• International conference on construction engineering and project management
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• 2009.05a
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• pp.432-439
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• 2009

This research project was carried out to develop the technique to assess quantitatively and rapidly the stability of a tunnel by using the measured displacement at the tunnel construction site under excavation. To achieve this purpose, a critical strain concept was introduced and applied to an assessment of a tunnel under construction. The new technique calculates numerically the strains of the surrounding ground by using the measured displacements during excavation. A numerical practical system was developed based on the proposed analysis technique in this study. The feasibility of the developed analysis module was verified by incorporating the analysis results obtained by commercial programs into the developed analysis module. To verify the feasibility of the developed analysis module, analysis results of models both elastic and elasto-plastic grounds were investigated for the circular tunnel design. Then the measured displacements obtained in the field are utilized practically to assess the safety of tunnels using critical strain concept. It was verified that stress conditions of in-situ ground and ground material properties were accurately assessed by inputting the calculated displacement obtained by commercial program into this module for the elastic ground. However for the elasto-plastic ground, analysis module can reproduce the initial conditions more closely for the soft rock ground than for the weathered soil ground. The stability of tunnels evaluated with two types of strains, that is, the strains obtained by dividing the crown displacement into a tunnel size and the strains obtained by using the analysis module. From this study, it is confirmed that the critical strain concept can be fully adopted within the engineering judgment in practical tunnel problems and the developed module can be used as a reasonable tool for the assessment of the tunnel stability in the field.

• Korean Journal of Construction Engineering and Management
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• v.17 no.2
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• pp.80-89
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• 2016

Recently, the paradigm shift of new construction into efficient operation and maintenance of infrastructure is seen. Also, concerns about infrastructure safety, especially the aged infrastructure, are on the increase. This study evaluates the current status of infrastructure safety and maintenance using data from 1994 to 2014 in Facility Management System operated by Korea Infrastructure Safety Corporation. Also, a quantitative analysis of safety performance of infrastructure is conducted to find out the enhancement of infrastructure safety in Korea. It was found that safety of facilities in Korea have been enhanced for the past decades. Improvement of safety performance of facilities is attributed to periodic safety inspection and repair and reinforcement. The result of the study can be used as a basic material for efficient and effective facility maintenance policies and strategies.

• Proceedings of the Korea Water Resources Association Conference
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• 2005.09b
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• pp.1245-1246
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• 2005

• Journal of Korean Tunnelling and Underground Space Association
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• v.17 no.5
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• pp.553-561
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• 2015

In this study, the performance assessment criterion for reasonable maintenance of shield TBM tunnel was presented. The performance assessment items such as crack, leakage, breakage, spalling, exfoliation/detachment, efflorescence, quality condition, exposure of steel, carbonation, faulting step, bolts condition, drainage condition, ground condition, contact section condition and conduit condition were selected by analyzing domestic and foreign performance assessment criterions and investigating segment lining deterioration cases through the site investigation and in-depth inspection analysis result on the shield TBM tunnel. In addition, the reasonable weight using AHP (Analytic Hierarchy Process) were estimated.

• Journal of the Korean Society of Safety
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• v.30 no.6
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• pp.56-62
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• 2015

Recently, one of countermeasures against aging SOC infrastructures, performance-focused management including the serviceability, functionality, durability, and economics has been changed from the structural safety-focused evaluation has changed into The current inspection and diagnosis for the major SOC facilities in Korea has been carried out by the specific principle of details, and most of them checked by the visual inspection are focused on the repair and rehabilitation of the damaged structures, thus they are the preventive maintenance. However, the performance-focused management should be replaced for the effective and economic maintenance as wells as for the minimization of the damage. In this regard, this study the appropriacy of the current evaluation items about the concrete retaining wall, one of SOC infrastructures as the previous step forward the performance-focused management. In order to deduct the effective evaluation items in order, the entropy, analytic hierachy process (AHP), and promethee analysis were peformed and the results were compared and discussed.

• The Journal of Engineering Geology
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• v.21 no.4
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• pp.361-367
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• 2011

The uniaxial compressive strength (UCS) is an important factor in the design and construction of surface and underground structures. However, the method employed to measure UCS is time consuming and expensive to apply in the field. Therefore, we developed a model to estimate UCS based on a few properties using linear regression analysis, which is a statistical method. To develop the model, valid factors from the test results were selected from a correlation analysis using a statistical program, and the model was formulated by linear regression based on the relationships among factors. UCS estimates derived from the model were compared with the results of UCS tests, to assess the reliability of the model. The relationship between rock properties and UCS indicates that the factors with the greatest influence on UCS are point load strength and shape facto r. The UCS values obtained using the model are in good agreement with the results of the UCS test. Therefore, the developed model may be used to estimate the UCS of rocks in regions with similar conditions to those of the present study area.

• 한국IT서비스학회:학술대회논문집
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• 2010.05a
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• pp.211-215
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• 2010

본 연구 성과는 국내토목구조물의 유지관리 업무를 지원하는 분야에 해당한다. 현재 우리나라 토목시설물은 법정비를 통해, 유지관리업무를 체계화시켜나가고 있는 상태이지만, 아직 그 결과물에 대한 DB 시스템이 일반화 되어 있지 못하며, 일부 개발된 툴들도 서로간의 유기적인 연결은 부족하다. 본 연구를 통해 개발한 지하구조물 유지관리 DB시스템을 이용해서 시설물 관리주체, 진단업체, 유지관리업체들이 상호간에 유기적으로 연결되고 효율적으로 데이터들을 관리할 수 있는 시스템을 제안하여, 국내 기간산업의 유지관리 업무 효율성을 높이는데 이바지 하고자 한다.

• Journal of the Korean Institute of Gas
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• v.12 no.2
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• pp.63-68
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• 2008

The ubiquitous technology is capable of innovating various area to constructing intelligent and network to all objects. This technology can construct network infrastructure to facilities for applying legacy industry and need to develop intelligent service that analyze context-aware through network. This paper derive and propose the introduction range of ubiquitous technology, which should be testified and analyzed network, and studied the detection and analysis of information for managing gas facilities. We investigate the current status of gas facilities and automatic reading system, testing and analyzing wireless personal area network and mobile communication by scalability, self-configuration, connection in underground. Furthermore, we propose modelization method for intelligent service and derive the introduction range for applying ubiquitous technologies for managing gas facilities.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.03a
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• pp.1304-1312
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• 2008

In this study, the analysis to the preference level on slope measuring instrument of weight values on effect factors find out the reasonable monitoring on slope was performed, in which used AHP(Analytic Hierarchy Process) techniques. The results on professional group, such as the industry, academic, institute and government, analyzed that the very important effect factors, which were indicator of various collapse type, convenience of instrument management, The evaluation of preference level on the slope measuring instrument analyzed the invar wire extensometer which was high level at convenience of install, economical efficiency of install and convenience of instrument management.

• Structural Engineering and Mechanics
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• v.17 no.5
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• pp.707-725
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• 2004

An optimal design method with nonlinear elastic analysis is presented. The proposed nonlinear elastic method overcomes the drawback of the conventional LRFD method that accounts for nonlinear effect by using the moment amplification factors of $B_1$ and $B_2$. The genetic algorithm used is a procedure based on Darwinian notions of survival of the fittest, where selection, crossover, and mutation operators are employed to look for high performance ones among sections in the database. They are satisfied with the constraint functions and give the lightest weight to the structure. The objective function taken is the total weight of the steel structure and the constraint functions are strength, serviceability, and ductility requirement. Case studies of a planar portal frame, a space two-story frame, and a three-dimensional steel arch bridge are presented.