• Structural Engineering and Mechanics
• /
• 제62권5호
• /
• pp.651-661
• /
• 2017

This paper presents an experimental study of bond-slip behavior of reinforced lightweight aggregate concrete (LC) and normal weight concrete (NC) with embedded steel bar. Tests were conducted on tension-pull specimens that had cross-sectional dimension with a reinforcing bar embedded in the center section. The experimental variables include concrete strength (20, 40, and 60 MPa) and coarse aggregate type (normal-weight aggregate and reservoir sludge lightweight aggregate). The test results show that as concrete compressive strength increased, the magnitudes of the slip of the LC specimens were greater than those of the NC specimens. Moreover, the bond strength and stiffness approaches zero at the loaded end, or close to the central anchored point of the specimen. In addition, the proposed bond stress-slip equation can effectively estimate the behavior of bond stress and steel bar slipping.

• 대한토목학회논문집
• /
• 제42권6호
• /
• pp.775-786
• /
• 2022

원자력발전소 구조물을 포함하여 플랜트 구조물에서는 사용 중 설비보강을 위하여 벽체 및 슬래브에 관통부를 신설하는 경우가 빈번히 발생하고 있으며, 관통부 설치작업 중에 철근이 절단되는 사례가 일부 발생하고 있다. 이 관통부들은 설계 또는 건설 단계에서 고려된 것이 아니므로 설치 중 발생한 철근의 절단은 사실상 구조물의 손상이기 때문에, 관통부 주변 응력 전이범위 또는 유효폭을 고려한 구조물의 건전성 평가가 필요하다. 본 연구에서는 가동중인 원자력발전소 벽식 건물의 전단벽에 관통부를 신설할 경우에 발생하는 철근 절단의 영향을 평가하기 위하여 다양한 비선형 해석과 정적 가력 실험을 수행하였다. 그리고 관통부 신설과 철근의 절단으로 인한 벽체의 강성저하와 관통부 주변 철근의 응력 및 변형률 분포를 평가하였다.

• 국제학술발표논문집
• /
• The 3th International Conference on Construction Engineering and Project Management
• /
• pp.1370-1376
• /
• 2009

Reinforcing steel works should be carefully controlled by the construction manager considering the severe fluctuation of the price of reinforcing steel bars and for the safety of structure in building constructions. In particular, preparing rebar placing drawings needs more effort and time than before because of the emergence of higher and more complicated buildings. Moreover, the experience of field engineers or foremen (fabricators or detailers) in preparing placing drawings gives rise to the differences in fabricated bar type and quantity of bars used. To address these problems, this study proposed the support system in preparing placing drawings for reinforcing steel works efficiency. In the near future, if this system can be made available on the web, multiple end-users will be able to share the result; the efficiency of rebar supply chain management will also be improved.

• Structural Engineering and Mechanics
• /
• 제41권3호
• /
• pp.379-393
• /
• 2012

Of the various methods of splicing reinforcing bar in reinforced concrete structure, mortar-filled sleeve reinforcement splice offers diverse benefits, not only in terms of structural performance but also for the construction process. Consequently, after the mortar-filled sleeve splices have been developed in recent years, research and development on these splices has been actively carried out, in order to evaluate its macro structural performance, such as its strength and stiffness, with the aim of enabling this system to be applied to construction in the field as early as possible. However, to make a proper evaluation on the overall structural performance of the mortar-filled sleeve reinforcing bar splice, it is of critical importance to understand the lateral confining action of the sleeve, which is known to affect the bond strength between the embedded bar and mortar in the sleeve. Accordingly, in this study, an experiment of monotonic loading and cyclic loading was conducted with a full-sized mortar-filled sleeve splice attaching strain gauges on the sleeve surface with experimental variables such as development length of bar, etc. Based on the test results, the effect of the lateral confining action of the sleeve was analyzed and considered in terms of the bond strength between the bar and mortar in this splice.

• 한국건축시공학회지
• /
• 제8권2호
• /
• pp.63-70
• /
• 2008

Reinforcing steel work plays an important role in terms of its structural performance or weight of construction cost for reinforced concrete structures. Precise estimation of re-bar quantity gives a basis for managing the reinforcing steel work effectively. However, the estimation process is still performed ineffectively based upon the expert's experience or manpower in spite of the advanced technology or improvement efforts. Therefore, the purpose of this research is to develop a prototype system for taking-off the quantity of reinforcing steel bars quickly and accurately in an order consistent with the specific members identified on the drawings. An estimate algorithm considering the connection, settlement and coating thickness of re-bars was suggested regarding to their replacement conditions which places more emphasis on constructibility. Also, this system produces the shop drawings automatically with the calculation results with work zone information.

• 한국구조물진단유지관리공학회 논문집
• /
• 제11권6호
• /
• pp.169-180
• /
• 2007

본 연구에서는 SD500 고강도 철근에 적합한 강관 스플라이스 슬리브를 개발한 후에 실물크기의 20개 실험체를 제작하여 가력실험을 실시하였다. 그리고 강도를 비롯한 구조성능을 철근의 정착길이, 슬리브의 타입, 철근의 규격과 같은 실험변수에 따른 영향을 분석하고, 국내기준을 비롯한 주요기준에 따라서 비교, 평가하였다. 실험 결과는 SD500 고강도 철근용으로 개발된 강관 스플라이스 슬리브 철근이음은 주요기준에서 요구하는 구조성능을 가지고 있는 것으로 확인되었고 SD500 고강도 철근용 슬리브 철근이음에 대한 구조설계 기준 확립을 위한 기술적 자료를 제시하였다.

• 콘크리트학회논문집
• /
• 제15권6호
• /
• pp.811-819
• /
• 2003

철근의 부식은 철근콘크리트 구조물의 주요파괴 원인이다. 철근의 부식에 대한 문제점을 해결할 가능성이 있는 재료 중 FRP 보강근은 그 가능성이 높다. 그렇지만 FRP 보강근은 보강철근과 다른 파괴 매카니즘으로 의하여 현저하게 성능이 저하될 가능성을 가지고 있다. 이와 같은 환경에는 알칼리, 산, 염해 및 물과 수분 등이 있다. 따라서 본 연구에서는 FRP 보강근의 화학적 환경하에서의 내구성능을 평가하고자 하였으며 사용된 FRP 보강근은 2가지 종류의 CFRP 보강근 및 GFRP 보강근, 한가지 종류의 AFRP 보강근으로 알칼리용액, 산용액, 염해환경 및 중성용액에 노출시켰다. FRP 보강근의 역학적 특성 및 내구특성은 인장, 압축 및 전단시험을 통하여 평가하였으며 시험결과 FRP 보강근은 매우 혹독한 화학적 환경에서 우수한 내구성을 가지고 있음을 알 수 있었다.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2008년도 추계학술대회 논문집
• /
• pp.1169-1177
• /
• 2008

The system of the railway signaling using the track transmits the approved speed to the location of a train and it. Referring to the way of transmitting train control information, there are the one transmitting it to the on-board system of a train using the direct track, the another transmitting it establishing an instrument, and the other transmitting an instrument by a railway track. The one is the method using the direct track as a conductor for composing the part of the track and attaining the information controlling a train by transmitting a signal to the track. It is used for the high-speed railway and the subway. The method using the track attains information by transmitting it to returned information, and the on-board system of a train attains it by magnetic coupling. Because many reinforcing bars on the concrete slab track are used, interaction between a rail and a reinforcing bar that is not produced on ballast track is made. Due to the interaction, the electric characteristic of rail is changed. In the current paper, we numerically computed the coupling coefficient between the rail and the reinforcing bar based on the concrete slab track throughout the model related to the rail and the reinforcing bar using the concrete slab track that is used in the second interval of the Gyeongbu high-speed railway, and we defined the coupling coefficient not changed in the electric characteristic of rail in the condition that there is no interaction between the rail and the reinforcing bar.

• 콘크리트학회논문집
• /
• 제13권5호
• /
• pp.516-524
• /
• 2001

여러가지 철근이음 방법중에서 고강도 모르타르 충전식 철근이음은 철근위치의 오차를 쉽게 흡수하여 시공이 용이하고 또한 최근에 많이 사용되고 있는 대구경 철근에 대해서도 적용성이 양호하기 때문에 프리캐스트 공법의 철근이음 방법으로 매우 유효한 수단이 된다. 이에 본 연구에서는 모르타르 충전식 철근이음법의 적용범위를 보다 확장하기 위하여 슬리브에 매입되는 철근직경이 상이한 경우와 충전 모르타르 강도를 700kgf/$\textrm{cm}^2$대로 낮춘 경우의 모르타르 충전식 철근이음에 대한 단조 및 반복가력 구조성능 실험을 실시한 후에 기존 실험결과와의 비교 분석을 통하여 다음과 같은 결론을 얻었다. 충전 모르타르 압축강도가 증가할수록 전체적인 구조성능은 증가하는 경향을 나타내었고 충전 모르타르 압축강도가 700kgf/$\textrm{cm}^2$이상이고 철근정착길이가 6.5d 이상이면 A급(AIJ 철근이음 성능 판정기준) 이상의 구조성능을 보유하고 있는 것이 확인되었다. 또한 슬리브 양단에 매입되는 철근의 직경이 상이한 경우는 굵은 철근에 대응되는 슬리브를 사용해야 하고 매입되는 가는 철근은 굵은 철근보다 2단계까지 가는 것을 사용할 수 있다는 것이 확인되었다.

• 도시과학
• /
• 제7권2호
• /
• pp.21-27
• /
• 2018

With the increase of the skyscraper center, the development of large-diameter and high-strength reinforcing bars is being carried out to solve the dense reinforcement. In case of the steel reinforced concrete with a small cross section such as beam-column joints, the development length becomes short when straight bars are used. Therefore, it is possible to solve the problem that the development length becomes short by using the bearing strength of the hooked bar and headed bar. In this study, the exterior beam-column joint test of SD700 hooked bar and headed bar with anchorage length of 20db was conducted to extend the development length limitation of hooked bar and headed bar. As a result of the evaluation of the anchorage strength using the design equation by KCI, the average of the [measured value]/[predicted value] ratio was 1.31 for the hooked reinforcing bars. In the case of headed bars, the average of the [measured value]/[predicted value] ratio was 1.12. In addition, in order to compare the anchorage performance of the hooked bar and the headed bar, the measured values were divided by the square root of the compressive strength of the concrete to compare the anchorage strength. Under the same conditions, the anchorage strength of headed bars was 8.5% higher than the hooked bars.