Displacement Capacity of Load-Bearing Masonry as a Basis for Seismic Design

The masonry still one of the widespread construction system for low-rise residential buildings even for countries prone to seismic risk. Seismic design methods yet in use are based on idea that controlling forces is better way to control earthquake induced damages. In recent decades, however, was highlighted as the differences in strength between two levels of damage is low, and therefore as the damage is better correlated to the displacement. Also, in recent years, has arose a widespread expectation for being able to control the damage based on the probability of occurrence of an earthquake or being able to base the design on different performance levels ("performance-based design"). In this context, the design of masonry buildings needs to develop these design methods. The results of experimental tests performed at the University of Padua in the recent years on different masonry systems both reinforced and unreinforced with different horizontal and vertical joints typologies, which were aimed to characterization under combined in-plane vertical and horizontal cyclic loading, were used to make different strategies of finite element modeling that reproduce and extend the experimental results using parametric analyses. These analyses allow a comparison and a validation of an analytical model which was then developed. This model is able to reproduce the envelope curves of the cyclic shear-compression tests and it is able to interpret the performances of panels linking them with limit states resulting from integration of cross-section equilibrium equations. Finally, it was applied a model able to reproduce the hysteretic behavior of masonry and were carried out dynamic analyses using the input data derived from the envelope curves. The data thus collected can be used as database and as input for displacement-based design methods.