• Journal of the Korea institute for structural maintenance and inspection
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• v.14 no.2
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• pp.67-74
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• 2010

A variation of temperature acting on a RC roof slab causes a change of stress in concrete since it expands during summer and is compressed during winter. This behavior repeats annually and makes an affection to the structural capacity of member for both serviceability and ultimate level. In this paper, a cyclic temperature loading variation is calculated by analyzing the weather data of Korea for 20 years. In addition, an experimental work is planned to find the long term effect of temperature variation. Six RC slab are made with same dimension. Test parameters are loading duration (10, 20, 30 year) and whether it has pre-damage or not. Observation of stiffness variations according to cyclic loading period shows that the serious stiffness drop happens after 10 year's cyclic loading at summer while after 30 year's loading at winter. From the fracture test about slabs damaged by long term cyclic loading, however, the capacity of member such as initial stiffness and maximum strength were not changed except yield strength according to the period of long term cyclic loading. The yield strength tends to decrease after 20 year's cyclic loading.

• Korean Journal of Heritage: History & Science
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• v.43 no.4
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• pp.24-55
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• 2010

Jangmyeongdeung Lantern (貞陵長明燈) refers to the stone lantern placed in front of the royal tomb. It serves both symbolic and decorative purposes; symbolic because it is supposed to guard and illuminate the buried, and decorative because it is a work of sculpture that adorns the entire graveyard. The Jangmyeongdeung of Jeongneung was the earliest stone lantern to be produced during the Joseon period. Its square shape is unique among those from the early to mid-Joseon period. The three major parts of Jangmyeongdeung - the stand, the lantern, and the roof-shaped cover parts - are square in shape, differing from the octagonal shaped Jangmyeongdeung. The stand consists of three single stone blocks, the Hadaeseok(下臺石), Ganjuseok(竿柱石), and Sangdaeseok(上臺石). The Hwasaseok(火舍石), or the lantern part, is also a single stone block. Jangmyeongdeung of Jeongneung succeeds the style of those of Hyeon-neung and Jeongneung(玄正陵) of the Goryeo period and is of a better artistic quality. As the first Jangmyeongdeung lantern, it is a refined work of art that marks the foundation of the Joseon Kingdom. This paper tries to ascertain the stylistic origin of the square-shaped Jangmyeongdeung of Jeongneung and compare it with those of Buddhist temples. Consequently, similarities were found among the stone lanterns of Zen priests 'Jigong'(指空) and 'Nawong'(懶翁) in the Hweamsa Temple(檜巖寺) site from the late Goryeo period, those of Zen priest 'Muhak'(無學) of the Hweamsa Temple site, and those of national priest 'Bogak'(普覺) of Cheongnyongsa Temple(靑龍寺) from the early Joseon period. Primarily, this is because the three components(the stand, the lantern part, and the roof-shaped cover) are essentially square-shaped. Second, as the Ganjuseok(one of the components of the stand) became shorter, the stand took a more stable form. Third, the Hwasaseok(the lantern part) consists of two stone blocks joined together. Fourth, the roof-shaped cover is also in square in shape. Similarly, the Jangmyeongdeung of Jeongneung contains Buddhist elements as well. The three-bead pattern that decorates the Ganjuseok stand is an example. The three-bead pattern is one of the symbolic elements related to Tantric Buddhism. It is found on the diadems worn by Bodhisattvas from the Goryeo and early Joseon periods. The Jangmyeongdeung of Jeongneung in early Joseon directly influenced the production of the square-shaped stone lanterns used to decorate the tombs during the Joseon period. After the latter half of the 15th century, however, the octagonal-shaped Jangmyeongdeung style began to prevail. The Jangmyeongdeung of Jeongneung reflects the succession of the tradition of royal tombs from Goryeo to Joseon, the introduction of square-shaped stone lanterns to Buddhist temples, and the influence of the Buddhist philosophy of the time. It is a living testimony to various elements of each time and corresponding cultural trends.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.2439-2449
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• 2011

Existing grade crossings between railway and roadway area gradually changed to grade separation systems by the law. In the case of new roadway construction which crosses railways, it shall be grade separation system in principle. With the railway underground crossing method, many practices have been developed which can minimize rail displacements and avoid rail release. With these methods, the effects to the train can be reduced. The underground crossing methods can be identified as open-cut methods and non open-cut methods. The open-cut methods include temporary support methods and special rail construction methods. Also the non open-cut methods includes pipe roof methods, front jacking methods, messer shield methods, NTR methods and JES methods. Among these, the most suitable method is applied considering safety, economy, class of each rail system (train passing frequency and velocity), etc. In the non open-cut methods, the cost and duration shall be increased to keep existing rail system during construction. In the open-cut methods which use plate girders, the rail speed shall be restricted due to the displacement and vibration of the girder. In this study new grade separation methods were developed. With this method, the safety during construction can be increased. This method refines temporary support methods, but pc slab girder with huge stiffness is applied instead of plate girders. With this method, the rail displacement can be reduced and higher safety can be obtained during construction. Also construction cost and duration can be minimized because the temporary work and the overburden soil depth can be reduced.

• Earthquakes and Structures
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• v.5 no.4
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• pp.439-459
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• 2013

Main objective of the present study is to determine the statistical properties and suitable probability distribution functions of spectral displacements from nonlinear static and nonlinear dynamic analysis within the frame work of Monte Carlo simulation for typical low rise and high rise RC framed buildings located in zone III and zone V and designed as per Indian seismic codes. Probabilistic analysis of spectral displacement is useful for strength assessment and loss estimation. To the author's knowledge, no study is reported in literature on comparison of spectral displacement including the uncertainties in capacity and demand in Indian context. In the present study, uncertainties in capacity of the building is modeled by choosing cross sectional dimensions of beams and columns, density and compressive strength of concrete, yield strength and elastic modulus of steel and, live load as random variables. Uncertainty in demand is modeled by choosing peak ground acceleration (PGA) as a random variable. Nonlinear static analysis (NSA) and nonlinear dynamic analysis (NDA) are carried out for typical low rise and high rise reinforced concrete framed buildings using IDARC 2D computer program with the random sample input parameters. Statistical properties are obtained for spectral displacements corresponding to performance point from NSA and maximum absolute roof displacement from NDA and suitable probability distribution functions viz., normal, Weibull, lognormal are examined for goodness-of-fit. From the hypothesis test for goodness-of-fit, lognormal function is found to be suitable to represent the statistical variation of spectral displacement obtained from NSA and NDA.

• Structural Engineering and Mechanics
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• v.49 no.2
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• pp.237-259
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• 2014

Wind-induced failure around screwed connections has been documented in roof and wall cladding systems made with steel sheet cold-formed panels during high wind events. Previous research has found that low cycle fatigue caused by stress concentration and fluctuating wind loads is responsible for most such failures. A dynamic load protocol was employed in this work to represent fatigue under wind effects. A finite element model and fatigue criteria were implemented and compared with laboratory experiments in order to predict the fatigue failure associated with fluctuating wind loads. Results are used to develop an analytical model which can be employed for the fatigue analysis of steel cold-formed cladding systems. Existing three dimensional fatigue criteria are implemented and correlated with fatigue damage observed on steel claddings. Parametric studies are used to formulate suitable yet simple fatigue criteria. Fatigue failure is predicted in different configurations of loads, types of connections, and thicknesses of steel folded plate cladding. The analytical model, which correlated with experimental results reported in a companion paper, was validated for the fatigue life prediction and failure mechanism of different connection types and thicknesses of cold-formed steel cladding.

• Wind and Structures
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• v.8 no.3
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• pp.213-233
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• 2005

Wind uplift rating of roofing systems is based on standardized test methods. Roof specimens are placed in an apparatus with a specified table size (length and width) then subjected to the required wind load cycle. Currently, there is no consensus on the table size to be used by these testing protocols in spite of the fact that the table size plays a significant role in wind uplift performance. Part I of this paper presented a study with the objective to investigate the impact of table size on the performance of roofing systems. To achieve this purpose, extensive numerical experiments using the finite element method have been conducted and benchmarked with results obtained from the experimental work. The present contribution is a continuation of the previous research and can be divided into two parts: (1) Undertake additional numerical simulations for wider membranes that were not addressed in the previous works. Due to the advancement in membrane technology, wider membranes are now available in the market and are used in commercial roofing practice as it reduces installation cost and (2) Formulate a logical step to combine and generalize over 400 numerical tests and experiments on various roofing configurations and develop correction factors such that it can be of practical use to determine the wind uplift resistance of roofs.

• Advances in Energy Research
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• v.4 no.1
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• pp.1-28
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• 2016

A grid-connected photovoltaic (PV) system comprised of multicrystalline silicon (mc-Si) modules was installed in a cold climate region in the U.S. This roof-mounted stationary PV system is a real-world application of PV for building energy generation in International Energy Conservation Code (IECC) Climate Zone 5 (and possibly similar climate zones such as 6, 7 and 8), and it served the purposes of research, demonstration, and education. The importance of this work is highlighted by the fact that there has been less emphasis on solar PV system in this region of the U.S. because of climate and latitude challenges. The system is equipped with an extensive data acquisition system capable of collecting performance and meteorological data while visually displaying real-time and historical data through an interactive online interface. Experimental data was collected and analyzed for the system over a one-year period with the focus of the study being on measurements of power production, energy generation, and efficiency. The annual average daily solar insolation incident upon the array was found to be $4.37kWh/m^2$. During the first year of operation, the PV system provided 5,801 kWh (1,264 kWh/kWp) of usable AC electrical energy, and it was found to operate at an annual average conversion efficiency and PR of 10.6 percent and 0.79, respectively. The annual average DC to AC conversion efficiency of the inverter was found to be 94 percent.

• Journal of architectural history
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• v.21 no.6
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• pp.35-44
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• 2012

This paper aimed at investigating into the origin and meaning of the Japanese architect Terunobu Fujimori's 'piercing column', and drew a conclusion as follows. First, the piercing column that made its first appearance in his architect debut work Jinchokan Moriya Historical Museum (1991) was conceived unexpectedly from pencil lines on a sketch that went through over the building's roof. And the tree-like natural treatment of the column's surface was influenced by Takamasa Yoshizaka's description of a Mongolian mud-house. Second, most of piercing columns in his later works have nothing to do with a structural role as in Jinchokan, but were designed for a visual effect and as a symbolic gesture. Again, they allude to a tree in nature through a roughly peeling treatment of the surface. Third, considering his ideas in History of Humankind and Architecture (2005), his column could be related to a universal origin of architecture and a symbol of the sun-god faith, and in particular to independent columns of Japanese Shito shrines, such as 'Onbashira' in Suwa and 'Iwanebashira' in Izumo. That is to say, the Fujimori column is a medium that implies the animistic nature-faith of Japan. Nevertheless, Fujimori's naturalism hints at a disquieting quality through an intentional artificiality and a provocative conflict between structure and finish of a building, which might be one aspect of the modern condition, 'uncanny'.

• Safety and Health at Work
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• v.3 no.3
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• pp.235-240
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• 2012

The objectives are to compare the airborne asbestos concentrations resulted from mitering of abestos cement roof sheets by a high-speed motor and a hand saw, and to monitor whether other workers near the test sites are vulnerable to the fibers exceeding the occupational exposure limit. Four test cases were carried out and altogether 7 personal and 4 area air samples were collected. The NIOSH method 7400 was employed for the air samplings and analysis. Using the phase contrast microscopy, fiber counting was conducted under Rule A. The study showed that the fiber concentration medians for personal air samples gathered from the two tools were 4.11 fibers/cc (ranged: 1.33-12.41 fibers/cc) and 0.13 fibers/cc (ranged: 0.01-5.00 fibers/cc) respectively. The median for the area samples was 0.59 fibers/cc (ranged: 0.14-3.32 fibers/cc). Comparing each study case, the concentration level caused by the high-speed motor saw was more than twice that of the hand saw. According to the area samples, the workers nearby the test site are at risk from high exposure to asbestos.

• Architectural research
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• v.15 no.2
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• pp.95-102
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• 2013

The study establishes the analytical frame composed of 22 items according to the category of passageway, shop, entrance and amenity for the purpose of executing the empirical investigation of the Underground Public Pedestrian Facilities in Daegu Metropolitan City of Korea. As a result of the research work, the study finds out some problems about the facilities as follows: (1) Passageway elements - the skylight was constructed only in one place. In contrast, the standards of passageway and plaza were well-fulfilled except for one or two cases. (2) Shop elements - the cases of installing shops where they should not be located were found the most, and a case of over-establishing the shop area was found as well. (3) Entrance elements - the cases not matching roof or canopy standard over entrance facilities were found the most. Overall, the entrances and their connection to the adjacent buildings are appraised as not well-established. (4) Amenity elements - these were appraised as insufficient in all except two cases. Regarding this, not only necessary are the establishment of facilities and the effort of facility managers, but also urgent is the institutional improvement.