SHEAR BEHAVIOUR OF FRP RETROFITTED MASONRY WITH UNCERTAINTIES IN THE MATERIAL PROPERTIES: PARAMETRIC STUDY

Mario Raúl Escalante¹; Viviana Carolina Rougier¹

¹ Facultad Regional Concepción del Uruguay, Universidad Tecnológica Nacional

doi:10.20906/CPS/CILAMCE2015-0534

Resumo

Masonry structures shear failure is generally preceded by a massive cracking development in the mortar joints. For this reason, the mortar joints limit the final strength. Depending on compression degree, failure can take place only in the joints, or combined crack brick-mortar joint. Mechanical properties degradation and structural safety loss make the rehabilitation or reinforcement necessary. The reinforcement and rehabilitation technique with fiber reinforcement polymers has experimentally proved to be very effective. Although the in-plane mechanical behaviour of unreinforced masonry and masonry retrofitted with fibre reinforced polymer (FRP) laminates has been studied by several authors, the analytical modelling of mechanical behaviour of masonry remains an open problem, due to its natural variability and inhomogeneity. Parameters, which are considered as deterministic values in many cases are plagued by uncertainties. For example, mechanical properties of masonry are much more variable than steel and concrete, and the thickness of the mortar joint is not regular. For this reason, a probabilistic approach provides a more realistic and rational framework for the analysis. In this work, an existing nonlinear finite element method, is used for predicting the response variability in the shear capacity of unreinforced and retrofitted masonry. A coupled damaged-plasticity model in which bricks and mortar are separately modelled (micro approach) is considered to analyze the in-plane shear resistance, in which spatial stochasticity occurs in the mechanical properties of the materials. Such micro model allows simulating the behaviour of masonry elements using the mechanical properties of constitutive materials and their layout and it also permits to take into account the debonding of the interface between bricks and mortar. Composite materials are modelled with a generalization of mixture theory, where each component exhibits orthotropic elasto-plastic behaviour. For comparison, experimental data are obtained fr

Palavras-chave: FRP reinforced masonry; shear strength; composites; uncertainties properties; numerical model