• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.302-311
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• 2008

There have been repetitive landslides and debris flows on natural terrain induced by intensive rainfalls which have never been experienced during the last a few decades in Korea. Frequencies and magnitudes of landslides and debris flows are steeply increased after 2000 resulting in huge damages of human beings and facilities. According to a statistical data from NEMA, the human deaths induced by landslides and slope hazards occupies 22.3% of the total human deaths by all the natural hazards in Korea during the last 30 years. Among the human deaths by landslides and slope hazards, 85% of the damages were caused by landslides and debris flows on natural hazards. Therefore, this paper summarizes important events of landslides and debris flows, their characteristics, and suggests some methods of damage mitigation.

• Journal of the Korean Society of Hazard Mitigation
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• v.10 no.6
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• pp.139-145
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• 2010

Recently, close-to-nature stream improvement works have been carried out in urban streams, where eco-friendly bank revetment methods have been adopted. These bank revetment methods are vulnerable to be damaged or washed away by floods compared to the traditional methods which use concrete materials. Damage analysis methods on the urban streams by the floods of severe rain storm are presented. The analysis methods are the graph-using method and the grid method, which are derived from the survey results at Gwangju stream. Damage analysis grid which is intersected velocity grid and material strength grid is the highest correlation with the damage survey grid. The biggest damage on the bank revetments have been occurred around the crossing structures. Big damages have also been occurred in the connection of low water revetment and the terrace land, and around the structures in the terrace land of the stream.

• Journal of the Korean Society of Hazard Mitigation
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• v.9 no.6
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• pp.57-68
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• 2009

Recently, damage scale of human-induced disaster is sharply increased but its occurrences and damages are so uncertain that it is hard to construct a resonable response & mitigation plan for infrastructures. Therefore, the needs for a advanced risk management technique based on a probabilistic and stochastic risk evaluation theory is increased. In this study, these evaluation methods were investigated and a advanced disaster risk evaluation method, which is based on the probabilistic or stochastic risk assessment theory and also is a quantitative evaluation technique, was suggested. With this method, the safety changes as the result of fire damage management for recent 40 years was analyzed. And the result was compared with that of Japan. Through the consilience of the traditional risk assessment method and this method, a stochastical estimation technique for the uncertainty of future disaster's damage could support a cost-effective information for a resonable decision making on disaster mitigation.

• Smart Structures and Systems
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• v.14 no.4
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• pp.595-615
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• 2014

This study aims to investigate the relationship between structural damage and sensitivity indices using the Hilbert-Huang transform (HHT) method. Two damage detection indices are proposed: the ratio of bandwidth (RB), and the ratio of effective stiffness (RES). The nonlinear four bays multiple degree of freedom models with various predominant frequencies are constructed using the SAP2000 program. Adjusted PGA earthquake data (Japan 311, Chi-Chi 921) are used as the excitations. Next the damage detection indices obtained using the HHT and the fast Fourier transform (FFT) methods are evaluated based on the acceleration responses of the structures to earthquakes. Simulation results indicate that, the column of the 1 st floor is the first yielding position and the RB value is changed when the RES<90% in all cases. Moreover, the RB value of the 1 st floor changes more sensitive than those from the top floor. In addition, when the structural response is nonlinear (i.e., RES<100%), the RB and the RES curves indicate the incremental change in the HHT spectra. However, the same phenomenon can be found from FFT spectra only when the stiffness reduction is large enough. Therefore, the RB estimated from the smoothed HHT spectra is an effective and sensitive index for detecting structural damage.

• Journal of the Korean Society of Hazard Mitigation
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• v.5 no.4 s.19
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• pp.85-93
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• 2005

It has been commonly assumed that during the 21st century, the korean peninsula may suffer huge earthquake damage to people, society, and economic system. The recent report of "Seoul Earthquake Response model development" conducted by the city of Seoul indicated that a magnitude 6.3 earthquake possibly hit Seoul, the capital of Korea. However, due to the insufficient amount of study on seismic performance of structures reflecting the various types of element peculiar to Korea application of the currently available earthquake damage evaluation methods has limitations. In order to conduct various studies on seismic hazards that are suitable for the actual conditions in Korea, therefore, fundamental studies first have to be properly conducted. The purpose of this study is to serve as the basis of establishing a reliable earthquake damage estimation system, and to provide essential data for the seismic damage evaluation of nonseismically reinforced concrete apartment structures. In this study, a standard type of nonseismically reinforced concrete apartments has been determined based on an extensive survey and careful review of such structures in Korea, and their performance level on seismic loading has been estimated.

• Geomechanics and Engineering
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• v.37 no.1
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• pp.21-29
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• 2024

The effective management of damage in tunnels is crucial for ensuring their safety, longevity, and operational efficiency. In this paper, we propose an educational management model tailored specifically for addressing damage in tunnels, utilizing numerical solution techniques. By leveraging advanced computational methods, we aim to develop a comprehensive understanding of the factors contributing to tunnel damage and to establish proactive measures for mitigation and repair. The proposed model integrates principles of tunnel engineering, structural mechanics, and numerical analysis to facilitate a systematic approach to damage assessment, diagnosis, and management. Through the application of numerical solution techniques, such as finite element analysis, we demonstrate the efficacy of the proposed model in simulating various damage scenarios and predicting their impact on tunnel performance. Additionally, the educational component of the model provides valuable insights and training opportunities for tunnel management personnel, empowering them to make informed decisions and implement effective strategies for ensuring the structural integrity and safety of tunnel infrastructure. Overall, the proposed educational management model represents a significant advancement in tunnel management practices, offering a proactive and knowledge-driven approach to addressing damage and enhancing the resilience of tunnel systems.

• Journal of Korean Society of Rural Planning
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• v.16 no.2
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• pp.31-45
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• 2010

Building a dam that is not considering the environmental impact and human social impact can cause the loss of entire ecospheres such as fragmentary green network, disturbance of plants ecosystem, the destruction of social and cultural indigenous resources, therefore, it can occur the environment change and distortion of ecosystem. The purpose of this study is that presenting the methods of ecosystem maintenance and ecosystem damage compensation about for environmentally direct impact i.e. the ecosystem change in the intended place for building a dam. According to the planning progress, the study was proceeded to planning site examine, assessment, conception plan. As the results of examine and assessment, it must be necessary to offered the maintenance and damage compensation if the site where include the 1st degree of biotope area, the 2nd degree of biotope and the 8th degree of green naturality area were damaged by being submerged and constructing road. In addition, according to the conception plan, we suggest the mitigation proposals such as plant communities transplant, planning of connecting green network against for influencing direct impact ecosystem that is destroying plant communities, damaging inhabitants, noise pollution, water pollution, etc.

• Journal of the Korea Safety Management & Science
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• v.13 no.1
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• pp.1-9
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• 2011

It is a significant issue for several country including Korea, where the natural and the weather conditions are severe, to keep the safety against disasters which occur frequently every year, especially in urban region crowded with population. In order to implement suitable and effective measures against various disasters in such area, development of method for evaluation of disaster prevention performance based on various disaster risks and effective disaster damage mitigation technologies is independable. In this paper, methods for hazard evaluation, vulnerability evaluation and loss evaluation, and damage technologies are proposed targetting man-made disaster and natural one like flood, earthquake and tsunami and so on. The method proposed in this paper is based on the research of USA and Japan for man-made disaster and natural disaster. The proposed method will be developed in detail in four years during research period funded by government.

• Journal of the Korean Society of Hazard Mitigation
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• v.8 no.6
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• pp.31-36
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• 2008

A water distribution system should be constructed reasonably to supply water for the customer with proper quality and pressure as demands at nodes fluctuate with time. Also it should be reliable to minimize undesirable effects on the customer when various accidents happen such as pipe failures. A new method is presented here to reduce damages by pipe failures. For the work, two methods, namely, the method for estimating practical extent of damage by pipe failures and for estimating water distribution reliability, are adopted to analyze a water distribution system and to explore the damage reduction by pipe failures. As the results from the analysis of the model, the damage can be reduced effectively by increasing durability of each pipe in minimum cutsets according to the order of priority. The suggested method was applied to the Cherry-Hill network to verify its applicability.

• Journal of the Korean Society of Hazard Mitigation
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• v.10 no.5
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• pp.41-47
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• 2010

For the enhancement of structural safety of thermally damaged reinforced concrete structure, rapid evaluation of damage in the structure is very important. This study addresses a simplified method which is equivalent to the standard fire curve (ISO 834) for the residual bond strength evaluation. In the proposed method, a exposure duration as well as the maximum temperature can be considered. For the comparisons with conventional methods, concrete properties obtained from the report of Daegu subway fire accident were referred and the results support the applicability of the proposed method in this study.