• International Journal of Air-Conditioning and Refrigeration
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• 제11권1호
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• pp.40-49
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• 2003

Dynamic characteristics of water hammer arresters installed in a building water supply system have been investigated numerically by utilizing a commercial code that employs the method of characteristics. Some preliminary results with those arrester models produced in this study agree well with the previously reported. Then, the arrester models have been incorporated into a water supply pipe system of a 59 $m^2$apartment unit constructed by a leading construction company, and their dynamic characteristics have been investigated, especially on the reduction in the water hammer pressure. It is found that the setting of the arresters in the pipe system, which is recommended by the company, may not be proper for reducing the pressure down below 1,082.0 kPa (10.0 kg$g_f$/$cm^2$) when quick-closure valves in the pipe system are closed within 30 ms at the static pressure of 542.6 kPa (4.5 kg$g_f$/$cm^2$). More arresters in the system may be required to meet pressure criteria stated on the related standards and codes.

• Earthquakes and Structures
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• 제10권4호
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• pp.735-755
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• 2016

This article presents a proposed analytical methodology to determine seismic force-resisting system R-values for steel diagrid framed systems. As current model building codes do not explicitly address the seismic design performance factors for this new and emerging structural system, the purpose of this study is to provide a sound and reliable basis for defining such seismic design parameters. An approach and methodology for the reliable determination of seismic performance factors for use in the design of steel diagrid framed structural systems is proposed. The recommended methodology is based on current state-of-the-art and state-of-the practice methods including structural nonlinear dynamic analysis techniques, testing data requirements, building code design procedures and earthquake ground motion characterization. In determining appropriate seismic performance factors (R, ${\Omega}_O$, $C_d$) for new archetypical building structural systems, the methodology defines acceptably low values of probability against collapse under maximum considered earthquake ground shaking.

• Earthquakes and Structures
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• 제20권3호
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• pp.239-260
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• 2021

Torsional response of buildings is attributed to poor structural configurations in plan, which arises due to two factors - torsional eccentricity and torsional flexibility. Usually, building codes address effects due to the former. This study examines both of these effects. Buildings with torsional eccentricity (e.g., those with large eccentricity) and with torsional flexibility (those with torsional mode as a fundamental mode) demand large deformations of vertical elements resisting lateral loads, especially those along the building perimeter in plan. Lateral-torsional responses are studied of unsymmetrical buildings through elastic and inelastic analyses using idealised single-storey building models (with two degrees of freedom). Displacement demands on vertical elements distributed in plan are non-uniform and sensitive to characteristics of both structure and earthquake ground motion. Limits are proposed to mitigate lateral-torsional effects, which guides in proportioning vertical elements and restricts amplification of lateral displacement in them and to avoid torsional mode as the first mode. Nonlinear static and dynamic analyses of multi-storey buildings are used to validate the limits proposed.

• 한국위성정보통신학회논문지
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• 제11권2호
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• pp.69-73
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• 2016

In order to derive reliable propagation models for future millimeter-wave frequency indoor pico-cellular communications systems, accurate reflectivity data of building materials is necessary. The broad variety of building materials and construction codes makes accurate attenuation prediction very difficult without the support of specific construction data or measurements. This paper derives a transmission and reflection coefficient based on 13 GHz to 28 GHz measurement data. Transmission and reflection is measured by applying change in the reception angle of each building material, such as plasterboard. The transmission and reflection coefficient derived shows a correlation between frequency dependence and angle. As a result, as the reception angle is reduced, the reflected angle from the transmitter that could be received increases, showing that there is a correlation. In addition, the fundamental investigations carried out lay the foundation for radio channel-related research, which is essential for the development of future millimeter-wave communications systems.

• 설비공학논문집
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• 제26권1호
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• pp.38-41
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• 2014

Fixture units and the diversity curve are used, in order to determine the required size of water supply pipe. However, the values of the National Plumbing Code, International Plumbing Code and National Standard Plumbing Code of America are not the same. The objective of this study is to comparatively analyze the fixture units and the peak flows of a 10th story office building, at any instant of time, according to the three codes.

• Journal of Construction Engineering and Project Management
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• 제4권4호
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• pp.1-8
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• 2014

The broad aim of this paper is to provide a detailed understanding of the post-war problems associated with materials for reconstruction in Libya, and to identify key problems and obstructions. Theoretical and empirical studies are being conducted in Libya. The theoretical study focuses on materials for construction and the key issues such as sources, transport and storage of materials, as well as their impact on the national economy, the nation's socio-economic development and the environment. This empirical study employed questionnaires, observations and a series of interviews with researchers, academics, suppliers and manufacturers, supported by the researcher's three decades of experience of working in the construction industry and its associated processes and operations. The empirical study illustrated that materials for post-disaster reconstruction in Libya suffer from external problems related to policies and decision-making in terms of availability of materials, fluctuation of prices of materials, specifications, building codes, legislation and regulations, and internal problems related to the construction and building material's key players: construction companies, consultancy firms, manufacturers and suppliers.

• Architectural research
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• 제22권4호
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• pp.105-112
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• 2020

The purpose of this study is to establish a method for assessing a building's risk against disaster, tentatively named the Korean integrated disaster evaluation simulator (K-IDES). Based on previous studies, FEMA's risk management series and FEMA IRVS are selected as case studies for developing a frame work of K-IDES, through the comparative analysis of domestic building design guides, codes, and special acts related to disasters, in order to develop a risk assessment methodology for quantitative results. The assessment method consists of a classification system and calculating risk, and a simulation applying the developed checklist in K-IDES to similar types of high-rise buildings will be conducted to validate its accuracy. The final goal is to systemize an integrated risk management in a high-rise building against disasters for the purpose of recognizing vulnerable areas from the beginning of the design process and reinforcing it from potential threats after construction.

• 한국화재소방학회:학술대회논문집
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• 한국화재소방학회 1997년도 International Symposium on Fire Science and Technology
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• pp.227-243
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• 1997

Fire and smoke can from a small ignition source develop rapidly. Active systems in combination with Passive Fire Protection measures will offer highest safety standards to the building's developers and occupants. Nevertheless, the fire growth is very unpredictable and it is therefore essential at the planning stage that tested solutions are well selected according to National codes and later on installed by qualified contractors to ensure optimum performance. This demonstrates that Passive Fire Protection as safety measure cannot be neglected. Recent fire cases all over the world still proof that fire can develop any time and any where even in countries of high safety standards.

• Structural Engineering and Mechanics
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• 제83권1호
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• pp.1-17
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• 2022

The static design approach in the current code implies that the inherent torsional moment represents the state of zero inertial torsional moments at the center of mass (CM). However, both experimental and analytical results prove the existence of a large amount of the inertial torsional moment at the CM. Also, the definition of eccentricity by engineers, which is referred to as the resistance eccentricity, is defined as the distance between the center of mass and the center of resistance, which is conceptually different from the static eccentricity in the current codes, defined as the arm length about the center of rotation. The difference in the definitions of eccentricity should be made clear to avoid confusion about the torsion design. This study proposed prediction equations as a function of resistance eccentricity based on a resistance eccentricity model with advantages of (1) the recognition of the existence of torsional moment at the CM, (2) the avoidance of the confusion by using resistance eccentricity instead of the design eccentricity, and (3) a clear relationship of applied inertial forces at the CM and resisting forces. These predictions are compared with the seismic responses obtained from time-history analyses of a five-story building structure under moderate and severe earthquakes. Then, the trend of the resistance eccentricity corresponding to the maximum edge drift is investigated for elastic and inelastic responses. The comparison given in this study shows that these prediction equations can serve as a useful reference for the prediction in both the elastic and the inelastic ranges.

• International Journal of Advanced Culture Technology
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• 제9권4호
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• pp.363-375
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• 2021

The purpose of this study is to analyze the safety of evacuation using the Pathfinder program for the alert at once, the priority alarm method, the priority alarm method for the four floors above, and the sequential priority alarm method, which is a modification of the priority alarm method specified in the tourist hotel building. Currently, in Korea's National Fire Safety Codes (NFSC), fire alarm methods are compulsorily applied differently depending on the number of floors and total floor area of a building. Although the growth rate is getting faster due to the diversification of building structures, it is still an obstacle to improving evacuation safety to comply with the standardized fire alarm method in NFSC. As a result of the experiment, the evacuation time was found to be faster with the priority alarm method for the four floors above than the priority alarm method applied to the specific firefighting object. Compared to the priority alarm method applied to the tourist hotel, which is a specific firefighting target with 5 or more floors and a total floor area of more than 3,000m2, the time was shortened by 3.7 seconds when measured by applying the priority alarm method for the four floors directly above. This indicates that it is necessary to take measures to select a fire alarm method suitable for the structure and environmental conditions of the building rather than applying the uniform NFSC regulations.