• Title/Summary/Keyword: flat plate structures

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Analytical Study on Punching Shear of Reinforced Concrete Flat Plates (철근콘크리트 플랫 플레이트의 뚫림전단 거동에 관한 해석적 연구)

  • Kim, Min-Sook;Lee, Young-Hak;Kim, Hee-Cheul
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.23 no.4
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    • pp.409-415
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    • 2010
  • A finite element model for punching shear of flat plate structures is presented. A parametric study also has been conducted to verification of influence of several parameters in terms of the flexural reinforcement ratio, slab thickness. Reisnner-Mindlin assumptions are adopted to consider of shear deformation. Layered shell element is considered for the material non-linearities. The finite element model of this study was verified comparing with existing experimental results. The model is able to predict the capacity of the flat plate structures. The punching shear of flat plate structures varied depending on the flexural reinforcement ratio, slab thickness.

Seismic Performance Evaluation of flat Plate Structures Retrofitted with Steel Plates and Braces (강판과 가새로 보강된 무량판 구조물의 내진 성능 평가)

  • Shin, Woo-Seung;Kim, Jin-Koo
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2008.04a
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    • pp.325-330
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    • 2008
  • In this study 3- and 6-story flat plate structures designed only for gravity load are retrofitted with steel plates and braces and their seismic performances are evaluated to verify the effect of seismic retrofit. According to the analysis results obtained from nonlinear static analysis both the strength and stiffness are significantly enhanced as a result of the seismic retrofit. When buckling-restrained braces are used instead of conventional braces, the structures show more ductile behavior, especially in the 3-story structure.

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Prediction and Evaluation on Inequality Shortening and Long-term Deflection of High-rise Flat Plate Structure using 3D Finite Element Analysis (3차원 유한요소해석을 이용한 고층 무량판 슬래브 구조물의 부등축소량 및 장기처짐 예측 평가)

  • Shim, Hak-Bo;Park, Soon-Jeon
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2020.06a
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    • pp.159-160
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    • 2020
  • Flat plate structures are designed in the form of long span due to the development of construction materials and the improvement of construction technology. However, a high-rise structure of a flat plate of 50 less floors is constructed without detailed review of the inequality shortening, long-term deflection of the slab, and cracks. Therefore, it is possible to examine the case of defects in the structure due to deformation and damage of non-structures such as crack and leak, deflection of the door frame, and deformation of equipment ducts. In this study, it is a high-rise structure, and the inequality shortening and long-term deflection of the slab of the flat plate structure were evaluated through finite element analysis, and it was confirmed that prior precision analysis and correction during construction is necessary.

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Nonlinear modeling of flat-plate structures using grid beam elements

  • Tian, Ying;Chen, Jianwei;Said, Aly;Zhao, Jian
    • Computers and Concrete
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    • v.10 no.5
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    • pp.489-505
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    • 2012
  • This paper presents a simplified grid beam model for simulating the nonlinear response of reinforced concrete flat-plate structures. The beam elements are defined with nonlinear behavior for bending moment and torsion. The flexural stiffness and torsional strength of the beam elements are defined based on experimental data to implicitly account for slab two-way bending effects. A failure criterion that considers the interaction between the punching strength and slab flexural behavior is incorporated in the model. The effects of bond-slip of slab reinforcement on connection stiffness are examined. The proposed grid beam model is validated by simulating large-scale tests of slab-column connections subjected to concentric gravity loading and unbalanced moment. This study also determines the critical parameters for a hysteretic model used to simulate flat-plates subjected to cyclic lateral loading.

Modeling Method of Slabs in RC Flat-Plate Structures Under Lateral loading (횡하중을 받는 RC 무량판 구조의 슬래브 모델링 기법)

  • 최정욱;송진규;이수곤;김진상
    • Journal of the Korea Concrete Institute
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    • v.14 no.4
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    • pp.615-622
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    • 2002
  • To reasonably predict the behaviors for RC flat-plate structures, analysis model considering the flexural stiffness of slabs is required. FEMA 273 and ACI 318-99 refer to theoretical analysis models of two-way slab systems under lateral loading but the actual application method is not suggested. In this study, the modeling and application methods of the flat-plates using effective beam concept are suggested. The results of this study are as follows. 1) The effective beam width model suggested in this study is very useful to model flat-Plate structures subjected to seismic loading for three dimensional analysis 2) The result of analysis for idealized flat-plate example using the effective beam widths considering the effect of the slab crack is shown upper value for displacements. Whereas the model considering effective beam width coefficients only is shown upper value for unbalanced moments

Numerical study on effect of integrity reinforcement on punching shear of flat plate

  • Ahsan, Raquib;Zahura, Fatema T.
    • Computers and Concrete
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    • v.20 no.6
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    • pp.731-738
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    • 2017
  • Reinforced concrete flat plates consist of slabs supported directly on columns. The absence of beams makes these systems attractive due to advantages such as economical formwork, shorter construction time, less total building height with more clear space and architectural flexibility. Punching shear failure is usually the governing failure mode of flat plate structures. Punching failure is brittle in nature which induces more vulnerability to this type of structure. To analyze the flat plate behavior under punching shear, twelve finite element models of flat plate on a column with different parameters have been developed and verified with experimental results. The maximum range of variation of punching stress, obtained numerically, is within 10% of the experimental results. Additional finite element models have been developed to analyze the influence of integrity reinforcement, clear cover and column reinforcement. Variation of clear cover influences the punching capacity of flat plate. Proposed finite element model can be a substitute to mechanical model to understand the influence of clear cover. Variation of slab thickness along with column reinforcement has noteworthy impact on punching capacity. From the study it has been noted that integrity reinforcement can increase the punching capacity as much as 19 percent in terms of force and 101 percent in terms of deformation.

Seismic Design Provisions and Revisions to the Guides for RC Flat Plate Systems in the US (미국에서의 RC무량판 내진설계기준과 개정 방향)

  • Kang, Thomas H.K.;Park, Hong-Gun
    • Magazine of the Korea Concrete Institute
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    • v.20 no.2
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    • pp.25-36
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    • 2008
  • Seismic design of reinforced concrete flat plate structures is often complicated as it deals with three dimensionality and continuous spans, and mostly material complexity and reinforcement variation. A great degree of uncertainty in such structural and material properties is thus inherent in the RC flat plate systems, and hinders simplification of the design process in terms of slab flexure, unbalanced moment transfer at a slab-column connection, and punching shear. For these reasons, there have been substantial changes and updates in building codes relating to flat plates and slab-column connections over a handful of decades. Also, for the same reason, some of codes never have been revised. As a consequence of nonsimultaneous development of each provision, it tends to confuse structural engineers when using a mixture of all different US code provisions. In this paper, in the step-by-step logical order, seismic design of the RC flat plate systems is re-organized and clarified to make it easier to apply. Furthermore, recent changes or proposed changes are introduced, and are explained as to how it will apply in practice.

Geometrical Nonlinear Analysis of Thin-walled Structures by Flat Shell Elements with Drilling D.O.F. (회전자유도를 갖는 평면쉘요소에 의한 박판구조물의 기하비선형해석)

  • 최창근;송명관
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 1998.04a
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    • pp.317-324
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    • 1998
  • A nonlinear anile element formulation of flat shell elements with drilling d.o.f, is presented for the geometrical nonlinear analysis of thin-walled structures. The shell element to be applied in finite element analysis was developed by combining a membrane element named as CLM with drilling rotation d.o.f, and plate bending element. The combined shell element possesses six degrees of freedom per node. The element showed the excellent performance in the linear analysis of the folded plate structures, in which the normal rotational rigidity of folded plates is considered, therefore, using this element geometrical nonlinear analysis of those structures is fulfilled in this study. An incremental total Larangian approach is adopted through out in which displacements are referred to the original configuration. Comparing the results with those of other researches shows the performance of this element and a folded plate structure is analyzed as an example.

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A method for effective beam widths of slabs in flat plate structures under gravity and lateral loads

  • Choi, Jung-Wook;Song, Jin-Gyu
    • Structural Engineering and Mechanics
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    • v.21 no.4
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    • pp.451-468
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    • 2005
  • Effective beam width models are commonly used to obtain the lateral stiffness of flat plate structures. In these models, an effective beam width is defined as the width when the flexural stiffness of the beam element equals the slab stiffness. In this present study, a method to obtain effective beam widths that considers the effects of connection geometry and slab cracking is analytically proposed. The rectangularity of the vertical member for the connection geometry and the combined effects of creep and shrinkage for the slab cracking are considered. The results from the proposed method are compared with experimental results from a test structure having nine slab-column connections.

Investigation on mechanical performance of flat steel plate-lightweight aggregate concrete hollow composite slab

  • Yang, Yong;Chen, Yang;Yang, Ye;Zeng, Susheng
    • Steel and Composite Structures
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    • v.31 no.4
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    • pp.329-340
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    • 2019
  • An innovated type of the flat steel plate-lightweight aggregate concrete hollow composite slab was presented in this paper. This kind of the slab is composed of flat steel plate and the lightweight aggregate concrete slab, which were interfaced with a set of perfobond shear connectors (PBL shear connectors) with circular hollow structural sections (CHSS) and the shear stud connectors. Five specimens were tested under static monotonic loading. In the test, the influence of shear span/height ratios and arrangements of CHSS on bending capacity and flexural rigidity of the composite slabs were investigated. Based on the test results, the crack patterns, failure modes, the bending moment-curvature curves as well as the strains of the flat steel plate and the concrete were focused and analyzed. The test results showed that the flat steel plate was fully connected to the lightweight aggregate concrete slab and no obvious slippage was observed between the steel plate and the concrete, and the composite slabs performed well in terms of bending capacity, flexural rigidity and ductility. It was further shown that all of the specimens failed in bending failure mode regardless of the shear span/height ratios and the arrangement of CHSS. Moreover, the plane-section assumption was proved to be valid, and the calculated formulas for predicting the bending capacity and the flexural rigidity of the composite slabs were proposed on the basis of the experimental results.