In the present paper, the authors consider the crack pattern developed by 4 FRP strengthened R/C beams brought to failure for flexure under uniform load conditions. All of the observed failure modes are due to concrete cover rip-off; the plate strain distribution and beam deflection for increasing load values are fully documented. Based on the available experimental results, a comparative study of different models for crack spacing evaluation is presented, accounting the influence of the FRP strengthening for flexure on crack development and stabilization. The proposed models are mechanically sound and derived by previous formulations developed for conventional R/C beams. Among the considered models, the authors select a simple and efficient expression suitable to be proposed as a design tool. Finally, thanks to the selected crack spacing model, the authors work out a simple model that can predict the rip-off failure load of R/C beams externally strengthened with FRP with an acceptable accuracy. The model is calibrated making use of the 4 available experimental beams and is validated accounting for 23 experimental beams derived from the literature. All of the considered experimental beams present concrete cover rip-off failure mode, despite the very different geometrical and mechanical characteristics.
Flexural Crack pattern on R/C Beams Strengthened with FRP
APRILE, Alessandra;
2006
Abstract
In the present paper, the authors consider the crack pattern developed by 4 FRP strengthened R/C beams brought to failure for flexure under uniform load conditions. All of the observed failure modes are due to concrete cover rip-off; the plate strain distribution and beam deflection for increasing load values are fully documented. Based on the available experimental results, a comparative study of different models for crack spacing evaluation is presented, accounting the influence of the FRP strengthening for flexure on crack development and stabilization. The proposed models are mechanically sound and derived by previous formulations developed for conventional R/C beams. Among the considered models, the authors select a simple and efficient expression suitable to be proposed as a design tool. Finally, thanks to the selected crack spacing model, the authors work out a simple model that can predict the rip-off failure load of R/C beams externally strengthened with FRP with an acceptable accuracy. The model is calibrated making use of the 4 available experimental beams and is validated accounting for 23 experimental beams derived from the literature. All of the considered experimental beams present concrete cover rip-off failure mode, despite the very different geometrical and mechanical characteristics.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
