• Title, Summary, Keyword: rectangular walls

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Response Modification Factor and Deformability for Structural Walls Designed with Different Details (구조 상세가 다른 벽체의 변형성능과 반응수정계수)

  • 오영훈;한상환
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.959-964
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    • 2001
  • This study investigates the seismic performance of bearing walls with rectangular sectional shape and specific details of reinforcements developed for 10 to 20-story apartment buildings in Korea. To investigate seismic behavior of structural walls, several specimens were experimented by author and laboratory test results by other researchers were collected and analysed. Structural behaviors of walls were evaluated by means of ductility, deformation, and strength capacities. For this purpose, thirty six specimens having different Properties such as aspect ratios and details were considered. Based on the results of this study, deformability of the walls with specific details is discussed. Also this study compares the response modification factor(R) for the bearing wall systems in seismic design provisions between Korea and United States.

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Seismic Behavior of Artificially Damaged R/C Rectangular Shear Walls with Opening Configurations (개구부를 위해 인위적 손상을 입은 철근콘크리트 장방형 전단벽의 내진거동)

  • Kim Sun Woo;Han Byung Chan;Kim Hyo Jin;Choi Gi Bong;Choi Chang Sik;Yun Hyun Do
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.457-460
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    • 2004
  • This study is an experimental study to investigate the shear behavior of reinforced concrete shear walls with openings and to determine the shear strength of those walls. This paper compares rigidities of walls with opening by different opening types. The experimental results, as expected, show that the crack load, yield load, and limited load are inferior for specimen with larger opening area. The magnitude of axial stress and shear stress had a significant effect on the deformability of shear walls with opening.

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Two-Dimensional Free Convection in a Rectangular Enclosure Composed of a Hot Wall and Partially Cold Side Wall (아래면이 고온이고 옆면의 일부가 저온인 4각형 밀폐공간에서의 2차원 자연대류에 관한 연구)

  • 이택식;고상근
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.9 no.2
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    • pp.213-221
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    • 1985
  • Two dimensional laminar natural convection in a rectangular enclousure composed of a hot bottom wall, a partially cold side wall and insulated walls except the above walls was studied by numerical analysis and also by esperiments. In the experiments, the temperature distributions in the enclosure and Nusselt number distribution along the hot and cold walls were obtained by the use of Mach-Zehnder interferometer. At first, numerical analysis with the boundary conditions of the experimental apparatus was performed and the comparison of the results of the numerical and the experimental results validated the numerical model good ennough. Heat transfer characteristics were investigated by applying the verified numerical model with the parameters, i.e. Grashof number, aspect ratio, position of cold plate and insulation condition. The results showed the optimal conditions of temperature distribution and the position of cold wall, and the characteristics of insulation materials.

Structural Steel as Boundary Elements in Ductile Concrete Walls

  • Cho, Soon-Ho
    • KCI Concrete Journal
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    • v.12 no.2
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    • pp.73-84
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    • 2000
  • A new form of construction utilizing structural steel as the boundary elements in ductile flexural concrete walls is proposed to solve the bar congestion problems in such a heavily reinforced region, while maintaining the ductility and energy absorption capacity comparable to their traditional form. Two wall specimens containing rectangular hollow structural sections (HSS) and channels at their ends respectively, and one companion standard reinforced concrete wall specimen with concentrated end reinforcement were constructed and tested under reversed cyclic loading to evaluate the construction process as well as the structural performance. Initially, all three specimens were chosen and detailed with some caution to have approximately the same flexural capacity without change of the original shape and dimension of a rectangular cross section correction. Analysis and comparison of test results indicated that the reversed cyclic responses of three walls showed similar hysteretic properties, but in those with steel boundaries, local buckling of the corresponding steel webs and flanges following significant yielding was a dominant factor to determine the hysteretic response. The monotonic and cyclic responses predicted based on a sectional approach was also presented and found to be in good agreement with measured results. Design recommendations considering local instability of the structural steel elements and the interaction between steel chords and a concrete web member in such a composite wall are presented.

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Hydrodynamic Characteristics of the Rectangular Type Circulating Fluidized Bed (4각 순환유동층의 수력학적 특성)

  • Hyun, Sang Yeol;Rhee, Kwan Seok
    • Journal of the Korean Society for Heat Treatment
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    • v.10 no.4
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    • pp.232-236
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    • 1997
  • A rectangular type circulating fluidized bed (CFB) with an internal nozzle and two partition walls was proposed. In this modified CFB, an internal nozzle and two slanted partition walls were additionally set in the riser. This cold mode apparatus was made of acrylic resin; the riser was 1500mm high and $1000{\times}1000mm^2$ in the cross sectional area, the internal nozzle was 200mm high and 10mm in the inner diameter, and the partition wall was 7mm thick. Glass beads of $91{\mu}m$ in the mean diameter were employed as bed materials. In the cold mode by using the proposed CFB with an internal nozzle, it was possible to change the particle hold up by changing the gas flow ratio of the nozzle to the total(Qn/Qt). It was found that the inflection point which devided the bed structure between the dense and the dilute phase in the riser varied with Qn/Qt.

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Numerical simulation of hydroelastic effects of sloshing phenomena in a rectangular tank (사각탱크내의 슬로싱 현상에 기인한 벽면운동에 대한 수치모사)

  • Ha, Minho;Cheong, Cheolung
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.534-537
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    • 2012
  • Hydroelastic effects on sloshing phenomena in a rectangular tank are numerically investigated. The dimension of the tank is $1000mm{\times}600mm$, and the filling ratio of water is 20% of tank height. One of the side walls of tank is assumed to be flexible. The tank is excited into sway motion with amplitude of 100mm and frequency of 0.53Hz that is first natural frequency of water inside the tank. Prediction results for time histories of pressure and displacement of flexible and rigid walls are compared to quantitatively assess hydroelastic effects on sloshing phenomena.

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Effect of Inclined Wall Number on Heat Transfer and Friction in the Smooth Channel (매끈한 사각채널에서 경사 벽면 수가 열전달과 마찰에 미치는 효과)

  • Lee, Myung-Sung;Ahn, Soo-Whan
    • Journal of the Korea Society For Power System Engineering
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    • v.18 no.3
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    • pp.66-72
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    • 2014
  • The local heat transfer and pressure drop of developed turbulent flows in the smooth convergent/divergent channels with rectangular and square cross-sectional areas along the axial distance have been investigated experimentally. The measurement was conducted within the range of Reynolds numbers from 15,000 to 89,000. The channel hydraulic diameter ratios of 0.67 and 1.49 in the rectangular channel with 2 inclined walls and the ratios 0.75 and 1.33 in the square channel with 4 inclined walls are considered. The comparison showed that among the four channels the square divergent channel has the highest thermal performance at the identical mass flow rate, at the identical pumping power, and at the static pressure drop.

Analytical Modeling of Natural Convection in a Tall Rectangular Enclosure with Multiple Disconnected Partitions

  • Bae, Youngmin;Kim, Seong Hoon;Seo, Jae-Kwang;Kim, Young In
    • Nuclear Engineering and Technology
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    • v.48 no.4
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    • pp.925-931
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    • 2016
  • In this study, laminar natural circulation and heat transfer in a tall rectangular enclosure with disconnected vertical partitions inside were investigated. Analytical expressions were developed to predict the circulation flow rate and the average Nusselt number in a partially partitioned enclosure with isothermal side walls at different temperatures and insulated top and bottom walls. The proposed formulas are then validated against numerical results for modified Rayleigh numbers of up to $10^6$. The impacts of the governing parameters are also examined along with a discussion of the heat transfer regimes.

Heat Transfer Behavior of Viscoelastic Fluid including buoyancy effect with Modified Temperature Dependent Viscosity Model in a Rectangular Duct (수정점도 모델을 이용한 직사각형 덕트에서의 부력을 고려한 점탄성 유체의 열전달 특성)

  • Sohn C. H.;Jang J. H.
    • 한국전산유체공학회:학술대회논문집
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    • pp.192-198
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    • 1999
  • The present study proposes modified temperature-dependent non-Newtonian viscosity model and investigates flow characters and heat transfer enhancement of the viscoelastic non-Newtonian fluid in a 2:1 rectangular duct. The proposed modified temperature dependent viscosity model has non-zero value near the high temperature and high shear rate region while on the existing viscosity models have zero value. Two versions of thermal boundary conditions involving difference combination of heated walls and adiabatic walls are analyzed in this study. The combined effect of temperature dependent viscosity, buoyancy, and secondary flow caused by second normal stress difference are ail considered. The Reiner-Rivlin model is adopted as a viscoelastic fluid model to simulate the secondary flow caused by second normal stress difference. Calculated Nusselt numbers by the modified temperature-dependent viscosity model gives under prediction than the existing temperature-dependent viscosity model in the regions of thermally developed with same secondary normal stress difference coefficients with experimental results in the regions of thermally developed. The heat transfer enhancement of the viscoelastic fluid in a 2:1 rectangular duct is highly dependent on the secondary flow caused by the magnitude of second normal stress difference.

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Heat Transfer and Frictions in the Convergent/divergent Channel with Λ/V-shaped Ribs on Two Walls

  • Kim, Beom-soo;Lee, Myung-sung;Ahn, Soo-whan
    • International Journal of Aeronautical and Space Sciences
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    • v.18 no.3
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    • pp.395-402
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    • 2017
  • The local heat transfer and total pressure drops of developed turbulent flows in the ribbed rectangular convergent/divergent channels with ${\Lambda}/V-shaped$ ribs have been investigated experimentally. The channels have the exit hydraulic diameter ($D_{ho}$) to inlet hydraulic diameter ($D_{hi}$) ratios of 0.67 for convergence and 1.49 for divergence, respectively. The ${\Lambda}/V-shaped$ ribs with three different flow attack angles of $30^{\circ}$, $45^{\circ}$, and $60^{\circ}$ are manufactured with a fixed rib height (e) of 10 mm and the ratio of rib spacing (S) to height (e) of 10 on the walls. Thermal performances of the ribbed rectangular convergent/divergent channels are compared with the smooth straight tube under identical pumping power. The results show that the flow attack angle of $45^{\circ}$ with ${\Lambda}-shaped$ rib has the greatest thermal performance at all the Reynolds numbers studied in the convergent channel; whereas, the flow attack angle of $60^{\circ}$ with V-shaped rib has the greatest thermal performance over Reynolds number of 30,000 in the divergent channel.