• Journal of the Korean Geotechnical Society
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• v.31 no.1
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• pp.15-24
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• 2015

This paper presents the results of a reduced-scale physical model investigation into the effect of drilling fluid with different mix designs for bore hole collapse prevention. The bore hole collapse prevention mechanism for the bentonite based drilling fluid was first discussed together with the effect of conditioning with different additives on engineering characteristics of bentonite based drilling fluid. Reduced-scale model tests were then carried out considering field procedures for cases with a decomposed granitic soil with 20% fines and a sand with various drilling fluids with different mix designs. The results indicated that the addition of polymer to the bentonite based drilling fluid decreases the amount of drilling fluid injected, the drilling fluid infiltration thickness and increases the final depth of excavation. Also revealed is that the effect of polymer on the performance of drilling fluid is more pronounced in the decomposed granite soil with 20% fines than the sand. Practical implications of the findings from this study are discussed in great detail.

• Journal of the Korea institute for structural maintenance and inspection
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• v.19 no.3
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• pp.48-54
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• 2015

In this study, we propose an innovative lateral force distribution building system between tall buildings by utilizing the difference of moment of inertia, resulting the reduction of lateral displacement and the lateral forces in terms of an alternative for the dense human and increased cost of lands in highly integrated city area. A successive collapse prevention means by providing additional bearing plate between connections is proposed. In addition to that, a more economical vibration reduction is expected due to the suggested tuned mass damper on the surface of spacial structure. In the considered verification examples, reduced drifts at the top location of the building systems are validated against static wind pressure loads and static earthquake loads. The suggested hybrid building system will improve the safety and reliability of the new or existing building system in terms of more than 30% reduced drift and vibration through the development of convergence of tall buildings and spatial structures.

• International Journal of High-Rise Buildings
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• v.4 no.1
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• pp.65-73
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• 2015

Detailed finite element (FE) analyses of a full-scale four-story steel frame structure, subjected to consecutive 60% and 100% excitations from the JR Takatori records during the 1995 Hyogoken-Nanbu earthquake, are conducted using E-Simulator. The four-story frame was tested at the largest shake-table facility in the world, E-Defense, in 2007. E-Simulator is a parallel FE analysis software package developed to accurately simulate structural behavior up to collapse by using a fine mesh of solid elements. To reduce computational time in consecutive dynamic time history analyses, static analysis with gravity force is introduced to terminate the vibration of the structure during the analysis of 60% excitation. An overall sway mechanism when subjected to 60% excitation and a story mechanism resulting from local buckling of the first-story columns when subjected to 100% excitation are simulated by using E-Simulator. The story drift response to the consecutive 60% and 100% excitations is slightly smaller than that for the single 100% excitation.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.825-830
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• 2005

Cut slope and facility of management investigation is the protection of humans and properties. it is very important the prevention of disaster facility and the damage of the slope protection facility. It is very difficult to forecast slope stability, disaster possibility and collapse. It will be able to minimize the damage which it prepare against slope facility and cut slope of deformable investigation and collapse and the disaster. therefore those deformable investigation is important. Investigations execute upheaval, crack, sliding for slope and cut slope reinforcement. Investigation executes forecast in place where the construction problem, the effect which the damage in road traffic or the contiguity facility.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2020.11a
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• pp.113-114
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• 2020

During the construction work, many deaths and injuries have occurred in the formwork. This study aims to analyze the perceptions of construction workers about the disaster of formwork collapse. In this study, the IPA(Importance-Performance Analysis) technique was used to analyze the perception of construction workers and derive urgent factors for improvement. As a result of IPA analysis, the fourth quadrant factor needed to be improved first, and the second quadrant factor needed effort distribution. Therefore, it is judged that this study can be used as basic data for safety management and disaster prevention activities.

• The Journal of Engineering Geology
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• v.30 no.4
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• pp.663-671
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• 2020

Recently, there have been many natural disasters in Korea, not only in forest areas but also in urban areas, and the national requirements for them are increasing. In particular, there is no pre-disaster information system that can systematically manage the collapse of the slope of the national highway. In this study, big data analysis was conducted on the factors causing slope collapse based on the detailed investigation report on the slope collapse of national roads in Gangwon-do and Gyeongsang-do areas managed by the Cut Slope Management System (CSMS) and the basic survey of slope failures. Based on the analysis results, a slope collapse risk prediction model was established through Adaboost, a classification-based machine learning model, reflecting the collapse slope location and weather information. It also developed a visualization map for the risk of slope collapse, which is a visualization program, to show that it can be used for preemptive disaster prevention measures by identifying the risk of slope due to changes in weather conditions.

• Journal of the Korean Society of Safety
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• v.17 no.2
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• pp.106-111
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• 2002

Recently the car and elevator accidents as well as the fire, explosion and collapse increased. The passenger elevator accident from 1993 year to 2001 year has about 56.7% of total accidents and the human victims of 180 according to the Korea Elevator Safety Institute. Accident cause and prevention were investigated for the elevator having the fall, impact and narrowness accident types. The prevention and protection methods of the elevator accident from analysis results were suggested by comparing and analogizing the accident statistics about the accident investigation of the passenger elevator according to the elevator accidents.

• Journal of the Earthquake Engineering Society of Korea
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• v.20 no.3
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• pp.181-190
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• 2016

The objective of this study is to apply performance-based seismic design to high-rise apartment buildings in Korean considering collapse prevention level. The possible issues during its application were studied and the suggestions were made based on the findings from the performance-based seismic design of a building with typical residential multi-unit layout. The lateral-force-resisting system of the building is ordinary shear walls system with a code exception of height limit. In order to allow the exception, the serviceability and the stability of the ordinary shear wall structure need to be evaluated to confirm that it has the equivalent performance as the one designed under the Korean Building Code 2009. The structure was evaluated whether it satisfied its performance objectives to withstand Service Level and Maximum Considered Earthquake.

• Journal of the Korean Geosynthetics Society
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• v.15 no.4
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• pp.43-52
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• 2016

This paper presents the results of a engineering characteristic to the effect of drilling fluid with different mix designs for use in bore hole collapse prevention. The bore hole collapse prevention mechanism for the bentonite based drilling fluid was first discussed together with the effect of conditioning with different additives on engineering characteristics of bentonite based drilling fluid. As result, bentonite with polymer have a outstanding characteristics as compared to CMC Properties thickening effect In the case of sea water with attatulgite be superior to bentonite. Therefore, in this paper presented qualitative result on the performance of the drilling fluid depending on the water.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2018.05a
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• pp.567-568
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• 2018

In recent years, there have been frequent occurrences of collapsing buildings and tilting accidents due to frequent earthquakes and aging of buildings. Various methods have been proposed to prevent disasters on these buildings. In this paper, we propose a system algorithm that provides an indication of anomalous phenomena such as collapse and tilting of buildings by real - time monitoring of IoT (Internet of Things) - based architectural anomalies. The multi-advanced sensor is based on the Inclinometer sensor and the Accelerometer sensor, transmits the detected data to the server in real time, accumulates the data, and provides the service to cope when the set threshold value is different. It is possible to evacuate and repair the collapse and tilting of the building by warning the occurrence of the upper threshold event event such as the collapse and tilting of the building.