Earthquake resilience : towards safer buildings

Widely used in modern reinforced concrete (RC) buildings around the world, masonry infills have shown to have a crucial influence on the global behaviour of a structure under seismic loading. As highlighted by the poor performance of some buildings in recent earthquakes, these panels built in between the columns and beams of the structural frame of a building can cause several dangerous effects, such as out-of-plane collapse for instance. However, current seismic risk assessment methods often fail to take them into account. In an effort to address this shortcoming, Dr. Maria Teresa De Risi aims to develop a reliable modelling technique for assessing the seismic performance of RC framed buildings with masonry infills. The overarching objective of her research is twofold, to guide the designers of the future both in the assessment and strengthening of existing buildings and in the design of new constructions, and to allow for the proper evaluation of expected losses due to a given earthquake scenario.

Whereas the structural frame ensures the bearing function, the infill wall primarily have to separate inner and outer space. « Because infills are considered partition elements, their contribution is generally neglected in common structural analyses », remarks Dr. Maria Teresa de Risi, postdoctoral researcher in Seismic risk. « And thus, despite the fact that they can play a crucial role in mechanisms such as building collapse, reduction in period of vibration, possible out-of-plane overturning, or possible induced brittle failure mechanisms in joints and columns, for instance. ». « There are some seismic models in literature that account for masonry infills in the context of concrete buildings but the majority is calibrated on a very few numbers of experiments ». Her project aims to contribute to filling that gap.

Helping building safer buildings and improving existing ones

The project’s preliminary missions will indeed consist of a series of experiments. The first sequence will concern the analysis of existing experimental data from laboratory tests of post-earthquake damage, including the 2009 L’Aquila earthquake. The second series consists in new experimental testing of both existing and future types of infills in RC buildings. Once these steps have been completed, the project’s ultimate goals are the proposal of a reliable modelling approach to assess the vulnerability of new and existing RC buildings and the study and proposal of both new construction and retrofitting strategies to limit damage to infills.

« RC buildings are particularly common in earthquake-prone areas. It is thus crucial to provide an as comprehensive as possible knowledge of all the vulnerability aspects of these structures », Dr. Maria Teresa De Risi stresses. « Due to the heterogeneity of infills typology and the large number of modelling issues to deal with, the road to a correct assessment of their performance is still long », she acknowledges. Her project proposes to perform an important step forward towards this objective.