Development of a fiber model for load-bearing masonry walls

In the last few years, the possibility of being able to control the damage based on the probability of occurrence of an earthquake and designing on the basis of different performance levels, has arose. Masonry is still a widespread construction system for low-rise residential buildings even for countries prone to seismic risk, hence masonry needs to develop these design concepts. Experimental tests were performed in recent years at the University of Padova on different masonry systems, both reinforced, and unreinforced with different joints types. The tests were aimed at characterizing the masonry behaviour under combined in-plane cyclic loading, and they were used to develop an analytical model that reproduce and extend the experimental results using parametric analyses. This model is a formulation of a fiber element and is cast in the general framework of the mixed method. It includes effects of shear deformation, diagonal shear failure mechanism and it is able follow response in post-peak phase. The model is able to interpret the performances of masonry panels linking them with limit states resulting from integration of cross-section equilibrium equations. Finally, its results were generalized proposing design equations directly related to performance levels and both geometrical and mechanical properties of URM panels.