Influence of high temperature on the bed joint reinforcement of brick masonry by CFRP bars

Fiber Reinforced Plastics (FRP) are particularly sensitive to high temperature influence, as their mechanical properties can be strongly compromised. This study proposes a first evaluation of the response of brick masonry strengthened by the bed joint reinforcement technique under fire conditions. In particular, the loss of adhesion of bars is considered, being one of the main characteristics which the efficiency of the intervention is responsible for. The technique is applied by the insertion of bars into previously excavated bed mortar joints, then refilled with proper material. It is particularly effective to counteract creep damage on massive structures and it has been until now performed only by stainless steel reduced size bars on historic constructions in Italy. The use of FRP’s seems to be very promising for restoration purposes, but specific performances still need to be clarified. In the paper, both numerical and analytical analyses are considered for the definition of the reference time for different strengthening configurations and the most common fire protection materials. The study allowed suggesting technical details for the optimization of the mechanical behaviour of the masonry in the repaired or strengthened conditions.