• Title, Summary, Keyword: Concrete Slab Placing Sequences

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Behavior of Steel Box Girder Bridge According to the Placing Sequences of Concrete Slab (II) (강합성 상자형 교량의 바닥판 타설에 따른 거동 연구(II) - 해석적 연구 및 균열제어 -)

  • Kwak, Hyo Gyoung;Seo, Young Jae;Jung, Chan Mook;Park, Young Ha
    • Journal of Korean Society of Steel Construction
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    • v.12 no.2
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    • pp.133-142
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    • 2000
  • This study deals with behavior of steel box girder bridges according to the concrete slab casting sequences and sectional types. The time dependent behavior of bridges caused by the differential setting of slab concrete resulting from time gap for each part of slab deck in a sequential placing method produces is analyzed. In correlation studies between girder section types and placing sequences, time dependent effects of concrete creep and shrinkage are implemented in the analytical model proposed in the previous study. Finally, field recommendations in terms of concrete slump and relative humidity are suggested to prevent early transverse cracking of concrete slabs.

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The Reasonable Concrete-Placing Methods and Sequences of Composite Steel Bridge (강합성형 교량의 합리적인 타설방법과 순서에 관한 연구)

  • Jo, Byung-Wan;Seo, Sug-Gu
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.3 no.2
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    • pp.205-212
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    • 1999
  • Recently, unexpected cracks in the concrete deck slab of composite steel bridges have been widely reported at an early age of concrete placing due to the concrete placing sequence and methods. Accordingly, the analytical research was carried out to verify the negative moment at an internal supports due to the several concrete pouring sequence and to determine the reasonable concrete placing method on the deck slab of composite steel bridge. The results show that the conventional concrete-placing method, which pours concrete first on the positive moment regions and then negative regions, leads to the minimum moment at an internal supports. However, the conventional method produces two impractical construction joints on every spans and makes field engineer to pour concrete continuously. In conclusion, this concrete-placing method was verified to be reasonable only when the construction joint was placed at the $\frac{5}{8}l{\sim}\frac{6}{8}l$ location of the middle span.

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Behavior of Composite Steel Bridges According to the Concrete Slab Casting Sequences (바닥판 콘크리트 타설순서에 따른 합성형교량의 거동해석)

  • Kwak, Hyo Gyoung;Seo, Young Jae;Jung, Chan Mook;Park, Young Ha
    • Journal of Korean Society of Steel Construction
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    • v.10 no.2
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    • pp.233-251
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    • 1998
  • This paper deals with the prediction of behavior of composite girder bridges according to the placing sequences of concrete deck. Based on a degenerate kernel of compliance function in the form of Dirichlet series, the time-dependent behaviors of bridges are simulated, and the layer approach is adopted to determine the equilibrium condition in a section. The variation of bending moments along the bridge length caused by the slab casting sequence is reviewed and correlation studies between section types and placing sequences are conducted with the objective to establish the validity of the continuous placing of concrete deck on the closed steel box-girder which is broadly used in practice.

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Behavior of Steel Box Girder Bridge According to the Placing Sequences of Concrete Slab (I) (강합성 상자형 교량의 바닥판 타설에 따른 거동 연구(I) - 해석모델 및 현장실험 -)

  • Kwak, Hyo Gyoung;Seo, Young Jae;Jung, Chan Mook;Park, Young Ha
    • Journal of Korean Society of Steel Construction
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    • v.12 no.2
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    • pp.123-131
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    • 2000
  • In this study, both experimental and analytical study for behavior of the existing composite steel box girder bridges, constructed along with the procedure of continuous placing slab, are conducted to establish the validity of the proposed model. The layer approach is adopted to determine the equilibrium condition in a section to consider the different material properties and concrete cracking across the sectional depth, and the beam element stiffness is constructed on the basis of the assumed displacement field formulation and the 3-points Gaussian Integration. In addition, the effects of creep and shrinkage of concrete for time-dependent behavior of the bridge are taken into consideration. Finally, both analytical and experimental results are compared.

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A Study on Construction Sequence Optimization and Structural Analysis in consideration of Structural Concept of Hanging Structure based on the Applied Case (적용사례 중심의 매달린 구조물의 구조적 특성을 고려한 시공순서 최적화 및 시공단계별 구조해석 연구)

  • Park, Yong-Hyeon;Kim, Jong-Soo;Ju, Young-Kyu
    • Journal of the Architectural Institute of Korea Structure & Construction
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    • v.35 no.7
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    • pp.147-156
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    • 2019
  • The purpose of this study is to consider structural issues and analyze construction sequences when constructing hanging floors supported by Mega truss. Since suspended structures were supported by the Mega truss, vertical load on suspended structures was needed to transfer from low to high. Deflection management of structures was the primary point under construction. The results of this study were as follows; The steel structures, which has relatively lighter self-weight, were constructed upwards after the base floor steel truss erection. Concrete Placing, which has relatively heavier self-weight, were performed in two phases to minimize structure's deflection. Slab was placed downwards from the top floor to lower floor whereas column was places upwards. Deflection measurements were carried out at every construction sequences.