• Architectural research
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• v.16 no.2
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• pp.67-74
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• 2014

Free vibration analysis of thin shells is carried out by using isogeometric approach. For this purpose, a thin shell element based on Kirchhoff-Love shell theory is developed. Non-uniform rational B-spline surface (NURBS) definition is introduced to represent the geometry of shell and also used to derive all terms required in the isogeometric element formulation. Gauss integration rule is used for stiffness and mass matrices. The present shell element is then applied to examine vibrational behaviours of thin plate and shell structures. From numerical results, it is found be that reliable natural frequencies and associated mode shapes of thin shell structures can be predicted by the present isogeometric shell element.

• Architectural research
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• v.16 no.3
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• pp.121-129
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• 2014

A plate element is developed by using isogeometric approach in order to determine natural frequencies of laminated composite plates. Reissner-Mindlin (RM) assumptions is adopted to consider the shear deformation and rotatory inertia effect. All terms required in isogeometric element formulation are consistently derived by using Non-uniform rational B-spline surface (NURBS) definition. Gauss quadrature rule is used to form the element stiffness matrix and separately Lobatto quadrature rule is used to calculate element mass matrix. The capability of the present plate element is demonstrated by using numerical examples. From numerical tests, the present isogeometric element produces reliable numerical results for both thin and thick plate situations.

• Architectural research
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• v.18 no.2
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• pp.65-74
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• 2016

Free vibration analysis of plates and shells is carried out by using isogeometric approach. For this purpose, an isogeometric shell element based on Reissner-Mindlin (RM) shell theory is developed. Non-uniform rational B-spline surface (NURBS) definition is introduced to represent the geometry of shell and it is also used to derive all terms required in the isogeometric element formulation. New anchor positions are proposed to calculate the shell normal vector. Gauss integration rule is used for the formation of stiffness and mass matrices. The proposed shell element is then used to examine vibrational behaviours of plate and shell structures. From numerical results, it is found to be that reliable natural frequencies and associated mode shapes can be predicted by the present isogeometric RM shell element.

• Computers and Concrete
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• v.18 no.6
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• pp.1213-1234
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• 2016

This paper describes a deformation-based strut-and-tie model for the flexural members at post-yield state. Boundary deformation conditions by flexural post-yield response are chosen in terms of the flexural bar strains as the main factor influenced on the shear strength. The main purpose of the proposed model is to predict the shear capacities of the flexural members associated with the given flexural deformation conditions. To verify the proposed strut-and-tie model, the estimated shear strengths depending on the flexural deformation are compared with the experimental results. The experimental data are in good agreement with the values obtained by the proposed model.

• Journal of Korean Association for Spatial Structures
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• v.18 no.3
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• pp.117-124
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• 2018

In the post-tensioned concrete member, additional reinforcement is required to prevent failure in the anchorage zone. In this study, the details of reinforcement suitable for the anchorage zone of the post-tensioned concrete member using circular anchorage was proposed based on the experimental results. The tests were conducted with the compressive strength of concrete and reinforcement types as variables. The experimental results indicated that the additional reinforcement for the anchorage zone is required when the compressive strength of concrete is less than 17.5 MPa. U-shaped reinforcement shows most effective performance in terms of maximum strength and cracks patterns.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.8
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• pp.7-17
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• 2015

Changes in melatonin concentration levels by differences in CCT of white LED light focused on Spectral Power Distribution (SPD) differences compared to the same CCT of conventional fluorescent light were analyzed. For this, melatonin concentration levels in saliva samples were taken over four different experiments at seven-day intervals. In 71.4% of participants, it was confirmed that melatonin concentration is suppressed by exposure to light, and a slight difference was observed by different CCTs. In addition, Experiment II with a high CCT was relatively high in terms of the melatonin suppression rate compared to Experiment III. A key finding was the possibility that different SPDs under a particular CCT of white LED light compared to the same CCT of conventional fluorescent light could have the same effect on the melatonin suppression.

• Structural Engineering and Mechanics
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• v.56 no.2
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• pp.293-315
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• 2015

While most of researches on system identification of building structures are aimed at finding modal parameters first and identifying the corresponding physical parameters by using the transformation in terms of transfer functions and cross spectra, etc., direct physical parameter system identification methods have been proposed recently. Due to the problem of signal/noise (SN) ratios, the previous methods are restricted mostly to earthquake records or forced vibration data. In this paper, a theoretical investigation is performed on the influence of wind disturbances on stiffness identification of building structures using micro-tremor at limited floors. It is concluded that the influence of wind disturbances on stiffness identification of building structures using micro-tremor at limited floors is restricted in case of using time-series data for low-rise buildings and does not cause serious problems.

• Journal of the Architectural Institute of Korea Planning & Design
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• v.35 no.2
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• pp.53-62
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• 2019

'Delirious New York(1978)' of Rem Koolhaas is not only a historical book but a double code text writing the history of Manhattan in parallel to surrealism. Throughout this book, the surrealist terminologies such as unconsciousness, desire, paranoid, automatism, cadavre exquis etc, are widely used to explain the urban phenomena and buildings of Manhattan. Among these methods, in the fifth chapter, Paranoid critical method(PCM) invented by Salvador Deli, is explained in detail and adapted to Corbusier's project and other architects of Manhattan. Koolhaas connect PCM to the conceptual transposition and draft in architectural thinking. This thesis is to analyse the terms and methods of surrealism and how these methods are used to explain the urban phenomenon of Manhattan in 'Delirious New York'.

• Journal of the Architectural Institute of Korea Planning & Design
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• v.35 no.10
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• pp.41-52
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• 2019

The purpose of this study was to analyze the historical development of high-rise buildings-promoting policies in Seoul in terms of modern urban redevelopment. The results of this study were as follows; The maximum height of the buildings has been limited by National codes since 1934. But at the same time, Seoul Metropolitan government had limited the minimum building floors of roadside buildings through local regulations after the Korean War. The high-rise city had been regarded as a means of beautifying Seoul for a long time. However since the 2000s, the minimum height limit for buildings was removed from local regulations and the concept of high-rise restrictions was no longer significant as before.

• Journal of the Korea Convergence Society
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• v.13 no.4
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• pp.299-306
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• 2022

In this study, the applications of the architectural design elements in the cultural rehabilitation of idle industrial facilities are categorized to define typology of rehabilitation design method. The design strategies which embodies historicity, symbolism, and sustainability are analysed in terms of structural, material, and resource with preservation, restoration and conversion by precedents study of idle industrial facilities that have been implemented and operated by the government.