• KIEAE Journal
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• 제10권1호
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• pp.25-31
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• 2010

An experimental investigation of composite beams composed of wide flange steel and precast concrete is presented. The bottom flange of the steel section is encased in precast concrete. The composite beams tested in this study were designed to reduce the depth of the slab and beam. The slabs are constructed on top of the edges of the Structural Composite Hybrid System, instead of on top of the steel flange, decreasing the depth of the beams. When concrete is cast on the metal deck plate located on the edges of the precast concrete, the weight of the concrete slabs and other construction loads must be supported by the contacts between the steel and the precast concrete. This interface must not exhibit bearing failures, shear failures, and failures caused by torque due to the loading of the precast concrete. When the contact area between the concrete and the bottom flange of the steel beam is small, these failures of the concrete are likely and must be prevented. The premature failure of precast concrete must not also be present when the weight of the concrete slabs and other construction loads is loaded. This paper presents a load carrying capacity of Structural Composite Hybrid System in order to observe the failure mode. The symmetrically distributed loading that caused the failure of the composite beam was found. The paper also provides design recommendations of such type of composite structure.

• Steel and Composite Structures
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• 제28권1호
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• pp.39-49
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• 2018

The concrete bridge decks are usually precast and in-situ assembled with steel girders with post-pouring joint in the construction practice of super-wide steel-concrete composite beam. But the difference of concrete age between the precast slabs and the post-pouring joint has been not yet considered for the long-term performance analysis of this kind composite beam. A simply supported precast-assembled T-shaped beam was taken as an example to analyze the long-term performance of steel-concrete composite beam with post-pouring joint. Based on the deformation coordination conditions of the old-new concrete deck and steel girder, a theoretical model for the long-term behavior of precast-assembled composite beam is proposed in this paper according to age-adjusted effective modulus method. Then, the feasibility of the proposed model is verified by the available test data from the Gilbert's composite beams. Parametric studies were preformed to evaluate the influences of the cross-sectional area ratio of the post-pouring joint to the whole bridge deck, as well as the difference of concrete age between the precast slabs and the post-pouring joint, on the long-term performance of the composite beam. The results indicate that the traditional method without considering the age difference would seriously underestimate the effect of creep and shrinkage of concrete bridge decks. The concrete age difference between the precast slabs and the post-pouring joint should be demonstrated for the life cycle design and long-term performance analysis of precast-assembled steel-concrete composite beams.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2013년도 춘계 학술논문 발표대회
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• pp.19-20
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• 2013

Green Frame is a column-beam system constructed by composite precast column and beam connected by embedded steel of their. From when the precast concrete beam of Green Frame is installed, until the concrete of slab and connection joint is cured, the self load of beam shall be supported by the embedded steel of it. Therefore, the concrete of beam could be separated from the embedded steel if the shear connector of beam of Green Frame is designed by the code on Structural standard. So, this study suggest an equation for the shear connection of composite precast concrete beams of Green Frame. The result of this study will be used as the main equation of the calculation model for shear connectors of composite precast concrete beams.

• 한국건설관리학회:학술대회논문집
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• 한국건설관리학회 2007년도 정기학술발표대회 논문집
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• pp.113-118
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• 2007

이번 연구는, 실제 공사 현장에서 적용할 수 있는 프리캐스트 복합화 콘크리트 공법을 선정하였다. 현장에서 프리캐스트 복합화 콘크리트 공법의 실제 공사비와 철근콘크리트 공법에 적용되는 추정 공사비를 비교하였다. 고강도 콘크리트와 프리스트레스트 콘크리트의 사용함으로서, 50%이상의 콘크리트 양을 줄일 수 있었지만, 프리캐스트 콘크리트 복합화공법의 주된 비용인 생산비와 운송비를 포함한 재료비는 큰 차이가 없었다. 그러나 철근콘크리트인 경우, 철근과 거푸집 노무비가 30%를 차지하며 추가비용으로 비계, 가설공사가 큰 비중을 차지하는 철근콘크리트 공법이 프리캐스트 콘크리트 복합화 공법과 비교하여 2배정도의 시공비용이 소요된다. 위의 결과를 분석하면 프리캐스트 복합화 공법이 철근콘크리트 공법의 비용보다 11%의 훌륭한 비용절감 효과가 나타났다.

• 한국구조물진단유지관리공학회 논문집
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• 제17권4호
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• pp.48-56
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• 2013

프리텐션 방식을 사용한 PSC 휨부재는 시공이 간편하고 품질관리가 용이하기 때문에 최근 토목분야에서 적용된 사례가 증가하고 있다. 특히, PSC 휨부재의 종류 중 하나인 반단면 프리캐스트 콘크리트 합성 슬래브는 롱라인 공법을 적용하여 최근에 개발되었다. 반단면 프리캐스트 콘크리트 합성 슬래브는 프리캐스트 콘크리트와 현장타설 콘크리트를 합성하여 제작한다. 이 연구에서는 롱라인 공법으로 제작한 프리캐스트 PSC를 적용한 반단면 프리캐스트 콘크리트 합성 슬래브의 프리스트레스 도입 효율과 휨강도에 대한 실험을 실시하고 그 결과를 제시하였다. 롱라인 공법은 한번의 긴장력 도입으로 여러 개의 부재를 생산할 수 있는 장점이 있다. 또한, 프리캐스트 PSC 내에 매입되어 있는 철근의 영향을 고려하여 반단면 프리캐스트 콘크리트 합성 슬래브의 휨강도를 합리적으로 평가할 수 있는 식을 제시하였다.

• Structural Engineering and Mechanics
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• 제71권4호
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• pp.433-444
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• 2019

Shear studs are often used to connect steel girders and concrete deck to form a composite bridge system. The application of precast concrete deck to steel-concrete composite bridges can improve the strength of decks and reduce the shrinkage and creep effect on the long-term behavior of structures. How to ensure the connection between steel girders and concrete deck directly influences the composite behavior between steel girder and precast concrete deck as well as the behavior of the structure system. Compared with traditional multi-I girder systems, a twin-I girder composite bridge system is more simplified but may lead to additional requirements on the shear studs connecting steel girders and decks due to the larger girder spacing. Up to date, only very limited quantity of researches has been conducted regarding the behavior of shear studs on twin-I girder bridge systems. One convenient way for steel composite bridge system is to cast concrete deck in place with shear studs uniformly-distributed along the span direction. For steel composite bridge system using precast concrete deck, voids are included in the precast concrete deck segments, and they are casted with cast-in-place concrete after the concrete segments are erected. In this paper, several sets of push-out tests are conducted, which are used to investigate the heavier of shear studs within the voids in the precast concrete deck. The test data are analyzed and compared with those from finite element models. A simplified shear stud model is proposed using a beam element instead of solid elements. It is used in the finite element model analyses of the twin-I girder composite bridge system to relieve the computational efforts of the shear studs. Additionally, a parametric study is developed to find the effects of void size, void spacing, and shear stud diameter and spacing. Finally, the recommendations are given for the design of precast deck using void for twin I-girder bridge systems.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2011년도 추계 학술논문 발표대회
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• pp.29-30
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• 2011

A Green Frame is a composite Rahmen precast concrete structure that utilizes the advantages of the steel frame and the reinforced concrete. Compared to bearing wall structure, the precast concrete structure may raise construction cost If the precast concrete members are produced in plant. Thus, if the precast concrete members can be produced in site, the cost-effectiveness and quality shall be increased. Various site conditions must be considered and reviewed to ensure a space for the in-situ production. Therefore, this study focuses on the basic study on the arrangement of in-situ production module of composite precast concrete members.

• 콘크리트학회논문집
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• 제15권4호
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• pp.625-633
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• 2003

For the construction of open-topped steel box girder bridges, prefabricated concrete slab could offer several advantages over cast-in-situ deck including good quality control, fast construction, and elimination of the formwork for concrete slab casting. However, precast decks without reinforcements at transverse joints between precast slabs should be designed to prevent the initiation of cracking at the joints, because the performance of the joint is especially crucial for the integrity of a structural system. Several prestressing methods are available to introduce proper compression at the joints, such as internal tendons, external tendons and support lowering after shear connection. In this paper, experimental results from a continuous composite bridge model with precast decks are presented. Internal tendons and external tendons were used to prevent cracking at the joints. Judging from the tests, precast decks in negative moment regions have the whole contribution to the flexural stiffness of composite section under service loads if appropriate prestressing is introduced. The validity of the calculation of a cracking load fur serviceability was presented by comparing an observed cracking load and the calculated value. Flexural behavior of the continuous composite beam with external prestressing before and after cracking was discussed by using the deflection and strain data.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2010년도 춘계 학술대회 제22권1호
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• pp.45-46
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• 2010

사장교에 경제적으로 적용가능한 장지간 프리캐스트 FRP-콘크리트 합성 바닥판에 대하여 피로 성능 평가를 수행하였다. 실험으로부터 프리캐스트 FRP-콘크리트 합성 바닥판은 충분한 피로 성능을 가짐을 확인하였다.

• 한국건축시공학회지
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• 제11권5호
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• pp.501-514
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• 2011

Recently, there have been many cases in which the difficulty of repair and replacement of principal elements in the bearing wall structure for apartment buildings, which is a major part of apartment buildings in Korea, has led to the reconstruction of buildings rather than their remodeling. To address this problem, the Korea government now allows a floor area ratio of up to 20 %, and has relaxed the building height limits to encourage the use of a rahmen structure instead of a bearing wall structure. However, since reinforced concrete rahmen structures have many problems, including higher floor height and greater construction cost, a great deal of research into rahmen composite precast concrete structures have been conducted. Green Frame, one of the developed prototypes, is expected to provide economic benefits through in-situ production for precast concrete column and beam. For in-situ production of composite precast concrete members, a detailed plan for production, curing, and installation is needed. However, it needs to be confirmed that the space is sufficient to produce the precast concrete members on-site before planning those activities. Therefore, this study proposes in-situ production analysis of composite precast concrete members of Green Frame with the evaluation of structural safety and available area on the parking structure. The result of this study shows that the in-situ production of precast concrete members is possible through a case study.