• 소성∙가공
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• 제7권5호
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• pp.496-504
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• 1998

The eccentric extrusion and bending process for the forming of the curved rectangular hollow tube is newly developed. Generally the bending process of hollow tube is the secondary process followed by the extrusion process of the hollow tube from the round billet. So many defects such as wrinkling and the difference of wall thickness can be happened during the secondary bending process. In order to avoid the defects the new process named as "the eccentric extrusion and bending process" is suggested and applied to the U-bending of rectangular hollow tube. In this paper the kinematically admissible velocity field between the dies surface and the internal plug boundary surface s developed for the curving velocity. By the using of this curving velocity field the curvature of extruded products can be calculated with the parameters such as eccentricity dies length friction constant aspect ratio.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 춘계 학술발표회 제16권1호
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• pp.730-733
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• 2004

Three Hollow RC piers were tested under a constant axial load and a cyclically reversed horizontal loadto investigate the structural behavior of hollow RC piers using the high strength concrete and the high strength rebars. The test variables include concrete compressive strength, steel strength, and steel ratio. The test results indicate that RC piers using the high strength concrete and high strength rebars exhibit ductile behavior and appropriate seismic performance, in compliance with the design code. The present study allows more realistic application of high strength rebars and concrete to RC piers, which will provide enhanced durability as well as more economy.

• 한국지진공학회논문집
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• 제19권3호
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• pp.109-120
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• 2015

The purpose of this study was to investigate the performance of new hollow reinforced concrete (RC) bridge pier sections with triangular reinforcement details. The proposed triangular reinforcement details are economically feasible and rational and facilitate shorter construction periods. A model of pier sections with triangular reinforcement details was tested under quasi-static monotonic loading. As a result, proposed triangular reinforcement details was equal to existing reinforcement details in terms of required performance. In the companion paper, the parametric study for the performance assessment of new hollow RC bridge pier sections with triangular reinforcement details is performed.

• 한국지진공학회논문집
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• 제19권3호
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• pp.121-132
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• 2015

The purpose of this study is to investigate the behavior characteristics of new hollow reinforced concrete (RC) bridge pier sections with triangular reinforcement details and to provide the details and reference data. Among the numerous parameters, this study concentrates on the shape of the section, the reinforcement details and the spacing of the transverse reinforcement. Additional eight column section specimens were tested under quasi-static monotonic loading. In this study, the computer program, named RCAHEST (Reinforced Concrete Analysis in Higher Evaluation System Technology), was used. A innovative confining effect model was adopted for new hollow bridge pier sections. This study documents the testing of new hollow RC bridge pier sections with triangular reinforcement details and presents conclusions based on the experimental and analytical findings.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2009년도 춘계 학술대회 제21권1호
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• pp.143-144
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• 2009

본 연구는 기존 PSC 교량 형식들이 지닌 단점을 극복하고, 시공성 및 경제성, 그리고 유지관리의 효율성을 모두 갖춘 새로운 거더를 개발함에 있다. HWPC 거더는 중공과 다단계 긴장을 통해 전 단면을 동일하게 함으로써 사하중의 감소, 지간의 장경간화를 이루는데 목적이 있다.

• 한국지진공학회논문집
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• 제4권3호
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• pp.67-81
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• 2000

서해대교는 국내에 교량구조물에 관한 내진설계가 도입되기 전 설계된 교량으로서 현재 내진설계 규준에 적합하지 않은 종방향철근 및 횡방향 철근이 겹침이음된 중공육각형 단면의 철근콘크리트 기둥으로 이미 시공이 완료된 상태이다. 최근, 지진에 대한 사회적 관심이 대두됨으로서 내진 설계 규준에 적합하지 않은 철근상세를 가지 서해대교 PSM교 교각의 내진성능이 의문시되었다. 따라서, 비내진 철근상세를 가진 서해대교 PSM교 교각의내진성능 평가를 위하여 교각의 축소모형 실험을 수행하였으며, 실험결과 종방향철근 겹침이음이 교각의 전체적인 내진거동에는 큰 영향을 미치지 않으며 기대 이상의 연성을 발휘할 수 있는 것으로 나타났다. 본 논문에서는 축소모형 실험결과에 의한 시험체의 파괴양상, 유효강성, 연성, 응답수 정계수 및 등가점성감쇠비를 분석하였으며, 아울러 가속도변위 응답스펙트럼을 이용하여 서해대교 PSM교 교각의 내진성능을 평가하였다.

• 한국지진공학회논문집
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• 제17권3호
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• pp.107-115
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• 2013

The purpose of this study was to investigate the performance of hollow reinforced concrete bridge column sections with reinforcement details for material quantity reduction. The proposed reinforcement details has have economic feasibility and rationality and makes construction periods shorter. A model of column sections with reinforcement details for material quantity reduction was tested under quasistatic monotonic loading. As a result, the proposed reinforcement details for material quantity reduction was were equal to existing reinforcement details in terms of the required performance. In the a subsequent paper, the an experimental and analytical study will be performed for the performance assessment of hollow reinforced concrete bridge column sections with reinforcement details for material quantity reduction will be performed.

• 한국안전학회지
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• 제24권2호
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• pp.55-61
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• 2009

Seismic Safety Analysis of Intake Tower is very important because failure of intake tower may incur huge chaos on the modem society. Recently, there has been growing much concern about earthquake resistance of existing structures. This research demonstrates the dynamic fluid pressure calculation using added mass simulation. The actual safety evaluation has been conducted through not only the static analysis but also the dynamic analysis. According to the analysis results, the vibration incurred by earthquake may induce considerable damage to the hydraulic structure. Therefore, the appropriate design process out of exact calculation is quite necessary.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2005년도 봄학술 발표회 논문집(I)
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• pp.63-66
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• 2005

Six RC pier were tested under a constant axial load and a cyclically reversed horizontal load to investigate the performance of RC piers used in the high strength concrete and the high strength rebar. It is designed with a hollow section according to the Korean Bridge Design Standard. The variables of the test were concrete strength, rebar strength, a ratio of lap splice and a ratio of transvere rebar. The test results show that the performance of a RC Pier; failure mode, crack pattern, maximum load and ductility.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 추계 학술발표회 논문집
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• pp.49-52
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• 2006

Unlike columns having lap-spliced longitudinal bars in plastic hinge regions columns having 50% of lap-spliced bars were reported to have good ductilities relatively. But the effect of transverse reinforcements to deformability is not clearly confirmed. In this study scale models with different confinements were tested under various loading conditions. It was confirmed that deformability was increased with increase of transverse reinforcement ratio regardless of loading conditions and 75% of confinement yielded the satisfactory deformability.