Loading...
6 results
Search Results
Now showing 1 - 6 of 6
- Punching shear strengthening of flat slabs: CFRP and shear reinforcementPublication . Moreno, Carlos; Ferreira, Débora; Bennani, Abdelkrim; Sarmento, Ana; Noverraz, MichelPunching in slabs is usually associated to the application of concentrated loads or to the presence of columns. One of the main concerns related to flat slabs is its punching shear capacity at slabcolumn connection, which is subjected to a very complex three-dimensional stress state. Provided that bending capacity is installed, punching shear failure is hence characterized by the development of a truncated cone shaped surface at the slab-column connection. The experimental programme carried out by the authors includes four normal strength concrete slabs (1100×1100×100 mm3), with and without shear reinforcement, submitted to punching under a concentrated load. One of the specimens included typical bent-down bars as shear reinforcement. Frequently, there is the need to strengthen existing flat slabs against punching shear failure. Current paper intends to further investigate the structural response of such reinforcement techniques. One of the strengthening practices, which have been tested within current experimental programme, consists on gluing carbon fibre reinforced polymers on concrete surface. Moreover, the near surface mounted technique has also been tested within current experimental work. Finally, a fourth specimen served as reference. The effects of shear reinforcement and of the carbon fibre reinforced polymers enhancing punching shear capacity are observed.
- Punching shear strengthening of flat slabs: CFRP and shear reinforcementPublication . Moreno, Carlos; Ferreira, Débora; Bennani, Abdelkrim; Sarmento, Ana; Noverraz, MichelPunching in slabs is usually associated to the application of concentrated loads or to the presence of columns. One of the main concerns related to flat slabs is its punching shear capacity at slabcolumn connection, which is subjected to a very complex three-dimensional stress state. Provided that bending capacity is installed, punching shear failure is hence characterized by the development of a truncated cone shaped surface at the slab-column connection. The experimental programme carried out by the authors includes four normal strength concrete slabs (1100×1100×100 mm3), with and without shear reinforcement, submitted to punching under a concentrated load. One of the specimens included typical bent-down bars as shear reinforcement. Frequently, there is the need to strengthen existing flat slabs against punching shear failure. Current paper intends to further investigate the structural response of such reinforcement techniques. One of the strengthening practices, which have been tested within current experimental programme, consists on gluing carbon fibre reinforced polymers on concrete surface. Moreover, the near surface mounted technique has also been tested within current experimental work. Finally, a fourth specimen served as reference. The effects of shear reinforcement and of the carbon fibre reinforced polymers enhancing punching shear capacity are observed.
- Punching shear analysis of slab-column connectionsPublication . Moreno, Carlos; Sarmento, Ana MariaThe paper aims to present an experimental testing program regarding reinforced concrete slabs, with and without shear reinforcement, submitted to punching under both symmetric and eccentric loading. Comparisons between numerical simulations and experimental behaviour results are carried on. The capabilities and limitations of the numerical model to reproduce the brittle punching-shear failure are discussed. The paper opted for a performance assessment of a numerical model, comparing FEM results with known experimental tests properly instrumented. Capability of DIANA software to simulate the punching behaviour of slabs is discussed. The paper demonstrates that the mechanical properties assigned to the element layer containing the bending reinforcement impose the load deflection stiffness behaviour. Good agreement was found between the predicted and the observed deformation behaviour. Nevertheless, the reproduction of the punching ultimate capacity is strongly dependent on the adopted value for the shear retention factor, which appears to be the major decisive parameter. This paper demonstrates that the smeared crack model based on both the concept of strain decomposition (SD) and total strain with fixed orthogonal cracks approach (TSF) can correctly be used for the analysis of the behaviour of slabs submitted to punching shear.
- Punching shear in eccentrical loaded flat slabsPublication . Moreno, Carlos; Bastos, Ana SarmentoThe effect of the eccentricity of loading on the behaviour of slab-column connections without or with headed studs as shear reinforcement is experimentally investigated. Normal and fibre reinforced concrete slabs were experimentally tested. Test results are compared with code provisions and with numerical simulation analyses.
- Strengthening slabs for punching shear using fibre reinforced polymerPublication . Moreno, Carlos; Ferreira, Débora; Sarmento, AnaPunching is generally associated to the application of concentrated loads or to the presence of columns. One of the main concerns related to flat slabs is its punching shear capacity at slab‐column connection, which is subjected to a very complex three‐dimensional stress state. Provided that bending capacity is installed, punching shear failure is characterized by the development of a truncated cone shaped surface at the slab‐column connection. Recurrently, there is the need to strengthen existing flat slabs against punching shear failure. The use of fibre‐reinforced polymer (FRP) is an innovative technology to strengthen concrete structures. In this paper, punching shear strengthening of flat slabs using carbon fibre reinforced polymer (CFRP) is studied. The experimental programme carried out by the authors includes four normal strength concrete slabs (1100×1100×100 mm3), with and without shear reinforcement, submitted to punching under a concentrated load. One of the specimens included typical bent‐down bars as shear reinforcement. Among available strengthening practices, the technique that consists on gluing CFRP on concrete surface have been tested within current experimental programme. Moreover, the near surface mounted (NSM) technique has also been tested within current experiments. Finally, a fourth specimen served as reference. The effects of shear reinforcement and of CFRP enhancing punching shear capacity are observed.
- Punching shear analysis of slab-column connectionsPublication . Moreno, Carlos; Sarmento, Ana MariaIn this study, numerical simulations of the experimental behaviour of reinforced concrete slabs tested under punching by the authors are presented. The capabilities and limitations of the numerical model to reproduce the brittle shear failure are discussed.