• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1999년도 학회창립 10주년 기념 1999년도 가을 학술발표회 논문집
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• pp.585-588
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• 1999

This study is performed to verify the effect of CSA expansive additives for concrete by material properties test and 4 point-bendig test of RC slabs. The result shows that the variations of compress strength, bending strength, and modulus of elasticity of expansive concrete are the same as those of plain concrete. And the crack load of RC slabs with expansive concrete are increased in comparision with that of plain concrete, but the ultimate strength of RC slabs with expansive concrete is decreased.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1998년도 가을 학술발표대회 논문집(III)
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• pp.827-832
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• 1998

Recently, Carbon Fiber Sheets(CFS) have been used for strengthening the deteriorated RC beams and bridge decks because of its resistant capacity of corrosion and easy repairing works. In this study, the static test tare performed on RC bridge decks strengthened with CFS. Test results show that ultimate strength of specimens strengthened with CFS is increased as 15~26% comparing to the control specimen.

• Structural Engineering and Mechanics
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• 제84권5호
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• pp.619-632
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• 2022

Reinforced concrete (RC) structures may be subjected to sudden dynamic impact loads such as explosions occurring for different reasons, the collision of masses driven by rockfall, flood, landslide, and avalanche effect structural members, the crash of vehicles to the highway and seaway structures. Many analytical, numerical, and experimental studies focused on the behavior of RC structural elements such as columns, beams, and slabs under sudden dynamic impact loads. However, there is no comprehensive study on the behavior of the RC column-beam connections under the effect of sudden dynamic impact loads. For this purpose, an experimental study was performed to investigate the behavior of RC column-beam connections under the effect of low-velocity impact loads. Sixteen RC beam-column connections with a scale of 1/3 were manufactured and tested under impact load using the drop-weight test setup. The concrete compressive strength, shear reinforcement spacing in the beam, and input impact energy applied to test specimens were taken as experimental variables. The time histories of impact load acting on test specimens, accelerations, and displacements measured from the test specimens were recorded in experiments. Besides, shear and bending crack widths were measured. The effect of experimental variables on the impact behavior of RC beam-column connections has been determined and interpreted in detail. Besides, a finite element model has been established for verification and comparison of the experimental results by using ABAQUS software. It has been demonstrated that concrete strength, shear reinforcement ratio, and impact energy significantly affect the impact behavior of RC column-beam connections.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2000년도 추계 학술발표회 논문집 Proceedings of EESK Conference-Fall 2000
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• pp.364-371
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• 2000

The pseudo dynamic test has been carried out so as to investigate the seismic performance of RC bridge piers strengthened with and without glass fiber sheets. The Lessons from severe demage of many infrastructures in Kobe(1995) and Northridge(1996) earthquakes have emphasized the need to develop the retrofit measures to enhance flexural strength, ductility and shear strength of RC bridge piers nonseismically designed before 1992. Therefore, the objective of this experimental research is to investigate the seismic behavior of circular reinforced concrete bridge piers by the pseudo dynamic test. and then to enhance the ductility of concrete piers strengthening with glass fiber sheets in the plastic hinge region. 7 circular RC bridge piers were made in a 1/3.4 scale. Important test parameters are confinement steel ratio, retrofitting. load pattern, etc. The seismic behavior of circular concrete piers under artificial ground motions has been evaluated through strength and stiffness degradation, energy dissipation. It can be concluded that existing bridge piers wrapped with glass fibers in the plastic hinge regions could have enough seismic performance.

• KCI Concrete Journal
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• 제13권2호
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• pp.3-9
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• 2001

Pseudo dynamic test for seven circular RC bridge piers has been carried out to investigate their seismic performance subjected to expected artificial earthquake motions. The objective of this experimental study is to investigate the hysteretic behavior of reinforced concrete bridge piers, which have been widely used for railway and urban transportation facilities. Important test parameters are confinement steel ratio, and input ground motion. The seismic behavior of circular RC bridge piers under artificial ground motions has been evaluated through displacement ductility, cumulative energy input, and dissipation capacity. It can be concluded that RC bridge piers designed in a limited ductile behavior provision of Eurocode 8 have been determined to show good seismic performance even under moderate artificial earthquakes.

• 한국안전학회지
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• 제25권4호
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• pp.48-60
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• 2010

The fire resistance performance of 2 RC slabs after exposure to the ISO-834 fire standard without loading has been experimentally investigated. A Comparison is made of the fire resistance performance between RC slabs without PP(polypropylene) fibers and RC slabs with PP fibers. From the fire test results, the presence of PP fibers in RC slabs can reduce spalling and enhance their fire resistance. Until now, the determination of fire resistance of reinforced concrete(RC) slabs has essentially been based on tabulated data. According to ACI 216 code and EUROCODE 2, the design of concrete structures is essentially based on tabulated data for appropriate concrete cover and various fire durations. From the comparison between fire test results and codes, current fire design provisions of codes such as the ACI 216 and the EUROCODE 2 are unconservative for estimating mechanical properties of RC slabs at elevated temperatures.

• 한국방재학회 논문집
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• 제10권5호
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• pp.35-40
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• 2010

본 연구에서는 RC슬래브 교량의 내하력을 향상시키기 위해 유리섬유 복합재(CAF)를 이용한 보강방법을 제시하였다. 보강 성능을 평가하기 위해 설계하중 DB 18로 설계된 실험대상 교량의 슬래브 하면에 단위폭당 50 cm로 CAF 복합재를 보강하여 정 동적재하시험을 수행하였다. 정 동적재하시험 결과 RC슬래브의 최대변위, 변형률, 충격계수는 보강전에 비하여 보강후에 각 14.7%, 5.0% 및 33.7% 감소하였다. 시험경간 중앙부에서의 RC슬래브의 공칭저항비는 27% 증가하였고, 공용내하력은 1,2 경간에서 44.6%, 48.9%증가하였다. 결론적으로 설계하중 DB 18로 설계된 노후된 RC슬래브 교량을 현행 1등급교의 설계하중 DB 24로 향상시키는데 CAF 복합재를 이용한 보강방법은 매우 효과적인 것으로 판단된다.

• Steel and Composite Structures
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• 제21권1호
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• pp.157-175
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• 2016

It was found that the lateral stiffness changes obvious at the transfer position of the section configuration from SRC to RC. This particular behavior leads to that the transfer columns become as the important elements in SRC-RC hybrid structures. A comprehensive study was conducted to investigate the seismic behavior of SRC-RC transfer columns based on a low cyclic loading test of 16 transfer columns compared with 1 RC column. Test results shows three failure modes for transfer columns, which are shear failure, bond failure and bend failure. Its seismic behavior was completely analyzed about the failure mode, hysteretic and skeleton curves, bearing capacity deformation ability, stiffness degradation and energy dissipation. It is further determined that displacement ductility coefficient of transfer columns changes from 1.97 to 5.99. The stiffness of transfer columns are at the interval of SRC and RC, and hence transfer columns can play the role of transition from SRC to RC. All specimens show similar discipline of stiffness degradation and the process can be divided into three parts. Some specimens of transfer column lose bearing capacity swiftly after shear cracking and showed weak energy dissipation ability, but the others show better ability of energy dissipation than RC column.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1998년도 가을 학술발표대회 논문집(III)
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• pp.851-856
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• 1998

In recent years, glassfibers have been used for strengthening in RC structure because of low material cost and easy repairing work. The purpose of this study is to experimentally and analytically investigate the effect of glassfibers for enhancing the capacity of RC structure. The result shows that yield and ultimate strength of RC beam with glassfibers are increased by approximate 13% and 26%, comparing with those for RC beam without glassfibers. It has been observed from the test that fatigue behaviors of RC beam with glassfibers have been significantly and large improved comparing with those for RC beam without glassfibers.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2008년도 춘계 학술발표회 제20권1호
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• pp.93-96
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• 2008

이 논문은 근단층지반운동(NFGM)하에서 내진성능을 평가하기 위한 RC교각의 진동대, 준정적, 유사동적 실험을 다룬다. 5개의 실험체가 수행되었다. 축소 모형을 제작하고 상부구조물의 중량 에 의한 축력의 효과는 프리스트레스에 의해 구현하였다. 지진이 발생할 때 상부 구조물의 횡방향 관성력은 진동대의 제한된 용량 때문에 교각 실험체에 연결한 질량 프레임으로 모사하였다. 특히, 진동대 실험에서 질량 모사 프레임이 교각 모델과 같은 변위로 움직이면서 마찰 효과를 최소화할 수 있도록 고려하였고 이에 대한 검증을 실시하였다. RC교각의 축소 계수를 4.25로 설정 하였다.