• 국제초고층학회논문집
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• 제9권1호
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• pp.53-60
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• 2020

"A practical architect might not unnaturally conceive the idea of erecting a vast edifice whose frame should be entirely of iron, and clothing the frame--preserving it--by means of a casing of stone…that shell must be regarded only as an envelope, having no function other than supporting itself..." --Viollet-le-Duc, 1868. Viollet-le-Duc's recipe for an encased iron frame foresaw the separation of structural and enclosing functions into discrete systems. This separation is an essential characteristic of skyscrapers today, but at the time of his writing cast iron's brittle nature meant that iron frames could not, on their own, resist lateral forces in tall structures. Instead, tall buildings had to be braced with masonry shear walls, which often also served as environmental enclosure. The commercial availability of steel after the 1880s allowed for self-braced metal frames while parallel advances in glass and terra cotta allowed exterior walls to achieve vanishingly thin proportions. Two Chicago buildings by D.H. Burnham & Co. were the first to match a frame "entirely of iron" with an "envelope" supporting only itself. The Reliance Building (1895) was the first of these, but the Fisher Building (1896) more fully exploited this new constructive typology, eschewing brick entirely, to become the first "building without walls," a break with millennia of tall construction reliant upon masonry

• 국제초고층학회논문집
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• 제2권2호
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• pp.123-130
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• 2013

In the past two decades, researchers from different countries have conducted series of experimental and theoretical studies to investigate the behaviour of structures in fire. Many new insights, data and calculation methods have been reported, which form the basis for modern interdisciplinary structural fire engineering. Some of those methods are now adopted in quantitative performance-based codes and have been migrated into practice. Mainly based on the achievements in structural fire research at China, the Chinese national code for fire safety of steel structures in buildings has been drafted and approved, and will be released in this year. The code is developed to prevent steel structures subjected to fire from collapsing, ensure safe evacuation of building occupants, and reduce the cost for repairing the damages of the structure caused by fire. This paper presents the main contents of the code, which includes the fire duration requirements of structural components, fundamental requirements on fire safety design of steel components, temperature increasing of atmosphere and structural components in fire, loading effect and capacity of various components in fire, and procedure for fire-resistant check and design of steel components. The analytical approaches employed in the code and their validation works are also presented.

• 한국식생활문화학회지
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• 제8권2호
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• pp.103-116
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• 1993

The purpose of this study was to assess the nutrition education and training needs as a basis for program planning for day care children. Nutrition achievement test developed by American National Dairy Council and Iowa state University was modified and used for measuring the level of basic knowledge of food and nutrition for day care children. The results of this study can be summarized as follows 1. Over 70% of mothers indicated their children had a certain degree of food behavior and feeding problems in terms of unbalanced food habit, irregular meal period. 2. Mean score for the nutrition achievement test for day care children was 9.3. 3. The nutrition achievement test score for children with high socio-economic status was significantly higher than those of children with middle and lower group. 4. Inspection of the difficulty difference indices showed that over the 50% of the children had more items that were easier in the content of physiological facts than in the food handling and social psychological aspects of foods.

• 한국재난정보학회 논문집
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• 제10권2호
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• pp.192-198
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• 2014

최근 세월호 침몰사고 등 대규모재난이 끊이지 않고 발생하고 있는 실정이며, 재난현장에서 피해를 감소시키기 위해 대응기관 간 신속한 정보의 전달, 공유는 피해의 규모를 결정하는 중요한 요소 중의 하나이다. 그러나 긴급하게 대응활동을 실시해야 하는 재난현장에서 재난대응기관 간 적절한 통신이 이루어지지 못하는 상황이 지속적으로 발생하고 있다. 이에 본 연구는 위기관리체계 확립을 위해 각 기관 간 통신방법, 무선망 등의 운영 실태에 대하여 주목을 하였고, 각 기관의 현황, 업무의 내용파악 등을 통하여 효율적이고 효과적인 통신망 구축방안을 제시하였다.

• 국제초고층학회논문집
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• 제8권3호
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• pp.211-220
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• 2019

Three cases of supertall connected structures are presented and each of them represents a quite style. The first case is a strong-connected structure. The coupling function of towers and connector contributes a lot to the structural stiffness and stability. Its special construction scheme had great impact on the construction quality and the structural safety, and must be accurately considered. For the second case which is a weak-connected structure, the influences of different connecting modes to the structural dynamic characteristic were explained. Then the combined bearings were proposed to achieve the design presume. In the third case which represents the multi-supported structures, the structural distinctive mechanical properties were discussed. For the structural state during construction process is quite different from that in final service condition, two construction procedures were simulated to get an optimal one. Although there are great challenges to designers, the advantages of the supertall connected buildings are obvious. Further work is needed in this area to adapt to the development of future cities.

• 국제초고층학회논문집
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• 제8권4호
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• pp.255-264
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• 2019

This paper describes large eddy simulation of wind pressures on a square cylinder in a uniform flow and a high-rise building immersed in an atmospheric turbulent boundary layer. For the atmospheric boundary layer case, the inflow turbulence is generated by a numerical wind tunnel. In the numerical simulation, particular attention is devoted to the performance of an auto hexahedral non-structural mesh. Both simulations are performed for three grid systems: an auto hexahedral non-structured grid, a structured Cartesian grid and a non-structured triangular prism grid, and for three grid numbers. The present study shows that the auto hexahedral unstructured mesh achieves the best simulation results for wind pressures on the square cylinder and the high-rise building. When the grid number is sufficiently large, the differences among the results obtained from the three investigated grid systems are not significant. However, the advantage of the auto hexahedral unstructured mesh becomes clear when the grid number decreases, because it enables a balanced distribution of orthogonal grids. The results described in this paper demonstrate that the auto hexahedral non-structured mesh has good potential applicability to simulation of urban flows.

• 국제초고층학회논문집
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• 제7권4호
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• pp.287-298
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• 2018

High strength steels have been widely applied in recent years due to high strength and good working performance. When subjected to fire conditions, the strength and elastic modulus of high strength steels deteriorate significantly and hence the load bearing capacity of structures reduces at elevated temperatures. The reduction factors of mechanical properties of high strength steels are quite different from mild steels. Therefore, the fire design methods deduced from mild steel structures are not applicable to high strength steel structures. In recent ten years, the first author of this paper has carried out a lot of fundamental research on fire behavior of high strength steels and structures. Summary of these research is presented in this paper, including mechanical properties of high strength steels at elevated temperature and after fire exposure, creep response of high strength steels at elevated temperature, residual stresses of welded high strength steel member after fire exposure, fire resistance of high strength steel columns, fire resistance of high strength steel beams, local buckling of high strength steel members, and residual strength of high strength steel columns after fire exposure. The results show that the mechanical properties of high strength steel in fire condition and the corresponding fire resistance of high strength steel structures are different from those of mild steel and structures, and the fire design methods recommended in current design codes are not applicable to high strength steel structures.

• 국제초고층학회논문집
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• 제7권4호
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• pp.313-325
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• 2018

Concrete-filled steel tubular (CFST) members are commonly used as composite columns in modern construction. However, the current guidelines for members' fire design (EN1994-1-2) have been proved to be unsafe in case the relative slenderness is higher than 0.5. In addition, the simplified design methods of Eurocode 4 are limited to circular and square CFST columns, while in practice columns with rectangular and elliptical hollow sections are being increasingly used because of their architectural aesthetics. In the last years a large experimental research has been carried out at Coimbra University on the topic. They have been tested concrete filled circular, square, rectangular and elliptical hollow columns with restrained thermal elongation. Some parameters such as the slenderness, the type of cross-section geometry as well as the axial and rotational restraint of the surrounding structure to the column have been tested in order to evaluate their influence on the fire resistance of such columns. In this paper it is evaluated the influence of the boundary conditions (pin-ended and semi-rigid end-support conditions) on the behavior of the columns in case of fire. In these tests it could not be seen a marked effect of the tested boundary conditions but it is believed that the increasing of rotational stiffness increases the fire resistance of the columns.

• International Journal of Computer Science & Network Security
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• 제22권2호
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• pp.394-398
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• 2022

The article determines that the study of the development of scientific and didactic knowledge about the educational process in higher education should be built mainly on the basis of qualitative research methods that ensure the identification and understanding of the changes taking place in didactic knowledge, in the unity of their internal and external manifestations. On the basis of the epistemological model of the study of science, a generalized model of didactic knowledge about the educational process in higher education, including didactic relations as a theoretical core, subject of research, research methods and positions of researchers, ways of interaction between science and educational practice, and thematic structures of didactic knowledge; scientific and methodological problems of didactic knowledge about the educational process in higher education at the present stage of its developments due to the post-nonclassical transformation and orientation of research towards the humanitarian ideal of scientific character.

• Wind and Structures
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• 제37권2호
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• pp.133-151
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• 2023

This paper first provides a wide overview about the design codes and standards covering the use of Computational Wind Engineering / Computational Fluid Dynamics (CWE/CFD) for wind-sensitive structures and built environment. Second, the paper sets out the basic assumptions and underlying concepts of the new Annex T "Simulations by Computational Fluid Dynamics (CFD/CWE)" of the revised version "Guide for the assessment of wind actions and effects on structures" issued by the Advisory Committee on Technical Recommendations for Constructions of the Italian National Research Council in February 2019 and drafted by the members of the Special Interest Group on Computational Wind Engineering of the Italian Association for Wind Engineering (ANIV-CWE). The same group is currently advising UNI CT021/SC1 in supporting the drafting of the new Annex K - "Derivation of design parameters from wind tunnel tests and numerical simulations" of the revised Eurocode 1: Actions on structures - Part 1-4: General actions - Wind actions. Finally, the paper outlines the subjects most open to development at the technical and applicative level.