• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.30 no.3A
• /
• pp.297-307
• /
• 2010

Recently, maintenance engineering and technology for civil and building structures have begun to draw big attention and actually the number of structures that need to be evaluate on structural safety due to deterioration and performance degradation of structures are rapidly increasing. When stiffness is decreased because of deterioration of structures and member cracks, dynamic characteristics of structures would be changed. And it is important that the damaged areas and extent of the damage are correctly evaluated by analyzing dynamic characteristics from the actual behavior of a structure. In general, typical measurement instruments used for structure monitoring are dynamic instruments. Existing dynamic instruments are not easy to obtain reliable data when the cable connecting measurement sensors and device is long, and have uneconomical for 1 to 1 connection process between each sensor and instrument. Therefore, a method without attaching sensors to measure vibration at a long range is required. The representative applicable non-contact methods to measure the vibration of structures are laser doppler effect, a method using GPS, and image processing technique. The method using laser doppler effect shows relatively high accuracy but uneconomical while the method using GPS requires expensive equipment, and has its signal's own error and limited speed of sampling rate. But the method using image signal is simple and economical, and is proper to get vibration of inaccessible structures and dynamic characteristics. Image signals of camera instead of sensors had been recently used by many researchers. But the existing method, which records a point of a target attached on a structure and then measures vibration using image processing technique, could have relatively the limited objects of measurement. Therefore, this study conducted shaking table test and field load test to verify the validity of the method that can measure multi-point displacement responses of structures using image processing technique.

• Spatial Information Research
• /
• v.19 no.2
• /
• pp.9-18
• /
• 2011

The purpose of this research is to evaluate an accurate biotope area ratio model with efficiency and convenience of database management through promoting sustainable development to provide people amenities in a new town. In particular, the biotope area ratio is used not only in the environment impact assessment but Green building certification criteria. But now there is no any index map of biotope. So it is very hard to implement with data for supplement results. In this research, we suggest the model of integrated attributable information. The evaluation of biotope area ratio is to include a basic land use planning map and a building coverage area which is a wall of greening surface and roof. In case of non building coverage area, the evaluation of biotope area ratio is to include water space, artificial ground, natural ground and pervious gap-pave. A weighted value on the spatial information is combined into the information. And then the merged one is given a land use planning information in a block. In the weighted value on the space type information, it is possible to in its circumstances. Therefore, it can be substituted a correspondence of numerical change for various values elastically in this model.

• Korean Journal of Heritage: History & Science
• /
• v.47 no.4
• /
• pp.74-91
• /
• 2014

The stone statues in the site of Mireuksaji Temple(Iksan, South Korea) were created after the stone pagoda was built in 639. They, transitional statues between animal sculptures and human shaped statues made from the late Goryeo dynasty until the early Joseon dynasty, were set up at the four corners of the stone pagoda by way of guardians. In the case of three statues, their surfaces were denudated and their iconographies have been indiscernible. However, the one in the southwest clearly shows its iconography. It is inferior in properties to the other three statues in the northwest, the northeast and the southeast respectively, but on the other hand its iconography has been well maintained. The reason is related to exposure to harmful environments; specifically, the retaining wall, built around the stone pagoda in the 17th century, had the southwest statue inside and could naturally worked as a buffer against harmful environments. As a result, for about 400 years there has been difference in weathering conditions between the three stone statues and the southwest statue, which brought denudation, the consequent indiscernibleness of iconography and biological invasion to the three statues, notwithstanding superior properties(northwest statue:$176kgf/cm^2$, northeast statue:$109kgf/cm^2$, southeast statue:$273kgf/cm^2$). In contrast, the southwest statue significantly shows its iconography with black contaminants and granule decomposition, despite inferior properties($133kgf/cm^2$). Defenseless exposure to external environment is not recommended for the stone statues, because it is hard to preserve the extant iconography. Herein lies the application of the data on microclimate around Mireuksaji Temple. As regards the weathering zone in which the stone statues are located, Conservation increases in acidity and frequency as years go by, Hereat, in the approach to the Conservation of stone statues, the first consideration needs to be morphological historicity rather than geographical location.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.19 no.5
• /
• pp.618-625
• /
• 2018

With the passing of time, exposed concrete structures are affected by a range of environmental, chemical, and physical factors. These factors seep into the concrete and have a deleterious influence compared to the initial performance. The importance of identifying and preventing further performance degradation due to the occurrence of deterioration has been greatly emphasized. In recent years, evaluations of the target life have attracted increasing interest. During the freezing-melting effect, a part of the concrete undergoes swelling and shrinking repeatedly. At these times, chloride ions present in seawater penetrate into the concrete, and accelerate the deterioration due to the corrosion of reinforced bars in the concrete structures. For that reason, concrete structures located onshore with a freezing-melting effect are more prone to this type of deterioration than inland structures. The aim of this study was to develop a high performance mortar mixed with a mineral admixture for the durability properties of concrete structures near sea water. In addition, experimental studies were carried out on the strength and durability of mortar. The mixing ratio of the silica fume and meta kaolin was 3, 7 and 10 %, respectively. Furthermore, the ultra-fine fly ash was mixed at 5, 10, 15, and 20%. The mortar specimens prepared by mixing the admixtures were subjected to a static strength test on the 1st and 28th days of age and degradation acceleration tests, such as the chloride ion penetration resistance test, sulfuric acid resistance test, and salt resistant test, were carried out at 28 days of age. The chloride diffusion coefficient was calculated from a series of rapid chloride penetration tests, and used to estimate the life time against corrosion due to chloride ion penetration according to the KCI, ACI, and FIB codes. The life time of mortar with 10% meta kaolin was the longest with a service life of approximately 470 years according to the KCI code.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.27 no.3
• /
• pp.21-29
• /
• 2023

In this study, the stress characteristics of temporary fixed steel rods were analyzed in the "temporary fixing system using internal prestressing tension", which is mainly applied to the construction of superstructures by FCM. It was difficult to confirm the changes in initial tensile force in this system because the steel rod was internally connected to the pier and the PSC BOX. Therefore, measurement was performed before and after the completion of each segment using an FBG sensor to measure the change in the micro length of the steel rod. The results of the analysis showed that 75% to 90% of the maximum vertical contraction of the steel rod that occurred until the completion of the cantilever segment occurred in the fixing ~ 1segment, and the maximum loss of initial prestressing force was 39%. Such excessive loss of tension force to 1 segment means that tension is needed to improve the precision of construction during the fixation, and re-tension is needed to secure stability for conduction of cantilever segments after the completion of 1segment. In the 2 ~ last segment, the stress of the steel rod decreased gradually, and in the summer, the decrease in stress tended to partially recover due to the increase in the length of the steel rod corresponding to the increase in the vertical volume of PSC BOX. The dominant factor in the stress change in 2~ last segment in this phenomenon is judged to be the change in the length of the steel rod according to the temperature. Unlike the change in length, the relaxation was 1.2-2.7%, which was mostly offset by the opposite stress corresponding to the temperature stress. Therefore, a plan was proposed to improve the internal stress, such as adjusting the fixation time.

• The Journal of the Korea Contents Association
• /
• v.18 no.7
• /
• pp.388-400
• /
• 2018

Small houses are continuously supplied after the alleviated housing act enacted in 2009. This study aimed to conduct a survey among an expert group associated with small house construction, propose problems by discovering difficulties and vulnerable points small and medium-sized construction companies experience while launching construction works as well as factors that impede the safety and housing environment of small houses. Furthermore, it ultimately intends to propose improvements. First, low-priced order is a major cause of unreasonable contract. Most companies were found to have low-priced orders in order to manage order performance. Low bidding and low-priced order are implemented to maintain construction businesses, ultimately threatening the safety environment of buildings. In addition, it is assumed that moderate bid periods and construction periods should be guaranteed. Second, work standardization for small and medium-sized companies is needed due to numerous cases that failed to meet order process. Additionally, regular instruction is required as many employees are not fully aware of relevant contents. Third, the most urgent policy direction turned out avoidance of low-priced bidding and removing insolvent enterprises from the market. Small and medium-sized construction companies that primarily build small houses undergo poor work condition. Therefore, the safety environment of small houses should be enhanced through work standardization and avoiding low-priced order.

• Journal of the Korean Institute of Traditional Landscape Architecture
• /
• v.28 no.3
• /
• pp.114-121
• /
• 2010

Traditional temples in Korea are the important cultural heritage because of artistic traditonal buildings and structures, paintings, sculptures, and big forest areas which are most ecological and beautiful in Korea. Since traditional temples still function as religious places for very long time, the sense of places intrinsic to the temples are very strong and vivid. The sense of place is very closely related to the conservation of the original landscape type. Recently however, there is a strong tendency to use solar energy in traditional temples because of the low energy efficiency of the old traditional architecture which may have negative impact on landscape which again in turn may lead to the destruction of the sense of place. The purpose of this study was to suggest some landscape design guidelines to protect the sense of place of traditional temple by investigating the impact of solar energy facility on the landscape experience of traditional temple. In order to do perform this purpose, Tongdosa was selected as a study site and four kinds of measurement tools(landscape image, temple identity, landscape satisfaction, degree of landscape improvement) were used as questionnaire items. 180 college students participated in the questionnaire survey. The analysis showed that the solar energy facility had very negative impact on landscape experience such as three landscape image factors(scenic beauty, openness, complexity), landscape satisfaction, temple identity, and landscape improvement. Based on the results, three landscape improvement plans were suggested. First, solar energy facility should be built in the forest in order not to be exposed to visitors, if possible. Second, the landscape management of traditional temple should emphasize on sustaining scenic beauty and temple identity along with the provision of openness. Lastly, detailed landscape guideline should be prepared to regulate the scale, ratio, and the form of the artificial buildings and structures to protect the sense of place of traditional temple.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.8 no.4
• /
• pp.853-860
• /
• 2007

In this modern era, human beings lead their life in complex environment where there are lots of parameters such as temperature, light, smell, sound, visual stimulus etc. that play important role for quality life. These parameters affect physical and mental behavior of a human being immensely. To ensure quality life the demand for quality products is always associated with human emotion and sensibility. Due to human sensibility and emotion involvement with quality life, the design stages of any kind of product must include some certain features related with emotion and sensibility. The cues for optimizing artificial environment are the physiological responses of human in that environment. The conventional approach of environmental physiology is to measure the relationship between environmental physical parameters and human psychological parameters under artificial conditions. Using that approach we tried to design an artificial environment for our daily lives and activities associated with both physiological and psychological behavior. We developed the technique to present the mock environment and software to measure and evaluate sensibility physiologically or psychologically and a simulator to measure and evaluate sensibility that can be utilized for large scale industrial production and design of environment. Simulator to measure and analyze human sensibility (SMAS) was constructed, which was utilized to estimate human sensibility and to simulate living and office environment.

• Journal of the Korean Institute of Traditional Landscape Architecture
• /
• v.31 no.1
• /
• pp.38-47
• /
• 2013

This study was performed in order to preserve and protect the scenic sites and surrounding environment is located in the Urban Residential Area. After classifying the type of area surrounding parcels of Seongbuk-dong is located in Seongragwon, Satisfaction Survey, scenic sites designated areas for residents living near the analyzed. Research methods, Cadastral research, literature survey, field survey, and the survey was conducted. Cultural heritage awareness about the collected questionnaires of frequency analysis, and reliability analysis for cultural heritages around satisfaction, satisfaction analysis by parcel area, parcel area for the verification of specific differences regression analysis for the full-on relationship satisfaction, one-way ANOVA was conducted for each. Overall Cultural awareness analysis results, the residence is located close to the Seoul Seonjamdanji, Seongragwon, Simujang, Sanghoe Lee Tae-Joon's houses, Seoul Hanyang castle showed that cultural heritage were know unfulfilled cultural heritage. The purpose of cultural heritage visit was to break/walks. Preservation was usually level and there is no inconvenience caused as a cultural heritage. Regulatory intensity level was usually level and showed a positive reaction to the impact of cultural heritage in Seongbuk-dong image mostly. cultural heritage have a positive impact on the image of the town. but access to cultural heritage is not easy and doesn't affect the life is expected. Overall satisfaction for cultural heritages in the surrounding space, the larger the size of the lot, and higher satisfaction. Seongbuk-dong most of the residents satisfaction was higher. Small lots of residents showed low satisfaction for safety when walking at night, heritage value rise, private ownership of heritage use, harmony with surrounding environment, Building exterior, non-physical uniqueness like culture art mental. It can be interpreted that small lots of residential environment quality is low compared to the large lots, influx of residents in other regions due to the redevelopment of one of Seongbuk-dong, private ownership of heritage use. And generally lower satisfaction on the harmonization of the facility(street lights, signs, etc.). Therefore cultural heritage signs for facility expansion, cultural educational programs, will be needed to maintain the uniqueness village when scenic sites in the city center around the area of management strategy.

• Korean Journal of Heritage: History & Science
• /
• v.54 no.4
• /
• pp.246-259
• /
• 2021

Research has been conducted in various fields on a local fortress (eupseong) in the Joseon Dynasty, but the archaeological research on the prison (獄), which is part of the internal government, has not been conducted properly. Since the prison was first discovered in Gyeongju in 1997, there has been a necessity for research on the deployment and structure of the prison. This includes the office where jailers worked and had night duty and also the enclosure that keeps the prisoners inside. But the research came to a standstill because there was no comparative data. However, compared to the more recent findings of the Yeonil Prison and the Gonju Prison, we can identify that the structure was built during the early to the late Joseon Dynasty. King Sejong designed the standard prison blueprint called Anokdo (犴獄圖) in 1426 to manage prisoners nationwide and revised it once in 1439 to give better treatment during the winter and summer seasons. The Yeonil Prison operated from 1421 to 1743 and shows the structure of the prisons during the early to mid-Joseon period. It was very similar to the Gyeongju Prison on a smaller scale, which was operated until the late Joseon Dynasty with two main structures, one east and one west, and a circular fence. This structure was maintained even in the Gongju Prison during the late Joseon Dynasty, and it remains visible in photographs. The prison of the Joseon Dynasty had a circular fence with an estimated height of 3 meters and two buildings that separated male and female prisoners. The prison was divided into men on the east and women on the west with tile-roofed house structures that were difficult to escape. In front of the circular fence, there was an office with a thatched roof for the jailers and access to the prison was only possible through a double prison gate. The layout of the building reflects the improvements of the king's prison design made during Joseon Dynasty improving the environment of prisoners who are on trial and separating men and women in order to embody humanism.