• Proceedings of the Korean Institute of Building Construction Conference
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• 2010.05a
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• pp.167-170
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• 2010

In tall building construction, It is important to reduce construction duration of slab form work. Therefore, the purpose of this study is to assess the required performance for reduction of construction duration in slab form work of tall buildings. We surveyed the required performance and their degrees of importance and economical efficiency through the interview and questionnaire survey by related experts. This study proposes the guideline to develop improved formwork system for reduction of construction duration.

• Journal of the Korean Recycled Construction Resources Institute
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• v.1 no.3
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• pp.163-172
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• 2013

This paper presents a comprehensive review of recent advances in ultra-high performance concrete (UHPC). Fundamental characteristics of UHPC are elaborated with focus on its material constituents, mixing, and formulation procedures. Use of state-of-the-art materials such as carbon nanotubes or nano-silica is discussed as well, whose inclusion may enhance the performance of UHPC. The review evaluates supplementary treatment methods (e.g., pressuring curing) and identifies applicable standard test methods for determining the properties and behavior of UHPC. Site implementation is provided to link laboratory research with full-scale application. Research needs are suggested to further develop UHPC technologies from technical and socio-economical perspectives.

• Journal of the Korean Solar Energy Society
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• v.23 no.4
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• pp.63-70
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• 2003

It is very important to improve the insulation performance of curtain wall anchoring unit since it is composed of materials with high thermal conductivity, such as aluminium, steel and so on. This study aims to evaluate the heating energy performance and economical efficiency of various alternatives which are different in position and material of insulation. As results, alternative of inserting the urethane washer & pad and coating the anchoring unit with urethane foam can improve the heating energy performance and L.C.C(Life Cycle Cost) by 6.33% and 0.95%, respectively, as compared with the existing case.

• 한국방재학회:학술대회논문집
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• 2008.02a
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• pp.53-56
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• 2008

A reinforced concrete (RC) cast-in-place (CIP) infill wall retrofitting method may provide an improved seismic performance and economical efficiency for the non-ductile rahmen structures. In this study, four one story-one bay non-ductile frame were constructed and retrofitted with CIP infill wall to evaluate seismic performance of CIP infill wall-frame. From the test results, infill wall-frame exhibited a marked increase in shear strength compared to non-ductile RC frame specimen. But the ductility and story-drift at maximum load were decreased when shear strength of infill wall larger than that of existing RC frame. Therefore, it is confirmed that adequate reinforcement detail is required to assure sufficient seismic performance.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2006.03a
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• pp.511-518
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• 2006

In this study, seismic response mitigation effect of an MR damper generating response-dependent frictional force is investigated. It has been reported in previous studies that passively operated MR damper with constant input current doesn't show better control performance than semi-active MR damper with varying input current calculated by control algorithms such as linear quadratic regulator and sliding mode control. However, in order to operate the MR damper semi-actively, other control systems besides the damper itself such as sensors for measuring structural responses and controller for calculating optimal input current are necessary, which deteriorate the economical efficiency. This study presents a MR damper generating frictional force of which magnitude is controlled in accordance to the displacement and velocity transferred to the damper. Numerical analyses results indicate that the performance of the response dependent MR damper is closely related with the range of the friction force and it can be designed to short better control performance than the passive MR damper.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2020.11a
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• pp.18-19
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• 2020

The ElectroMagnetic Pulse (EMP) destroys social infrastructure at once and causes social chaos. However, currently major infrastructures are constructed of concrete that does not have electromagnetic shielding performance. In this study, using the arc metal spraying method is used to evaluate the shielding performance and construction performance of concrete. The electro-magnetic shielding effect is measured by fabricating a shielding room with reference to MIL-STD-188-125, and the construction performance is evaluated by measuring the adhesion strength of thin metal sprayed film-concrete. As a result of the study, when the metal spraying method is applied, the shielding effect is higher than that of the special electro-magnetic shielding concrete, and it is considered to be more economical than the existing metal plate (3~5 mm).

• Applied Chemistry for Engineering
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• v.20 no.2
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• pp.126-133
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• 2009

The surfactants applied in household detergents and industrial cleansers should satisfy the requirement of not just the basic function such as emulsification, solubilisation, dispersion, detergency, wetting and foaming, but also the economical efficiency and the safety to human and environment. In the viewpoint of the sustainable development, the surfactants, moreover, have to reduce raw materials and energy consumption and waste disposal when they are being manufactured and also consumed for their purposes. New high-performance surfactants have been extensively studied and developed in order to respond the change in social and economical environment. Noticeable progresses have been achieved so far, which are the significant increase in solubility and surface activity through the minor modification of existing surfactant molecular structure and the synergistic increase in a surface activity shown in the mixed surfactant system of anionic and cationic surfactants. In this review, the important and meaningful progresses achieved recently in technological advance and practical application will be summarized and discussed.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.925-928
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• 2008

Fiber is an important ingredient in strain-hardening cementitious composite (SHCC), which can control fracture of cementitious composite by bridging action. The properties of reinforcing fiber, as tensile strength, aspect ratio and elastic modulus, have great effect on the fracture behavior of SHCC. To apply SHCC to structural member, SHCC must have economical efficiency and workability as well as own excellent tensile performance. For these purposes, four-point bending and direct tensile tests on SHCC with only hybrid synthetic fibers, total fiber volume fraction, $V_f$, is 1.5%, are carried out. The research emphasis is on the mechanical properties of SHCC made in Polyvinyl alcohol (PVA) and Polyethylene (PE) fibers, and how this affects the composite property, and ultimately its strain-hardening performance. Also, effect of hybrid type and water-cement ratio on the behavior of SHCC was evaluated in this paper.

• Journal of the Korean Society of Hazard Mitigation
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• v.8 no.1
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• pp.15-21
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• 2008

The internally confined hollow-concrete filled tube (ICH-CFT) column has two tubes on the both sides (hollow part and outer part) of the concrete. The inner tube and the outer tube perform great seismic abilities, ductility and absorption of energy due to the steel tubes and the hollow part. So, the study of this column type for the practical use is needed. In this study, the qualitative analysis about seismic capacities depending on parameters is performed for the practical design of the ICH-CFT column. The parameters are diameter of column, hollow ratio and thickness of tubes with the same resistance of the moment. Also, the economical evaluation of ductility and comparison with CFT column make this study to be of practical use. Especially, a change of seismic performance depends on the hollow ratio and the thickness of the outer tube, and the economical hollow ratios according to the thickness of the outer tube in the ICH-CFT column are suggested.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2008.04a
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• pp.225-230
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• 2008

High-rise and high-density apartment complexes has been built and supplied on a large scale in the metropolis and metropolitan areas since 1980s in order to solve housing shortage in cities. Recently they are raising deterioration problems for aging more than 20 years. moreover, those problems show very special characters such as simultaneity and a large scale. The purpose of this study is to propose a direction for the development of the evaluating indicators to measure the level of deterioration of apartments. The level of deterioration of apartments can be evaluated by housing performance. In order to evaluate the deterioration comprehensively, the housing performance indicators should be developed on the social, economical, and physical dimension. This study analyzed the concept of the apartment deterioration and compared housing performance indicators through literature review. First of all, when considering various factors in the evaluation of the deteriorated apartments, such as evaluating ranges, attributes and dimensions, housing performance indicators should be structured with the hierarchical framework. Second, housing performance indicators evaluating the level of deterioration of apartments should include social, psychological, and cultural aspects of home environments in order to understand adequately the attitude of the middle class toward services that apartments provide. Third, in previous researches, most criteria have been developed and weighted based on only expert opinions regarding performance indicators. So, It is necessary to include residents' opinions in developing performance indicators since they can provide more practical and feasible aspects the experts could not experience or understand.