• Title/Summary/Keyword: Angle-tie Method

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Effect of Bending Angle and Embedment Length on the Bond Characteristics of V-shaped Tie Reinforcement (절곡각 및 묻힘길이에 따른 V형 띠철근의 부착특성)

  • Kim, Won-Woo;Yang, Keun-Hyeok
    • Journal of the Korea Institute of Building Construction
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    • v.15 no.5
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    • pp.465-471
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    • 2015
  • This study proposed V-shaped tie bar method as an alternative of internal cross-tie for reinforced concrete columns in order to enhance the constructability and confinement effectiveness of the lateral tie bars. A total of 35 pull-out specimens were prepared with the parameters of concrete compressive strength and bending angle and embedment length of the V-shaped bar to examine the bond stress-slip relationship of the V-shaped tie bar. The bond strength of the V-shaped tie bars with the bending angle not exceeding $60^{\circ}$ was higher than the predictions obtained from the equations of CEB-FIP provision. Considering the constructability and bond behavior of the V-shpaed tie bar, the bending angle and embedment length of such bar can be optimally recommended as $45^{\circ}$ and 6db, respectively, where db is the diameter of the tie bar.

Substation Bus Voltage Angle Calculation Method Using Voltage Angle Difference Measured at the Tie Switch in the Distribution Line (배전선로 상시연계점 측정 전압 위상차를 이용한 변전소 모선 위상각 추정 방법)

  • Son, Ju-Hwan;Lim, Seong-Il
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.65 no.1
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    • pp.9-15
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    • 2016
  • Distribution networks are operated in radial fashion during the normal state. Loop configuration is also required temporally in case of live load transfer among the adjacent feeders. Voltage angles of each substation buses are very important data in order to calculate power flow of the loop structured distribution feeders. This paper proposes substation bus voltage angle calculation method using voltage angle difference measured at the normally open tie switches. Simulation case studies using Matlab simulink have been performed to establish feasibility of proposed method.

Loop Current Calculation based on Voltage Angle Difference at Tie Switch for Switching Plan Validation in Distribution System Operation (상시개방점 양단전압 측정값을 이용한 배전선로 루프운전 가능 여부 판단 방법)

  • Son, Juhwan;Lim, Seongil
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.29 no.7
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    • pp.14-21
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    • 2015
  • Distribution systems are operated in radial structure, but temporal loop structure could be founded the live load transfer. Main purposes of reconfiguration of distribution network are load balancing, loss minimization and voltage drop maintaining. In the loop structure, huge loop current can be flowed between two substations in case of large voltage angle difference. Protection devices of distribution line can be triped by this huge loop current. So, precise calculation of loop current is very important for secure switching. This paper proposes a novel calculation method of loop current using the voltage angle differences measured at the tie switches. Feasibility of the propose method has been verified by various case studies based on Matlab simulation.

Shear mechanism of steel fiber reinforced concrete deep coupling beams

  • Li, Kou;Zhao, Jun;Ren, Wenbo
    • Structural Engineering and Mechanics
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    • v.73 no.2
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    • pp.143-152
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    • 2020
  • Deep coupling beams are more prone to suffer brittle shear failure. The addition of steel fibers to seismic members such as coupling beams can improve their shear performance and ductility. Based on the test results of steel fiber reinforced concrete(SFRC) coupling beams with span-to-depth ratio between 1.5 and 2.5 under lateral reverse cyclic load, the shear mechanism were analyzed by using strut-and-tie model theory, and the effects of the span-to-depth ratio, compressive strength and volume fraction of steel fiber on shear strengths were also discussed. A simplified calculation method to predict the shear capacity of SFRC deep coupling beams was proposed. The results show that the shear force is mainly transmitted by a strut-and-tie mechanism composed of three types of inclined concrete struts, vertical reinforcement ties and nodes. The influence of span-to-depth ratio on shear capacity is mainly due to the change of inclination angle of main inclined struts. The increasing of concrete compressive strength or volume fraction of steel fiber can improve the shear capacity of SFRC deep coupling beams mainly by enhancing the bearing capacity of compressive struts or tensile strength of the vertical tie. The proposed calculation method is verified using experimental data, and comparative results show that the prediction values agree well with the test ones.

Design of Compact Log-Periodic Half-Bow-tie Dipole Array Antenna for UWB Band (UWB 대역 소형 대수-주기 반-보우타이 다이폴 배열 안테나 설계)

  • Yeo, Junho;Lee, Jong-Ig
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2016.05a
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    • pp.81-82
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    • 2016
  • In this paper, a design method for a compact log-periodic half-bow-tie dipole array antenna for an operation in UWB band is studied. The proposed antenna is miniaturized by using half-bow-tie shaped dipole elements instead of strip-type dipole elements, which are commonly used in general log-periodic dipole array antenna, and by reducing the element spacing. The effects of the flare angle of the half-bow-tie elements and the element spacing on input reflection coefficient and realized gain characteristics of the proposed log-periodic antenna are analyzed. The optimized antenna is designed on FR4 substrate, and it operates in the frequency band of 3.05-13.96 GHz for a VSWR < 2, which assures the operation in the UWB band.

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Numerical method for the strength of two-dimensional concrete struts

  • Yun, Y.M.
    • Computers and Concrete
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    • v.28 no.6
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    • pp.621-634
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    • 2021
  • For the reliable strut-and-tie model (STM) design of disturbed regions of concrete members, structural designers must accurately determine the strength of concrete struts to check the strength conditions of a selected STM el and the anchorage of reinforcing bars in nodal zones. In this study, the author proposed a consistent numerical method for strut strength, applicable to all two-dimensional STMs. The proposed method includes the effects of a biaxial stress state associated with tensile strains in reinforcing bars crossing a strut, deviation angle between strut orientation and compressive principal stress flow, and degree of confinement provided by reinforcement. The author examined the method's validity through the STM prediction of the ultimate strengths of 517 reinforced concrete (RC) deep beams, 24 RC panels, and 258 RC corbels, all tested to failure.

Change of Substructure Design with Changed Angle of Skew Bridges (사교의 사각에 따른 하부구조 설계변화)

  • 이주호;염종윤;박경래;배한욱
    • Journal of the Korea Concrete Institute
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    • v.11 no.3
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    • pp.3-12
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    • 1999
  • This study presents a suggestion of regulation of skewed slab bridge. In order to find the characteristic behavior of skew bridge, many cases of skew bridges were analyzed with changed angle of skew. The comparison of design methods for cantilever part in pier was also made. It was found that : (1) The lower the skew angle was, the higher the maximum support reaction forces at the end point were. (2) The higher the ratio of L/B was, the higher the maximum support reaction force at the point was. (3) The effect of skew may be neglected for skew angles of $70^{\circ}$or more. (4) If elastic springs are applied to the boundary conditions to simulate the rubber pad bearings, the results will be more reasonable. (5) The shear deformation effect must be considered in the analysis of cantilever part of substructure. (6) Using strut and tie model to design cantilever part of pier, it will be more simple than finite element method with same accuracy and more accurate than using frame element.

Constructional Tradition and Meaning of the Corner High Column Method (귀고주방식의 조영전통과 의미)

  • Hong, Byung-Hwa;Lee, Eun-Soo
    • Journal of architectural history
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    • v.19 no.3
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    • pp.107-124
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    • 2010
  • The coner high column method that is used in the multi-roof building Sungryemoon seems to have been used for the first time during the Choseon Dynasty, and it's characteristics and trend of usage are studied in this paper. In the results, it was confirmed that the coner high column method is economic and structurally safe, and selectively combines the structural factors used in the Chinese seats. It was found that this method was a newly adopted construction method to effectively express the authority of the country with the establishment of a new dynasty. Also the meaning of the method could be guessed since it was continuously used in important structures from the Choseon Dynasty to the Daehan Empire, in spite of the new multi-roof building technologies.

Single-shot Transport-of-intensity Equation Using a Wollaston Prism for Biological Samples

  • Joseph Vermont Bunyi Bandoy;Cuong Manh Nguyen;An Nazmus Sakib;Suhyeon Kim;Hyuk-Sang Kwon
    • Current Optics and Photonics
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    • v.8 no.5
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    • pp.502-507
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    • 2024
  • The Wollaston prism (WP) has shown promise in enabling single-shot transport-of-intensity equation (ssTIE) measurements, facilitating efficient phase retrieval in microscopy. The 1-degree prism which produces the minor beam-separation angle is used to prevent distortions. An optical-glass plate is employed in the duplicated beam path to introduce defocusing. This configuration is also advantageous when aligning the beams laterally caused by the refraction of the optical-glass plate, thus allowing another method for single-shot measurements. We applied the proposed method to image the red blood cells (RBCs), demonstrating that the proposed method could be useful in various biological and medical applications.

Miniaturized Design of Log-Periodic Dipole Array Antenna Using Half-Bowtie Dipole Elements (반-보우타이 모양 다이폴 소자를 이용한 대수-주기 다이폴 배열 안테나의 소형화 설계)

  • Yeo, Junho;Lee, Jong-Ig
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.20 no.6
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    • pp.1057-1062
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    • 2016
  • In this paper, a design method for a compact log-perio dic half-bow-tie dipole array antenna for an operation in a UWB band(3.1-10.6 GHz) is studied. The proposed antenna is miniaturized by using half-bow-tie shaped dipole elements instead of strip-type dipole elements, which are commonly used in a general log-periodic dipole array(LPDA) antenna, and by reducing the element spacing. The effects of the flare angle of the half-bow-tie elements and the spacing factor on input reflection coefficient and realized gain characteristics of the proposed log-periodic antenna are analyzed. The optimized antenna is fabricated on an FR4 substrate, and the experiment results show that the antenna has a frequency band of 2.95-11.31 GHz for a VSWR < 2, which assures the operation in the UWB band. In addition, the length and width of the proposed antenna are reduced to 32.1 % and 18.3 %, respectively, compared to the LPDA antenna.