• Title/Summary/Keyword: R/C beam

Search Result 349, Processing Time 0.033 seconds

Finite Element Analysis of Exterior R.C. Beam-Column Joints Containing Headed Bars utilized for Enhanced Seismic Performance (Headed bar를 사용한 외부 철근 콘크리트 보-기둥 접합부의 강화된 내진 성능에 대한 유한요소해석)

  • Bang, Suk;Lee, Joo-Ha;Yoon, Young-Soo
    • Proceedings of the Korea Concrete Institute Conference
    • /
    • 2004.05a
    • /
    • pp.506-509
    • /
    • 2004
  • This paper proposes Headed bar as reinforcement of beam-column joint, and proves seismic performance and reduction of reinforcement congestion. In these case, the use of Headed bars have obvious advantages. The greatest benefit of using Headed bars is not only improved structural performance of beam-column joints, but also the ease of fabrication, construction, and placement. Three-dimensional finite element analysis model is compared with test program which was fulfilled by the proposed model with Headed bar. Also, the plastic hinge region is relocated to the center of the longitudinal beam length according to the strong column-weak beam design philosophy, so Headed bar is used as the joint reinforcement. Therefore, this paper presents results of a computer analysis of a practical solution for relocating potential beam plastic hinge regions by the placing of straight - Headed bar.

  • PDF

Shear Behavior of Wide Beam-Column Joints with Slab (슬래브가 있는 넓은 보-기둥 접합부의 전단거동)

  • 안종문;최종인;신성우;이범식;박성식;양지수
    • Proceedings of the Korea Concrete Institute Conference
    • /
    • 2003.05a
    • /
    • pp.157-162
    • /
    • 2003
  • An experimental investigation was conducted to study the behavior of high-strength RC wide beam-column joints with slab subjected to reversed cyclic loads under constant axial load. Six half scale interior wide beam-column assemblies representing a portion of a frame subjected to simulated seismic loading were tested, including three specimens without slab and three specimens with slab. The primary variables were compressive strength of concrete($f_ck$=285, 460kgf/$cm^2$), the ratio of the column-to-beam flexural capacity($M_r$=$\Sigma M_c / \Sigma M_b$ ; 0.77 -2.26), extended length of the column concrete($l_d$ ; 0, 12.5, 30cm), ratio of the column-to-beam width(b/H ; 1.54, 1.67). Test results are shown that (1) the behavior of specimen using high-strength concrete satisfied for required minimum ductile capacity according to increase the compressive strength, (2) the current design code and practice for interior joints(type 2) are apply to the wide beam-high strength concrete column.

  • PDF

Use of Beam Transmissometer as an Indirect Measure of Suspended Sediment Concentration in the Estuarine Environment: Application and Problems (강하구에서의 부유물질농도 결정을 위한 광전도측정기의 이용 및 문제점)

  • KIM Seok-Yun
    • Korean Journal of Fisheries and Aquatic Sciences
    • /
    • v.27 no.6
    • /
    • pp.771-781
    • /
    • 1994
  • Monthly measurements made at 15 stations along the axis of the upper Neuse River estuary show a highly variable degree of correlation between concentration of suspended particulate material (SPM) and attenuation coefficient (c) of light as measured by transmissometer. Coefficients of determination along transect lines ranged from $0.12{\sim}0.93$ and calibration slopes ranged from $0.50{\sim}5.63$. When examined on a station-by-station basis, coefficients of determination ranged from $0.21{\sim}0.96$ and calibration slopes ranged from $1.04{\sim}4.94$. Surface calibrations made at individual stations over the full 13-month period were the most consistent of all observations and were considerably better than calibrations made using all of the stations on a given day. Organic content, which can dominate the suspended sediment load during some months, does not appear to explain the variations in reliability of the calibrations. However, an abundance of large aggregates with time-varying size and shape distributions may be partly responsible for variations in optical properties of the sediments, and thus may confound the relationship between SPM and c in the Neuse River estuary Time-varying calibrations to account for non-negligible changes in optical properties may not suffice in complex estuarine environments where the in situ particle dynamics are poorly understood. However, the best use of Beam Transmissometer will continue to be for applications such as detecting water-column events or for use in situations where wide error bars in establishing SPM concentrations are acceptable.

  • PDF

Stress Concentration Factor and Stress Intensity Factor with U-notch and Crack in the Beam (U-노치 및 균열을 갖는 보의 응력집중계수 및 응력확대계수)

  • Seo, Bo Seong;Lee, Kwang Ho
    • Transactions of the Korean Society of Mechanical Engineers A
    • /
    • v.40 no.5
    • /
    • pp.513-523
    • /
    • 2016
  • The stress concentration factors and stress intensity factors for a simple beam and a cantilever are analyzed by using finite element method and phtoelasticity. Using the analyzed results, the estimated graphs on stress concentration factors and stress intensity factors are obtained. To analyze stress concentration factors of notch, the dimensionless notch length H(height of specimen)/h=1.1~2 and dimensionless gap space r(radius at the notch tip)/h=0.1~0.5 are used. where h=H-c and c is the notch length. As the notch gap length increases and the gap decreases, the stress concentration factors increase. Stress concentration factors of a simple beam are greater than those of a cantilever beam. However, actually, the maximum stress values under a load, a notch length and a gap occur more greatly in the cantilever beam than in the simple beam. To analyze stress intensity factors, the normalized crack length a(crack length)/H=0.2~0.5 is used. As the length of the crack increases, the normalized stress intensity factors increase. The stress intensity factors under a constant load and a crack length occur more greatly in the cantilever beam than in the simple beam.

Influence of surface geometrical structures on the secondary electron emission coefficient $({\gamma})$ of MgO protective layer

  • Park, W.B.;Lim, J.Y.;Oh, J.S.;Jeong, H.S.;Jeong, J.C.;Kim, S.B.;Cho, I.R.;Cho, J.W.;Kang, S.O.;Choi, E.H.
    • 한국정보디스플레이학회:학술대회논문집
    • /
    • 2003.07a
    • /
    • pp.806-809
    • /
    • 2003
  • Ion-induced secondary electron emission coefficient $({\gamma})$. of the patterned MgO thin film with geometrical structures has been measured by ${\gamma}$ - FIB(focused ion beam) system. The patterned MgO thin film with geometrical structures has been formed by the mask (mesh of ${\sim}$ $10{\mu}m^{2})$ under electron beam evaporation method. It is found that the higher ${\gamma}$. has been achieved by the patterned MgO thin film than the normal ones without patterning.

  • PDF

Analysis of Electrical Properties of Ti/Pt/Au Schottky Contacts on (n)GaAs Formed by Electron Beam Deposition and RF Sputtering

  • Sehgal, B-K;Balakrishnan, V-R;R Gulati;Tewari, S-P
    • JSTS:Journal of Semiconductor Technology and Science
    • /
    • v.3 no.1
    • /
    • pp.1-12
    • /
    • 2003
  • This paper describes a study on the abnormal behavior of the electrical characteristics of the (n)GaAs/Ti/Pt/Au Schottky contacts prepared by the two techniques of electron beam deposition and rf sputtering and after an annealing treatment. The samples were characterized by I-V and C-V measurements carried out over the temperature range of 150 - 350 K both in the as prepared state and after a 300 C, 30 min. anneal step. The variation of ideality factor with forward bias, the variation of ideality factor and barrier height with temperature and the difference between the capacitance barrier and current barrier show the presence of a thin interfacial oxide layer along with barrier height inhomogenieties at the metal/semiconductor interface. This barrier height inhomogeneity model also explains the lower barrier height for the sputtered samples to be due to the presence of low barrier height patches produced because of high plasma energy. After the annealing step the contacts prepared by electron beam have the highest typical current barrier height of 0.85 eV and capacitance barrier height of 0.86 eV whereas those prepared by sputtering (at the highest power studied) have the lowest typical current barrier height of 0.67 eV and capacitance barrier height of 0.78 eV.

Study of Inelastic Responses of a 1:12 Scale 10-Story R.C. Frame-Wall Structure (1:12축소 10층 R.C. 골조-벽식 구조의 비선형 거동 연구)

  • 이한선;김상호;유은진
    • Proceedings of the Korea Concrete Institute Conference
    • /
    • 2000.10b
    • /
    • pp.867-872
    • /
    • 2000
  • A 1:12 scale 10-story RC building structure was constructed and the experiment was performed. The test results are presented and compared with the results of the analysis conducted with DRAIN-2DX. It is concluded that some local deformations cannot be described reasonably with the wall model using only Plastic Hinge Beam-Column Element(TYPE02) in DRAIN-2DX whereas the strength and stiffness of the whole structure can be predicted with high reliability.

Laser Damage Threshold Increase of A/R Coating Films for 200MHz AOM (A/R 코팅 변화에 따른 200MHz AOM의 laser damage threshold 증가)

  • Kim, Yong-Hun;Lee, Hang-Hun;Lee, Jin-Ho;Park, Yeong-Jun;Park, Jeong-Ho
    • Korean Journal of Materials Research
    • /
    • v.7 no.3
    • /
    • pp.213-217
    • /
    • 1997
  • AOhf(Hcousto-r)l)tic niodulator) with :!OOlIiz freclucncl- and Sfi(;(Seconrl harmonic generation) green lasel-Lvith 53% nm wavelength were used for Il\'IIII~Dii.it,ii v~ilco disk recorder) FOI rhe appli~aptin of high densit]. optical recording, a high po\ver I ~ c r is r c ~ ~ l i ~ i l - u l ic I !tic. s\-sti,m a n d optic.,~I io;iting l,t)c>rs of each optical device must have a high laser damage threshoid hie rn;itie ant] retlwtive coatings on a $TeO_{2}$ singlc crystal. which is used as an acoustooptic material, by E-beam evaporation method. Laser damage threshold \vas nicdsureci hy Ar laser with the input power oi 0.55LV 1,aser damage threiholti 01 $ZrO_{2}$ and $SiO_{2}$. filn-is were higher than $AI_{2}O_{3}$ f i l m U'e also investigated a long--tern1 stability of the output po\ver of St{(; green laser

  • PDF

The Characteristics of Dielectric Breakdown for Epoxy Resin irradiated Electron Beam (전자선 조사된 에폭시 수지의 절연파괴 특성)

  • Hong, Nung-Pyo;Cho, Dong-Chan;Park, Heung-Kyu;So, Byung-Mun;Kim, Wang-Kon;Hong, Jin-Woong
    • Proceedings of the KIEE Conference
    • /
    • 1995.11a
    • /
    • pp.430-432
    • /
    • 1995
  • In this paper, the electron beam with 1[Mrad], 2[Mrad], 4[Mrad], 8[Mrad] and 24[Mrad] is irradiated for specimen experiments on physical properties which is investigated by FTIR, and dielectric breakdown among the electrical characteristics of specimen are carried out. For the dielectric breakdown experiment, external 60 [Hz] AC voltage is applied to specimen with the rising voltage of 3[kV/cm] until dielectric breakdown occured. We made a breakdown experiment under the temperature condition of 50[$^{\circ}C$], 100[$^{\circ}C$], 150[$^{\circ}C$] in the silicone oils of dynamic viscosity of 100[cSt].

  • PDF

Estimation of Flexural Rigidity of R/C Beam Strengthened with CFS subjected to repeated loadings (반복하중을 받는 CFS로 보강된 R/C 보의 휨 강성 평가)

  • Kim, Chung-Ho;Jang, Jong-Wan
    • Journal of the Korea institute for structural maintenance and inspection
    • /
    • v.8 no.2
    • /
    • pp.231-238
    • /
    • 2004
  • The deterioration of the flexural capacity by progressive crack and over deflection in R/C bridges is developed actually from the dynamic repeated loading due to vehicle traffics. Such a fact suggest a necessities of confirmation and estimation of the data acquired from monotonic incremental loading test. Therefore, this study carry out the monotonic incremental loading test and dynamic repeated loading test in R/C beams strengthened with CFS. By dynamic repeated loading test, the experiments confirmed the validities and fittness of the results acquired from monotonic incremental loading test and estimated the characteristics of the moment-curvature, degradation of the flexural rigidity, crack and failure.