• Title/Summary/Keyword: 바닥 구조 시스템

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Applications of Practical Analysis Scheme for Evaluating Effects of Over-Loads during Construction on Deflections of Flat Plate System (플랫 플레이트 시스템의 처짐에 대한 시공 중 과하중의 영향 평가를 위한 실용해석 기법의 적용)

  • Kim, Jae-Yo
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.22 no.1
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    • pp.25-34
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    • 2009
  • RC flat plate, which has no large flexural stiffness by boundary beams, may be governed by serviceability as well as strength condition. A construction sequence and its impact on distributions of construction loads among slabs tied by shores are decisive factors on immediate and long term performances of flat plate. The over-loading and tensile cracking in early-aged slabs significantly increase the deflection of flat plate system. In this study, for slab deflections, the practical analysis scheme using a linear analysis program is formulated with considering construction sequence and concrete cracking effects. The concept of the effective moment of inertia in calculating deflections of one-way bending member, that is presented in structural design codes, is extended to the finite element analysis of the two-way slab system of flat plates. Effects of over-loads during construction on deflections of flat plate system are analyzed by applying the proposed practical analysis scheme into the critical construction load conditions calculated from the simplified method.

Performance Evaluation of Removable PC Slab Connection for the Reusable Steel Structural System (강구조 재사용 시스템을 위한 탈부착이 가능한 PC 슬래브 접합부의 성능평가)

  • Shim, Hyun Ju;Oh, Eun Ji;Lee, Eun Taik
    • Journal of Korean Society of Steel Construction
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    • v.25 no.6
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    • pp.649-658
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    • 2013
  • Recently, an urgent issue of the global environment in the 21st century is the well-established paradigm of a sustainable and circulatory system. In the field of construction, it is important to approach sustainablity issues from a structural engineering point of view. The reusable steel structural system, which can adapt to changes in socio-economic conditions and varied demands, realized that the consumption of natural resources was minimized, the environmental load was reduced as much as possible. In order to reuse and recombinant the structural members, removable PC slab connection was introduced. This paper investigates the structural performance and serviceability by the dynamic characteristics of the steel beam to concrete slab connection.

Ultra-Wideband Microstrip-to-Finite Ground Coplanar Waveguide Transition for Millimeter-Wave Systems (밀리미터파 시스템용 초광대역 마이크로스트립-FGCPW 전이구조 설계)

  • Kim, Young-Gon;Kim, Hong-Rak;Jung, Bae-Ho;Kim, Kang Wook
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.27 no.8
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    • pp.701-708
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    • 2016
  • A new design for an ultra-wideband microstrip-to-FGCPW(Finite Ground Coplanar Waveguide) transition is presented. The proposed transition provides the electric field and impedance matching between adjacent transmission lines by ground shaping. The transition is designed on the analytical expressions of whole transitional structure. Conformal mapping is applied to obtain the characteristic impedance of FGCPW with bottom aperture within 3.3 % accuracy as compared with the EM-simulation results. As design example, the fabricated transition in back-to-back configuration provides insertion loss less than 1 dB per transition and return loss better than 10 dB for frequencies from 9 GHz to over 40 GHz.

Development of PSC I Girder Bridge Weigh-in-Motion System without Axle Detector (축감지기가 없는 PSC I 거더교의 주행중 차량하중분석시스템 개발)

  • Park, Min-Seok;Jo, Byung-Wan;Lee, Jungwhee;Kim, Sungkon
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.28 no.5A
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    • pp.673-683
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    • 2008
  • This study improved the existing method of using the longitudinal strain and concept of influence line to develop Bridge Weigh-in-Motion system without axle detector using the dynamic strain of the bridge girders and concrete slab. This paper first describes the considered algorithms of extracting passing vehicle information from the dynamic strain signal measured at the bridge slab, girders, and cross beams. Two different analysis methods of 1) influence line method, and 2) neural network method are considered, and parameter study of measurement locations is also performed. Then the procedures and the results of field tests are described. The field tests are performed to acquire training sets and test sets for neural networks, and also to verify and compare performances of the considered algorithms. Finally, comparison between the results of different algorithms and discussions are followed. For a PSC I-girder bridge, vehicle weight can be calculated within a reasonable error range using the dynamic strain gauge installed on the girders. The passing lane and passing speed of the vehicle can be accurately estimated using the strain signal from the concrete slab. The passing speed and peak duration were added to the input variables to reflect the influence of the dynamic interaction between the bridge and vehicles, and impact of the distance between axles, respectively; thus improving the accuracy of the weight calculation.

Exchange Bias Perpendicular Magnetic Anisotropy by Buffer Layer and Inserted Layer in [Pd/Co]5/FeMn Multilayer ([Pd/Co]5/FeMn 막에서의 바닥층과 삽입층에 의한 교환바이어스수직자기이방성)

  • Joo, Ho-Wan;An, Jin-Hee;Lee, Mi-Sun;Kim, Bo-Keun;Choi, Sang-Dea;Lee, Kee-Am
    • Journal of the Korean Magnetics Society
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    • v.14 no.5
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    • pp.192-195
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    • 2004
  • Magnetic properties by exchange biased perpendicular magnetic anisotropy in [Pd(0.8 nm)/Co(0.8 nm)]$_{5}$/FeMn(15 nm) multilayers deposited by dc magnetron sputtering system are investigated. As inserted Pd layer of interface between [Pd/Co] multilayer and FeMn film, the Hex of perpendicular anisotropy was improved from 127 Oe to 145 Oe. But result of an experiment by thermal stability, the Hex of the case that an inserted layer was inserted in decreased from low 20$0^{\circ}C$ in about 5$0^{\circ}C$ more if not inserted. If Ta was a buffer layer, the experiment results along material of buffer layer, the H$_{ex}$ obtained the largest 127 Oe. And if Pd was a buffer layer, H$_{ex}$ obtained the largest 169 Oe. Also, the Hc in buffer layer of Ta and Pd obtained the largest 203 Oe and 453 Oe, respectively.

Ultimate Strength Interaction of Steel/Concrete Composite Trapezoidal Box Girders Subjected to Concurrent Action of Bending and Torsion (휨과 비틀림을 동시에 받는 강/콘크리트 합성 제형 박스거더의 극한강도 상호작용)

  • Kim, Kyung-Sik
    • Journal of Korean Society of Steel Construction
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    • v.22 no.5
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    • pp.465-475
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    • 2010
  • In the horizontally curved bridges, girders are subjected to the combined action of vertical bending and torsion due to their curvatures without any eccentric loads. As subjected to bending and torsion, the ultimate strength of steel/concrete composite box girders are limited by the diagonal tensile stress in the deck concrete induced by the St. Venant torsion. To determine the ultimate strength of composite box girders in bending and torsion and their interactions, this study conducted a 3-dimensional FEA and classical strength of materials investigation. Using ABAQUS, the FEA fully utilized advanced nonlinear analysis techniques simulating material/geometrical nonlinearity and post-cracking behaviors. The ultimate strength from numerical data were compared with theoretically derived values. Concurrent compressive stresses in the concrete deck improve the shear-resisting capacity of concrete, thereby resulting in an increased torsional resistance of the composite box girder in positive bending. The proposed interaction equation is very simple yet it provides a rational lower bound in determining the ultimate strength of concrete/steel composite box girders.

A Numerical Study on the Apartment Structure Using Crossed Wide Girder (교차형 와이드 거더를 이용한 아파트구조의 수치해석적 연구)

  • Park, Jung-Hyun
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.8 no.5
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    • pp.1186-1191
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    • 2007
  • The study uses the crossed wide girder(waffle slab type) in apartment structural system comparing with existing shear wall system. The crossed wide girder will be able to secure the span of the longest which is possible with minimum slab thickness by not increasing the height. The research sees continuity arranges the crossed wide girder in schedule interval following the stress distribution. Namely, it is to make the interior space with the space without column and wall in the minimum height. In order to check the numerical value of this study which it interpreted the ductile frame system due to the crossed wide girder and existing shear wall system used the Midas Gen is a program which 3-dimension laterial force designs are possible. Analysis results, the crossed wide girder system is not disadvantageously laterial drift, drift ratio and deflection of slab compares with existing shear wall system. Also the whole concrete amount is similar existing shear wall system. The crossed wide girder is advantage which secure a architectal variability.

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Development of temperature monitoring system for bus duct (부스닥트용 온도감시 시스템 개발)

  • Kim, Dong-Wook;Nam, Suk-Hyun;Park, Sung-Ju;Huh, Sung-Su
    • Proceedings of the KIEE Conference
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    • 2006.07e
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    • pp.15-16
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    • 2006
  • 배전선로에 전력을 공급하는 방식은 일반적으로 22.9kV급 XLPE 케이블에 의한 전력공급이 주를 이루어 왔다. 한편으로 대규모 전력을 소비하는 공장 및 고층 빌딩의 전력 공급에 있어서는 일반적으로 각각 부하로의 많은 회선수의 케이블 포설을 요하는 전력케이블 보다는, 한 선로로 보다 많은 대전류를 수송하면서 부하 가까이에서 필요한 전류를 간편하게 분기해 공급받는 부스덕트 시스템이 시공 및 배전선로 관리의 간편성에 의해 점차 용도가 늘어나고 있다. 부스닥트 시스템의 대부분은 일단 시설물이 건축될 때 건축물의 상부 공간 또는 설비가 위치한 하부 바닥 구간을 통해 설치된 이후, 기타 배관, 가스관 등의 추가적인 건축 구조물과 함께 설치되어 이후 선로의 보수 진단 등이 대부분 어렵게 되어진다. 본 논문에서 소개하는 부스덕트의 온도감시 시스템은 아무리 복잡하고 협소한 설치 환경이라도 특수한 포설 공법에 의해 광화이버를 포설하고, 이를 활용하여 실시간으로 부스덕트 선로의 표면온도와 주변온도를 상시 감시함으로써, 효율적인 부스덕트 선로의 활용뿐만 아니라 과열에 의한 절연사고를 미연 방지하는 운전신뢰성과 안정성을 높이는 것이 가능하게 되었다.

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Efficient Three Dimensional Analysis of High-Rise Shear Wall Building with Openings (개구부가 있는 고층 벽식 구조물의 효율적인 3차원 해석)

  • 김현수;남궁계홍;이동근
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.15 no.2
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    • pp.351-365
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    • 2002
  • The box system that is composed only of reinforced concrete walls and slabs we adopted on many high-rise apartment buildings recently constructed in Korea. And the framed structure with shear wall core that can effectively resist horizontal forces is frequently adopted for the structural system for high-rise building structures. In these structures, a shear wall may have one or more openings for functional reasons. It is necessary to use subdivided finite elements for accurate analysis of the shear wall with openings. But it would take significant amount of computational time and memory if the entire building structure is subdivided into a finer mesh. An efficient analysis method that can be used regardless of the number, size and location of openings is proposed in this study. The analysis method uses super element, substructure, matrix condensation technique and fictitious beam technique. Three-dimensional analyses of the box system and the framed structure with shear wall core having various types of openings were performed to verify the efficiency of the proposed method. It was confirmed that the proposed method have outstanding accuracy with drastically reduced time and computer memory from the analyses of example structures.

Experimental Study on Shear Capacity of I-slab System Using Slim Precast Slab Deck (슬림 프리캐스트 슬래브 데크를 사용한 I-슬래브 시스템의 전단 성능에 관한 실험적 연구)

  • Kim, Seung-Hun
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.21 no.1
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    • pp.126-133
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    • 2017
  • This paper presents the shear capacities of hollow slab with plate and octagonal pillar type hollow sphere. Recently, the interest in precast hollow slab system for buildings is growing up according to the demand for high quality control and the increase in slab thickness. A hollow slab system is widely known as one of the effective slab system which can reduce self-weight of slab. However, hollow slabs are vulnerable to the deterioration in the shear strength due to the decrease of concrete at slab web which resists shear. Especially, in case of precast hollow slabs, it has joint surface between precast concrete slab modules along transverse axis of slab, and shear failure, that is caused by cracks at joints, has to be prevented. Therefore, in this study, shear capacity of the I-slab system is evaluated by 3-points-supported shear test along the longitudinal and transverse axis of slab specimen. Test results showed that I-slab had enough shear strength compared to theoretical shear strength even if it included the joint surfaces.