Out-of-Plane Flexure of Masonry Panels with External Thermal Insulation

The combined seismic and energy retrofit of existing aged buildings represents a topic of importance for the building stock. The current study investigates the out-of-plane performance of a specific type of thermo-insulation scheme with panels attached on the external facades of multistory buildings. The investigation was carried out through flexure tests of prototype masonry specimens. From the comparison of their flexural performance, with or without thermo-insulating attachments, the influence of thermal insulation on the out-of-plane behavior of clay brick masonry is demonstrated. It was found that when the thermo-insulating attachment is in tension from such out-of-plane flexure of the masonry facade it performs in a satisfactory way and gives an increased flexural capacity for the assembly. The thermal insulating panels, although partially debonded from the masonry substrate at a limit-state, do not collapse, even when the masonry panel develops large flexural cracks. This is due to the presence of the used plastic anchors. When the thermo-insulating panel is subjected to compression during such an out-of-plane flexure the resulting increase in the out-of-plane load bearing capacity is relatively small. Based on these observations it can be concluded that such thermo-insulating panels may also lead to a less vulnerable seismic performance than that of the same masonry panel without this type of thermo-insulating attachment. This was also confirmed when the in-plane behavior was considered from a separate investigation already published. The employed numerical modeling was successful in simulating the most important aspects of the out-of-plane response of the tested masonry wallets with or without thermo-insulating attachments. The good agreement with observed performance as well as the general nature of this numerical simulation confirms its validity for further use.

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