elastic and elastic-plastic story deformation capacity of L-shaped column frame joints satisfied the code requirement. A design formula of joint shear resistance based on the superposition theory and equilibrium plasticity truss model was proposed for engineering application.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 추계학술대회 논문집
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• pp.1088-1092
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• 2002

The purpose of this investigation was to study the kinematics of joints between foot segments based on computer graphic-based model during the stance phase of walking. In the model, ail joints were assumed to act as monocentric, single degree of freedom hinge joints. The motion of foot was captured by a video collection system using four cameras. The model fitted in an individual subject was simulated with this motion data. The kinematic data of tarsometatarsal joints and metatarso-phalangeal joint were quantitatively similar to the previous data. Therefore, our method using the computer graphic-based model is considered useful.

• 한국안전학회지
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• 제32권3호
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• pp.60-65
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• 2017

This study examined the effect of rotational stiffness of joints between vertical and horizontal members in system supports. In order to prevent repeated disasters of system supports, it is important to examine the accurate behavior of system supports. Among various factors affecting the complex behavior of system supports, this study focused on the stiffness of joints between vertical and horizontal members. The considered joint was modelled by a rotational spring, but the translational displacements were fixed. The stiffness of rotational spring was calculated by utilizing the usable experimental data. In addition, the hinge connection condition, which is generally considered in design and only restrict the translational displacements, was modelled to compare the results. The case with the rotational stiffness in joints showed 3.5 times buckling loads compared to the case without the rotational stiffness. Thus, the structural behavior of the vertical member in system supports was similar to the vertical member with the fixed condition. For the combined stresses of vertical members, the combined stress ratios were reduced 5~6% by considering the rotational stiffness of connecting parts. However, for the horizontal member where showed relatively small stress range, the stresses were increased 2.3~7.6 times by considering the rotational stiffness in connecting parts.

• Steel and Composite Structures
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• 제28권1호
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• pp.83-98
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• 2018

This research was conducted to study the behavior of exterior concrete beam-column joints with reinforced shape memory alloy (SMA) bars tested under cyclic loading. These bars benefit from superelastic behavior and can stand high loads without residual strains. The experimental part of the study, 8 specimens of exterior concrete beam-column joints were made and tested. Two different types of concrete with 30 and 45 MPa were used. Four specimens contained SMA bars and 4 specimens contained steel bars in beam-column joints. Furthermore, different transverse reinforcements were used in beams investigate the effects of concrete confinement. Specimens were tested under cyclic loading. Results show that SMA bars are capable of recentering to their original shape after standing large displacements. Due to the superelastic behavior of SMA bars, cracks at the joint core vanish under cyclic loading. As the cyclic loading increased, bending failure occurred in the beam outside the joint core. In the analytical parts of the study, specimens were simulated using the SeismoStruct software. Experimental and analytical results showed a satisfactory correlation. Plastic hinge length at the beam joint for specimens with SMA and steel bars was calculated by empirical equations, experimental and analytical results. It was shown that Paulay's and Priestley's equations are appropriate for concrete beam-column joints in both types of bars.

• Earthquakes and Structures
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• 제20권4호
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• pp.417-430
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• 2021

Due to functional requirements, SRC column-RC beam abnormal joints with characteristics of strong beam weak column, variable column section, unequal beam height and staggered height exist in the Steel reinforced concrete (SRC) frame-bent main building structure of thermal power plant (TPP). This paper presents the experimental results of these abnormal joints through cyclic loading tests on five specimens with scaling factor of 1/5. The staggered height and whether adding H-shaped steel in beam or not were changing parameters of specimens. The failure patterns, bearing capacity, energy dissipation and ductile performance were analyzed. In addition, the stress mechanism of the abnormal joint was discussed based on the diagonal strut model. The research results showed that the abnormal exterior joints occurred shear failure and column end hinge flexural failure; reducing beam height through adding H-shaped steel in the beam of abnormal exterior joint could improve the crack resistance and ductility; the abnormal interior joints with different staggered heights occurred column ends flexural failure; the joint with larger staggered height had the higher bearing capacity and stiffness, but lower ductility. The concrete compression strut mechanism is still applicable to the abnormal joints in TPP, but it is affected by the abnormal characteristics.

• 한국산학기술학회논문지
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• 제1권2호
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• pp.1-8
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• 2000

본 연구에서는 상용 순수 티타늄 소재를 사용하여 안경테를 레이저 빔 용접으로 제조하기 위하여 광섬유로 전송되는 가변 펄스곡 80 ㎲-10 ms. 최대 평균출력 200 W, 첨두출력 12 kW와 최대 펄스에너지 50J성능의 초정밀 Nd:YAG 레이저 용접장치를 설계 제작하고 이 장치를 사용하여 안경테 제조를 위한 최적 용접조건을 선정하기 위한 실험을 수행하였다. 안경테를 위한 T이음 및 맞대기 이음형상을 용접할 때 평균출력, 광섬유 형태, 초점위치 등에서 용입상태와 용접결함을 조사하여 최적 용접조건을 선정하였고 안경테 부품 장석(temple hinge)과 다리, 톱바를 레이저 용접으로 시제품을 제작하였다.

• Structural Monitoring and Maintenance
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• 제7권3호
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• pp.167-193
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• 2020

In this paper, the behavior of interior steel fiber reinforced concrete beam - column joints (BCJs) under cyclic loading is investigated. An experimental program including tests on twelve reinforced concrete (BCJs) specimens under cyclic loading was carried out. The test specimens are divided into two groups having different geometry: group (G1) (symmetrical BCJs specimens) and group (G2) (nonsymmetrical BCJs specimens). The parameters considered in this study are the steel fibers (SFs) content by volume of concrete (V_f), the spacing of shear reinforcement at the joint region, and the area of longitudinal flexural reinforcement. Test results show that the addition of 0.5% SFs with stirrups spacing S=S_max has effectively enhanced the overall performance of BCJs with respect to energy dissipation, ductility ratio, spreading and width of cracks. The failure of specimens is governed mainly by the formation of a plastic hinge at the face column and outside the beam-column junction. Secondary shear cracks were also observed in the beam-column junctions.

• Computers and Concrete
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• 제13권2호
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• pp.221-234
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• 2014

A nonlinear finite element analysis using ANSYS is used to evaluate the seismic behavior of reinforced concrete exterior beam-column joints. The behavior of the finite element models under cyclic loading is compared with the experimental results. Two beam-column joint specimens (SH and SHD) with square hoop confinement in joint and throughout the column with detailing as per IS 13920 are studied. The specimen SHD was provided with additional diagonal bars from column to beam to relocate the plastic hinge formation from beam-column interface. The load-displacement relationship, joint shear stress and strain in beam obtained from numerical study showed good agreement with the experimental results. This investigation proves that seismic behaviour of reinforced concrete beam-column joints under reversed cyclic loading can be evaluated successfully using finite element modeling and analysis.