• Journal of the Korea institute for structural maintenance and inspection
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• v.22 no.5
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• pp.91-100
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• 2018

The new seismic retrofit system in study propose is the Dual system, which aims to be applied to the seismically vulnerable low-story buildings. The Dual system is composed of existing structure, external retrofit frame and hysteretic steel dampers installed between former two components. The Dual system dissipates the energy by plastic deformation of steel damper caused by relative displacement due to the differences in stiffness, weight, and eigenperiod of each components. The dynamic test with shaking table was performed to verify the seismic performance of the proposed Dual system. As a result of the dynamic test, it is expected that the Dual system will improve the seismic performance due to the reduction of strain of 56% and the damage reduction of 93%, even though the energy is 1.84 times higher than that of the dual system. And the results of the study are presented as basic data of the study for setting the design range of the dual system.

• Proceedings of the Korean Society for Rock Mechanics Conference
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• 2000.09a
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• pp.171-181
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• 2000

Many Studies of tunnel and tunnelling safety have been developed continuously based on the increasing social interests in underground space since 1990's in Korea. Because the growth of population in metropolitan has been accelerated at a faster pace than the development of the cities, underground facilities have been created as a great extent in view of less land space available. In this study, a lot of types of tunnel failure were surveyed and the detail causes were studied after many cases of tunnel failure were collected. There were suggested brief countermeasure of tunnel failure through case study. An expert system was developed to predict the safety of tunnel and choose proper tunnel reinforcement system using fuzzy quantification theory and fuzzy inference rule based on tunnel information database. The comparison result between the predicted reinforcement system level and measured ones was very similar. In-situ data were obtained in three tunnel sites including subway tunnel under Han river. This system will be very helpful to make the most of in-situ data and suggest proper applicability of tunnel reinforcement system developing more resonable tunnel support method from dependance of some experienced experts for the absent of guide.

• Tunnel and Underground Space
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• v.10 no.3
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• pp.418-429
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• 2000

Many Studies of tunnel and tunnelling safety have been developed continuously based on the increasing social interests in underground space since 1990's in Korea. Because the growth of population in metropolitan has been accelerated at a faster pace than the development of the cities, underground facilities have been created as a great extent in view of less land space available. In this study, a lot of types of tunnel failure were surveyed and the detail causes were studied after many cases of tunnel failure were collected. There were suggested brief countermeasure of tunnel failure through case study. An expert system was developed to predict the safety of tunnel and choose proper tunnel reinforcement system using fuzzy quantification theory and fuzzy inference rule based on tunnel information database. The comparison result between the predicted reinforcement system level and measured ones was very similar. In-situ data were obtained in three tunnel sites including subway tunnel under Han river. This system will be very helpful to make the most of in-situ data and suggest proper applicability of tunnel reinforcement system developing more resonable tunnel support method from dependance of some experienced experts for the absent of guide.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.12
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• pp.5984-5989
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• 2011

The buckling strength of a pin-ended column may be increased significantly by reinforcing it with an assemblage of cross-arm members rigidly connected to the modpoint of the column and stayed members connecting the ends of the columns and cross-arm members. The purpose of the stays and cross-arm members is to introduce restraint against translation and rotation and thereby decrease the effective buckling length of the column. In this study, buckling strengths of the reinforced columns were quantitatively evaluated from analytical solutions and elastic/inelastic finite elements analysis and the results were compared each other. It was found that the reinforcing system may increase the buckling strength up to 8 times compared to ones without reinforcing system.

• TTA Journal
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• s.163
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• pp.144-147
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• 2016

2011년 사업을 시작해 현재 국내 최고의 통합 솔루션 전문기업으로 발돋움한 (주)뉴론웍스는 대한민국 ICT의 역사를 개척한다는 자부심으로 가득한 회사이다. 제조 ICT, 물류 ICT 등 다양한 ICT 서비스를 제공하고 있으며, 전체 직원의 70%가 연구 개발 인력으로 이루어져 있다. 이러한 인적 자원은 (주)뉴론웍스가 중소 규모 SI 플랫폼, 클라우드 기반 모바일 솔루션, 웹서비스, 스마트팩토리 솔루션 등 여러 첨단 융합 ICT 분야에서 우수한 기술력과 경쟁력을 축적하는 데 중요한 바탕으로 작용했다. 한편 섬유정보화 전문기업인 (주)보강시스템은 1994년 설립 이후 제직, 염색, 후가공 등 섬유업종 정보화 시스템을 구축해왔다. 보강시스템의 솔루션은 20년 간의 축적된 기술력을 바탕으로 230여 개의 섬유업체에서 이용되고 있다. 각자의 전문 분야에서 인정받고 있는 뉴론웍스와 보강시스템은 IoT 기반의 스마트 팩토리 구현을 위해 힘을 합쳤다. 하지만 인적 자원에 투자를 함에도 중소기업 단독으로 기술 개발 및 성장을 하는 데는 한계가 있었고, 고민 끝에 한국정보통신기술협회(TTA)의 표준 자문서비스의 문을 두드리게 되었다.

• Journal of the Korean GEO-environmental Society
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• v.4 no.4
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• pp.85-96
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• 2003

The Geocell system is the advanced system of Geo-grids, and is one of geosynthetics used for earth reinforcement of weak soil. It is the way to increase earth strength and bearing capacity by using three dimension type of geo-composite. This paper analyzed the bearing capacity mechanism of Geocell system for earth reinforcement. Plate loading tests under the model laboratory condition were performed, and the increase of bearing capacity and the decrease of settlement with shallow foundation were evaluated.

• Journal of the Korea institute for structural maintenance and inspection
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• v.26 no.5
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• pp.1-9
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• 2022

In this study, the in-plane and out-of-plane seismic performance of the masonry wall strengthened using the steel bar truss system proposed by Hwang et al. (2021a, 2021b) or using FRP sheets were compared and evaluated. The maximum strength of the masonry wall reinforced with FRP sheets for the in-plane and out-of-plane loading was 71% and 85%, respectively, of that of the non-reinforced masonry wall. Meanwhile, the maximum strength of the masonry wall reinforced with the steel bar truss system was approximately 1.8 times higher than that of the non-reinforced masonry wall. Compared with the FRP sheet method, the steel bar truss system was excellent at improving the maximum load capacity, rigidity, and energy dissipation capacity. However, in the case of a masonry wall reinforced with FRP sheets, the masonry wall was overstrengthened with the FRP sheets covering the entire masonry wall, and it is considered that the overstrengthened specimen experienced sliding failure, resulting in a lower strength than the other specimens. A follow-up study is needed to compare the seismic performance of the specimen involving only a part of the masonry wall reinforced with the FRP sheets and the specimen reinforced using the steel bar truss system.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.3A
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• pp.349-356
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• 2008

Recently FRP (Fiber Reinforcement Polymer) is widely used for the strengthening of damaged RC beams. Although many tests were carried out to verify flexural capacity of RC beams strengthened with FRP sheet or plate, the behavior of strengthened RC beams has not yet clearly verified. To investigate the strengthening efficiency of the Near Surface Mounted Reinforcement (NSMR) technique experimentally and analytically, a total of 7 specimens have been tested. The experimental results revealed that specimens strengthened with NSMR improved the flexural capacity of RC beams. Also, while the NSMR specimens utilized CFRP reinforcement efficiently compared to the EBR (Externally Bonded Reinforcement) specimen, the NSMR specimens still have debonding failure between epoxy and concrete interface. This study has proposed the model to predict failure modes and failure loads. Good agreement was obtained between the predicted and the experimental results.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.4A
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• pp.447-456
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• 2008

This paper suggests a modified debonding failure model for the externally bonded prestressed CFRP plate strengthening system. In order to reduce the error that may occur in the experimental results, statistical analysis of the experimental results produced by previous researchers was conducted to propose a debonding failure model. The experimental results of beams strengthened with bonded CFRP plates have made it possible to verify the debonding failure occurring before the final failure in the prestressing system. The corresponding strain increased with the effective prestress. Accordingly, the debonding failure model was modified by considering the effective prestress so as to fit with the CFRP prestressing system.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.23 no.2
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• pp.227-234
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• 2010

To investigate the flexural behavior of RC beams strengthened with carbon fiber sheets, 1 control beam and 8 strengthened beams(4 NU-beams without U-shaped band and 4 U-beams with U-shaped band) are tested. The variables of experiment are composed of the number of carbon fiber sheets and the existence of U-shaped band, etc. The experimental results showed that the strengthening system with U-shaped band controls the premature debonding and provides a more ductile failure mode than the strengthening system without U-shaped band. It can be found from the load-deflection curves that as the number of fiber sheets is increased, the maximum strength and the flexural rigidity is increased. The experimental results are compared with the analytical results of nonlinear flexural behaviors for strengthened RC beam. The proposed analytical method for strengthened beams is proved to be accurate by an experimental investigation of load-deflection curve, yield load, maximum load, and flexural rigidities in the pre- and post-yielding stages.