• Journal of the Korean Wood Science and Technology
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• v.52 no.5
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• pp.405-422
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• 2024

This study investigated the resistance of domestic wood species used as wood members in general wood construction and Korean wood cultural properties to the termite Reticulitermes speratus using no-choice and two-choice tests. The results of the no-choice experiment confirmed that hardwood has higher termite resistance than that of softwood. In addition, R. speratus prefers softwood, including Abies holophylla, which has low density, is easy to feed on, and does not contain repellent extracts. In a two-choice test, Zelkova serrata was found to be the most termite-resistant wood species used in wooden cultural buildings. In addition, we investigated the effects of different wood extraction methods and their components on termite resistance. The cold-water extraction of softwood increased the feeding activity of termites; however, the cold-water extraction of hardwood had little effect on the feeding activity of termites. In natural environments with repeated exposure to moisture, such as rainfall, water-soluble extracts present in wood species are relatively more likely to dissolve and removed, making softwood more likely to be damaged by termites than hardwood. Untreated Quercus variabilis showed an extremely weak feeding activity of termites compared with that in other wood species; however, feeding termites with the alcohol-benzene extract of Q. variabilis had no inhibitory effect on their feeding activity. Therefore, we believe that the high density of Oriental cork oak wood inhibits the feeding activity of R. speratus. In contrast, the alcohol-benzene extracts of Z. serrata, Prunus sargentii, and Castanea crenata showed a strong inhibition of the feeding activity of termites.

• Steel and Composite Structures
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• v.53 no.1
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• pp.103-114
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• 2024

This study proposes a new hybrid approach that utilizes post-earthquake survey data and numerical analysis results from an evolving finite element routing model to capture vulnerability processes. In order to achieve cost-effective evaluation and optimization, this study introduced an online data evolution data platform. The proposed method consists of four stages: 1) development of diagnostic sensitivity curve; 2) determination of probability distribution parameters of throughput threshold through optimization; 3) update of distribution parameters using smart evolution method; 4) derivation of updated diffusion parameters. Produce a blending curve. The analytical curves were initially obtained based on a finite element model used to represent a similar RC building with an estimated (previous) capacity height in the damaged area. The previous data are updated based on the estimated empirical failure probabilities from the post-earthquake survey data, and the mixed sensitivity curve is constructed using the update (subsequent) that best describes the empirical failure probabilities. The results show that the earthquake rupture estimate is close to the empirical rupture probability and corresponds very accurately to the real engineering online practical analysis. The objectives of this paper are to obtain adequate, safe and affordable housing and basic services, promote inclusive and sustainable urbanization and participation, implement sustainable and disaster-resilient buildings, sustainable human settlement planning and management. Therefore, with the continuous development of artificial intelligence and management strategy, this goal is expected to be achieved in the near future.

• Journal of the Korea Institute of Building Construction
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• v.15 no.5
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• pp.483-489
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• 2015

The Purpose of this study was to establish the basic data on the mechanical properties of PCM in the high temperature range. To this end, an experiment was conducted on the characteristics of the residual compressive strength by temperature (100, 200, 400 and $600^{\circ}C$) with a fixed temperature heating. An after heating test was performed to investigate the properties after fire damage. The result showed that the residual compressive strength of PCM had a tendency to decrease, regardless of the type of polymer. It was also found that when the contents were low, the residual compressive strength started to greatly decrease from the high temperature range of $400^{\circ}C$, and that the specimen containing PAE showed a steeper slope than the specimen containing EVA. However, since little studies have been conducted on the mechanical properties of PCM with the high temperature, it is considered that, in addition to this study, basic studies must be preceded, including studies on the repairing methods.

• The Journal of Engineering Geology
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• v.28 no.2
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• pp.267-276
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• 2018

Volcanic ash from volcanic eruptions spreads to vast areas hundreds of kilometers away, and when volcanic ash flows into surface waters, it will be damaged by water supply. In case of water supply facilities, it provides to people drinking water and domestic water, be consumed by the people cause social disorder when water supply is cut off due to damage such as water pollution caused by harmful materials of volcanic ash. However, when we looked at the disaster management manual, the establishment of a water supply facility manual to deal with the damage of volcanic ash was found to be insufficient. Therefore, in this study, the existing volcanic and water pollution related manuals were analyzed and problems were derived. In order to make quick situation judgment and response activities, we have suggested the scope of the water supply facility manual, disaster type, major missions and system of related organizations, and scenario of crisis situation by disaster type.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.7
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• pp.105-111
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• 2018

This study aims to evaluate the safety for cable stayed bridge due to damages on the cable system. Many cable supported bridges, including cable stayed bridge and suspension bridge, have been built in the Korean peninsula. This requires efficient maintenance and management since this structure has complex structural components and system. This large structure also often faces risks either from manmade or natural phenomenon. In 2015 one cable-stayed bridge in South Korea had been struck by a bolt of lightning on the cables. This event had led to fire on cables. These cables had been damaged and putting the bridge at risk. This bridge was back in used after a few weeks of investigations and replacements of the cables. However, enormous social and economic expense were paid for recovery. After this event risk based management for infra structures is required by public demands. Therefore, this study was initiated and aimed to evaluate risks on the cable system due to potential damages. In this paper one cable-stayed bridge in South Korea was selected and investigated its safety based on the damage scenarios of cable system for efficient and prompt management, and for supporting decision making. FEM analysis was conducted to evaluate the safety of the bridges due to damages on the cable system.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.7
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• pp.88-94
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• 2018

This study examined the safety of a cable stayed bridge caused by damage to the cable system. Many cable-supported bridges, including cable-stayed bridges and suspension bridges, have been constructed on the Korean peninsula. This requires efficient maintenance and management because this structure has complex structural components and systems. This large structure also often faces risks either from manmade causes or natural phenomena. In 2015, the cables on one cable-stayed bridge in South Korea was struck by lightning, which led to a fire on the cables. These cables were damaged, which put the bridge at risk. This bridge was back in use after a few weeks of investigations and replacements of the cables but this was done at enormous social and economic expense. After this event, risk-based management for infrastructure is required by public demand. Therefore, this study examined the risks on the cable system due to potential damage. In this paper, a one cable-stayed bridge in South Korea was selected and its safety was investigated based on the damage scenarios of cable system for efficient and prompt management, and to support decision making. FEM analysis was conducted to evaluate the safety of the bridges after damage to the cable system.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.27 no.5
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• pp.437-450
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• 2014

In this study, we developed a methodology to determine the reference parameter for an aircraft impact induced risk assessment of nuclear power plant (NPP) using finite element impact analysis of containment building. The target structure used to develop the method of reference parameter selection is one of the typical Korean PWR type containment buildings. We composed a three-dimensional finite element model of the containment building. The concrete damaged plasticity model was used for the concrete material model. The steels in the tendon, rebar, and liner were modeled using the piecewise-linear stress-strain curves. To evaluate the correlations between structural response and each candidate parameter, we developed Riera's aircraft impact force-time history function with respect to the variation of the loading parameters, i.e., impact velocity and mass of the remaining fuel. For each force-time history, the type of aircraft is assumed to be a Boeing 767 model. The variation ranges of the impact velocity and remaining fuel percentage are 50 to 200m/s, and 30 to 90%, respectively. Four parameters, i.e., kinetic energy, total impulse, maximum impulse, and maximum force are proposed for candidates of the reference parameter. The wellness of the correlation between the reference parameter and structural responses was formulated using the coefficient of determination ($R^2$). From the results, we found that the maximum force showed the highest $R^2$ value in most responses in the materials. The simplicity and intuitiveness of the maximum force parameter are also remarkable compared to the other candidate parameters. Therefore, it can be concluded that the maximum force is the most proper candidate for the reference parameter to assess the aircraft impact induced risk of NPPs.

• Fire Science and Engineering
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• v.28 no.6
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• pp.82-89
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• 2014

Disasters that destroy homes and infrastructure and cause significant financial damage are becoming more common as population centers grow. In addition, several natural disasters have resulted in a major loss of life and created countless refugees due to damage to housing. After major catastrophic disasters, it is very important that the government agencies respond to post-disaster housing issues and provide resources such as temporary housing before the full rehabilitation and reconstruction of destroyed and damaged housing. To provide affordable temporary housing for residents who may lose their homes as the result of a catastrophic disaster including storms, government agencies must develop a post-disaster housing prototype. In general, government agencies should explore several different forms of factory-built single-story, single family housing, such as modular homes, panelized homes, and precut homes. In urban cities including New York and Seoul, it is very important to provide housing which supports the demand for higher-density living spaces than single-family homes or trailers typically available due to the high population density and the desire to resettle as many residents as possible in their former neighborhoods. This study identified the urban post-disaster housing prototypes that may provide higher density housing with high quality living spaces, high air quality, and energy efficiency as well as rapid deployment. A case study of "Urban Post-Disaster Housing Prototype Program in New York" was conducted through a detailed interview process with a designer, engineer, contractor, the Office of Emergency Management (OEM) in New York, the U.S. Army Corps of Engineers (USACE), and temporary occupants. An appropriate disaster housing program that can provide living spaces for victims of disasters that keeps residents in their community and allows them to live and work in their neighborhoods was developed.

• Journal of Wetlands Research
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• v.17 no.4
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• pp.370-379
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• 2015

In recent, the natural disaster like localized heavy rainfall due to the climate change is increasing. Therefore, it is important issue that the precise observation of rainfall and accurate spatial distribution of the rainfall for fast recovery of damaged region. Thus, researches on the use of the radar rainfall data have been performed. But there is a limitation in the estimation of spatial distribution of rainfall using rain gauge. Accordingly, this study uses the Kriging method which is a spatial interpolation method, to measure the rainfall field in Namgang river dam basin. The purpose of this study is to apply KED(Kriging with External Drift) with OK(Ordinary Kriging) and CK(Co-Kriging), generally used in Korea, to estimate rainfall field and compare each method for evaluate the applicability of each method. As a result of the quantitative assessment, the OK method using the raingauge only has 0.978 of correlation coefficient, 0.915 of slope best-fit line, and 0.957 of $R^2$ and shows an excellent result that MAE, RMSE, MSSE, and MRE are the closest to zero. Then KED and CK are in order of their good results. But the quantitative assessment alone has limitations in the evaluation of the methods for the precise estimation of the spatial distribution of rainfall. Thus, it is considered that there is a need to application of more sophisticated methods which can quantify the spatial distribution and this can be used to compare the similarity of rainfall field.

• Journal of the Korea Institute of Building Construction
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• v.22 no.1
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• pp.91-102
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• 2022

Many industries are being severely damaged by COVID-19, a respiratory infection that has recently been prevalent around the world. In particular, for workers in the construction industry, it is impossible to work from home, and if an outbreak on a construction site is confirmed, it can lead to great damage. Accordingly, the government has drafted 「Guidelines for Response to Construction Sites for Prevention and Spread of COVID-19」. In addition, domestic and foreign research about COVID-19 in the field of construction sites is being actively conducted. However, Korea has lacked studies on the effectiveness of the countermeasures in place at construction sites, or that reflect the opinions of construction site workers. Therefore, this study conducted a survey of construction site workers by dividing the construction of the COVID-19 quarantine management system and response plan into on-site management and social management. Through the AHP/IPA analysis, it was found that among social management, 'infectious disease management system and cooperation system with related institutions' and 'reduction of working hours' are areas with high importance but low satisfaction. After that, the causes of the two items were analyzed and related countermeasures were suggested. The results of this study will be able to contribute to the improvement of the quarantine management system and response plan at construction sites, and to minimize the damage to the construction industry related to COVID-19.