• Journal of Korean Association for Spatial Structures
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• v.13 no.4
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• pp.75-81
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• 2013

The circular hollow section is usually used for member of main frame to carry the external load in single layer lattice dome. But, the H-shaped section may be used for member of main frame since it is convenient for attaching roof panels. Single layer lattice domes have various buckling characteristics, such as the overall buckling, the member buckling, and nodal buckling. The purpose of this study is to compare buckling characteristics of single-layer lattice domes in which the H-shaped steel section as the existing domestically-produced structural steel is used as main frames to those of domes in which a circular hollow section is used as main frames.

• International Journal of High-Rise Buildings
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• v.8 no.3
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• pp.201-209
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• 2019

This paper presents a structural design of the "(Tentative Name) Toranomon Hills Residential Tower" which is currently under construction in Tokyo. The building is a reinforced concrete high-rise residential complex building with 54 stories above ground, 4 basement levels, and a building height of about 220 m. It is a requirement to provide the highest grade of residence in Japan, and in terms of the structural design, it is required to provide wide and comfortable spaces with high seismic performance. These requirements are satisfied by providing a total of 774 vibration control walls of two types. Also, to further improve the structural performance, steel fibers at the rate of 1.0vol% are provided in the ultra-high strength concrete used in the column members.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.52 no.1
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• pp.16-22
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• 2003

While passing through the AC/DC section insulators installed at electric railroad catenary, some electric trains undergo mis-operation of main circuit breaker after AC/DC change-over operation. This paper provides insulation resistance measurements of AC/DC section insulators, which confirm the insulation levels of section insulators are below the standard of insulators. The insulation deterioration and pantograph arrangement on the electric train can produce voltage impression on section insulator which induces mis-operation of main circuit breaker To mitigate the insulation deterioration of the section insulator installed at underground railroads, the section insulators have been cleaned periodically, but section insulator structure should be modified to make the section insulator performance perfect. Based on the above analysis, effective modification method of AC/DC section insulator is provided.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.634-643
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• 2011

The neutral section was installed in order to prevent conflict with different phase angle source in electric railway catenary system. The speed of electric train reduced due to coasting operation by notch off when it passed the neutral section. And, the catenary wire was damaged and the accident might be happened because of the arc generation when the electric train passed the neutral section with notch off condition. The inrush current of main transformer installed tiling train is analyzed during the operation of MCB(main circuit break) passing through the neutral section. The instantaneous waveform of load current were analyzed in case of powering and regenerative braking. Inrush current waveform with run of AC railway train showed that inrush current waveform and harmonics, the inrush current generated from main transformer in train has bad effects on power quality problem. In order to reduce these inrush currents, the MCB is connected when the phase angle of voltage is 90 degree. This paper is to measure inrush current and harmonics in main transformer of high speed train in neutral section of electric railway. This measurement report is used to control minimum inrush current in algorithm and power phase angle.

• Journal of the Korean Institute of Landscape Architecture
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• v.28 no.1
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• pp.136-146
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• 2000

Although the urban elevated road is welcomed in modern society to deal with urban traffic problems, its negative influence on both the pedestrian environment and urban landscape has been frequently observed. Furthermore, the space under elevated structures has been ignored, being the lost space. Recently, several efforts have been devoted into bringing back the lostspace. However, any specific design guidelines shown in the street design of Japan and Singapore have not been suggested in Korea, yet. This study proposes a case of the Nengdong-Ro street design where the two-story urban elevated road is being constructed and negative effects of the elevated road are largely expected. One of the purposes of Nengdong-Ro street design proposed in this study is to relieve the negative effect os the two-story elevated road, and to provide a better pedestrian environment in Nengdong-Ro. The other purpose is to suggest general guidelines that can be applied to the similar context as Nengdong-Ro. It is considered that the space under the elevated road generally consist of three sections: 1) main section where the elevated road runs parallel with the ground, 2) landing section where elevated road goes down to the ground, and 3) facility section where facilities such as the platform and the ticketing booth are located. The design guidelines are suggested for each section, because each section has a different situation. Plans, section and elevations and the details of the street furniture are also incorporated to support the design guidelines.

• International Journal of High-Rise Buildings
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• v.3 no.1
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• pp.35-48
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• 2014

In designing a 300 meter high skyscraper expected to be the tallest building in Japan, an earthquake-ridden country, we launched on the full-scale performance based design to ensure redundancy and establish new specifications using below new techniques. The following new techniques are applied because the existing techniques/materials are not enough to meet the established design criteria for the large-scale, irregularly-shaped building, and earth-conscious material saving and construction streamlining for reconstructing a station building are also required: ${\bullet}$ High strength materials: Concrete filled steel tube ("CFT") columns made of high-strength concrete and steels; ${\bullet}$ New joint system: Combination of outer diaphragm and aluminium spray jointing; ${\bullet}$ Various dampers including corrugated steel-plate walls, rotational friction dampers, oil dampers, and inverted-pendulum adaptive tuned mass damper (ATMD): Installed as appropriate; and ${\bullet}$ Foundation system: Piled raft foundation, soil cement earth-retaining wall construction, and beer bottle shaped high-strength CFT piles.

• International Journal of High-Rise Buildings
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• v.7 no.3
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• pp.255-264
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• 2018

This paper introduces three distinctive means for the use of a 189-meter high damped structure ensuring safety against earthquake: 1. Realization of L-shaped elevational structural planning: The bottom and top of the tower have belt trusses and hat trusses respectively to restrain the bending deformation. Furthermore, large-capacity oil dampers (damping force 6,000 kN) are installed in the middle part of the tower to restrain the higher-mode deformation. 2. Realization of L-shaped planar structural planning: We devised a means of matching the centers of gravity and rigidity by adjusting planar rigidity. Moreover, viscous damping devices are located at the edges of the L-shaped plan, where torsional deformation tends to be amplified. We call this the "Damping Tail" system. 3. Composite foundation to equalize deformations under different loading conditions: We studied the vertical and horizontal deformations using sway-rocking and 3D FEM models including the ground, and applied multi-stage diameter-enlarged piles to the tower and a mat foundation to the podium to keep the foundations from torsional deformations and ensure structural safety.

• Journal of Aerospace System Engineering
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• v.15 no.1
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• pp.72-79
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• 2021

In this study, as part of the development of an autonomous flying personal aircraft, an equivalent model of the main wing assembly of an Optionally Piloted Personal Air Vehicle (OPPAV) was developed. Reliability of the developed equivalent model was verified by eigenvalue analysis. The main wing assembly consisted of a main wing, an inboard pod, and an outboard pod. First, for developing an equivalent model of each component, components to produce the equivalent model were divided into several sections. Nodes were then created on the axis of the equivalent model at both ends of each section. In addition, static analysis with unit force and unit moment was performed to calculate the deformation or the amount of rotation at the node to be used in the equivalent model. Equivalent axial, bending, and torsional stiffness of each section were calculated by applying the beam theory. Once the equivalent stiffness of each section was calculated, information of a mass and moment of inertia for each section was entered by creating a lumped mass in the center of each section. An equivalent model was developed using beam element. Finally, the reliability of the developed equivalent model was verified by comparison with results of mode analysis of the fine model.

• Journal of the Korea institute for structural maintenance and inspection
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• v.28 no.4
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• pp.1-12
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• 2024

In this study, a determination method of structural member section based on Nonlinear behaviors of steel cable-stayed bridges and the Harmony Search algorithm was presented. The Harmony Search algorithm determines the structural member section of cable-stayed bridges by repeating the process of setting the initial value, initializing the harmony memory, configuring the new harmony memory, and updating the harmony memory to search for the optimal value. The nonlinear initial shape analysis of a three-dimensional steel cable-stayed bridge was performed with the cross-section of the main member selected by the Harmony Search algorithm, and the optimal cross-section of the main members of the cable-stayed bridge, such as pylons, girders, cross-beams, and cables, reflecting the complex behavior characteristics and the nonlinearity of each member was determined in consideration of the initial tension and shape. The total weight was used as the objective function for determining the cross-section of the main member of the cable-stayed bridges, and the load resistance ability and serviceability based on the ultimate state design method were used as the restraint conditions. The width and height ratio of the girder and cross-section were considered additional restraint conditions. The optimal sections of the main members were made possible to be determined by considering the geometry and material nonlinearity of the pylons, girders, and cross-sections and the nonlinearity of the cable members. As a result of determining the optimal cross-section, it was confirmed that the proposed analysis method can determine the optimal cross-section according to the various constraint conditions of the cable-stayed bridge, and the structural member section of the cable-stayed bridge considering the nonlinearity can be determined through the Harmony Search algorithm.

• Proceedings of the Materials Research Society of Korea Conference
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• 1998.08a
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• pp.55.1-55
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• 1998