Retrofit solution for timber framed masonry system using aramid fiber reinforced polymers (AFRP)

Although the timber framed masonry structures are considered earthquake resistant, for many of them the construction details are poor. Connections are the weakest parts of the system, especially the bottom ones, at every floor level or at the connection with foundation. Also, in past earthquakes out-of-plane collapse was observed usually for the upper masonry panels, though without causing a general collapse of the building. Since for some countries (Portugal, Italy, Greece, Haiti, etc.) the system can be found in heritage buildings, a retrofitting solution was studied in order to improve the behavior of timber framed masonry structures. Thus, AFRP sheets (uni-directional and bi- directional) were applied on a full scale timber framed masonry wall part and in-plane static cyclic tests were conducted. The retrofit solution, all layouts, proved to be efficient, with a 70% increase in strength for two of the specimens and 26% for the third, respectively. Based on the test results a simplified strength evaluation was calibrated for the contribution of the AFRP sheets.