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- Fall, David, 1983, et al.
(författare)
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Modelling cracking and bending failure of SFRC beams with conventional reinforcement
- 2013
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Ingår i: 8th International Conference on Fracture Mechanics of Concrete and Concrete Structures. - 9788494100413 ; , s. 1276-1285
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Konferensbidrag (refereegranskat)abstract
- In this study three beams, with varying contents of steel fibre reinforcement, were tested in four point bending and compared with results from FE-analysis. The beams were part of a larger experimental programme where relevant material properties were investigated. FE-modelling was performed using a two dimensional model. Concrete was represented by four-node quadrilateral isoperimetric plane stress elements. The smeared crack approach was utilized and the stress-strain relation describing the tensile behavior of the concrete was calculated from uni-axial test results, assuming the crack bandwidth to be equal to the element length. In compression, the concrete was assumed to behave elasto ideal-plastic. The reinforcement was modelled by straight 2-node truss elements connected to the concrete by two-dimensional interface elements providing the bond-slip properties. A material model including hardening effects was derived from tension tests of reinforcement bars and used for modelling the conventional reinforcement. A multi-linear bond-slip model was established through pull-out tests. As an alternative, analyses were also performed taking into account a reduction of the bond stress after yielding of the reinforcement occurred. Loading was applied in two phases: the first comprehending only the self-weight, while incremental loading was applied by deformation control during the second phase. General agreement between experiments and FE-analyses was obtained with regard to load-displacement behaviour. By observing the crack patterns, both from FE-analysis and experiments, it can be concluded that the general behaviour agreed; however, in the analyses not all cracks were fully localized. A higher degree of crack localization was obtained when the bond loss at yielding was included.
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| 2. |
- Williams Portal, Natalie, 1986, et al.
(författare)
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Numerical Modelling of Textile Reinforced Concrete
- 2013
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Ingår i: Proceedings of VIII International Conference on Fracture Mechanics of Concrete and Concrete Structures. - 9788494100413 ; , s. 886-897
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Konferensbidrag (refereegranskat)abstract
- The design and building construction industry is in need of a paradigm shift. One way of dealing with this need is by exploring the use of alternative building materials, such as Textile Reinforced Concrete (TRC). TRC encompasses a fine-grained concrete matrix reinforced by multi-axial textile fabrics, which replaces the traditionally used reinforcement methods. Investigations of new materials are necessary in order to quantify its expected structural performance and integrity. The purpose of this study is to investigate the structural behaviour of a thin TRC slab under bending stress. Four-point bending tests were conducted on thin TRC specimens strengthened by carbonfibre textiles. One of the test configurations was modelled using non-linear finite element methods. The influence of varying the contact perimeter between the textile reinforcement mesh and the concrete matrix was also studied. The finite element software DIANA with the pre- and post-processor FX+ was used. The numerical analysis primarily consisted of 2-D non-linear FE modelling of a thin TRC slab specimen. Cracking of the cement matrix was modelled with a smeared rotating crack model. The bond between the textile and the cement matrix was modelled using bond-slip, with input based on pull-out tests from literature. Simplified bi-linear stress-strain laws were assigned to the textile reinforcement. The main failure mode observed was in bending with the delamination of the textiles from the mortar or by the tensile failure of the textile.
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