Analytical and numerical modeling of composite-to-brick bond

In masonry components strengthened with externally bonded composites, good bonding is one of the most important aspects governing structural behavior, since failure usually takes place with detachment between reinforcement and substrate. This type of event is a brittle, sudden and therefore undesirable failure mechanism; nor does it allow the full strength of the reinforcement to be exploited. Many experimental data on bonding have recently become available from a Round Robin Test carried out within the framework of RILEM TC-223. In the present paper, experimental tests were simulated at increasing levels of complexity; bond behavior was first studied with an analytical model based on bi-linear representation of bond law. Two-dimensional and three-dimensional finite element analyses were then performed, according to various bond-slip laws. In particular, a number of bi-linear and non-linear interface laws were used, calibrated according to several strategies but with the same experimental population. Lastly, several commercial codes and types of finite elements were examined. This work may be said to represent a numerical Round Robin Test, with various simulations and modeling approaches. Analytical and numerical results are compared with experimental ones, in terms of both overall behavior (load to displacement curve) and local behavior (strain profiles on reinforcements at increasing load values), showing the importance of both types of information in order to obtain reliable predictions of experimental results.