• 한국공간구조학회논문집
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• 제12권1호
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• pp.51-58
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• 2012

압출성형 ECC 패널을 활용한 철근콘크리트 복합 슬래브 구조에 대한 비선형 휨 해석 모델을 새롭게 제시하였다. ECC 패널은 직접인장시험 결과로부터 균열 이후에 고인성 인장거동을 하는 재료로 모델링하였다. 개발 모델을 기존 철근콘크리트 슬래브 및 ECC 패널 철근콘크리트 복합슬래브 실험체의 휨 실험결과와 비교하였다. 예측결과는 실험결과와 잘 일치하였으며, ECC 패널 적용 철근콘크리트 복합슬래브는 균열제어, 휨내력 및 휨변형능력 개선에 장점이 있는 것으로 판단되었다.

• Structural Engineering and Mechanics
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• 제92권1호
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• pp.1-23
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• 2024

The current study examines the experimental and numerical performance of reinforced concrete (RC) channel slabs made of ferrocement that have been reinforced with fiber glass, expanded steel mesh, and welded steel mesh. As part of the testing program, ten RC channel slabs with dimensions of 500 mm×40 mm×2500 mm were loaded flexibly. The three main factors that can be altered are the mesh layer count, the type of reinforcing materials, and the reinforcement volume fraction. The main objective is to assess the effects of fortifying composite RC channel slabs with novel inventive materials. ANSYS-16.0 Software was used to simulate the behavior of composite channel slabs using nonlinear finite element analysis (NLFEA). It also shows how parametric analysis can be used to pinpoint variables like variations in slab dimensions that could significantly affect the mechanical behavior of the model. The obtained experimental and numerical results showed that finite element (FE) simulations had a tolerable degree of accuracy in estimating experimental values. It is crucial to show that specimens strengthened with fiber glass meshes gained about 12% lessstrength than specimens strengthened with expanded or welded steel meshes. In addition, RC channel slab reinforcement made of welded steel meshes has a 24% higher strength than expanded steel meshes. Tested under flexural loads, ferrocement specimens outperform conventional reinforced concrete specimens in terms of ultimate loads and energy absorption.

• Structural Engineering and Mechanics
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• 제54권6호
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• pp.1135-1152
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• 2015

Most of current bridge decks are made of reinforced concrete and often deteriorate at a relatively rapid rate in operational environments. The quick deterioration of the deck often impacts other critical components of the bridge. Another disadvantage of the concrete deck is its high weight in long-span bridges. Therefore, it is essential to examine new materials and innovative designs using hybrid system consisting conventional materials such as concrete and steel with FRP plates which is also known as composite deck. Since these decks are relatively new, so it would be useful to evaluate their performances in more details. The present study is dedicated to Hat-Shape composite girder with concrete slab. The structural performance of girder was evaluated with nonlinear finite element method by using ABAQUS and numerical results have been compared with experimental results of other researches. After ensuring the validity of numerical modeling of composite deck, parametric studies have been conducted; such as investigating the effects of constituent properties by changing the compressive strength of concrete slab and Elasticity modulus of GFRP materials. The efficacy of the GFRP box girders has been studied by changing GFRP material to steel and aluminum. In addition, the effect of Cross-Sectional Configuration has been evaluated. It was found that the behavior of this type of composite girders can be studied with numerical methods without carrying out costly experiments. The material properties can be modified to improve ultimate load capacity of the composite girder. strength-to-weight ratio of the girder increased by changing the GFRP material to aluminum and ultimate load capacity enhanced by deformation of composite girder cross-section.

• Structural Engineering and Mechanics
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• 제42권1호
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• pp.55-72
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• 2012

Precast-cast insitu concrete bridge construction is widely practiced for small to medium span structures. These bridges consist of precast pre-stressed concrete beams of various cross-sections with a cast in-situ reinforced concrete slab. The connection between the beams and the slab is via shear links often included during the manufacturing process of the beams. This form of construction is attractive as it provides for standardisation, reduced formwork and construction time. The assessment of the integrity of shear connectors in existing bridges is a major challenge. A procedure for assessment of shear connectors based on vibration testing and finite element model updating is proposed. The technique is applied successfully to a scaled model bridge model and an existing bridge structure.

• 한국강구조학회 논문집
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• 제16권6호통권73호
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• pp.807-818
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• 2004

콘크리트의 건조수축에 의한 합성거더의 장기거동을 평가하기 위해 수행한 실험과 이론적 분석방법에 대해 기술하였다. 합성거더를 제작하여 장기간 실내실험을 통해 콘크리트의 건조수축에 따른 합성보의 처짐, 곡률변화 및 변형률변화를 측정하였으며, 실험결과를 AEMM(Age-adjusted Effective Modulus Method)을 이용한 해석치와 비교하였다. 또한 콘크리트의 건조수축에 의한 합성거더의 장기거동에 영향을 미치는 여러 변수들에 대한 해석을 수행하였다. 실험결과 합성거더의 장기거동은 AEMM에 의해 적절히 평가할 수 있다는 것을 확인할 수 있었다. 합성거더의 콘크리트 단면에 커다란 인장응력이 발생하기 때문에 연속교 부모멘트부뿐만 아니라 단순교 정모멘트부에도 횡방향균열이 발생할 수 있다는 것을 보였으며, 횡방향 균열을 무시하는 경우 강거더에 작용하는 응력이 과대평가 될 수 있다는 것을 확인하였다. 이상의 연구결과를 토대로 콘크리트의 건조수축에 의한 합성거더의 장기거동 평가시 콘크리트 단면에 발생할 수 있는 횡방향균열을 고려하는 것이 합리적이라고 판단된다.

• 산업기술연구
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• 제17권
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• pp.199-204
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• 1997

In this paper, the result of application of vibration method to the orthotropic plates with free edges supported on elastic foundation and with a pair of opposite edges under axial forces is presented. Such plates represent the concrete highway slab and hybrid composite pavement of bridges. The reinforced concrete slab can be assumed as a special orthotropic plate, as a close approximation. The highway slab is supported on elastic foundation, with free boundaries. Sometimes, the pair of edges perpendicular to the traffic direction may be subject to the axial forces. The plate is subject to the concentrated load/loads, in the form of traffic loads, or the test equipments. Finite difference method is used to obtain the deflection influence surfaces needed for vibration analysis. The influence of the modulus of the foundation, the aspect ratio of the plate, and the magnitudes of the axial forces and the concentrated attached mass on the plate, under the natural frequency is thoroughly studied.

• 한국구조물진단유지관리공학회 논문집
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• 제21권4호
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• pp.30-38
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• 2017

최근 거푸집 작업과 철근 배근 공정을 생략하여 공정의 단순화를 통한 공기단축 합성 슬래브 시스템의 개발 연구가 진행 중이다. 이 연구에서는 구조용 데크플레이트를 활용하여 거푸집 및 인장철근의 배근을 대체하고 강섬유보강 콘크리트를 사용하여 온도철근의 역할을 대체하는 단순슬래브 시스템의 장기거동을 평가하는 것이 목적이다. 구조용 데크플레이트를 활용하는 기존 합성슬래브 공법은 건조수축에 의한 균열 제어를 위해 용접 철망을 배근하는 것이 일반적이나, 이는 균열을 억제하는 데 효과적이지 못한 것으로 선행연구들에서 지적되었다. 본 연구에서는, 일반적인 건축물의 하중 조건으로 제작 된 연속 두 경간을 갖는 강섬유보강 데크플레이트 슬래브의 장기적인 균열 및 처짐 거동을 평가하도록 하였다. 실험 결과, 실험체의 비 내력부에서는 장기균열의 개수 및 폭이 현저하게 감소하는 것으로 나타나 강섬유보강 콘크리트의 건조수축과 균열 제어 성능이 우수한 것으로 평가되었으며, 처짐량도 강섬유보강 데크플레이트 슬래브가 우수한 것을 확인하였다. 다만, 부모멘트가 작용되는 슬래브 연속단부에서는 사용하중 단계에서 균열폭을 제어하고 하중 제거 시 처짐을 회복하기 위한 디테일의 적용이 필요한 것으로 분석되었다.

• Steel and Composite Structures
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• 제10권3호
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• pp.281-295
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• 2010

An experimental and a non linear finite element investigation on the behavior of steel-concrete composite beams stiffened in hogging moment region with Carbon Fiber Reinforced Plastics (CFRP) sheets is presented in this paper. A total of five specimens were tested under two-point loads. Three of the composite beams included concrete slab while the other two beams had composite slabs. The stiffening was achieved by attaching CFRP sheets to the concrete surface at the position of negative bending moment. The suggested CFRP sheets arrangement enhanced the overall beam behavior and increased the composite beam capacity. Valuable parametric study was conducted using a three dimensional finite element model using ANSYS program. Both geometrical and material nonlinearity were included. The studied parameters included CFRP sheet arrangement, concrete strength and degree of shear connection.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2001년도 가을 학술발표회 논문집
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• pp.167-172
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• 2001

Hollow core slabs generally have not been used for a bridge slab or a parking in Korea. In this study, high performance hollow core slabs, which has been the most thick one in domestic are re-designed and examined for practical use. Flexural tests were performed on four 315mm deep hollow core slabs to investigate adaptability for high vehicle live loadings and composite action with topping concrete. The precast slabs were reinforced with 10-l/2 inch dia-strands at the lower of slab and 4-l/2 inch dia-strands at tile upper of slab, and cast with 80mm deep topping concrete. Those tested hollow core slabs showed ductile failure behaviors which were conform to the current Ultimate Strength Design Method for a span of l0m up to the live load of 1, 000 kg/$m^2$.

• Steel and Composite Structures
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• 제34권3호
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• pp.441-452
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• 2020

Within the French CIFRE research project COMINO, an innovative type of composite beam was developed for buildings that need fire resistance with no additional supports in construction stage. The developed solution is composed of a steel U-shaped beam acting as a formwork in construction stage for a reinforced concrete part that provides the fire resistance. In the exploitation stage, the steel and the reinforced concrete are acting together as a composite beam. This paper presents the investigation made on the load bearing capacity of this new developed steel-concrete composite section. A full-scale test has been carried out at the Laboratory of Structural Engineering of the University of Luxembourg. The paper presents the configuration of the specimen, the fabrication process and the obtained test results. The beam behaved compositely and exhibited high ductility and bending resistance. The shear connection in the tension zone was effective. The beam failed by a separation between the slab and the beam at high deformations, excessive shear forces conducted to a failure of the stirrups in this zone. The test results are then compared with good agreement to analytical methods of design based on EN 1994 and design guidelines are given.