• 제목/요약/키워드: exterior beam-column joint

검색결과 127건 처리시간 0.025초

Effects of joint aspect ratio on required transverse reinforcement of exterior joints subjected to cyclic loading

  • Chun, Sung Chul
    • Earthquakes and Structures
    • /
    • 제7권5호
    • /
    • pp.705-718
    • /
    • 2014
  • This paper presents an analytical model for determining the transverse reinforcement required for reinforced concrete exterior beam-column joints subjected to reversed cyclic loading. Although the joint aspect ratio can affect joint shear strength, current design codes do not consider its effects in calculating joint shear strength and the necessary amount of transverse reinforcement. This study re-evaluated previous exterior beam-column joint tests collected from 11 references and showed that the joint shear strength decreases as the joint aspect ratio increases. An analytical model was developed, to quantify the transverse reinforcement required to secure safe load flows in exterior beam-column joints. Comparisons with a database of exterior beam-column joint tests from published literature validated the model. The required sectional ratios of horizontal transverse reinforcement calculated by the proposed model were compared with those specified in ACI 352R-02. More transverse reinforcement is required as the joint aspect ratio increases, or as the ratio of vertical reinforcement decreases; however, ACI 352R-02 specifies a constant transverse reinforcement, regardless of the joint aspect ratio. This reevaluation of test data and the results of the analytical model demonstrate a need for new criteria that take the effects of joint aspect ratio into account in exterior joint design.

Parametrical study of the behavior of exterior unreinforced concrete beam-column joints through numerical modeling

  • Silva, Matheus F.A.;Haach, Vladimir G.
    • Computers and Concrete
    • /
    • 제18권2호
    • /
    • pp.215-233
    • /
    • 2016
  • Exterior beam-column joints are structural elements that ensure connection between beams and columns. The joint strength is generally assumed to be governed by the structural element of lowest load capacity (beam or column), however, the joint may be the weakest link. The joint shear behavior is still not well understood due to the influence of several variables, such as geometry of the connection, stress level in the column, concrete strength and longitudinal beam reinforcement. A parametrical study based only on experiments would be impracticable and not necessarily exposes the failure mechanisms. This paper reports on a set of numerical simulations conducted in DIANA$^{(R)}$ software for the investigation of the shear strength of exterior joints. The geometry of the joints and stress level on the column are the variables evaluated. Results have led to empirical expressions that provide the shear strength of unreinforced exterior beam-column joints.

Seismic performance of exterior R/C beam-column joint under varying axial force

  • Hu, Yanbing;Maeda, Masaki;Suzuki, Yusuke;Jin, Kiwoong
    • Structural Engineering and Mechanics
    • /
    • 제78권5호
    • /
    • pp.623-635
    • /
    • 2021
  • Previous studies have suggested the maximum experimental story shear force of beam-column joint frame does not reach its theoretical value due to beam-column joint failure when the column-to-beam moment capacity ratio was close to 1.0. It was also pointed out that under a certain amount of axial force, an axial collapse and a sudden decrease of lateral load-carrying capacity may occur at the joint. Although increasing joint transverse reinforcement could improve the lateral load-carrying capacity and axial load-carrying capacity of beam-column joint frame, the conditions considering varying axial force were still not well investigated. For this purpose, 7 full-scale specimens with no-axial force and 14 half-scale specimens with varying axial force are designed and subjected to static loading tests. Comparing the experimental results of the two types of specimens, it has indicated that introducing the varying axial force leads to a reduction of the required joint transverse reinforcement ratio which can avoid the beam-column joint failure. For specimens with varying axial force, to prevent beam-column joint failure and axial collapse, the lower limit of joint transverse reinforcement ratio is acquired when given a column-to-beam moment capacity ratio.

고강도 재료를 사용한 철근 콘크리트 보.기둥 외부접합부의 전단내력에 관한 실험적 연구 (An Experimental Study on Shear on Shear Capacity of Reinforced Concrete Exterior Beam-Column Joint with High Strength Concrete)

  • 박기철;황홍순;정헌수
    • 한국콘크리트학회:학술대회논문집
    • /
    • 한국콘크리트학회 1992년도 봄 학술발표회 논문집
    • /
    • pp.59-66
    • /
    • 1992
  • The objective of this investigation was to dvaluater the factors influencing the vasic shear strength of Exterior Beam-Column Joint. Reversec cyclic loading were carride out for 10 reinforced concrete Exterior Beam-Column subassemblages. All the specimens finally failed in joint shear.

  • PDF

Experimental and numerical studies on seismic behaviour of exterior beam-column joints

  • Asha, P.;Sundararajan, R.
    • Computers and Concrete
    • /
    • 제13권2호
    • /
    • pp.221-234
    • /
    • 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.

비부착 강연선과 고강도 콘크리트를 적용한 철근콘크리트 외부 접합부의 내진 거동 (Seismic Behavior of RC Beam-Column Exterior Joints with Unbonded Tendons and High Strength Concrete)

  • 권병운;강현구
    • 한국지진공학회논문집
    • /
    • 제19권6호
    • /
    • pp.283-292
    • /
    • 2015
  • In the moment frame subjected to earthquake loads, beam-column joint is structurally important for ductile behavior of a system. ACI Committee 352 proposed guidelines for designing beam-column joint details. The guidelines, however, need to be updated because of the lack of data regarding several factors that may improve the performance of joints. The purpose of this study is to investigate the seismic performance of reinforced concrete exterior joints with high-strength materials and unbonded tendons. Three specimens with different joint shear demand-to-strength ratios were constructed and tested, where headed bars were used to anchor the beam bars into the joint. All specimens showed satisfactory seismic behavior including moment strength of 1.3 times the nominal moment, ductile performance (ductility factor = at least 2.4), and sufficiently large dissipated energy.

헌치를 이용하여 보강된 RC 보-기둥 외부접합부의 반복이력 특성 (Hysteresis Characteristics of RC Exterior Beam-Column Joint Retrofitted with Haunch)

  • 이영욱;박형권
    • 한국지진공학회논문집
    • /
    • 제21권3호
    • /
    • pp.115-123
    • /
    • 2017
  • To investigate the cyclic characteristics of the retrofitted exterior joints of RC frame with haunch, 70% scaled 6 beam-column exterior joint subassemblies were designed according to design guideline according to 1988 and tested with cyclic loading up to 3.5% story drift ratio. During the experiments axial forces are applied to columns to simulate gravity load. Experimental results shows that the strength of retrofitted specimens was increased steadily until 2.5% story drift ratio and their strengths increased more than 1.7 times of the non-retrofitted in case that main bar was bent away from exterior joint. The joint strength and effective stiffness of the retrofitted specimen was increased and results in more deformation capacity compared to the non-retrofitted.

볼트 접합 및 프리스트레스를 적용한 프리캐스트 콘크리트 보-기둥 외부접합부의 내진실험 (Seismic Experiment of Precast Concrete Exterior Beam-Column Joint Using Bolt Type Connection and Prestressing Method)

  • 이동주;이주동;오태수;강현구
    • 콘크리트학회논문집
    • /
    • 제26권2호
    • /
    • pp.125-133
    • /
    • 2014
  • 이 연구에서는 볼트접합 및 프리스트레스를 적용한 프리캐스트 콘크리트 보-기둥 외부접합부의 내진 및 구조적 성능을 평가하였다. 총 5개의 보-기둥 외부접합부 실험체를 제작하고 보 단부에 변위제어 방식으로 반복하중을 가하며 실험을 수행하였다. 이 연구의 결과를 근거로 다음과 같은 결론을 얻을 수 있었다. 완전 건식공법이 적용된 PC 접합부는 완전 습식공법이 적용된 RC 접합부보다 에너지소산이나 핀칭현상에 있어서 불리한 거동을 보였지만 이는 설계과정에서 의도된 현상이며, 횡변형 능력에 있어서는 우수한 결과를 보였다. 또한 층간변위비 4%까지 횡하중 저항성능의 손실이 발생하지 않았고 매설용너트에 항복이 집중되는 메커니즘을 보이는 점으로 미루어 볼 때 개발된 접합부는 외부접합부 횡저항시스템으로서 적합한 것으로 사료된다. 추가적인 프리스트레스는 PC 접합부의 과도한 핀칭현상 방지 및 접합부 균열제어에 효과적이었으며 PC 접합부의 전체적인 내진성능을 향상시켰다.

Investigation of shear strength models for exterior RC beam-column joint

  • Parate, Kanak;Kumar, Ratnesh
    • Structural Engineering and Mechanics
    • /
    • 제58권3호
    • /
    • pp.475-514
    • /
    • 2016
  • Various models have been proposed by several researchers for predicting the exterior RC beam-column joint shear strength. Most of these models were calibrated and verified with some limited experimental database. From the models it has been identified that the joint shear strength majorly depends on ten governing parameters. In the present paper, detailed investigation of twelve analytical models for predicting shear strength of exterior beam-column joint has been carried out. The study shows the effect of each governing parameter on joint shear strength predicted by various models. It has been observed that the consensus on effect of few of the governing parameters amongst the considered analytical models has not been attained. Moreover, the predicted joint strength by different models varies significantly. Further, the prediction of joint shear strength by these analytical models has also been compared with a set of 200 experimental results from the literature. It has been observed that none of the twelve models are capable of predicting joint shear strength with sufficient accuracy for the complete range of experimental results. The research community has to reconsider the effect of each parameters based on larger set of test results and new improved analytical models should be proposed.

Design procedure for seismic retrofit of RC beam-column joint using single diagonal haunch

  • Zabihi, Alireza;Tsang, Hing-Ho;Gad, Emad F.;Wilson, John L.
    • Structural Engineering and Mechanics
    • /
    • 제71권4호
    • /
    • pp.341-350
    • /
    • 2019
  • Exterior beam-column joint is typically the weakest link in a limited-ductile reinforced concrete (RC) frame structure. The use of diagonal haunch element has been considered as a desirable seismic retrofit option for reducing the seismic demand at the joint. Previous research globally has focused on implementing double haunches, while the use of single haunch element as a less-invasive and more architecturally favorable retrofit option has not been investigated. In this paper, the key formulations and a design procedure for the single haunch system for retrofitting RC exterior beam-column joint are developed. An application of the proposed design procedure is then illustrated through a case study.