• Journal of Korean Tunnelling and Underground Space Association
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• v.9 no.1
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• pp.37-47
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• 2007

The shield tunneling method has been increasingly employed to minimize environmental damages and civil complaints in the populated and developed area. A lining segment, which is a main structure of the shield tunnel, consists of joints. Conventional foreign and domestic design data have been commonly used for design practices without a specific verification of structural analysis models, design load, and the effect of soil characteristics on the performance of lining segment. In this study, the suitability of existing analytic models used for the design of shield tunnel lining segment has been evaluated through a comparison between analytical and numerical solutions. Based on the evaluation of their suitability performed in the study, a full-circumferential beam jointed spring model (1R-S0) is proposed for design practices by considering user's convenience, the applicability of field conditions and the accuracy of analysis result. By using the proposed model, the parameter analysis was performed to investigate the effects of joint stiffness, ground rigidity, joint distribution and the number of joints on the behavior of lining segment. Parameters considered in the investigation have been appeared to affect the behavior of lining segment. Among those parameters, joint stiffness has been appeared to have the most significant effect on the bending moment and displacement of lining segment.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.2
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• pp.632-638
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• 2018

Recently, damage to waterside structures, such as bridges or retaining walls, is increasing due to typhoons, flooding, aging, etc. In such cases, the damage is not limited to the structures themselves, but can include effects on a wider scale, such as the suspension of and restriction of access to the facilities, human injury, economic loss, etc. To preclude such damage, recovery methods suitable for the particular field circumstances should be applied when damage occurs. By enforcing prompt repairs, the material and human damage and losses that can occur can be minimized. Since the impact of losses caused by damage and disaster increases with the elapse of time, emergency recovery is even more important. In the emergency recovery process, appropriate repair and reinforcement is crucial. In the present study, the derivation scenarios of the emergency recovery method were applied to some field recovery cases, and their applicability was verified by comparison with the recovery methods actually used. It is expected that the results of this study will be useful for practical application, by suggesting more appropriate recovery methods.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.05a
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• pp.384-387
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• 2022

This study was conducted to design and apply simulation-based problem-based learning classes, and then analyze the effects of class management using focus group interviews. In paramedicine, practical learning that can respond to various emergency situations based on major knowledge is important. In the case of problem-based learning classes, it is suitable for operating various topics covered by the Department of Paramedicine as it can improve capabilities such as problem-solving strategies, skills, and teamwork by providing practicality related to field situations for learning. This study developed a PBL module focusing on patients with dyspnea and applied it to medical emergencies and practice courses taken by 16 third graders of S University's Paramedicine department. Overall class satisfaction was high from 4.76 to 4.92. In particular, by resetting the learning strategy through PBL classes and experiencing cooperative learning, positive learning outcomes could be obtained and self-efficacy was experienced.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.29 no.5
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• pp.483-490
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• 2016

In plant industry, sulfur storage tank is made of steel and annular plate is connected with concrete foundation of ring wall type by anchor bolt. Due to keep sulfur at high temperature in tank by coil, sulfur storage tank is expanded larger than another tank stores fluid at room temperature. Generally, structural design of tank foundation is performed analysis with loading of temperature gradient between inner and outer surface, this method can't consider the phenomenon that load is intensively transferred to concrete foundation at anchor bolt. This means that temperature load is underestimated and causes crack of concrete near anchor bolt. In this study, evaluation formula considering temperature load transfer mechanism through anchor bolt is proposed and load acting on concrete foundation is rationally decided. For this purpose, it is analyzed variation of thermal load per various anchor bolt number using finite element model including tank annular plate and anchor bolt. Solution is proposed as specified term combining result of analysis and theoretical solution for evaluating load transferred by anchor bolt. For confirmation of validation of proposed formula, it is applied in design of sulfur storage tank at plant site, it shows that the formula can be practically applied.

• International Journal of Highway Engineering
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• v.8 no.1 s.27
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• pp.131-138
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• 2006

Methods of back calculation for either design procedures or elastic moduli obtained from FWD(Falling Weight Deflectometer) tests have widely been used to predict remaining life of airfield concrete pavements. Since the variation of the elastic modulus obtained from the FWD test depends on the back calculation methods, prediction of remaining life of airfield pavement using the back calculation method has not been reliable. In addition, the FWD method only concentrates on the structural integrity of the pavement without considering functional distress. In this study, a newly developed remaining life estimation procedure is proposed. This methodology includes both structural and functional consideration and suggests models and decision criteria for each stage. In order to improve the estimation procedure on remaining life of pavement, conducted the several tests on an old airfield concrete pavement. As a result, it is concluded that the load transfer efficiency on joint is better for predicting remaining life of pavement than the elastic modulus, which is commonly used. In order to verify applicability of the newly developed estimation procedure and detailed models, investigation and analysis were conducted according to the new methodology on C-airfield pavement. Finally, it is confirmed that the efficiency of the proposed method for practical application was good enough.

• Journal of the Korea Concrete Institute
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• v.14 no.3
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• pp.291-298
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• 2002

Recently, construction of reinforced concrete tall buildings is widely increased according to the improvement of material quality and design technology. Therefore, differential shortenings of columns due to elastic, creep, and shrinkage have been an important issue. But it has been neglected to predict the Inelastic behavior of RC structures even though those deformations make a serious problem on the partition wall, external cladding, duct, etc. In this paper, analysis system for prediction and compensation of the differential column shortenings considering time-dependent deformations and construction sequence is developed using the objected-oriented technique. Developed analysis system considers the construction sequence, especially time-dependent deformation in early days, and is composed of input module, database module, database store module, analysis module, and analysis result generation module. Graphic user interface(GUI) is supported for user's convenience. After performing the analysis, the output results like deflections and member forces according to the time can be observed in the generation module using the graphic diagram, table, and chart supported by the integrated environment.

• Journal of the Korea institute for structural maintenance and inspection
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• v.20 no.1
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• pp.104-111
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• 2016

The steel frame modular housing of which the research and development has been actively carried out recently cannot be constructed through monolithic placement like the reinforced concrete deck of general structure due to the characteristics of construction method of production in the factory and assembly on the site. And floor vertical vibration and deflection caused by inhabitants' activities may become an important issue in the aspect of usability evaluation due to a decrease in the section size of member, a decrease in weight, and so on. Therefore, this study evaluated the vibration performance of deck by using formula of AISC Design Guide 11(hereinafter AISC formula) which was practically used in general for modules where a stud was and wasn't installed at the center of beam in the longitudinal direction in the modular housing to be studied, and examined the applicability of AISC formula through comparison with the results of analysis using a general-purpose analysis program. On the basis of this, a structural cause for an error to occur between analysis result and AISC formula in the deck of module in which a stud was installed was analysed, and measures for considering this were suggested. Besides, an analysis model with the variables of measures for improving the floor vibration performance of modular housing to be studied was established. And measures having excellent vibration performance and economic feasibility were suggested through vibration response analysis and economic evaluation.

• Journal of Digital Convergence
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• v.16 no.7
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• pp.107-116
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• 2018

One of the key mission is to develop and prompte the use National Competency Standards, which is defined to be the systemization of competencies(knowledge, skills and attitudes) required to perform duties at the workplace by the nation for each industrial sector and level. This provides the basis for the design of training and detailed specifications for workplace assessment. To promote the data-driven service improvement, the commercial product Splunk was introduced, and has grown to become an extremely useful platform because it enables the users to search, collect, and organize data in a far more comprehensive, far less labor-intensive way than traditional databases. Leveraging Splunk's built-in data visualization and analytical features, HRD Korea have built custom tools to gain new insight and operational intelligence that organizations have never had before. This paper analyzes the NCS homepage. Concretely, applying Splunk in creating visualizations, dashboards and performing various functional and statistical analysis and structure without Web development skills. We presented practical use and implications through case studies.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.5A
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• pp.407-415
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• 2010

In Korea, more than 90% of the total number of steel bridges built for 40~70 m span length is a steel box-girder bridge type. A steel box-girder bridge is suitable for long span or curved bridges with outstanding flexural and torsional rigidity as well as good constructability and safety. However, a steel box-girder bridge is uneconomical, requiring many secondary members and workmanship such as stiffeners and ribs requiring welding attachments to flanges or webs. Therefore, in US and Japan, a plate girder bridge, which is relatively cheap and easy to construct is generally used. One type of the plate girder bridge is the two- or three-main girder plate bridge, which is a composite plate girder bridge that minimizes the number of required main girders by increasing the distance between the adjacent girders. Also, for the simplification of girder section, the stiffener which requires attachment to the web is not required. The two-main steel girder plate bridge is a representative type of plate girder bridges, which is suitable for bridges with 10 m effective width and has been developed in the early 1960s in France. To ensure greater safety of two- or three-main girder plate bridges, a larger steel section is used in the bridge domestically than in Europe or Japan. Also, the total number of two- or three-main girder plate bridge constructed in Korea is significantly less than the steel box girder bridge due to a lack of designers' familiarity with more complex design detailing of the bridge compare to that of a steel box girder bridge design. In this study, a new construction method called Turn Over method is proposed to minimize the steel section size used in a two- or three-main girder plate bridge by applying prestressing force to the member using confining concrete section's weight to reduce construction cost. Also, a full scale 20 m Turn Over girder specimen and a Turn Over girder bridge specimen were tested to evaluate constructability and structural safety of the members constructed using Turn Over process.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.225-225
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• 2023

하상 측정은 하천 유지관리, 수공구조물 설계 및 보수, 수생태 조사의 필수적인 자료이다. 최근 4대강 대규모 사업 이후 자연적 안정화로 인해 침식 및 재퇴적이 진행되어 정밀 하상 모니터링이 요구되고 있다. 통상적인 하상 조사 기법은 레벨측량 및 RTK-GPS 등을 활용하여 점단위로 직접 계측하는 기법과 수심이 깊을 경우 ADCP와 같은 음향측심기법을 통해 하상변동을 계측하고 있다. 하지만 점단위 직접 측정은 사구와 사련과 같은 하상 구조 교란 및 계측 시 위험을 동반하고 수심자료의 측정오차가 크게 발생하는 한계점이 존재한다. 또한 초음파 방식의 경우 막음길이와 바닥면 노이즈 등의 한계점으로 50 cm 미만의 저수심부 하상 측정이 불가능한 실정이다. 이러한 한계점을 극복하기 위해 최근 드론의 보급으로 수심라이다(Bathymetry LiDAR), SFM, 드론 탑재 초분광 영상을 활용한 초분광수심법과 같은 저고도, 고해상도의 비접촉식 면단위 하상 측정 기법이 대안으로 각광받고 있고 최근 관심은 해당 최신 기술의 성능 점검 및 적용성 평가에 있다. 따라서 본 연구에서는 초분광수심법 중 보편적으로 적용할 수 있는 최적밴드비분석(OBRA)의 성능 점검과 실무 적용성을 국내 하천을 대상으로 검토하였다. 해당 기술의 실무 적용성 평가항목 중 수심 적용 범위가 경제적이고 효율적인 성능 평가의 주된 항목이다. 선행 연구에 따르면 감천을 대상으로 저수심부의 성능 평가를 진행한 결과 상세한 하상계측이 가능하다고 제시하였다. 따라서 본 연구는 낙동강-황강 합류부를 대상으로 전형적인 평수기 탁도 조건에서 초분광수심법을 적용할 경우 최대측정가능수심의 범위를 결정하는 방법 및 결과를 제시하려고 한다. 또한 현장실험 당시 합천댐 방류로 인하여 황강의 탁도가 높아진 상태에 기인하여 고탁도 조건에서 초분광수심법의 적용성 평가도 추가 검토하였다. 해당 연구는 수심과 밴드비의 비선형성을 통해 최적 밴드비 분석의 결과로 도출될 수 있는 상관계수와 평균 제곱근 오차(RMSE)의 동향을 보아 다양한 시나리오의 배제수심을 통해 최대측정가능수심을 산정하였으며 그 이상의 범위는 수심맵 산정에서 제외하였다. 그 결과로 낙동강 본류에서 2.5 m 이하, 황강 지류에서 1.25 m 이하의 최대측정가능수심이 나타났고 해당 범위 이하에서는 상세한 하상이 나타났다. 또한 고탁도 조건인 황강에서는 낙동강에 비해 절반 수준의 최대측정가능수심 범위가 나타나 탁도 조건에 따른 초분광수심법의 한계가 있는 것을 확인하였다.