• Journal of the Korea Concrete Institute
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• v.19 no.5
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• pp.557-567
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• 2007

In underground parking lots of apartment housing, the story height is increased by $300{\sim}400mm$ because of various ducts for HVAC. In order to reduce this story height, this study proposed the 'hybrid beam', which is composed of PC beam with embedded steel beam and insitu concrete. The depth of the hybrid beam is reduced by 300 mm and then the steel beam is embedded over the length of reduced depth to compensate for the loss of strength. Then, we performed the large-scale structural tests on 9 specimens and investigated the flexural behavior of the specimens. The parameters of tests were the shape of steel beam section, the length of the reduced depth, the stage of construction, the effects of slab and shear connectors. The test results showed that the specimens, after the insitu concrete has cured, has the flexural capacity which exceeds the required design capacity regardless of other parameters. On the other hand, the specimens of construction stage do not have sufficient strength. Based on these results, it is thought that the proposed hybrid beam with reduced depth is applicable to the underground parking lots of apartment housing as long as the support is placed at construction stage.

• Journal of the Korean Society for Advanced Composite Structures
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• v.2 no.3
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• pp.30-35
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• 2011

This study investigates the optimum section properties of newly developed steel-concrete composite beam. For that purpose we developed computer program calculating section properties. The suggested new beam section highly contribute to save inter-story height and reduce construction duration and cost compared with conventional steel works such as H-beam and column + RC slab system. But the section shape have different section modulus with upper and lower fiber because of the unsymmetric cross section. Therefore the parametric study on thickness-ratio of top and bottom flange plate is needed. In this paper the change of neutral axis and section modulus for thickness-ratio of up and down flage plate is analysed and discussed.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.13 no.5
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• pp.172-179
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• 2010

This study was conducted to establish a management plan for the Songrim woodland restoration by analyzing the site characteristics of the Songrim Woodland Natural Monument (Natural Monument 445) in Hadong-Gun, Gyeongsangnam-Do, Korea. The Songrim woodland was a pure pine forest. To stimulate the growth of sub-trees or mid- story vegetation in both a non-rest year forest and a rest year forest, it is recommended to take a silvicultural practices such as pruning because canopy of over-story trees was closely covered. The Songrim woodland in the non-rest year forest severely competed among individual trees of DBH classes of 60 cm and height of 18 m, while the woodland in the rest-year forest competed with DBH classes of 62 cm and height of 10 m, respectively. Soil physical property such as soil hardness, soil pore space rates, and pF 2.7 was restored following the rest-year forest designation. Mean salt concentration in the Songrim woodland soils was 0.006%. The result suggests that it is needed to take a study to prevent the salt inputs to conserve the Songrim woodland.

• Journal of Korean Society of Steel Construction
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• v.20 no.1
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• pp.165-173
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• 2008

In order to promote the practicality of high-rise steel buildings, the development of structural system which have the better fire resistance, the changeable plan, and the quality control of construction with general composite beams is needed. In this research, new semi-slim floor which the defect of general slim floor was complemented was evaluated to investigate the concrete integration with slim-flor beam and the flexural performance. 5 simply supported semi-slim floor beam tests were performed with parameters; structural form of slab support beam, slab thickness, with or without web opening, and shear connection. Experimental results showed that all specimen s had good ductile behavior.

• Structural Engineering and Mechanics
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• v.52 no.3
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• pp.573-593
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• 2014

Pounding between adjacent buildings is a significant challenge in metropolitan areas because buildings of different heights collide during earthquake excitations due to varying dynamic properties and narrow separation gaps. The seismic responses of adjacent buildings of varying height, coupled through soil subjected to earthquake-induced pounding, are evaluated in this paper. The lumped mass model is used to simulate the buildings and soil, while the linear visco-elastic contact force model is used to simulate pounding forces. The results indicate while the taller building is almost unaffected when the shorter building is very short, it suffers more from pounding with increasing height of the shorter building. The shorter building suffers more from the pounding with decreasing height and when its height differs substantially from that of the taller building. The minimum required separation gap to prevent pounding is increased with increasing height of the shorter building until the buildings become almost in-phase. Considering the soil effect; pounding forces are reduced, displacements and story shears are increased after pounding, and also, minimum separation gap required to prevent pounding is increased.

• Computers and Concrete
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• v.19 no.1
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• pp.7-17
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• 2017

In Chinese Design Codes, for super high-rise buildings with complex structural distribution, which are regarded as code-exceeding buildings, elasto-plastic time history analysis is needed to validate the requirement of "no collapse under rare earthquake". In this paper, a 117-story super high-rise building is discussed. It has a height of 597 m and a height-width ratio of 9.5, which have both exceeded the limitations stipulated by the Chinese Design Codes. Mega columns adopted in this structure have cross section area of about $45m^2$ at the bottom, which is infrequent in practical projects. NosaCAD and Perform-3D, both widely used in nonlinear analyses, were chosen in this study, with which two model were established and analyzed, respectively. Elasto-plastic time history analysis was conducted to look into its seismic behavior, emphasizing on the stress state and deformation abilities under intensive seismic excitation.From the comparisons on the results under rare earthquake obtained from NosaCAD and Perform-3D, the overall responses such as roof displacement, inter story drift, base shear and damage pattern of the whole structure from each software show agreement to an extent. Besides, the deformation of the structure is below the limitation of the Chinese Codes, the time sequence and distribution of damages on core tubes are reasonable, and can dissipate certain inputted energy, which indicates that the structure can meet the requirement of "no collapse under rare earthquake".

• Earthquakes and Structures
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• v.23 no.2
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• pp.139-150
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• 2022

In most self-center braces, decreasing residual deformation is possible only by increasing pretension force, which results in lower energy dissipation capacity. On the other hand, increasing energy dissipation capacity means higher values of residual deformation. The goal of this research was to find the best design for a self-centering buckling restrained brace (SC-BRB) system by balancing self-centering capability and energy dissipation. Three, six, and nine-story structures were investigated using OpenSees software and the TCL programming language to achieve this goal. For each height, 62 different SC-BRBs were considered using different values for the pretension force of cables, the area of the buckling restrained brace (BRB) core plate, and the yield stress of the core plate. The residual deformation and dissipated energy of all the models were calculated using nonlinear analyses after cyclic loading was applied. The optimum design for each height was determined among all the models and was compared to the structure equipped with the usual BRB. The residual deformation of the framed buildings was significantly reduced, according to the findings. Also the reduction of the energy dissipation was acceptable. The optimum design of SC-BRB in 6-story building has the most reduction percent in residual deformation, it can reduce residual deformation of building 83% while causing only a 57% of reduction in dissipated energy. The greatest reduction in residual deformation versus dissipated energy reduction was for the optimum SC-BRB design of 9-story building, results indicated that it can reduce residual deformation of building 69% while causing only a 42% of reduction in dissipated energy.

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.39-40
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• 2010

The demands for longer span and reduction of story height have greatly increased as building structures become much larger and higher in recent years. Although the development of flexural members for reducing story height or making long span has been studied by many researchers and engineers, there is still a lack of efficient systems that meet these two demands simultaneously. This study aimed at developing a new composite beam system suitable for long span and reduction of story height, and proposed a prestressed composite beam with corrugated web. It has great resistance against non-symmetric construction load due to its strong out-of-plane shear strength with relatively small member height as well as good constructability and economic efficiency by removing/minimizing form work. The corrugated webs also make accordion effect introducing larger effective prestressing force to top and bottom flanges, which causes larger upward camber reducing the member deflection. Five full-scale specimens with key test parameters, which are web sectional shapes and number of drape points, were tested to understand their flexural behavior and to verify the performance of the proposed method. The experimental test results showed that the proposed prestressed composite beam had greater flexural strength and stiffness than the ordinary non-prestressed composite beam.

• Journal of the Korea institute for structural maintenance and inspection
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• v.21 no.6
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• pp.44-51
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• 2017

Recently, the parking in downtown area has caused severe problem due to the dramatic increase of possessing automobile in the country. A parking structure has been on the spotlight to solve the parking problem in downtown area. However, the overall height of parking structure is stipulated less than 8 m. Therefore, in this research, 'wide composite beam', which is possible for reducing story height and having long span, is developed and the flexural capacity of the wide composite beam is evaluated. Based on the result of the flexural test, the flexural strength of wide composite beam increased by 20% as the thickness of steel beam increased by 3 mm ($6mm{\rightarrow}9mm$) The shapes of rebar (whether it is triangle or rectangular shape) in the wide composite beam did not affect its flexural strength. The flexural strength of wide composite beam without rebar decreased by 10% compared to that of wide composite beam with rebar. In addition, the neutral axis moved upward as a load increased, but the neutral axis moved downward, when the load exceeded a certain level of load.

• Journal of architectural history
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• v.7 no.4 s.17
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• pp.61-75
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• 1998

The Unite d'Habitation at Marseilles was an experimental project that Le Corbusier had been waiting for since 1920s in order to explore his ideals and visions in mass housing and city planning. As a leader of the first generation members in CIAM, Le Corbusier tried to give a new form and an order to the Unite d'Habitation at Marseilles in both building design and city planning level. The purpose of this research is to investigate the design characteristics of the Unite d'Habitation at Marseilles in three different levels of built environment with a particular emphasis on the process through which an original form is derived from its contextual settings. In the level of city planning, Le Corbusier aimed to reshape traditional low-rise urban housing by deploying several Unites spaciously. Le Corbusier believed that the spacious deployment of Unites would bring us both the functional economy in the city and the natural amenity in the suburbs. As Unite d'Habitation would be called frequently as vertical garden city, the influence of suburban garden city on Unite d'Habitation is apparent. In the building level, the binomial harmony of individual-collectivity was pursued by providing three different public floors and by combining 23 different family unit types in the Unite d'Habitation at Marseilles. In order to visualize the concept of object-type, family units were prefabricated and inserted into the structural frame of the Unite d'Habitation at Marseilles. Two family units are combined to make a three-story section with street corridor in the middle. This three-story section unit is very original as it has access corridor every third floor and each unit could have considerable depth with the help of the living space of two story height. In consideration of formal and plan similarity as well as contextual edivdence, it is concluded that the three-story section of the Unite d'Habitation is derived more from Narkomfin Apartments than from the monastery at Ema or Immuble Villas.