• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.985-988
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• 2008

Maglev is a system that a train runs levitated above a rail. Therefore it is very important to maintain a constant levitation gap for achieving serviceability and ride comfort. This study is a cooperation research subject of the 3-1 subject, performance improvement of maglev track structures, of the Center for Urban Maglev Program in Korea, started in 2006. The aim of this study is development of rapid constructions of bridge superstructure for maglev. At present, precast deck is widely used because of its superiority to cast-in-place concrete on quality and the term of works. The research group suggested basic systems of maglev guideway with PSC-U type and trapezoidal open steel box type girder, and precast deck, cooperating with Korea Railroad Research Institute, the managing institute of the 3-1 subject. In this study, full-scale structure was fabricated for structural safety evaluation of precast decks and rail, and a static performance test of those structures was performed.

• Journal of the Korea institute for structural maintenance and inspection
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• v.6 no.1
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• pp.141-147
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• 2002

국내 주거의 주종인 아파트의 구조형식은 벽식 철근콘크리트조로 경제성 때문에 대부분 고층으로 지어지고 있다. 철근 콘크리트구조 건물을 구체공사비중 상당부분이 거푸집공사에 투입되고 있다. 구체공사의 공기(工期)는 층당 소요일수로 산정할 수 있는데 공사비 절감 및 공기단축을 통한 시공효율상의 향상을 위해서는 지주시스템의 효율적인 전용(轉用)이 필수적이라 할 수 있다. 본 연구에서는 벽식구조 아파트의 현장조사를 토대로, 현재 사용되고 있는 지주시스템 및 바닥슬래브에 대한 응력해석을 수행하고, 이를 분석하여 공기단축의 가능성을 검토하였다.

• Journal of Korean Association for Spatial Structures
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• v.5 no.3 s.17
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• pp.26-32
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• 2005

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.1A
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• pp.35-43
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• 2006

In this paper, procedures and research results involved in the development of glass reinforced composite bridge deck of hollow section were presented. Laminate design for the 3 cell deck section was performed. Structural characteristics such as serviceability, strength, failure and stability for DB24 load were analytically studied through the finite element analysis for the composite deck plate girder bridge. Composite deck tube was fabricated with pultrusion and extensive tests such as flexural test, girder-connection test, barrier-connection test, compression fatigue test and flexural fatigue test were carried out to evaluate structural behavior experimentally. Also, field load test was conducted for the demonstration plate girder bridge with composite deck and requirements for the strength and serviceability were reviewed.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.197-202
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• 2014

Floor Impact Noise is a structure-borne noise which is mainly caused by vibration of concrete slabs. The majority of previous studies have focused on investigating performance of absorbing sheets on the reduction of floor impact noise. But absorbing sheets do not efficiently reduce heavy-weight floor impact noise level because it cannot absorb slab vibration, which is the fundamental noise source. In this study, double-floor system was developed in order to reduce floor impact noise level in residual buildings. This floor system reduces heavy-weight impact noise level by reducing vibration response at the center of slab, which has maximum amplitude in the 1st vibration mode. In order to identify the performance of the double-floor system, experiments were planned. Primary test parameters are span of double floor, arrangement and types of absorbing sheets.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.30 no.8
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• pp.54-59
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• 2001

바낙 공기 급기(UFAD, underfloor air distribution)는 사무실과 상업 건물의 공조를 위하여 바닥 하부 공간을 사용하는 혁신적인 기술이다. 북미에서는 UFAD가 기존 천장 공기 급기 방식에 비하여 많은 장점을 지니므로 그 수요가 날로 증가하고 있다. 잘 설계된 UFAD 시스템은 다음과 같은 장점을 지닌다. - 건물의 용도 변경에 따픈 유연성이 우수하므로 건물의 생애 주기 비용을 감소시킨다. - 개별 쾌적성 제어가 가능하므로 온열 쾌적성, 거주자의 만족도 그리고 생산성을 향상시킨다. - 거주자주변에 직접 선선한 공기를 공급하므로 환기 효율, 실내 공기질 그리고 건강 상태를 향상시킨다. - 이코노마이저 운전, 온도 성층화 그리고 낮은 정합 운전에 의하여 에너지 비용을 감소시킨다. - 설비 공간이 축소되고 표준 철골 구조에서는 콘크리트 구조체 변경이 가능하므로 새 건축 공법에서는 충고를 감소시킬 수 있다. 1995년까지만 해도 UFAD는 파격적인 설계 기법이라고 여겨졌지만, 이제 설계자와 건축업자들은 2004년까지 신축되는 사무용 건축품의 35%는 바닥을 높인 기법이 적용되며 이 중 반 정도가 UFAD를 채택할 것이라고 예측하고 있다. 2000년 2억불이라고 추정되던 바닥을 높이는 건축의 시장 규모가 2004년에는 최소 10억불이 되리라고 예측된다. UFAD는 기본 연구에 의한 정립된 표준화된 설계 기법과 지침이 아직 마련되지 않았음에도 불구하고 현재 설계, 시공되고 있다. 이라한 경향은 펄수적인 연구가 수행되어 관련 업계가 지식과 경험을 충분히 쌓기 전까지는 계속될 전망이다. 본고는 시스템 설계와 운영의 주요한 특징, 기존 방식과 비교하여 지니고 있는 잠재적인 장점, 한계와 기술 개발의 필요성, UFAD 기술 개발을 위하여 계속적으로 요구되는 연구 분야 등을 서술함으로써 현재 UFAD 기술에 대한 평가를 한다.

• Journal of the Korean Society for Railway
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• v.12 no.5
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• pp.800-805
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• 2009

This paper proposes the track system with twin block sleeper for a LIM type maglev railroad. Because a LIM type maglev railroad is expected to be constructed in inner city, social costs can be required under construction. Accordingly, superstructure using precast plate was adopted and twin block sleeper which can be constructed together with precast plate was developed to reduce the construction period. To examine the structural safety of the proposed track system with twin block sleeper, the finite element analyses and the laboratory experiments were performed. Also, the workability of the proposed track system was investigated through the construction simulation test and construction experience in test bed.

• Proceedings of the KSR Conference
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• 2004.06a
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• pp.994-1000
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• 2004

대형시험장비가 설치되는 실험실의 계획에서 장비의 진동은 간과할 수 없는 고려사항이다. 따라서 시험장비를 지지하는 구조물과 기초의 설계시 시험장비의 운행 중 발생하는 공진을 피할 수 있는 구조적 체계의 진동특성에 대한 적절한 평가가 요구된다. 본 논문은 동적특성을 얻기 위해 바닥구조물의 FE 모델링에 관하여 기술하였다. 또한 진동저감을 위한 시험장비기초의 설계를 위해 tuning, 진동기준. 방진시스템을 검토하였다. 시험장비의 진동을 줄이는 최선의 방법은 low tuning 이였으며 이의 구현을 위해 방진스프링과 함께 단단한 콘크리트 블록위에 시험장비를 설치하였다. 총체적인 방진시스템의 구조적 진동특성은 이동성, 힘, 속도 스펙트라를 이용해 표현되었다. 전달과 지점이동 FRF의 비를 시뮬레이션을 통해 비교함으로서 바닥 슬래브의 진동전달 정도가 관찰되었다.

• Journal of the Korea institute for structural maintenance and inspection
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• v.15 no.6
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• pp.92-99
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• 2011

Ultra High Performance Concrete(UHPC) is a superior structural material with high strength and durability. Construction of light and slim structures is realized to apply this expectable new materials in practice. This research is a part of the project to develop UHPC precast deck system for hybrid cable stayed bridge. The main object of this study is to investigate behavior of the lap-spliced reinforced connection in UHPC. The major parameter considered in experimental plan was lap-spliced length. The 4-points bending test for 12 specimens were conducted to verify the effect of considered parameters. Test results show that the minimum value of lap spliced length of 300mm which specified in current korea high bridge design code was very conservative for UHPC precast deck system.

• Journal of the Earthquake Engineering Society of Korea
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• v.5 no.5
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• pp.35-45
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• 2001

Recently, the floor systems those require large open space may have low inherent damping due to the decline of the use of curtain walls. Furthermore, the use of the high strength materials has resulted in more flexible and longer spanning in floor systems. The long span structures such as shopping malls, offices and large assembly rooms may lead to significant dynamic response due to human activities. Excessive vibrations make the occupants uncomfortable and deteriorate the serviceability of buildings. It is now proved that footfall loading is the major source of floor vibrations. The common method of application of walking loads for the vibration analysis of structures subjected to walking loads is to inflict measured walking loads and periodic function at a node. But this method could not account for the moving effect of walking. In this study, natural frequency and damping ratio of example structure are evaluated by heel drop tests. And the application of equivalent walking loads is used for on efficient vibration analysis of the plate structures subjected to walking loads.