• Proceeding of EDISON Challenge
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• 2015.03a
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• pp.251-256
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• 2015

In this paper, an systematic approach is presented, in which the bridge-type traffic sign structure is body out by CSDDA PrePost Processor. There is dead load and wind load that is working on the structure which will make force and moment. Analyzied the stress distribution of the standard form and by changing the shape, compared the safety in terms of deflection and stress (with the standard form) to know the effect of each component in the bridge-type traffic sign structure. The safety of deflection and stress is evaluated by maximum distance/100) and ASIC code respectively. The standard form of bridge-type traffic sign structure is established by two pairs of pillar and two pairs of floor beam. Replaced the links which is consist of flange and screws as the torsion spring and nm our analysis program. By adjusting variable of rigidity modulus of torsion spring, moment between column and beam is controled depending on value of rigidity modulus.

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.475-475
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• 2009

Recent alarming acceleration of global warming has made power generations using renewable energy to be in the middle of the spotlight. Korean government has also announced that it will make the related industry to be nation's one of main export items with high investments to low carbon green growth industry. To achieve this goal of exporting the renewable energy power generation system beyond domestic use, internationally acceptable rules should be applied and the three step processes of design, performance assessment and certification should follow international standards. Corresponding this international requests, IEC(International Electrotechnical Commission) is conducting the establishment of rules in TC88 for technical requirements of wind turbines. Design life-time of a wind turbine is required to be at least 20 years. In the meantime, the wind turbine will experience a lot of load cases such as extreme loads and fatigue loads which will include several typhoons per year and extreme gusts with 50 years recurrence period as well as endless turbulence flow. Therefore, IEC 61400-1 specifies design load cases to be considered in the wind turbine design and requires the wind turbine to withstand the load cases in various operational situations. It thus appears that the examination of contents and decisions discussed in the international standard committee will help people in the field of offshore wind energy and ocean energy converters.

• Wind and Structures
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• v.21 no.5
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• pp.461-487
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• 2015

In recent years, the Graphics Processing Unit (GPU) has become a competitive computing technology in comparison with the standard Central Processing Unit (CPU) technology due to reduced unit cost, energy and computing time. This paper describes the derivation and implementation of GPU-based algorithms for the analysis of wind loading uncertainty on high-rise systems, in line with the research field of probability-based wind engineering. The study begins by presenting an application of the GPU technology to basic linear algebra problems to demonstrate advantages and limitations. Subsequently, Monte-Carlo integration and synthetic generation of wind turbulence are examined. Finally, the GPU architecture is used for the dynamic analysis of three high-rise structural systems under uncertain wind loads. In the first example the fragility analysis of a single degree-of-freedom structure is illustrated. Since fragility analysis employs sampling-based Monte Carlo simulation, it is feasible to distribute the evaluation of different random parameters among different GPU threads and to compute the results in parallel. In the second case the fragility analysis is carried out on a continuum structure, i.e., a tall building, in which double integration is required to evaluate the generalized turbulent wind load and the dynamic response in the frequency domain. The third example examines the computation of the generalized coupled wind load and response on a tall building in both along-wind and cross-wind directions. It is concluded that the GPU can perform computational tasks on average 10 times faster than the CPU.

• Wind and Structures
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• v.14 no.5
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• pp.383-411
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• 2011

Roof is an integral part of building envelope. It protects occupants from environmental forces such as wind, rain, snow and others. Among those environmental forces, wind is a major factor that can cause structural roof damages. Roof due to wind actions can exhibit either flexible or rigid system responses. At present, a dynamic test procedure available is CSA A123.21-04 for the wind uplift resistance evaluation of flexible membrane-roofing systems and there is no dynamic test procedure available in North America for wind uplift resistance evaluation of rigid membrane-roofing system. In order to incorporate rigid membrane-roofing systems into the CSA A123.21-04 testing procedure, this paper presents the development of a load cycle. For this process, the present study compared the wind performance of rigid systems with the flexible systems. Analysis of the pressure time histories data using probability distribution function and power spectral density verified that these two roofs types exhibit different system responses under wind forces. Rain flow counting method was applied on the wind tunnel time histories data. Calculated wind load cycles were compared with the existing load cycle of CSA A123.21-04. With the input from the roof manufacturers and roofing associations, the developed load cycles had been generalized and extended to evaluate the ultimate wind uplift resistance capacity of rigid roofs. This new knowledge is integrated into the new edition of CSA A123.21-10 so that the standard can be used to evaluate wind uplift resistance capacity of membrane roofing systems.

• Journal of The Korean Society of Agricultural Engineers
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• v.66 no.1
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• pp.39-48
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• 2024

Plastic greenhouses are simple structures consisting of lightweight materials such as steel pipes and polyvinyl chloride. However, serious damage occurs due to heavy winds and typhoon every year. To prevent a collapse of structural members, the Ministry of Agriculture and Rural Development has distributed plans and specifications for disaster-resistant standards. Despite these efforts, more than 50% of greenhouses still do not satisfy the disaster-resistant standards. Among the greenhouses that do not meet these standards, 85% are single-span greenhouses proposed 20 years ago. Consequently, there is a need to evaluate the safety of wind loads for the single-span greenhouse. Unfortunately, there are no design specifications for the greenhouses under wind loads. Therefore, a Korean design standard (KDS) has been utilized. KDS is defined with reference to wind speeds occurring once every 500 years, raising concerns about potential overdesign when considering the durability of plastic greenhouses. To address this, the modified wind load, considering the durability of the plastic greenhouse, was calculated, and a safety evaluation was conducted for sigle G-type plastic greenhouse. It was observed that the moment acting on the windward surface was substantial, and there was a risk of the foundation being pulled out if the basic wind speed exceeded 32 m/s. In terms of the combination strength ratio, it was less than 1.0 only on the leeward side when the basic wind speed was 24 m/s and 26 m/s. However, in all other cases, it exceeded 1.0, indicating an unsafe condition and highlighting the necessity for reinforcement.

• Journal of the Korean Society of Safety
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• v.34 no.5
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• pp.72-77
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• 2019

Vinyl house consists of main rafter, lateral member, clamps and polyethylene film. Many vinyl houses are used to grow fruits, flowers and vegetables in the countryside. Due to climate change, vinyl houses are often destroyed by strong winds or typhoons in summer. Many farmers suffer great economic damage from the collapse of vinyl houses. So it is very important to build a safe vinyl house and find a method to withstand this heavy wind load. In this study, a structural analysis was performed on four types of vinyl houses(10-single-4, 10-single-6, 10-single-7, 10-single-10). In addition, axial force and flexural moment are obtained from the structural analysis of four types of vinyl house. For these four types of vinyl house, structural safety was reviewed by obtaining the combined stress ratio by the strength design method. This structural review showed that the specifications for the vinyl house proposed in the design are not safe. Especially, the result of structural analysis for four types of vinyl house showed that the vinyl house structure constructed as a standard was a very dangerous structure. Therefore, it is necessary to devise diverse methods in order to make vinyl houses structurally safe for heavy wind load in the future. Also a variety of manual development is needed to prevent the collapse of vinyl houses at heavy wind load.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.11
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• pp.1535-1542
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• 2015

An increasing number of electric vehicles (EVs) in power system affects its reliability in various aspects. Especially under high EV penetration level, new generating units are required to satisfy system's adequacy criterion. Wind power generation is expected to take the major portion of the new units due to environmental and economic issues. In this paper, the system reliability is analyzed using Loss of Load Expectation (LOLE) and Expected Energy Not Served (EENS) under each and both cases of increasing wind power generation and EVs. A probabilistic multi-state modeling method of wind turbine generator under various power output for adequate reliability evaluation is presented as well. EVs are modeled as loads under charging algorithm with Time-Of-Use (TOU) rates in order to incorporate EVs into hour-to-hour yearly load curve. With the expected load curve, the impact of EVs on the system adequacy is analyzed. Simulations show the reliability evaluation of increasing wind power capacity and number of EVs. With this method, system operator becomes capable of measuring appropriate wind power capacity to meet system reliability standard.

• Structural Engineering and Mechanics
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• v.48 no.4
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• pp.467-477
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• 2013

Municipalities in the United Arab Emirates approve reinforced concrete design of building structures to follow either the ACI 318 or the BS 8110 code. Since the requirements of these codes are different from each, there is a need to compare the structural demand in the two codes. The main objective of this study is to compare the design requirements of the ACI 318 code with the BS 8110 code for the flexural, shear and axial compression limit states. The load factors and load combinations in the two codes are also compared. To do so, a large number of cross-sections with different geometries, material properties, and reinforcement ratios are analyzed following the procedures in the two codes. The relevant factored load combinations in the two codes are also investigated for a wide range of live-to-dead load ratios and for various wind-to-dead load ratios. The study showed that the differences between the design capacities in the ACI 318 and BS 8110 codes are minor for flexure, moderate for axial compression, and major for shear. Furthermore, the factored load combinations for dead load, live load and wind in the two codes yield minor-to-moderate differences, depending on the live-to-dead load ratio and intensity of wind.

• Wind and Structures
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• v.12 no.4
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• pp.383-400
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• 2009

Low rise building roofs can be subjected to large fluctuating pressures during a tropical cyclone resulting in fatigue failure of cladding. Following the damage to housing in Tropical Cyclone Tracy in Darwin, Australia, the Darwin Area Building Manual (DABM) cyclic loading test criteria, that loaded the cladding for 10000 cycles oscillating from zero to a permissible stress design pressure, and the Experimental Building Station TR440 test of 10200 load cycles which increased in steps to the permissible stress design pressure, were developed for assessing building elements susceptible to low cycle fatigue failure. Recently the 'Low-High-Low' (L-H-L) cyclic test for metal roofing was introduced into the Building Code of Australia (2007). Following advances in wind tunnel data acquisition and full-scale wind loading simulators, this paper presents a comparison of wind-induced cladding damage, from a "design" cyclone proposed by Jancauskas, et al. (1994), with current test criteria developed by Mahendran (1995). Wind tunnel data were used to generate the external and net pressure time histories on the roof of a low-rise building during the passage of the "design" cyclone. The peak pressures generated at the windward roof corner for a tributary area representative of a cladding fastener are underestimated by the Australian/New Zealand Wind Actions Standard. The "design" cyclone, with increasing and decreasing wind speeds combined with changes in wind direction, generated increasing then decreasing pressures in a manner similar to that specified in the L-H-L test. However, the L-H-L test underestimated the magnitude and number of large load cycles, but overestimated the number of cycles in the mid ranges. Cladding elements subjected to the L-H-L test showed greater fatigue damage than when experiencing a five hour "design" cyclone containing higher peak pressures. It is evident that the increased fatigue damage was due to the L-H-L test having a large number of load cycles cycling from zero load (R=0) in contrast to that produced during the cyclone.

• Wind and Structures
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• v.9 no.3
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• pp.217-230
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• 2006

This paper describes a procedure to develop fragility curves for woodframe structures subjected to lateral wind loads. The fragilities are cast in terms of horizontal displacement criteria (maximum drift at the top of the shearwalls). The procedure is illustrated through the development of fragility curves for one and two-story residential woodframe buildings in high wind regions. The structures were analyzed using a monotonic pushover analysis to develop the relationship between displacement and base shear. The base shear values were then transformed to equivalent nominal wind speeds using information on the geometry of the baseline buildings and the wind load equations (and associated parameters) in ASCE 7-02. Displacement vs. equivalent nominal wind speed curves were used to determine the critical wind direction, and Monte Carlo simulation was used along with wind load parameter statistics provided by Ellingwood and Tekie (1999) to construct displacement vs. wind speed curves. Wind speeds corresponding to a presumed limit displacement were used to construct fragility curves. Since the fragilities were fit well using a lognormal CDF and had similar logarithmic standard deviations (${\xi}$), a quick analysis to develop approximate fragilities is possible, and this also is illustrated. Finally, a compound fragility curve, defined as a weighted combination of individual fragilities, is developed.