In the present work, an innovative finite element (FE) approach for simulating cover separation failure in RC beams with externally bonded strengthening (e.g. FRP) systems is proposed. Several experimental and theoretical studies have clearly shown that externally bonded FRP composites can be successfully used to improve the structural performances of concrete members, although an important issue, concerning the reliability and the safety of this strengthening method, is the occurrence of potential brittle failures of FRP systems, which could significantly reduce their effectiveness. In this regard the present paper deals with a novel numerical framework for the collapse analysis of reinforced concrete (RC) structures strengthened with FRP plates, based on an inter-element fracture approach for concrete, used in combination with an embedded truss model, for taking into account the interaction between concrete cracks and tensile steel rebars, and with additional mixed-mode cohesive elements along the adhesive/concrete (AC) and adhesive/plate (AP) material interfaces. The reliability and the effectiveness of the proposed fracture approach have been shown by means of comparisons with available experimental results and the numerical model has been exploited for predicting the load-carrying capacity and the related failure mode of real-scale retrofitted RC elements. The proposed model, developed in a 2D finite element setting and implemented within a commercial software with programming capabilities, represents an innovative and versatile numerical tool able to analyze in an effective manner all the main failure mechanisms in FRP/concrete systems due to multiple crack initiation, propagation and coalescence, unlike for most existing models. In particular, the adopted inter-element approach dramatically simplifies the simulation of complex fracture phenomena.
An inter-element fracture approach for the analysis of concrete cover separation failure in frp-reinforced rc beams
Greco F.;Luciano R.;
2020-01-01
Abstract
In the present work, an innovative finite element (FE) approach for simulating cover separation failure in RC beams with externally bonded strengthening (e.g. FRP) systems is proposed. Several experimental and theoretical studies have clearly shown that externally bonded FRP composites can be successfully used to improve the structural performances of concrete members, although an important issue, concerning the reliability and the safety of this strengthening method, is the occurrence of potential brittle failures of FRP systems, which could significantly reduce their effectiveness. In this regard the present paper deals with a novel numerical framework for the collapse analysis of reinforced concrete (RC) structures strengthened with FRP plates, based on an inter-element fracture approach for concrete, used in combination with an embedded truss model, for taking into account the interaction between concrete cracks and tensile steel rebars, and with additional mixed-mode cohesive elements along the adhesive/concrete (AC) and adhesive/plate (AP) material interfaces. The reliability and the effectiveness of the proposed fracture approach have been shown by means of comparisons with available experimental results and the numerical model has been exploited for predicting the load-carrying capacity and the related failure mode of real-scale retrofitted RC elements. The proposed model, developed in a 2D finite element setting and implemented within a commercial software with programming capabilities, represents an innovative and versatile numerical tool able to analyze in an effective manner all the main failure mechanisms in FRP/concrete systems due to multiple crack initiation, propagation and coalescence, unlike for most existing models. In particular, the adopted inter-element approach dramatically simplifies the simulation of complex fracture phenomena.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
