• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.4A
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• pp.457-463
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• 2008

The longitudinal stiffener performs its role to increase the local buckling strength by making simple support upon compression flange. In the recent researches, it is investigated that compression flange with point supports on certain arrangement reveals the same strength with longitudinal stiffeners. From this results, it is predictable that shear stud could perform the role of longitudinal stiffener if shear stud embedded in concrete satisfies the requirement to point-support under yield stress of the compression flange. In this study, the researches were performed to investigate the optimally required arrangement space of longitudinal point-support for which the shear stud replacing the longitudinal stiffeners and simultaneously determine the required numbers and space of shear stud for completely composite behavior between compression bottom flange and bottom concrete on the double composite girder system.

• Journal of the Korea Concrete Institute
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• v.19 no.5
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• pp.557-567
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• 2007

In underground parking lots of apartment housing, the story height is increased by $300{\sim}400mm$ because of various ducts for HVAC. In order to reduce this story height, this study proposed the 'hybrid beam', which is composed of PC beam with embedded steel beam and insitu concrete. The depth of the hybrid beam is reduced by 300 mm and then the steel beam is embedded over the length of reduced depth to compensate for the loss of strength. Then, we performed the large-scale structural tests on 9 specimens and investigated the flexural behavior of the specimens. The parameters of tests were the shape of steel beam section, the length of the reduced depth, the stage of construction, the effects of slab and shear connectors. The test results showed that the specimens, after the insitu concrete has cured, has the flexural capacity which exceeds the required design capacity regardless of other parameters. On the other hand, the specimens of construction stage do not have sufficient strength. Based on these results, it is thought that the proposed hybrid beam with reduced depth is applicable to the underground parking lots of apartment housing as long as the support is placed at construction stage.

• Journal of the Korean Arthroscopy Society
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• v.12 no.1
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• pp.12-17
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• 2008

Purpose: This study presents clinical results of anterior cruciate ligament(ACL) augmentation using autogenous two-strand semitendinosus tendon in the treatment of partial ACL tears with preservation of residual portion. Materials and Methods: From January 2004 to June 2006, twenty two patients who had an ACL injury underwent ACL augmentation using autogenous two-strand semitendinosus tendon were enrolled in this study. We evaluated the clinical results with regard to clinical findings(range of motion, Lachman test, pivot shift test), standard knee scales(Lysholm, Modified Feagin Scoring System), and KT-1000 arthrometer testing. Results: At minimum one year postoperatively, there was no limitation of range of motion. Lachman and pivot shift tests were negative in all knees. On instrumented anterior laxity test by KT-1000 arthrometer, mean side to side difference was improved from 4.6mm preoperatively to 1.7mm postoperatively. Average Lysholm score was improved from 70 to 92. Ninety one percent of cases were rated as good or excellent in Modified Feagin Scoring System. Conclusion: Augmentation using autogenous two-strand semitendinosus tendon with preservation of residual portion of the ACL seems to be an acceptable method for restoring knee stability and proprioceptive function.

• Journal of the Korea Concrete Institute
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• v.14 no.1
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• pp.83-91
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• 2002

A common form of construction for apartment buildings consists of walls and coupling elements. But, the structural behavior of coupling elements are very complex and affected by the properties of coupling elements. The objective of this study is to estimate the behavior of coupling elements in wall-dominant systems. For the purpose of this study, two wall-slab specimens and two wall-beam specimens were tested. The specimens with different reinforcement layouts were subjected to reversed cyclic loading, consistent with coupling action, with increasing imposed inelastic deformations. From the results of this study, 1) in coupling slabs, the stresses were not uniform across the width, 2) the effective width of coupling slabs was found smaller than that of predicted from previous studies, 3) diagonally reinforced coupling beam with slab showed larger ductility and more amount of energy dissipation to be attained compared with conventionally reinforced coupling beam.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.3
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• pp.535-541
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• 2018

Most construction methods for the repair and reinforcement of old reinforced concrete harbor structures involve a process of applying a fiber complex or fiber complex panel just like wallpaper to the bottom of structures, such as slabs or beams. On the other hand, these techniques result in the sealing of repaired and reinforced portions of the structures by the fiber products, preventing moisture, such as rainwater entering the structures through the upper surfaces of the slabs or beams from being released, and causing the entire concrete covering of the structures to be peeled off in the long run. To prevent this, it is necessary to develop a technique to protect the basic salt from the sea water from penetrating into the structures while expelling the water absorbed in the structures swiftly. This study attempted to solve the problem by modifying the anchor bolts currently used to repair and reinforce the port structure. That is, by drilling holes into the body of anchor bolts and modifying the caps of the bolts to produce a structure that would let the water flow like a toilet trap, the moisture inside of the structure could be drained through the holes in the anchor bolts. The water discharge anchor bolts developed were tested and observed for 6 months; the water was discharged in 73% of the anchors (200 anchor installation, 145 anchors).

• Journal of the Computational Structural Engineering Institute of Korea
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• v.17 no.4
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• pp.375-387
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• 2004

A new finite element model will be presented to analyze the nonlinear behavior of RC beams and slabs strengthened by a patch repair. The numerical approach is based on the p-version degenerate shell element including theory of anisotropic laminated composites, theory of materially and geometrically nonlinear plates. In the nonlinear formulation of this model, the total Lagrangian formulation is adopted with large deflections and moderate rotations being accounted for in the sense of von Karman hypothesis. The material model is based on hardening rule, crushing condition, plate-end debonding strength model and so on. The Gauss-Lobatto numerical quadrature is applied to calculate the stresses at the nodal points instead of Gauss points. The validity of the proposed p-version nonlinear finite element model is demonstrated through the load-deflection curves, the ultimate loads, and the failure modes of RC beams or slabs bonded with steel plates or FRP plates compared with available result of experiment and other numerical methods.

• Magazine of the Korea Concrete Institute
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• v.4 no.1
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• pp.119-126
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• 1992

AC] 318-H9 Recommended that when the specified compressive strength of concrete in a column is greater than 1. 4 times that specified for a floor system, top surface of the colurrm concrete shall extend 2ftU;OOrrun) into the slab from the face of colUlml to avoid unexpected brittle failure. The purpose of this investigation is to suggest the basic information for the structural safety, The major variables are com preSSlve strength of concrete, shear confinement ratio, and loading types. The test results showed that the load capaCIty of speCImen subjected to monotOI1lC loading had more than that of specimen subjected to one way cyclic loading. The failure modes of specimens under cyclic loading were concentrated at 5-20cm apart region from beam-column joint face and ductility index are increased with increasing of shear confinement ratio. Keywords: ACI 318-89, High and Low Strength Concrete, Beam-Column Joint, Shear Confinement Ratio, Loading Type, Ductility Index, Extension Distance.

• Journal of Korean Society of Steel Construction
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• v.15 no.2
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• pp.167-174
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• 2003

This paper presented the results of cyclic loading tests of 7 full-scale beams to column subassemblages with improved connection detail i.e., fillets of the stiffening plates at the column corners and ends of the stiffener-to-beam flange weld. Major findings from the test results were: (1) Fillets reduced the stress concentrations that may cause early brittle fractures and considerably improved the cyclic performance compared to the detail without fillets. (2) As the width of the stiffening plate increased, the stiffness and peak strength increased and energy dissipation capacity decreased. (3) While all specimens failed by a fracture, they could develop a total rotation of 0.04 radian required for special moment resisting frames.

• Proceedings of the Korea Association of Information Systems Conference
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• 2001.12a
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• pp.413-426
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• 2001

본 연구는 첫째, 정보통신기술의 발달이 시각장애인 복지 증진에 미칠 수 있는 가능성에 대한 이론적인 부분을 고찰하였다. 둘째, 우리나라 시각장애인 정보화의 문제점과 해결책을 도출하였고 셋째, 시각장애 사용자를 위한 전자상거래 인터페이스 디자인의 분석 및 설계를 통해 전자상거래에서 시각장애 사용자들이 큰 제약없이 사용할 수 있는 방안을 제시하고자 한다. 현재 시각장애인들의 웹 사용을 보면 시각장애 전용 S/W의 보조 하에 사용을 하고 있다. 그러한 보조 도구의 실정에 맞도록 텍스트 버전 및 Non-Frame버전, Alt-Text 옵션, 캡션 등을 넣어 접근성을 확보하고 인터넷을 큰 제약을 받지않고 이용할 수 있도록 웹 페이지의 설계가 필요한 실정이다. 이를 위하여 먼저 시각장애에 대한 개념과 원인 및 종류 그리고 특성을 통해 시각장애인에 대한 이론적 배경을 파악하였다. 그리고 시각장애인의 정보화 환경과 이용 현황과 시각장애인의 정보 접근을 제도적, 기기 및 소프트웨어 개발 측면에서 분석을 하였고, 장애인을 위한 정보통신기술 중 대표적인 사례를 검토해 보았다. 다음으로 국내외의 대표적인 전자상거래 사이트에서의 인터페이스를 화면구성(Layout), 텍스트(Text), 그래픽(Graphic), 멀티미디어(MultiMedia) 측면에서 분석을 하였다. 분석한 내용을 바탕으로 시각장애 사용자의 입력(User Input) 부분을 고려한 인터페이스 방향을 제시하고 프로토타입을 개발하여 시험 대상 사이트와의 만족도를 시각장애 사용자를 통해 비교 ·분석하였다. 결론부분에서는 정보불평등을 해소하고, 정보통신기술이 장애인의 복지향상에 기여하도록 하기 위해 전자상거래 싸이트에서의 시각 장애인들을 위한 방향을 제시하고자 한다.박의 표현, 등록 및 색인방법 (c) 공급 선박의 분류와 표현 방법 (d) 에이전트의 정보 수집을 위한 메시지 표현 방법 (e) 수집된 선박정보의 데이터베이스 저장 표현방법 (f) 요구 선박을 찾아주는 정보제공 서비스가 요구된다.동을 보여 조사대상 5호분, 6호분, 7호분, 중 가장 심한 거동을 보이고 있다. 이는 고분 벽돌의 깨짐이 6호분이 가장 심하다는 사실과 무관하지 않은 것으로 판단된다. 봉분내부의 토양층구조에 대한 지오레이다 영상단면을 분석한 결과 무령왕릉 연도상부의 누수지방지층이 심하게 균열되어 있음을 발견하였다. 이 곳은 고분내부로 직접누수가 발생하는 곳이다. 직접누수와 지하수 형태로 유입된 침투수는 고분군 주위의 지반의 함수비를 증가시켜 지반의 지지력을 약화시키고 또한 고분내로 서서히 유입되어 고분내부의 습도를 100%로 유지시키는 주된 원인이다. 이러한 높은 습도는 고분내의 남조류의 번식을 가져왔으며 남조류의 번식은 현재 6호분이 가장 심각하고 7호분이 우려되는 수준이며 5호분은 문제가 없는 것으로 판단된다. 이와 같이 고분군의 발굴후 인위적인 환경변화와 지속적인 강우침투 및 배수 불량의 영향은 고분군의 안정성에 상당한 위험을 초래하였으며, 현 상태는 각 고분에 대한 보강이 불가피한 것으로 판단된다. 고분 벽돌의 깨짐, 고분 벽체의 거동, 조류의 서식등을 포함하여 송산리 고분군에서 발생되고 있는 보존상의 제반 문제점들을 일차적으로 누수 및 침투수에 의한 결과이다. 그러므로 무엇보다도 고분군 내부 및 고분 주변으로의 강우 및 지하수 침투를 막는 차수 대책이 시급한 것으로 판단된다. 또한 이미 발생한 변위가 더 이상 진행되지 않도록 하중을 경감하고 토압의 균형을 이루는 보강대책이 시급한 실정이다. 고분군

• Geotechnical Engineering
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• v.12 no.3
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• pp.127-148
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• 1996

Recently, foundations of heavy structures such as bridge abutments have been built on slopes or near the crest of slopes at an increasing rate. Because the bearing capacity of such foundations is considerably lower than the bearing capacity of the same soil on a level ground, deep footings such as piles and caissons are often used. However, the costs of such methods are generally very high. One of the new techniques to overcome the problem is to place reinforcing members such as geosynthetics or metal strips horizontally at some depths beneath the footings. Rational methods of analysis to predict the bearing capacity of footings in reinforced slopes are therefore needed. This paper proposes an analytical method for estimating the increase in bearing capacity gained from the included horizontal strips or ties of tensile reinforcing in the foundation soil below the footing built near the crest of a slope. A failure mechanism, including the concept of'wide slab effect', adopted in the present study for analyzing the bearing capacity of foundations in reinforced slopes, is established through the observed model test behaviors described by Binquet SE Lee and Huang et al, and the Boussinesq solutions. The analytical results are then compared with the experimental data described in the paper by Huang et al. Also in order to properly evaluate the soil reinforcement interaction, typical pullout test values of the apparent friction coefficient, which usually vary with depths owing to both the increase of the shearing volume and the increase in local stress caused by soil dilatancy, are analyzed and related functionally. Furthermore, analytical parametric studies are carried out to investigate the effect and significance of various pertinent parameters associated with design of reinforced slope foundations. Keywords : Bearing capacity, Reinforced slope, Slab effect, Friction coefficient.