In-Plane Behaviour And Damage Assessment Of Masonry Infills With Hollow Clay Bricks In RC Structures

Reinforced Concrete (RC) framed buildings with clay masonry infills represent a very common structural typology worldwide for civil, strategic or productive use. Nevertheless damage to infills may cause danger for human lives and strongly affected economic losses due to past earthquakes, in current practice, infills are considered as partition elements without any structural function. However, their role is crucial in terms of global and local response of RC buildings in the event of earthquake. Their behaviour under seismic actions should be reliably characterized, starting from the analysis of their displacement capacity at different performance levels due to in-plane actions, and a proper numerical modelling, able to reproduce the influence of infills on the global behavior of RC frames under seismic actions. Some models have been already proposed in literature, but their reliability should be yet proved on the basis of an as huge as possible experimental database. In this paper, a homogenous extensive database of experimental tests on RC frames infilled with hollow claymasonry infills – typical of Mediterranean RC building stock – is collected and presented. The experimental responses of masonry infills under lateral loads are obtained. The main numerical models existing in literature for infills are investigated and compared with the experimental results in order to select the model that minimize the prediction error or to propose a new simplified model for the envelope of the infill response. The evolutions of damage under increasing displacement demand are also analyzed, and the displacement capacity at given performance levels are identified and correlated to the in-plane response of the infill panels. The analysis of the damage evolution to the infills during the experimental tests finally allows the definition of drift-based fragility functions for these non-structural components, representing a key point for a reliable estimation of losses due to earthquakes.