Experimental investigations on the influence of thermal elements on the structural stability of modern masonry walls

The presence of additional elements specifically aiming at improving the energy efficiency of buildings (thermal layers, disconnections) is known as potentially having a significant impact on the resistance and stability of load-bearing masonry walls. On the one hand, the presence of these thermal elements induces potential weaknesses in the walls, modifying their resistance at local level. On the other hand, these elements also modify the boundary conditions of the walls and are thus likely to have an influence on the buckling behaviour. It is therefore necessary to adjust accordingly the design procedures suggested for instance by Eurocode 6 to check the wall stability against gravity loading. Experimental studies concerning the interaction between thermal performance and structural stability of unreinforced masonry (URM) structures remain however limited. Therefore, the objective of the current study is to develop a better understanding of the behaviour of current URM structures in presence of such thermal layers. A typical example is for instance the presence of a layer of aerated concrete blocks at the bottom of a clay masonry wall. This study includes a comprehensive testing program considering different types of masonry elements subjected to various load conditions. This paper plans to summarise the experimental campaign and the design of the test setup and test specimens. The research work aims on the long term at the identification of the interaction of various parameters (compression level, mortar type, unit type, type of thermal elements) on the strength capacity and stability of URM walls.