• Wind and Structures
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• 제32권3호
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• pp.227-238
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• 2021

This study analyzed the pressure patterns and local pressure of tall buildings with corner modifications (recessed and chamfered corner) using wind tunnel tests and proper orthogonal decomposition (POD). POD can distinguish pressure patterns by POD mode and more dominant pressure patterns can be found according to the order of POD modes. Results show that both recessed and chamfered corners effectively reduced wind-induced responses. Additionally, unique effects were observed depending on the ratio of corner modification. Tall building models with recessed corners showed fluctuations in the approaching wind flow in the first POD mode and vortex shedding effects in the second POD mode. With large corner modification, energy distribution became small in the first POD mode, which shows that the effect of the first POD mode reduced. Among building models with chamfered corners, vortex shedding effects appeared in the first POD mode, except for the model with the highest ratio of corner modifications. The POD confirmed that both recessed and chamfered corners play a role in reducing vortex shedding effects, and the normalized power spectral density peak value of modes showing vortex shedding was smaller than that of the building model with a square section. Vortex shedding effects were observed on the front corner surfaces resulting from corner modification, as with the side surface. For buildings with recessed corners, the local pressure on corner surfaces was larger than that of side surfaces. Moreover, the average wind pressure was effectively reduced to 88.42% and 92.40% in RE1 on the windward surface and CH1 on the side surface, respectively.

• KIEAE Journal
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• 제8권4호
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• pp.37-42
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• 2008

In the case that high-rise building is constructed, the surrounding wind velocity increase more than 50~100%. From this cause, many wind environmental problems can be occurred. For example, ordinary wind environmental disaster may be occurred in a region, or walking disturbed. In developed countries including USA, EU, and Japan, many efforts have been made for building wind prevention by grasping previously the effects before building constructed. But, We are bearing risk of wind environmental disaster because we have not enough recognition about building wind, and have not architectural prevention counterplans. This study aims to examine wind environmental characteristics of domestic apartment complex, and effective architectural counterplans. As the basic stage for this, we investigated pre-estimate tools and risk assessment methods of building wind in apartment complex, applied to two apart complex in Cheon-An region by CFD. As the result, serious damages were not presented. But, it is obvious that various architectural counterplans will be presented by this example researches.

• Wind and Structures
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• 제27권2호
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• pp.89-100
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• 2018

3D simulations based on an impinging jet were carried out to investigate the flow field of a steady downburst and its effects on a high-rise building by applying the SST k-${\omega}$ turbulence model. The vertical profile of radial wind speed obtained from the simulation was compared with experimental data and empirical models in order to validate the accuracy of the present numerical method. Then wind profiles and the influence of jet velocity and jet height were investigated. Focusing on a high-rise building, the flow structures around the building, pressure distributions on the building surfaces and aerodynamic forces were analyzed in order to enhance the understanding of wind load characteristics on a high-rise building immersed in a downburst.

• 한국디지털건축인테리어학회논문집
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• 제3권1호
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• pp.23-28
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• 2003

In spite of The exterior design of buildings has a remarkably significant value in terms of public aspect some exposed architectural equipments spoil the appearance of building. The design elements of exposed architectural equipments were partially changed and assessed in the semantic differential method. Thus the aesthetically favorable impression and values of public interest were able to be increased. The reasons why those hideous exposed architectural equipments were constructed, seemed to be as follows; the builders' selfishness, the citizens' ignorance and the immature social institutions that cannot restrict undesirable design efforts. Building equipments located outside are not classified as major elements in building regulations and thus can be installed and altered without any limitations even though they have great effects on the shape and colors of a building. So we have more interest in exposed architectural equipments and more deliberation of exterior design of a building.

• 한국태양에너지학회 논문집
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• 제31권1호
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• pp.78-86
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• 2011

Recently due to the crisis of environment and resources, construction industry that effects a lot on nature than any other industries is essentially required to consider environment element through the life cycle. With the increase in the demand for sustainable and environmentally-friendly development, Green Building Certification System came into force in 2002. Lots of advanced countries and Korea have been running green building certification system. But many people of Korea is getting interested in LEED. We spend too much money to get a LEED Certification. So we need to develop our own green building certification that fits our environment. In this study, we are going to compare GBCC with LEED to develop our Green Building Rating System.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2021년도 봄 학술논문 발표대회
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• pp.87-88
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• 2021

Due to the effects of COVID-19 and the Fourth Industrial Revolution, construction engineering education has been required to change. As part of efforts to respond to changes, innovative teaching methods such as team-based learning have been introduced, but specific measures are still lacking. In this regard, this study proposed plans for building construction curriculum operation applied with team-based learning, building construction course operation applied with team-based learning, and building construction course grade evaluation applied with team-based learning. It is expected that the proposed operation plans can be used in educational settings where team-based learning is to be applied in a changing class environment.

• Earthquakes and Structures
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• 제8권2호
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• pp.443-462
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• 2015

Some model building codes stipulate that the design displacement of a building can be computed using the elastic static analysis results multiplied by the deflection amplification factor, $C_d$. This approach for estimating the design displacement is essential and appealing in structural engineering practice when nonlinear response history analysis (NRHA) is not required. Furthermore, building codes stipulate the consideration of accidental torsion effects using accidental eccentricity, whether the buildings are symmetric-plan, or asymmetric-plan. In some model building codes, the accidental eccentricity is further amplified by the torsional amplification factor $A_x$ in order to minimize the discrepancy between statically and dynamically estimated responses. Therefore, this warrants exploration of the reliability of statically estimated design displacements in accordance with the building code requirements. This study uses the discrepancy curves as a way of assessing the reliability of the design displacement estimates resulting from the factors $C_d$ and $A_x$. The discrepancy curves show the exceedance probabilities of the differences between the statically estimated design displacements and NRHA results. The discrepancy curves of 3-story, 9-story, and 20-story example buildings are investigated in this study. The example buildings are steel special moment frames with frequency ratios equal to 0.7, 1.0, 1.3, and 1.6, as well as existing eccentricity ratios ranging from 0% to 30%.

• Wind and Structures
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• 제11권2호
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• pp.153-178
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• 2008

Based on the empirical formulas for power spectra of generalized modal forces and local fluctuating wind forces in across-wind and torsional directions, the wind-induced lateral-torsional coupled response analysis of a representative rectangular tall building was conducted by setting various parameters such as eccentricities in centers of mass and/or rigidity and considering different torsional to lateral stiffness ratios. The eccentricity effects on the lateral-torsional coupled responses of the tall building were studied comprehensively by structural dynamic analysis. Extensive computational results indicated that the torsional responses at the geometric center of the building may be significantly affected by the eccentricities in the centers of mass and/or rigidity. Covariance responses were found to be in the same order of magnitude as the along-wind or across-wind responses in many eccentricity cases, suggesting that the lateral-torsional coupled effects on the overall wind-induced responses can not be neglected for such situations. The calculated results also demonstrated that the torsional motion contributed significantly to the total responses of rectangular tall buildings with mass and/or rigidity eccentricities. It was shown through this study that the framework presented in this paper provides a useful tool to evaluate the wind-induced lateral-torsional coupled responses of rectangular buildings, which will enable structural engineers in the preliminary design stages to assess the serviceability of tall buildings, potential structural vibration problems and the need for a detailed wind tunnel test.

• 한국재료학회지
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• 제29권11호
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• pp.664-669
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• 2019

In this paper, a water-based green polymer mud is synthesized by simple compounding method. Effects of different kinds of tackifiers, their molecular weight on the viscosity of polymer mud and the effects of different fluid loss additives on mud fluid loss are studied. The results show that when polystyrene and anionic polyacrylamide with molecular weight of 8 ~ 10 million are used as the main thickening ingredient, polymer mud with high viscosity and high stability can be obtained. When the prepared polymer mud is formulated as NPAM: PEO: Hydroxypropyl cellulose(HPC) : Water = 42:10:10:100000 (unit: kg), the viscosity can reach 20.6 s, the filtration loss in 7.5 min is 24 mL, and the sand content is only 0.1 %. Compared with traditional bentonite mud, the green environment-friendly polymer mud has the advantages of small amount of waste, low environmental pollution, and low pulping cost, and can meet the construction needs for most topography and geomorphology drilling engineering.

• 한국대기환경학회지
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• 제23권2호
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• pp.214-224
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• 2007

A three-dimensional computational fluid dynamics (CFD) model with the renormalization group (RNG) $k-{\varepsilon}$ turbulence model is used to examine the effects of difference in building height on flow and pollutant dispersion in asymmetric street canyons. Three numerical experiments with different street canyons formed by two isolated buildings are performed. In the experiment with equal building height, a portal vortex is formed in the street canyon and a typical recirculation zone is formed behind the downwind building. In the experiment with the downwind building being higher than the upwind building, the ambient flow comes into the street canyon at the front of the downwind building and incoming flow diverges strongly in the street canyon. Hence, pollutants released therein are strongly dispersed through the lateral sides of the street canyon. In the experiment with the upwind building being higher than the downwind building, a large recirculation zone is formed behind the upwind building, which is disturbed by the downwind building. Pollutants are weakly dispersed from the street canyon and the residue concentration ratio is largest among the three experiments. This study shows that the difference in upwind and downwind building height significantly influences flow and pollutant dispersion in and around the street canyon.