YU YUAN(1), *, GABRIELE MILANI(2)

(1) PhD student, Department of Architecture, Built Environment, and Construction Engineering ABC, Politecnico di

Milano, 20133 Milan, Italy, yu.yuan@polimi.it

(2) Full Professor, Department of Architecture, Built Environment, and Construction Engineering ABC, Politecnico di

Milano, 20133 Milan, Italy, gabriele.milani@polimi.it

ABSTRACT

In recent years, FRP (Fiber Reinforced Polymer) reinforcement has been adopted as building strengthening, including in existing masonry structures. A key factor of externally bonded reinforcement quality, is interface bond behaviour, which has been the focus of much research interest. A proper interface model which allows for the inelastic and brittle behaviour of the FRP-masonry interface is important. In this article, a simple numerical model based on “knots iteration” along the FRP bond length is proposed. A simplified mathematical model is established to derive differential equations deduced from the equilibrium and compatibility conditions, in which all the non-linearities of the reinforced FRP-masonry system are assumed to be lumped at the interface. By increasing the slip value at the free edge, the whole procedure of loading can be described by iteration. Such iteration is achieved by a simple forward scheme that estimates the slip value and its derivatives on specific knots along the bond length. This approach was then validated against some experimental and numerical results, and proved to be able to predict the bond strength in a reasonable range, as well to reproduce the global load-displacement curves gained in standard single-lap shear tests.

KEYWORDS: FRP, masonry, bond behaviour, interface model, iterative numerical method