• Title/Summary/Keyword: Slab Formwork

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Investigation on the flexural behavior of an innovative U-shaped steel-concrete composite beam

  • Turetta, Maxime;Odenbreit, Christoph;Khelil, Abdelouahab;Martin, Pierre-Olivier
    • Steel and Composite Structures
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    • v.34 no.3
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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.

Improvement of the behaviour of composite slabs: A new type of end anchorage

  • Fonseca, Alexandre;Marques, Bruno;Simoes, Rui
    • Steel and Composite Structures
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    • v.19 no.6
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    • pp.1381-1402
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    • 2015
  • The application of composite steel-concrete slabs with profiled steel sheeting has increased, due to the various advantages in relation to reinforced concrete slabs such as, the reduced thickness, the reduced amount of lost formwork needed, as well as the speed of execution. The loss of longitudinal shear resistance is, generally, the governing design mode for simply supported spans of common lengths. For common distributed loadings, the composite behaviour is influenced by the partial shear connection between the concrete and the steel sheeting. The present research work is intended to contribute to improving the ultimate limit state behaviour of composite slabs using end anchorage. Eurocode 4, Part 1.1 (EN 1994-1-1) provides an analytical methodology for predicting the increase of longitudinal resistance, achieved by using shear studs welded through the steel sheeting as the end anchorage mechanism. The code does not supply an analytical methodology for other kinds of end anchorage so, additional tests or studies are needed to prove the effectiveness of these types of anchorage. The influence of end anchorage mechanisms provided by transverse rebars at the ends of simply supported composite slabs is analysed in this paper. Two experimental programmes were carried out, the first to determine the resistance provided by the new end anchorage mechanism and the second to analyse its influence on the behaviour of simply supported composite slabs.

A Study on Early-strength Development of Concrete Using Accelerating AE Water Reducing Agents for the Estimation of Optimum Duration (촉진형 AE감수제를 사용한 콘크리트의 최적공기산정을 위한 조기강도 발현 특성 연구)

  • Lee, Joo-Hun;Sa, Soon-Heon;Ji, Suk-Won;Jeon, Hyun-Gyu;Seo, Chee-Ho
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2006.11a
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    • pp.91-94
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    • 2006
  • The way to shorten a construction period is considered to an very important technology development element as reducing the formwork removal periods with promoting strength revelation own concrete. This study executed experiment to review usability of early strength revelation chemical admixture which is judged in ways effective with premature removal of form about concrete. Use of early strength revelation AE water reducin admixture is apperaing so that strength revelation by early hydration promotions is excellent. The results of being applied proposed work process are that compressive strength are appeared more than 5MPa within 16 hours so that removal of vertical form was possible. the concrete compressive strength satisfied with a more than 2/3 of specified concrete strength for removal of horizontal form are appeared in 42 hours of 27 MPa proportioning strength, in 36 hours of 30, 35 MPa proportioning strength so that the 6 days cycle time of concrete structural frame work is cut by 2 days as shortening delayed period in works of removing slab forms. So construction cost reductions and a construction period shortening are judged so that it is possible.

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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.

Test research of Structural Safety for Steel Wire-Integrated Deck Plate System (철선일체형 데크 플레이트 구조성능평가를 위한 실험적 연구)

  • Lee, Yong-Jae
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.14 no.6
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    • pp.220-228
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    • 2010
  • A steel wire-integrated deck plate that welds integrated triangle truss steel wires on a galvanized steel sheet is developed to reduce construction costs of a slab or formwork such as shores and supports, and it is already widely applied in many construction fields. This study selected upper and lower steel wires, lattice steel wires, span, and cutting methods of ends as variables, and conducted an experimental test by manufacturing a total of 32 full scale test bodies. According to the result, changes in final destruction types of the test bodies and cutting methods of ends didn't affect structural performance of test bodies, and for a 3.2m-span test body, there was no big problems in using ${\Phi}4.5$ of lattice steel wires.