• Title/Summary/Keyword: R/C beam

Search Result 349, Processing Time 0.037 seconds

The Effects of Shear Capacity on the Locations and Sizes of New Opening in Existing Reinforced Concrete Beams (기존 철근콘크리트 보에서 신설 개구부의 위치와 크기가 전단내력에 미치는 효과)

  • 강민철;이주나;연규원;박찬수
    • Proceedings of the Korea Concrete Institute Conference
    • /
    • 2000.10b
    • /
    • pp.891-896
    • /
    • 2000
  • It is necessary to drill new opening in an existing R.C beam either for service ducts and pipes or the determination of in place concrete strength. Therefore, to simulate in this study, 18-R.C beams were fabricated with circular openings. The major parameters considered are the sizes, location of opening and cut-off stirrup. These beams are tested shear failure and capacity under a point loading. The sizes of opening are changed 0.11, 0.2, 0.3 times of beam-depth and the locations of opening are divided into $X_1$ zone, $X_2$ zone, $X_3$zone. Loads are applied up to failure to observe the cracking initiation and propagation, initial diagonal cracking, midspan deflection. As a result, the sizes of opening with 0.11D and 0.2D in R.C beams without cutoff stirrup are profitable in $X_1$ and $X_3$zone. R.C beams with 0.3D and cutoff stirrup are advantageous in $X_3$zone.

Strengthening Effect Evaluation Technique of R/C Beams using the Vibration Test (진동시험을 통한 R/C Beam의 보강효과 검증기법)

  • 심종성;유태석
    • Proceedings of the Korea Concrete Institute Conference
    • /
    • 1994.10a
    • /
    • pp.255-260
    • /
    • 1994
  • This study suggests a strengthening effect evaluation technique of reinforced concrete beams using the vibration test. To evaluate the strengthening effect of R/C beams, Strengthening Factor(Sf) was suggested. Using the value of Sf, 20 beams were evaluated. According to these results the effects of R/C beams strengthened by steel plate is superior than those of R/C beams strengthened by carbon fiber sheet.

  • PDF

23' LCD TV by using ALT plasma beam alignment technology

  • Lee, C.Y.;Tang, H.C.;Chen, C.W.;Shih, Y.J.;Liu, C.H.;Lin, C.H.;Yang, K.H.;Lin, S.H.;Chang, H.C.
    • 한국정보디스플레이학회:학술대회논문집
    • /
    • 2006.08a
    • /
    • pp.776-779
    • /
    • 2006
  • The alignment of liquid crystal (LC) is one of the key issues of liquid crystal display (LCD) technologies. In this study, we aligned polyimide (as the LC alignment layer) by ALT plasma beam and to realize the stability and characteristics of this technology. The characteristics such as anchoring energy, pre-tilt angle, voltage holding ratio(VHR) and residual direct current(Rdc) were discussed. Besides, we applied it to the in plane switch (IPS) mode 23" WXGA real panel, the performance parameters and electrical properties were measured and compared with those of rubbing alignment. From the result, we demonstrated a successful LC alignment treatment process in real panel by ALT plasma beam.

  • PDF

A Experiment Study on the Rehabilitation Techniqcs of R/C/ Shear Member (철근콘크리트보의 전단내력보강공법에 관한 실험적 연구)

  • Moon, Hee-Jeung;Lee, Young-Jae;Yoo, Seong-Hoon;Kim, Joong-Koo;Chung, Lan
    • Proceedings of the Korea Concrete Institute Conference
    • /
    • 1997.10a
    • /
    • pp.685-690
    • /
    • 1997
  • In this study, the behavior of R/C beam strengthened with carbon fiber laminate (C.F.L.) is analyzed from the test results. The purpose of this study is to evaluate the shearing rehabilitation effects of R/C beam with C.F.L. Test parameters are the thickness of C.F.L. and existence of stirrups. Test results how that the shear capacity of specimen without stirrups was increased and shear capacity of specimen with stirrups was not increased due to the insufficient fabrication of specimen and curing.

  • PDF

A Study on the Development and Test on Bearing Resistance of R/C Column-Steel Girder Connection (철근콘크리트 기둥과 철골보의 접합부 개발 및 지압성능에 관한 시험적 연구)

  • 최광호;이세웅;김재순;김상식
    • Proceedings of the Korea Concrete Institute Conference
    • /
    • 1997.04a
    • /
    • pp.515-520
    • /
    • 1997
  • This research is aimed at the development of the composite beam-column connection system by which the steel beam can be connected to the R/C column with smooth stress transfer. As the first step of the structural performance tests of the system, bearing resistance test has been carried out for actual size specimen. From the test, the connection system has been proved to take good bonding and stress transfer to the surrounding concrete with negligible relative displacements.

  • PDF

Potential for Novel Magnetic Structures by Nanowire Growth Mechanisms

  • Lapierre R.R.;Plante M.C.
    • Journal of Magnetics
    • /
    • v.10 no.3
    • /
    • pp.108-112
    • /
    • 2005
  • GaAs nanowires were grown on GaAs (111)B substrates in a gas source molecular beam epitaxy system, using self-assembled Au particles with diameters between 25 and 200 nm as the catalytic agents. The growth rate and structure of the nanowires were investigated for substrate temperatures between 500 and $600^{\circ}C$ to study the mass transport mechanisms that drive the growth of these crystals. The possibilities for fabrication of novel magnetic nanostructures by suitable choice of growth conditions are discussed.

Study of Driving and Thermal Stability of Anode-type Ion Beam Source by Charge Repulsion Mechanism

  • Huh, Yunsung;Hwang, Yunseok;Kim, Jeha
    • Applied Science and Convergence Technology
    • /
    • v.27 no.3
    • /
    • pp.47-51
    • /
    • 2018
  • We fabricated an anode-type ion beam source and studied its driving characteristics of the initial extraction of ions using two driving mechanisms: a diffusion phenomenon and a charge repulsion phenomenon. For specimen exposed to the ion beam in two methods, the surface impurity element was investigated by using X-ray photoelectron spectroscopy. Upon Ar gas injection for plasma generation the ion beam source was operated for 48 hours. We found a Fe 2p peak 5.4 at. % in the initial ions by the diffusion mechanism while no indication of Fe in the ions released in the charge repulsion mechanism. As for a long operation of 200 min, the temperature of ion beam sources was measured to increase at the rate of ${\sim}0.1^{\circ}C/min$ and kept at the initial value of $27^{\circ}C$ for driving by diffusion and charge repulsion mechanism, respectively. In this study, we confirmed that the ion beam source driven by the charge repulsion mechanism was very efficient for a long operation as proved by little electrode damage and thermal stability.

A thermal properties of micro hot plate and the characteristics of Pt/Cr bilayers due to annealing temperature (미세 발열체의 발열특성과 열처리 온도에 따른 Pt/Cr 이중층의 특성)

  • Yi, Seung-Hwan;Suh, Im-Choon;Sung, Yong-Kwon
    • Journal of Sensor Science and Technology
    • /
    • v.5 no.5
    • /
    • pp.69-77
    • /
    • 1996
  • In this paper, we fabricated the micro hotplate which consisted of a thin film heater(Pt/Cr bilayers) sandwiched with the thermal oxide and E-beam evaporated oxide. And we studied the electrical and the structural properties of Pt/Cr bilayers due to annealing temperature. When we compared the temperature measured from type k thermocouples with the temperature acquired from I.R. thermo-vision system according to the variations of emissivity, the emissivity of I-beam evaporated oxide was 0.5. The sheet resistance of Pt/Cr bilayers didn't depend on the Cr layer thickness, and it was considered as the existence of CrO between the Pt and the Cr layer. When the annealing temperature was increased from $500^{\circ}C$ to $700^{\circ}C$, the out-diffusions of Cr were increased(which was confirmed by AES depth profile) and the grain size of Pt(220) phase was enlarged also(analyzed by XRD and SEM photographs). From the results of XRD analysis and AES depth profile, the Pt/Cr bilayers annealed at $500^{\circ}C$ were more stable than any other cases in structural properties.

  • PDF

Forced vibration analysis of damped beam structures with composite cross-section using Timoshenko beam element

  • Won, S.G.;Bae, S.H.;Jeong, W.B.;Cho, J.R.;Bae, S.R.
    • Structural Engineering and Mechanics
    • /
    • v.43 no.1
    • /
    • pp.15-30
    • /
    • 2012
  • A damped Timoshenko beam element is introduced for the DOF-efficient forced vibration analysis of beam-like structures coated with viscoelastic damping layers. The rotary inertia as well as the shear deformation is considered, and the damping effect of viscoelastic layers is modeled as an imaginary loss factor in the complex shear modulus. A complex composite cross-section of structures is replaced with a homogeneous one by means of the transformed section approach in order to construct an equivalent single-layer finite element model capable of employing the standard $C^{0}$-continuity basis functions. The numerical reliability and the DOF-efficiency are explored through the comparative numerical experiments.

Long-term Deflection of R/C Beam with Variable Substitution Ratio of Recycled Aggregate (순환골재 치환율에 따른 R/C보의 장기처짐에 관한 연구)

  • Yoon, Seung-Joe;Seo, Soo-Yeon;Lee, Woo- Jin;Kang, Seong-Duk;Kim, Dae-Young
    • Proceedings of the Korea Concrete Institute Conference
    • /
    • 2006.11a
    • /
    • pp.37-40
    • /
    • 2006
  • In this paper, long term deflection of RC beam with variable substitution ratio of recycled aggregate is investigated. 6 RC beam specimens are designed using concrete made of coarse aggregate of 25mm size, mix strength of 21MPa, slump of 12cm and air content of $5.0{\pm}1.5%$. A few concrete blocks are made and used for long term loading. The loading and deflection instrumentation are conducted following the process codified in ACI 318-05 code. Test result shows that the deflection of specimens depends on the compressive strength of concrete. And it is concluded that the deflection of RC beam can be predicted like normal beam using ACI formula if certain level of compressive strength is acquired even recycled aggregate is used in making the beam.

  • PDF