Masonry structures reinforced with FRP materials optimization for seismic actions

The structural behaviour of masonry structures can be described, for low values of the applied forces with an elastic theory, whilst the failure load can be determined with the classical limit analysis, based on the hypothesis of no-tension material. As well known the collapse multiplier is a function of the applied loads and of the geometry of the scheme. The application of the FRP material gives rise to a very different behaviour that is generally characterised by an almost linear response up the reaching of the maximum load, generally related to a brittle failure. The structural application of composite materials for the strengthening of masonry structures subjected to seismic actions requires the development of suitable methodologies able to provide a quick evaluation of the structural response to the vertical and horizontal actions. Aim of the paper is the optimization of the composite material to be applied on simple schemes of masonry walls in order to obtain the best performance under seismic actions. For this purpose simple models are developed for the evaluation of the behaviour of the schemes subjected to vertical and horizontal forces and compared with the un-reinforced ones. The optimization of the response is calibrated according to a performance based procedure, by analysing the seismic demand and the seismic capacity. A practical example of the methodology is developed and discussed.