이 논문은 고강도 콘크리트를 사용한 철근콘크리트 외부 보-기둥 접합부의 실험결과를 보고한 것이다. 실험체의 주요 실험변수는 접합부 파괴모드, 콘크리트 압축강도, 철근의 정착 방법이다. 모든 실험체는 ACI 352R-02 기준에 바탕을 두어 J파괴와 BJ파괴가 되도록 계획하였다. 주철근은 90도 표준갈고리로 하거나 확대머리철근으로 하였다. 실험결과는 콘크리트 압축강도에 제한되는 현행 ACI 설계 기준식이 고강도 콘크리트를 사용한 보-기둥 접합부의 강도를 다소 과소평가하고 있음을 보여준다. 또한 확대머리철근을 가진 J파괴형 보-기둥 접합부의 강도는 표준갈고리를 가진 접합부보다 약 10% 이상 높게 평가되었다.

In this study, experimental research was carried out to improve and evaluate the seismic performance of reinforced exterior concrete beam-column joint strengthened with different anchorage length of embedded CFRP Rods in existing reinforced concrete building. Test result shows that retrofitting specimen(RBCJ-SR2T1, SR2T2) designed by the improvement of seismic performance of reinforced concrete beam-column joints, maximum load-carrying capacities were increased 2.24 ~ 2.24 times in comparison with the standard specimen(RBCJC). Also, retrofitting specimens showed stable hysteretic behavior compared to the standard specimen(RBCJC).

In this research, a total of seven specimens were tested under reversed cyclic loading, controlled by displacement and three times of reversed loads were given at each displacement. The goal of experiments is to identify the seismic and structural performance of pure dry precast concrete beam-column joints using bolt type connection and/or prestressing methods. Two representative results are examined and compared in this paper.

This paper evaluates the shear strength, behavior and failure mode of reinforced concrete beams with deformed GFRP reinforcing bar. Four concrete beam specimens were constructed and tested. It was carried out to observe failure behavior and load-deflection of simply supported concrete beams subjected to four-point monotonic loading. Load-deflection for FRP reinforced concrete beam member were predicted.

In this study it was developed FRP rod embedding FBG sensor, and compared the performance of sensor of the new rods and the existing strain gauge by applying the reinforced concrete beam-column joint in the same location. And it was found that new FRP rod was improved the structural performance and sufficiently sensing accuracy.

본 논문은 강-콘크리트 슬립실험으로 결정된 계면 계수값을 휨 하중을 받는 콘크리트 충전강관 합성보 실험의 결과예측에 적용하여 콘크리트 충전강관 합성보의 계면거동과 구속효과를 규명하였다. 원형단면의 콘크리트가 전단면압축을 받도록 하기 위해서 콘크리트 충전강관에 웨브와 플랜지를 추가한 콘크리트 충전강관 합성보를 사용하여 휨 거동실험을 수행하였다. 콘크리트가 전단면 압축을 받는 단부가 개방된 콘크리트 충전합성강관의 경우에는 구속효과에 의해 약 16%의 강도증진효과를 확인하였으며, 단부를 폐쇄하여 구속효과가 커진 콘크리트충전 합성강관의 경우에는 35% 정도의 큰 강도증진효과가 발생하는 것을 확인하였다. 실험과 수치해석을 통해 얻은 이러한 결과는 콘크리트 충전강관을 이용한 교량의 상부 거더나 아치리브에 대한 단면 결정에 적용되는 적용성을 갖는다.

본 연구에서는 기존 철근콘크리트 건물의 보-기둥 접합부의 내진성능의 개선을 위해 보-기둥 접합부 영역을 FRP보강재(매입형 CFRP Rod, CFRP시트)를 사용하여 보강한 후 내진성능을 평가하였다. 총 6개의 실험체를 제작하고 실험을 수행하여 내진성능을 평가하였으며, 본 연구의 실험결과를 근거로 다음과 같은 결론을 얻었다. 기존 철근콘크리트 보-기둥 접합부의 접합부 영역을 보강한 결과, 초기 재하시 접합부 영역의 균열억제 효과와 재하 전 과정을 통하여 보강재의 구속효과로 인하여 균열억제 효과가 커서 안정적인 파괴형태 및 내력향상 효과를 나타내었다. 매입형 CFRP Rod와 CFRP시트를 활용한 RC 외부 보-기둥 접합부 실험체 RBCJ-SRC2는 표준실험체 RBCJ와 비교하여 변위연성4, 7에서 각각 최대 내력은 1.97배, 에너지소산능력은 2.08배 증가하였다. 또한, 실험체 RBCJ-SR시리즈와 비교하여 최대내력이 1.09~1.11배 증가하였다. 그리고 실험체 RBCJ-CS, RBCJ-SR시리즈, RBCJ-SRC2는 변위연성 5, 6에서 표준실험체 RBCJ 보다 에너지소산능력이 1.10~2.30배 증가하였다. 그리고 에너지소산능력은 변위연성 4에서 13.0~14.4% 증가하였다.

In this study, experimental research was carried out to improve and evaluate the seismic performance of reinforced concrete beam-column joint using Groove and Embedding FRP Rod and CFRP Sheet in existing reinforced concrete building. Test result shows that retrofitting specimen(RBCJ-SR2, SRCB2) designed by the improvement of seismic performance of reinforced concrete beam-column joints load-carrying capacities were increased 1.78 ~ 2.29 times in comparison with the standard specimen.

In this study, experimental research was carried out to evaluate the structural performance of the reinforced concrete beam hybrid retrofitting with two materials(groove and embedding FRP rod, CFRP sheet) in existing reinforced concrete buildings. Test results showed that the maximum load carrying capacity of retrofitted specimens(NER1, NER1B, NER1L) were increased by 1.11 ~ 1.22 times respectively in comparison with the standard specimen NBS.

This study targets the development of technologies of reclaimed noise blocking engineering to improve endurance which may unify noise-blocking construction against noise and vibration and earthquake-preventive construction during rebuilding. This paper is to find the validity of construction methodology with RC beam additional materials to apply to slab and walls.

This paper describes the analysis results of coupling beams using steel fiber reinforced concrete for comparison with measure behaviors. Analysis is performed by the finite element analysis program, Vector 2. The results show possibility that relieve complex detail of diagonally reinforced coupling beam.

The composite beam is efficient and easy to construction. But shear connector is needed for the composite action. This research developed SPC beam in order to reduce the shear connector with utilization of mechanical bonded force by the cross sectional shape. The flexural behavior of SPC beam was evaluated through two point loading test.

Mathematical models of shrinkage and creep are based on the experimental evidences obtained from the ideal laboratory environment. In case of the age-dependent behavior of RC beam, the shrinkage strain may not be uniform through the depth of beam whereas it has been usually assumed to be uniform through the beam depth. This paper addresses the assumption of uniform shrink\age strain through the beam depth and flexural creep that has been observed from the recent test program.

In this study, experimental research was carried out to improve and evaluate the seismic performance of reinforced concrete beam-column joint using Embedded Carbon Fiber Rod and Carbon Fiber Sheet in existing reinforced concrete building. Test result shows that retrofitting specimen(LBCJ-SP45, CS2, CRUS) designed by the improvement of seismic performance of reinforced concrete beam-column joints load-carrying capacities were increased 1.34 ~ 1.54 times in comparison with the standard specimen.

In this study, a 3D FE model is developed by which one can analyze the composite action in the composite beam subjected to the hogging moment. Analysis results show that the reinforcement ratio and crack behaviour of the slab are main factors which exert a strong influence on the composite action. The existing experimental results, that the design of partial interaction can be more efficient in designing of shear connection of the composite beams, are indirectly verified by the FE analysis.

In this study, an experimental study to investigate the load transfer behavior of the CFT column to steel beam connection was carried out. The load transfer mechanism and the effect of the load transfer length were examined, and the results were also compared with finite element analysis results. Finally, the results are to be used for the basic reference of the design guideline for the CFT column connection.

In this study, it was developed eco-friendly zero cement fiber reinforced concrete using ground granulated blast furnace slag and alkali activator(water glass, sodium hydroxides). Also, it was evaluated the flexure capacity of the RC beams using zero cement concrete. The eco-friendly concrete using zero cement encouraged alkali activation reaction has rapid hardening speed and showed possibility as a high strength concrete. Also, the RC beams applied this showed similar movement and destroy tendency with RC used previous cement.

Under cyclic loading, the shear capacity of reinforced concrete (RC) beam-column connections is significantly decreased by the joint bond-slip and shear cracking as deformation increases. In the present study, Joint shear strength model on the basis of bond-slip was developed to evaluate deformability at the joint shear failure.

In this study, experimental research was carried out to evaluate the structural performance of the reinforced concrete beam retrofitted by strengthening methods(embedded FRP rod of hexagon, metal fittings) in existing reinforced concrete buildings. Test results showed that the maximum load carrying capacity of retrofitted specimens(BCR, BCR-AC1, BCR-AC2) were increased by 55%, 47%, and 52% respectively in comparison with the standard specimen BSS.

Amorphous metal fibers can improve the brittleness of concrete and enhance the shear and tensile strength of reinforced concrete (RC) members. A series of experimental studies RC composite beams with amorphous metal fiber composites were conducted, and it was shown that the RC beam with amorphous metal fiber composites could give improved flexural responses to compare with the reinforced concrete beam.