• Structural Engineering and Mechanics
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• 제10권3호
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• pp.263-275
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• 2000

In this paper, a core wall structure coupled with connecting beams is discretized and modeled as an equivalent thin-walled member with closed section, while the connecting beams between openings are replaced by an equivalent shear diaphragm. Then, a numerical method (finite member element method, FMEM) for dynamic analysis of the core wall structure is proposed. The numerical method combines the advantages of the FMEM and Vlasov's thin-walled beam theory and the effects of torsion, warping and, especially, the shearing strains in the middle surface of the walls are considered. The results presented in this paper are very promising compared with the ones obtained from finite element method.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 추계학술대회논문집
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• pp.751-754
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• 2004

This paper presents a design of the directional radiation pattern by using the structural-acoustic interaction. For this purpose, prediction of the pressure distribution of the field points and radiation pattern of the structural-acoustic coupling system is shown. In order to get a strong coupling, coupled system that has a finite space and a semi-infinite space separated by two flexible walls and an opening is selected. A volume interaction can be occurred in structure boundary and a pressure interaction can be happened in the opening boundary. The coupled system is maximized the radiation power on the main axis and minimized the side lobe level.

• 산업기술연구
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• 제3권
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• pp.103-116
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• 1983

Recent developments in multi-storey buildings for residential purpose have led to the extensive use of shear walls for the basic structural system. When the coupled shear wall system is used, joined together with cast-in-place concrete or mortar (or grout), the function of the continuous joints is a crucial factor in determining the safety of L.P. Precast concrete shear wall structures, because the function of the continuous joints(Vertical wall to wall joints) is to transfer froces from one element(shear wall panel) to another, and if sufficient strength and ductility is not developed in the continuous joints, the available strength in the adjoining elements may not be fully utilized. In this paper, the influence of the stiffness of vertical joints(wet vertical keyed shear joints) on the behaviour of precast shear walls is theoretically investigated. To define how the stiffness of the vertical joints affect the load carrying capacity of L.P.Precast concrete shear wall structure, the L.P.Precast concrete shear wall structure is analyzed, with the stiffness of the vertical joints varying from $K=0.07kg/mm^3$(50MN/m/m) to $K=1.43kg/mm^3$(1000MN/m/m), by using the continuous connection method. The results of the analysis shows that at the low values of the vertical stiffness, i.e. from $K=0.07kg/mm^3$(50MN/m/m) to $K=0.57kg/mm^3$(400MN/m/m), the resisting bending moment and shearing force of precast shear walls, the resisting shearing force of vertical joints and connecting beams are significantly affected. The detailed results of analysis are represented in the following figures and Tables.

• Steel and Composite Structures
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• 제7권4호
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• pp.279-301
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• 2007

When coupling beams are proportioned appropriately in coupled core wall (CCW) systems, the input energy from ground motions is dissipated primarily through inelastic deformations in plastic hinge regions at the ends of the coupling beams. It is desirable that the plastic hinges form at the beam ends while the base wall piers remain elastic. The strength and stiffness of the coupling beams are, therefore, crucial if the desired global behavior of the CCW system is to be achieved. This paper presents the results of nonlinear response history analysis of two 20-story CCW buildings. Both buildings have the same geometric dimensions, and the components of the buildings are designed based on the equivalent lateral force procedure. However, one building is fitted with steel coupling beams while the other is fitted with diagonally reinforced concrete coupling beams. The force-deflection relationships of both beams are based on experimental data, while the moment-curvature and axial load-moment relationships of the wall piers are analytically generated from cross-sectional fiber analyses. Using the aforementioned beam and wall properties, nonlinear response history analyses are performed. Superiority of the steel coupling beams is demonstrated through detailed evaluations of local and global responses computed for a number of recorded and artificially generated ground motions.

• 콘크리트학회논문집
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• 제25권6호
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• pp.649-656
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• 2013

병렬전단벽시스템은 경제적이고 효율적인 구조시스템이지만, 연결보의 복잡한 철근상세가 요구된다. 이를 보완하고자 ACI-318에서는 개선된 철근상세를 제안하고 있지만 과도한 횡보강근으로 현장 적용에 어려움이 따른다. 이 연구에서는 횡보강 철근량을 감소시킨 대각철근을 갖는 HPFRCC 연결보 상세를 제안하고, 형상비 2.0 실험체를 통해 현행 기준에 만족하는 대각철근을 갖는 철근콘크리트 연결보와 이력거동을 비교 평가하였다. 그 결과, HPFRCC의 횡구속 효과를 확인하였고, 횡구속 철근을 기준의 1/2로 배근하고 HPFRCC로 보강한 연결보는 현행기준에 따른 연결보와 유사한 내진성능을 보였다. HPFRCC 보강을 통해 대각보강된 철근콘크리트 연결보의 횡구속 철근량을 감소시킴으로써 철근상세의 단순화가 가능할 것으로 판단된다.

• 콘크리트학회논문집
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• 제27권6호
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• pp.661-668
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• 2015

병렬전단벽시스템은 횡력저항에 있어서 효율적인 구조시스템이지만, 각 독립벽체를 연결하는 연결보의 복잡한 철근상세로 인해 시공상의 어려움이 있다. ACI-318에서는 개선된 철근상세를 제안했지만, 이 또한 과도한 횡보강근으로 인해 대각철근의 중심부의 철근 배근 혼잡으로 인해 현장 적용에 어려움이 따른다. 본 연구에서는 프리캐스트를 통하여 철근 배근 오차 및 콘크리트 품질 등의 저하를 줄이고 ACI 318-11의 개선된 상세에 따른 기준 실험체와 일반대각철근을 묶음대각철근으로 대체한 철근콘크리트 연결보의 이력거동을 비교 평가하였다. 그 결과, 묶음대각철근을 적용한 실험체는 현행기준에 따른 연결보와 비교하여 유사한 이력거동을 나타냈고, 더 우수한 에너지소산능력을 나타냈다. 묶음대각철근을 적용한 철근콘크리트 연결보가 현행기준에 따르는 연결보를 대체하여 현장적용이 가능할 것으로 판단된다.

• KSTLE International Journal
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• 제7권2호
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• pp.35-44
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• 2006

Turbocharger bearings are under the circumstance of high temperature, moreover rotated at high speed. It is necessary to be designed overcoming the high temperature. So the type of oil inlet port, the inlet oil temperature and the sort of engine oil should be designed, controlled and selected carefully in order to reduce the bearing inside temperature. In this study, the influence of aerated oil on a high-speed journal bearing is also examined by using the classical thermohydrodynamic lubrication theory coupled with analytical models for viscosity and density of air-oil mixture in fluid-film bearing. Convection to the walls and mixing with supply oil and re-circulating oil are considered. The considered parameters for the study of bubbly lubrication are oil inlet port's type, oil aeration level and shaft speed. It is found that the type of oil inlet ports and shaft speed play important roles in determining the temperature and pressure, then the friction and load of journal bearing at high speed operation. Also, the results show that, under extremely high shaft speed, the high shear effects on aerated oil and the high temperature effects are canceled out each other. So, the bearing load and friction show almost no difference between the aerated oil and pure oil.

• Coupled systems mechanics
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• 제2권4호
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• pp.329-348
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• 2013

This study aims at observing the coupling behaviours between suspended ceilings and partition walls in terms of their global seismic performance using full-scale shake table tests. The suspended ceilings with planar dimensions of $6.0m{\times}3.6m$ were tested with two types of panels: acoustic lay-in and metal clip-on panels. They were further categorized as seismic-braced, seismic-unbraced, and non-seismic installations. Also, two configurations of 2.7 m high partition wall specimens, with C-shape and I-shape in the plane layouts, were tested. In total, seven ceiling-partition-coupling (CPC) specimens were tested utilizing a unidirectional seismic simulator. The test results indicate that the damage patterns of the tested CPC systems included failure of the ceiling grids, shearing-off of the wall top railing, and, most destructively, numerous partial detachments and falling of the ceiling panels. The loss of panels was mostly concentrated near the center of the tested partition wall. The testing results also confirmed that the failure mode of the non-seismic CPC systems was brittle: The whole system would collapse suddenly all at once when the magnitude of the inputs hit the capacity threshold, rather than displaying progressive damage. Overall, the seismic capacity of the unbraced and braced CPC systems could be up to 1.23 g and 2.67 g, respectively; these accelerations were both achieved at the base of the partition wall. Nonetheless, for practical applications, it is noteworthy that the three-dimensional nature of seismic excitations and the size effect of the ceiling area are parameters that exacerbate the CPC's seismic response so that their actual capacity may be dramatically decreased, leading to important losses even in moderate seismic events.

• 한국지반공학회논문집
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• 제36권12호
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• pp.17-25
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• 2020

인공동결 공법은 지반에 영구적인 영향을 초래하지 않는 지반개량 공법으로 인공동결 공법의 효율성 및 설계기준을 결정하는 핵심인자는 물의 흐름이다. 따라서 인공동결 공법을 적용하기 위해서는 동결구근 및 벽체 형성에 물의 흐름이 미치는 영향에 대한 연구가 선행되어야 한다. 본 논문에서는 물의 흐름이 동결구근 및 벽체 형성에 미치는 영향을 극대화하기 위해 순수한 물을 활용한 실내실험과 수치해석 연구를 수행하였다. 열-수리 연계 해석모델을 새롭게 제안하고 이를 실험적으로 검증하였으며, 유량이 동결벽체 형성 시간 및 형상을 결정짓는 핵심인자임을 확인하였다. 나아가, 동결구근 및 벽체를 가시적으로 확인하기 어려운 지반에서 활용성이 높을 것으로 예상되는 동결벽체 형성 시간을 간접적으로 예측할 수 있는 방안을 새롭게 제시하였다.

• Earthquakes and Structures
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• 제7권5호
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• pp.817-842
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• 2014

ASCE/SEI 41-13 provides modeling parameters and numerical acceptance criteria for various types of members that are useful for evaluating the seismic performance of reinforced concrete (RC) building structures. To accurately evaluate the global performance of a coupled wall system, it is crucial to first properly define the component behaviors (i.e., force-displacement relationships of shear walls and coupling beams). However, only a few studies have investigated on the modeling of RC coupling beams subjected to earthquake loading to date. The main objective of this study is to assess the reliability of ASCE 41-13 modeling parameters specified for RC coupling beams with various design details, based on a database compiling almost all coupling beam tests available worldwide. Several recently developed coupling beam models are also reviewed. Finally, a rational method is proposed for determining the chord yield rotation of RC coupling beams.