• Journal of the Earthquake Engineering Society of Korea
• /
• v.14 no.6
• /
• pp.11-21
• /
• 2010

This study presents seismic responses of 5-story reinforced concrete structures retrofitted with the buckling-restrained braces using a time-dependent element. The time-dependent element having birth and death times can freely be activated within the user defined time intervals during the time history analysis. The buckling-restrained brace that showed the largest energy dissipation capacity among the test specimens in previous research was used for retrofitting the RC buildings in this study. It was assumed that the first story of the damaged building under the first earthquake was retrofitted with the buckling-restrained braces considered as the time-dependent element before the second of the successive earthquakes occurs. Under this assumption, this paper compares seismic responses of the RC structures with the time-dependent element subjected to the successive earthquake. Subjected to the second earthquake, it was observed that activation of the BRB systems largely decreases deformation of the moment frame where the damage was concentrated under the first earthquake. However, damages to the shear wall systems were increased after activation of the BRB systems. Since the cumulative damages of the shear wall systems were infinitesimal compared with the retrofit effect of the moment frame, the BRB system was effective under the successive earthquake.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.25 no.4
• /
• pp.153-159
• /
• 2015

Inorganic pigments have been received a great attention for various applications including paint, glazed ceramic ink, art tile, and building exterior due to their excellent thermal and chemical stability. Traditionally, the compositions of $PbCrO_4$, CdS and CdSe have been widely used as a yellow inorganic pigment. However, the use of these compositions has been restricted in recent years, because they contain harmful elements such as Cd, Cr, Pb and Se. In this study, new environment-friendly ceria-based pigment was synthesized using solid state reaction. Crystal structure and morphology of the obtained $Ce_{1-x}Zr_xBi_yO_{2-y/2}$ yellow pigment were analyzed using XRD and SEM, respectively. Substitutional effect of Zr and Bi on the pigment color was analyzed using UV-vis. spectrophotometer and CIE $L^*a^*b^*$ analysis. The crystal structure of the obtained pigments was dependent on the calcination temperature. The color characteristics and absorption band of the pigments were dependent on the calcination temperature and Zr, Bi contents. As a result, all the obtained yellow pigments showed the effective absorption ranged from ultraviolet to visible light, and $Ce_{0.44}Zr_{0.36}Bi_{0.20}O_{0.19}$ (x = 0.36, y = 0.20) pigment showed the most brilliant yellow color.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.32 no.5D
• /
• pp.507-517
• /
• 2012

The main purpose of this study is to address flooding resilient land use management strategy based on the distributional characteristics of storm damage areas in Gyeonggi-do. The employed methods are 1) Exploratory Spatial Data Analysis (ESDA) to understand the spatial patterns of storm damage areas occurred from 2005 to 2009, 2) Local Indicator of Spatial Association (LISA) to examine spatial autocorrelation existed in storm damage areas for the year of 2009. The results show that 1) crop land damage is very sensitive to heavy precipitation, 2) damaged buildings are found in all over the Gyeonggi areas, but relatively more damages are in the regions closed to the City of Seoul, 3) damaged roads-bridges, streams, and reaches are found in mostly rural areas, 4) building and crop land damage occurs mostly in lowlands with different spatial patterns. These findings imply that 1) it will be useful to consider the average distances and slopes of damaged building and crop lands from streams for the decision making of land use management strategy, 2) further management efforts are required in the north, east, and south regions of Gyeonggi areas to prevent roads-bridge, stream, and reach damages, 3) the present land use pattern needs to be carefully investigated by considering the damage clustered areas for the year of 2009 based on watershed and municipality boundaries.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2008.04a
• /
• pp.413-416
• /
• 2008

The concrete used most in construction materials. There is an overcrowded iron dimensions use of the concrete at time of the other concrete theory on the reinforcing rod back which did congestion and compares it with this, and there are more few dimensions of the aggregate than concrete, and quantity of aggregate passage is superior in mortar than concrete. If a volume rate of the aggregate writes mortar than concrete against this, therefore, unit amount increases, and quantity of paste increases and quantity of dry shrinkage than increase concrete. However, I let I regulate lay priest distribution of the aggregate, and the results rates increase and reduce unit amount and decrease quantity of dry shrinkage, and separation resistance and the gap passage characteristics are judged because it can be it in a substitute document of very superior concrete. I came to carry out the study that I watched to let I was useful a little more and do the improvement repair of a become building wall body, a basement pillar and repair reinforcement of the assistant in the reinforcing rod back, the old age when I made congestion here. I regulated lay priest distribution of the aggregate in the study and regulated substitution rate of the aggregate (40%, 50%, 60%) and divided W/C 30%, 40% standards and produced mortar and I compared quantity of air by this, slump, compression robbery and showed it this time.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.23 no.2
• /
• pp.1-9
• /
• 2009

Impact of daylighting on the visual environment can improve occupant's well-being by providing visual comfort. Also, daylighting can save energy. However, glare from window can be a direct hazard to vision and can cause serious discomfort. Selecting glare source on a window plane is very important for evaluating discomfort glare from windows. But former glare indices can not identify the range of the glare source properly. In this study, difference in glare sensation with uniform and non-uniform glare sources are evaluated to identify the range of the glare source. The glare source was assumed as $120{\times}120[cm]$ window model. The window was divided into three parts with different luminance values. The experiment was conducted under 1[m], 1.5[m], 3[m] distance from the glare source. Two results were obtained from the experiments. First, the degree of discomfort glare increased as average window luminance increased. Second, the middle and lower part of the window plane can affect evaluation of discomfort glare as well as the upper part of the window plan. These results can be used for selecting the glare source in a window with non-uniform luminance.

• Korean Journal of Construction Engineering and Management
• /
• v.17 no.5
• /
• pp.45-53
• /
• 2016

As the number of units increased by vertical extension is recently allowed according to the Housing Law, the aged apartment remodeling projects using the same allowed method are pursued in several apartment complex located in Bundang and Pyungchon. However, progress of the projects is not advanced due to uncertainty of the process. Therefore, the purpose of this study is to improve a business process model for the aged apartment remodeling in case of the number of units are increased for the remodeling union to pursue the remodeling project easily. In order to improve the process model, requirements for the Housing Act are analyzed, the existing process model is developed based upon the requirements, uncertainty of the existing process is examined and a to be process model is proposed to eliminate the uncertainty. Many architects and engineers are consulted to discuss the uncertainty and process model. This model will help the Government to reform the Housing Act and remodeling unions to pursue the aged apartment remodeling.

• Korean Journal of Construction Engineering and Management
• /
• v.18 no.3
• /
• pp.63-73
• /
• 2017

In contemporary society, it is increasingly common to spend more time indoors. As such, there is a continually growing desire to build comfortable and safe indoor environments. Along with this trend, however, there are some serious indoor-environment challenges, such as the quality of indoor air and Sick House Syndrome. To address these concerns the government implements various systems to supervise and manage indoor environments. For example, green building certification is now compulsory for public buildings. There are three categories of green building certification related to indoor air in Korea: Health-Friendly Housing Construction Standards, Green Standard for Energy & Environmental Design(G-SEED), and Indoor Air Certification. The first two types of certification, Health-Friendly Housing Construction Standards and G-SEED, evaluate data in a drawing plan. In comparison, the Indoor Air Certification evaluates measured data. The certification using data from a drawing requires a considerable amount of time compared to other work. A 2D tool needs to be employed to measure the area manually. Thus, this study proposes an automatic assessment process using a Building Information Modeling(BIM) model based on 3D data. This process, using open source Industry Foundation Classes(IFC), exports data for the certification system, and extracts the data to create an Excel sheet for the certification. This is expected to improve the work process and reduce the workload associated with evaluating indoor air conditions.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.22 no.4
• /
• pp.355-362
• /
• 2009

Many of residential buildings, which have pilotis in lower stories to meet the architectural needs, are recently constructed in Korea. Usually, infill walls located in the upper stories of these buildings may cause a soft first story, which is very weak from the earthquake resistance. In the design of the buildings, the infill walls of upper stories are usually considered as non-structural elements and thus they are not included in the analytical model. However, the infill walls may affect the seismic behavior of the residential buildings. Therefore, the differences in seismic behaviors of RC buildings with and without masonry infill walls are required to be investigated. In this study, seismic fragility analyses were performed for masonry infilled low-rise RC moment-resisting frames. And seismic behaviors of RC moment-resisting frame with/without masonry infill walls were evaluated. Two types of structural system with the same frame and different allocation of infill walls are used to evaluate the influence of masonry infill walls on seismic behavior of RC moment-resisting frames. The infill walls were modeled as bi-equivalent diagonal struts. The fragility analyses show that the seismic performance of RC moment-resisting frames with soft story is below the desirable building seismic performance level recommended by current seismic codes, indicating high vulnerability of RC moment-resisting frames with soft story.

• Proceedings of the KSR Conference
• /
• 2003.10c
• /
• pp.287-294
• /
• 2003

There are a lot of curved subway stations in Seoul metropolitan area. These must be straightly constructed as many as possible. But some of stations are roundly designed and built in order to avoid pre-existed underground obstacle such as basement of high rise building, underground gas or water pipe line and subway stations from another line. As shown fig 1, one of the biggest problem occurring curved subway station is considered large gap between platform and vehicle when vehicle completely stop at the station. The gap potentially is in existence to subway passenger as very dangerous factors in rush hours. If passenger accidentally drop their food or leg between this gap when they get on the train and train leaves station, the passenger will be seriously injured by vehicle. In this paper, various design and instruments are introduced and best solution for this matter will be presented. In order to eliminate any possibility of accident happened gap between platform and vehicle, KRRI(Korea Railroad Research Institute) have been developed new safety instrument. These technologies were applied for patent by KRRI. These mechanisms will provide confidence as well as safety to Korean subway passenger

• Elastomers and Composites
• /
• v.44 no.3
• /
• pp.282-289
• /
• 2009

The pressure-sensitive adhesive(PSA) tapes are widely used as floor-sealing material in Korean constructive industry. However, the general PSA tapes can not seal the apertures completely. This is one of main reasons to cause imperfect finishing. In order to solve the problems, the asphalts were modified by FKM powder and SBS in this study. The physical properties of modified asphalts were examined by measuring the softening point, viscosity, tensile strength and adhesion strength of FKM and SBS modified asphalt. The softening point of SBS modified asphalt was increased greatly due to the formation of network structure in asphalt. Also, the change of adhesion strength of SBS modified asphalt with temperature was not so great comparing to those of pure asphalt and FKM modified asphalt. The best results of pressure-sensitive adhesion could be obtained by the SBS(linear) modified asphalt containing 6 wt.% of linear type SBS.