• Journal of Korean Society of Steel Construction
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• v.22 no.1
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• pp.67-74
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• 2010

The cases of collapse of greenhouses in rural areas have been increasing due to the unexpected heavy snow load. Studies on how to prevent the collapse of greenhouses are rare, however, and the damages are repeated annually. This studysuggests two reinforcing methods: the use of ahigh-strength tapered module, and the addition of a pre-tension tie. The high-strength tapered section is installed where the bending moment is maximum. The design of a plastic greenhouse is controlled by its strength rather than its deflection. The shape of a greenhouse resembles that of an arch system, but its actual structural behavior is the frame behavior, because it is non-continually composed of a curved element (a beam) and vertical elements (columns). This system is too weak and slender to resist a vertical load, because an external load is resisted by the moment rather than by axial force. In this study, a new method, the installation of a temporary tie at the junction of the arch and the column only during snow accumulation, is proposed. The tie changes the action of the greenhouse frame to an arch action. The arch action is more effective when the pre-tension force is applied in the tie, which results in a very strong temporary structural system during snowfall. As a result of using this high-strength tapered section, the combined strength ratio of what? decreased from 10% to 30%. In the case of the additional reinforcement with a tie, it was reduced by half.

• Korean Institute of Interior Design Journal
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• v.24 no.5
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• pp.108-116
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• 2015

This study intends to research the spatial characteristics of Asian interim housing that accommodates sufferers pro tempore after disasters. The scope of this research covers the interim spaces used for housing people after natural disasters that occurred in Asia for the past fifteen years. Within this scope, literature review was conducted as the basis to derive the characteristics and environmental elements of interim housing, which provided the criteria to compare and evaluate cases of interim housing along with characteristic elements required of interim housing found in previous studies. According to literature review, interim housing can be classified by life-span, region, economy, climate, type, number of household, square measure, residential cost, structure/material, and service life. Within the scope of the present research, literature review showed a total of twenty-eight cases of interim housing in fifteen countries revealing a high rate of disaster occurrence in the subtropic and tropic climate of Southeast Asia. A great percentage of interim housing was used for long-term stay of over a year. The structure of interim housing varied from lightweight steel, wooden, masonry, membrane, to traditional structure and the type were divided into temporary shelter, transitional housing, temporary housing, and permanent housing. Followed by literature review, the characteristics required of post-disaster interim housing were analyzed based on previous research and case studies. The characteristics of interim housing can be divided into environmental, technological, and socio-cultural ones. Sub-characterical items according to such division include amenity, health, surroundings, structure, convenience, eco-friendliness, safety, communication, and locality. As a result of evaluation, most items met the required characteristics of interim housing, while technological characteristics such as structure and convenience varied with the types of interim housing and appeared even unnecessary in some cases. According to analysis, amenity is maintained through the structural and material characteristics of interim housing and is also facilitated by increasing number of infrastructure such as educational, sanitary, and convenience facilities provided by the governmental and organizational bodies. It is expected that this study will be utilized as preliminary data for follow-up studies that improve the environment of post-disaster interim housing suitable for domestic circumstances in environmental, technological, and socio-cultural respects.

• Corrosion Science and Technology
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• v.12 no.1
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• pp.27-33
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• 2013

According to its merits about high curing speed and low emission of volatile organic compounds, UV curable inorganic-organic coating technology has been developed as an alternative for toxic and carcinogenic chromate-based treatments for years. It is consistently observed that ultra-thin films offer excellent corrosion protection as well as paint adhesion to metals. Based on the tetra-ethylorthosilicate(TEOS) and methacryloxypropyl trimethoxysilane(MPTMS), inorganic sol was synthesized and formed hybrid networks with UV curable acrylic monomer, 6-hexanediol diacrylate(HDDA), trimethylolpropane triacrylate(TMPTA), pentaerylthritol triacrylate(PETA). Several methods were used to test their properties such as salt spray test, potentiodynamic measurement, tape peel test, etc. It was shown that anti-corrosive property and stability of storage were affected by the molecular ratios of inorganic and organic compounds. It was not only the stability of storage, but had a excellent anti-corrosive, paint adhesive, and anti-solvent properties in a final molar ratios of 0.6/0.04/0.86/0.005 (TEOS/MPTMS/Acetone/HNO3) and 0.08/0.106/0.081/0.02 (TMPTA/HDDA/PETA/photo initiator).

• Journal of Korean Society of Steel Construction
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• v.27 no.4
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• pp.371-376
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• 2015

This study was conducted for the torsional behavior of catwalk system which is a temporary structure on a suspension bridge. The torsional deformation of the catwalk structure has a significant effect on the workability and safety of workers during main cable erection. For this reason, the torsional deformation of catwalk is controlled to be acceptable levels below by adjusting the cross bridge interval in design stage. This study analyzed the effect of separation between cross bridge associated with twist safety of catwalk system. For the analytical approach, a detailed analysis model was created including cross bridge. Both wind load within the wind velocity range that allows the construction and eccentric load of Prefabricated Parallel Wire Strand were analyzed by analysis model. Result of study shows that separation between cross bridges has a significant effect on the torsional behavior of the catwalk.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.19 no.2
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• pp.84-92
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• 2023

As temporary storage facilities for spent nuclear fuels in domestic nuclear power plants are expected to be saturated, external intermediate storage facilities would be required in the future. Spent nuclear fuels are stored in metal canisters and then placed in a dry environment within concrete or metal casing for operation. In the United States, the dry storage method for spent nuclear fuels has been operated for an extended period. Based on the corrosion experiences of dry storage canisters in chloride environments, numerous studies have been conducted to reduce corrosion in welds. With the construction of intermediate storage facilities in Korea for spent nuclear fuels expected near coastal areas adjacent to nuclear power plants, there is a need for research on the corrosion occurrence of welds and mitigation methods for canisters in chloride environments. In this paper, we measured and compared the residual stresses in the Heat-Affected Zones (HAZ) after electron beam welding (EBW) and gas tungsten arc welding (GTAW) processes for candidate materials such as 304L, 316L, and duplex stainless steel(DSS). We investigated the possibility of microstructure control through the application of surface modification processes using friction stir processing (FSP). Corrosion tests on each welded specimen revealed a higher corrosion rate in EBW welds compared to GTAW. Furthermore, it was confirmed that corrosion resistance improved due to phase refinement and redistribution of precipitates when FSP was applied.

• Journal of the Korean Society of Safety
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• v.23 no.4
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• pp.67-71
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• 2008

Formwork is a temporary structure that supports its weight and that of fresh concrete as well as construction live loads. Slab formwork consists of sheathing, stringer, hanger and shore. In construction site, pipe supports are usually used as shores which are consisted of the slab formwork. In this study, compressive strength of 80 pipe supports was measured by knife edge test and plate test. Buckling load of pipe supports was analyzed by structural analysis program(MlDAS). Theoretical buckling load with/without initial deformation was got by theoretical analysis. According to these results, buckling load which was analyzed by structural analysis program(MlDAS) was larger than compressive strength of knife edge test and plate test. Theoretical buckling load without initial deformation was larger than compressive strength of knife edge test and plate test. But Theoretical buckling load with initial deformation was lower than compressive strength of knife edge test and plate test. Initial deformation equation for test method according to the pipe support length was suggested. Therefore, the present study results will be used to design the slab formwork safely.

• Structural Engineering and Mechanics
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• v.59 no.6
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• pp.1095-1120
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• 2016

This paper investigates the change of structural characteristics of steel cable-stayed bridges after cable failure. Cables, considered as the intermediate supports of cable-stayed bridges, can break or fail for several reasons, such as fire, direct vehicle clash accident, extreme weather conditions, and fatigue of cable or anchorage. Also, the replacement of cables can cause temporary disconnection. Because of the structural characteristics with various geometric nonlinearities of cable-stayed bridges, cable failure may cause significant change to the structural state and ultimate behavior. Until now, the characteristics of structural behavior after cable failure have rarely been studied. In this study, rational cable failure analysis is suggested to trace the new equilibrium with structural configuration after the cable failure. Also, the sequence of ultimate analysis for the structure that suffers cable failure is suggested, to study the change of ultimate behavior and load carrying capacity under specific live load conditions. Using these analysis methods, the statical behavior after individual cable failure is studied based on the change of structural configuration, and distribution of internal forces. Also, the change of the ultimate behavior and load carrying capacity under specific live load conditions is investigated, using the proposed analysis method. According to the study, significant change of the statical behavior and ultimate capacity occurs although just one cable fails.

• Journal of the Korea Convergence Society
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• v.6 no.6
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• pp.163-169
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• 2015

This study was intended to suggest a new-concept construction method of permanent basement wall combined with earth retaining wall by using PHC piles to overcome the disadvantages of conventional CIP methods or the like which have been used just for earth retaining walls during field construction, and to determine its applicability. PHC piles are characterized by the reliable quality attributed to prefabrication (shop fabrication) as well as superior concrete strength and prestressing steel strength to that of CIP in the aspect of materials, and also higher bending moment than that of CIP in the aspect of structure.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.225-226
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• 2009

Day by day, concrete buildings and structure became high-rising and magnificently vast scheduled, as contributed from the development of improved equipments that suitable to specific construction works and high qualitied Material, the durability of the concrete was highly improved. The temporary elastic reduction occur at vertical members such as walls and columns under vertical loads. Specially, inelastic reduction such as creep and shrinkage occur long termly with elastic one in case of reinforced concrete members. Generally, creep and shrinkage depend on time and this is affected by concrete strength, concrete type, member size, steel ratio, and relative humidity. And elastic reduction rely on time, too because concrete is loaded before revelation of perfect strength in terms of construction conditions. So, tests on mechanical properties of concrete certainly need in order to apply to construction by forecasting an amount of reduction caused by the complex factors. Therefore, in this study the tests on creep, shrinkage are carried out to offer basic data for predicting an amount of long-term Properties at the concrete columns of an object structure, and results of the tests are described.

• Journal of the Korean Society of Safety
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• v.32 no.5
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• pp.96-102
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• 2017

The highest fatal accident ratio was recorded in the construction industry. According to the industrial insurance premium rate & business type example, among the construction industry, the architectural work has the highest fatal and loss time accident ratio. Previous literature has investigated various aspects of accident occurrence and prevention in architectural work. However, those studied were limited in that they only focused on the fatal accident without considering the loss time accident. But non fatal accidents were recorded more than 50 times of fatal accidents. Therefore non fatal accidents must be controlled to lessen industrial accidents. Based on this, the goal of this study was to investigate the nature of the loss time accident and derive the risk index of work type in architectural work. In this study, opinions of safety experts were gathered and the risk index of work type was derived using AHP(Analytic Hierarchy Process). And verification was accomplished by comparing the results of this study with the risk index derived by analysis of accident records. Results showed that the risk index of work type was significantly higher in steel frame work, temporary installation work, earth & foundation work, facilities work, concrete work. And statistical analysis for verification showed that coefficient of Pearson correlation was 0.686 and P-value was 0.001.