• Journal of Korean Society of Coastal and Ocean Engineers
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• v.26 no.5
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• pp.335-341
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• 2014

Physical experiments were carried out to measure the wave force on the vertical walls of perforated breakwater considering several phases of a wave acting on the breakwater. The maximum horizontal wave force acting on each vertical wall was compared between single and double chamber caisson breakwater. The experimental data in this study showed that the total horizontal wave force for double chamber caisson was 9.6% smaller on average than that for single chamber caisson when the total chamber width was the same for both caissons. Such reduction of the wave force is due to the dissipation of wave energy at the porous middle wall, which is located between the porous front wall and non-porous rear wall.

• Journal of The Korean Society of Agricultural Engineers
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• v.46 no.2
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• pp.3-14
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• 2004

This study was conducted to assess the possibility of the field application of the iceharbor-type precast fishway. When overflow depth of weir is 4.0 cm in model fishway, upper part velocities appear appropriate for upstream migration of fish and the lowest overflow wall (right line) in lower part has shown velocity distribution more or less inadequate for upstream migration. Except that right line, left and middle line revealed that velocities are appropriate for upstream migration of fish. Therefore, we concluded that this fishway owing to be not broad growth width of overflow velocities according to increasing discharges can correspond to variation of water level. Also We consider that various velocities in fishway were effective, because slow velocity line can guide flow for upstream migration. For low flow, the arrangement of different crest level or each overflow part (higher left, middle and lower right, or lower left, middle and higher right) was more effactive than unform crert level. Hole plays an important role as migration pass during drought and flood flow. Therefore, We concluded that this fishway can cope with water depth variation by various overflow wall height change and raise the field applicability with better performance hydraulically and structurally.

• Journal of the Semiconductor & Display Technology
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• v.13 no.2
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• pp.57-62
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• 2014

In the study, a numerical analysis is conducted to investigate the heat transfer characteristics of an inverter system inside a panel for three locations (bottom, middle and top). A conjugate heat transfer is simulated using a CFD (computational fluid dynamics) code since the heat transfer through the surrounding panel walls is important. It is shown that the heat flux through the left wall, which is important for the safety of the electronic equipment, is the biggest when the inverter is located at bottom. On the other hand, the heat flux through the left wall is negligible when the inverter at middle or top. It is also found that the heat flux to the surrounding walls is the lowest when the inverter is at middle.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.18 no.8
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• pp.856-863
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• 2008

High-rise apartments of shear wall system are governed by flexural behavior like a cantilever beam. Installation of the damper-brace system in a structure governed by flexural behavior is not suitable. Because of relatively high lateral stiffness of the shear wall, a load is not concentrate on the brace and the brace cannot perform a role as a damping device. In this paper, a friction damper applying flexibility of shear wall is proposed in order to reduce the deformation of a structure. To evaluate performance of the proposed friction damper, nonlinear time history analysis is executed by SeismoStruct analysis program and MVLEM(multi vertical linear element model) be used for simulating flexural behavior of the shear wall. It is found that control performance of the proposed friction damper is superior to one of a coupled wall with rigid beam. In conclusion, this study verified that the optimal control performance of the proposed friction damper is equal to 45 % of the maximum shear force inducing in middle-floor beam with rigid beam.

• International journal of steel structures
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• v.18 no.4
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• pp.1107-1124
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• 2018

The structural behavior of reinforced concrete coupled shear wall structures is greatly influenced by the behavior of their coupling beams. This paper presents a process of the seismic analysis of reinforced concrete coupled shear wall-frame system linked by hysteretic dampers at each floor. The hysteretic dampers are located at the middle portion of the linked beams which most of the inelastic damage would be concentrated. This study concerned particularly with wall-frame structures that do not twist. The proposed method, which is based on the energy equilibrium method, offers an important design method by the result of increasing energy dissipation capacity and reducing damage to the wall's base. The optimum distribution of yield shear force coefficients is to evenly distribute the damage at dampers over the structural height based on the cumulative plastic deformation ratio of the dissipation device. Nonlinear dynamic analysis indicates that, with a proper set of damping parameters, the wall's dynamic responses can be well controlled. Finally, based on the total plastic strain energy and its trend through the height of the buildings, a prediction equation is suggested.

• Journal of the Earthquake Engineering Society of Korea
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• v.25 no.1
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• pp.1-9
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• 2021

Most commercial buildings among existing RC buildings in Korea have a multi-story wall-frame structure where RC shear wall is commonly used as its core at stairways or elevators. The members of the existing middle and low-rise wall-frame buildings are likely arranged in ordinary details considering building occupancy, and the importance and difficulty of member design. This is because there are few limitations, considerations, and financial burdens on the code for designing members with ordinary details. Compared with the intermediate or unique details, the ductility and overstrength are insufficient. Furthermore, the behavior of the member can be shear-dominated. Since shear failure in vertical members can cause a collapse of the entire structure, nonlinear characteristics such as shear strength and stiffness deterioration should be adequately reflected in the analysis model. With this background, an 8-story RC wall-frame building was designed as a building frame system with ordinary shear walls, and the effect of reflecting the shear failure mode of columns and walls on the collapse mechanism was investigated. As a result, the shear failure mode effect on the collapse mechanism was evident in walls, not columns. Consequently, it is recommended that the shear behavior characteristics of walls are explicitly considered in the analysis of wall-frame buildings with ordinary details.

• Journal of the Korean Society for Nondestructive Testing
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• v.32 no.3
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• pp.241-262
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• 2012

Some applications require structural health monitoring in inaccessible components. This paper presents a technique useful for Structural Health Monitoring of double wall structures, such as double wall steam pipes and double wall pressure vessels separated from an ultrasonic transducer by three layers. Detection has been demonstrated at distances in excess of one meter for a fixed transducer. The case presented here is for one of the layers, the middle layer, being a fluid. For certain transducer configurations the wave propagating in the fluid is a wave with low velocity and attenuation. The paper presents a model based on wave theory and finite element simulation; the experimental set-up and observations, and comparison between theory and experiment. The results provide a description of the technique, understanding of the phenomenon and its possible applications in Structural Health Monitoring.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.05a
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• pp.244-247
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• 2004

This study proposes the design method of the shear walls with openings using strut-and-tie models. Strut-and-tie models are constructed for opening near the middle of the wall and for opening near a wall boundary. These enables an admissible load path for the horizontal earthquake force. These models consider the size and position of opening effectively. Each model is suitable for the seismic response corresponding with lateral forces in a given direction to be considered. The proposed models are good agreements with nonlinear finite element analysis(DIANA) results.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.13 no.11
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• pp.1156-1164
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• 2001

This study aims to suggest envelope structure which can improve the insulation performance of cold storage warehouse with cost effectiveness. Envelope structures are classified and economical efficiency of each type is evaluated to the model warehouse. As results, type 3 (PC wall) and 4(sandwich panel wall) have benefits to the middle/large (lifetime of 25 years) and small (lifetime of 12∼13 years) warehouse, respectively.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.25 no.5
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• pp.397-404
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• 2012

Fragility curves show the probability of a system reaching a limit state as a function of some measure of seismic intensity. To obtain fragility curves of six and twelve story staggered wall structures with middle corridor, incremental dynamic analyses were carried out using twenty two pairs of earthquake records, and their failure probabilities for various intensity of seismic load were investigated. The performances of staggered wall structures with added columns along the central corridor and the structures with their first story walls replaced by columns were compared with those of the regular staggered wall structures. Based on the analysis results it was concluded that staggered wall structures with central columns have the largest safety margin for the same level of seismic load.