• Computers and Concrete
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• v.17 no.2
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• pp.281-294
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• 2016

The increased awareness of electromagnetic wave hazards has prompted studies on electromagnetic shielding using conductive materials in the construction industry. Previous studies have explored the effects of the types of conductive materials and their mix proportions on the electromagnetic shielding performance; however, there has been insufficient research on the effect of the geometry of the conductive materials on the electromagnetic shielding performance. Therefore, in this study, the dependence of the electromagnetic shielding performance on the cross-sectional geometry, diameter and length of fibers was investigated. The results showed that the electromagnetic shielding performance improved when the fiber length increased or the diameter decreased, but the effect of the cross-sectional geometry of the fibers was smaller than the effect of the fiber spacing factor.

• Structural Engineering and Mechanics
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• v.43 no.3
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• pp.287-309
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• 2012

Precast segmental bridge columns (PSBC) are alternatives for monolithic cast-in-situ concrete columns in bridge substructures, with fast construction speed and structural durability. The analytical tool for common use is demonstrated applicable for seismic performance prediction of PSBCs through experiment conducted earlier. Then the analytical program was used for parameter optimization of PSBC configurations under reversal cyclic loading. Shear strength by pushover analysis was compared with theoretical prediction. Moreover, seismic response of PSBC with energy dissipation (ED) bars was compared with its no ED bar counterpart under three history ground acceleration records. The investigation shows that appropriate ED bar and post-tensioned tendon arrangement is important for higher lateral bearing capacity and good ductility performance of PSBCs.

• 한국태양에너지학회:학술대회논문집
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• 2009.04a
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• pp.256-262
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• 2009

Purpose of this study is embody the environmental-friendly military facility model that applied renewable energy, passive design method and high efficiency equipment. In the introduction of this study, defined problem of existing military facility and classification of military facility are performed. Also, environmental friendly military facility is defined through classified by scale and building equipment method. In the renewable energy chapter, photovoltaic system and wind turbine system are considered And then, LED light, photovoltaic panel, motor, inverter are analyzed in the high efficiency equipment chapter.

• 한국태양에너지학회:학술대회논문집
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• 2008.11a
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• pp.263-268
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• 2008

In a residential complex case, the efficiency of land use are maximized, but a variation of external condition such as load in-equality, the increase in wind velocity and solar radiation by a height causes increasing energy in a building. Besides, because of increasing window size for a lighting and a view, it comes heating load in winter and cooling load in summer. A choice of cooling-system is important for this reason. Recently an internal high-rise residential complex installs an air-cooling system and operates individual heating. However, this study applies water-cooling used one public cooling-tower instead of an air-cooling system, also with an efficiency test of an air and a water-cooling system, consider an internal applicability.

• Journal of the Korea Institute of Building Construction
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• v.13 no.6
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• pp.594-601
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• 2013

One of the important problems associated with building demolition is the dust generated during the work. The only way to reduce the demolition dust is to use a dust net during water spraying. However, it is difficult to supply the necessary amount of water to remove demolition dust, thus making it difficult to apply this method on a demolition site. This work attempted to find an alternative approach to dust removal by incorporating surfactant and high range AE water reducer in the water being sprayed. Through the experiment, it was found that the addition of surfactant did not contribute to the removal of demolition dust. However, the use of high range AE water reducer showed better performance than spraying plain water, indicating that some amount of demolition dust had been adsorbed on the high range AE water reducer.

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.469-470
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• 2010

The high-strength concrete(HSC) compared to normal concrete represents higher autogenous shrinkage due to lower water-to-binder ratio(W/B) and supplementaries, fly ash(FA) and granulated blast-furnace slag(BFS), etc. The potential of early age cracking which reduces durability of concrete structures is normally influenced by autogenous shrinkage and degree of restraint. Therefore, this paper studies on the evaluation of the characteristics of autogenous shrinkage for HSC, ultra-high-strength concrete(UHSC) containing admixtures by experimental test and the test results are compared with existed prediction models.

• Computers and Concrete
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• v.2 no.2
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• pp.147-164
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• 2005

This paper summarizes an experimental study on the seismic behavior of lower stories of a mid-rise reinforced concrete frame building. Two reinforced concrete frames with two stories and one span were tested and each frame represents lower two stories of an 11-story RC frame building. Both frames were designed in accordance with Japanese design guidelines and were identical except in the variation of axial force. The tests demonstrated that the overall load-displacement relations of the two frames were nearly the same and the first-story column shear was closely related to the column axial load. The columns and beams elongated during both of the tests, with the second-floor beam elongation exceeding 1.5% of the beam clear span length. The frame with higher axial loads developed more cracks that the frame under moderate axial load.

• Proceedings of the SAREK Conference
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• 2009.06a
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• pp.565-572
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• 2009

Deterioration of the outdoor thermal environment in urban areas such as heat island has become worse due to urbanization and overpopulation, etc. In this study, a new method which is coupled simulation of convection and radiation to evaluate outdoor thermal environment in urban area will be proposed. Because the solar radiation affects on outdoor thermal environment massively, therefore the radiation calculation is very important in outdoor thermal environment prediction. The coupled simulation proposed in this study can assess the outdoor thermal environment with accurate.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.05a
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• pp.193-194
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• 2018

Tn this present study, the superhydrophobic surface was developed on the cement mortar surface by using water repellent materials. For better superhydropohicity, it was developed by using silane as binder and which was enriched with filler materials of SiO₂ and TiO₂ nanomaterials. Those nanomaterials enriched with silanes were admixed in cement mortar during casting time and another was coated on the cement mortar surface. The water repellent properties of spray coated and admixed cement mortars were evaluated by measuring the contact angle which was compared with normal cement mortar.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.13 no.1
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• pp.14-20
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• 2017

Groundwater heat pump (GWHP) system can achieve higher performance of the system by utilizing heat source of the annual constant groundwater temperature. The performance of GWHP system depends on the ground thermal environment such as groundwater temperature, groundwater flow rate and hydraulic conductivity. In this study, the geothermal environment was analyzed by using numerical simulation for develop the two-well geothermal system. As the result, this paper shows the change of the groundwater level and underground temperature around wells according to the conditions of flow rate and hydraulic conductivity.