Bed joints reinforcement in historic structures

A study concerning a technique for cautious strengthening of the walls of massive buildings is presented. The technique is based on the insertion of reinforcement in the bed mortar joints of the masonry previously excavated and then refilled by a repointing material. Several reinforcement materials (steel, FRP laminates) and different kind of mortars (lime or cement mortars, synthetic resins) can be used. Some considerations on the technical feasibility of the intervention are first illustrated and the results of an experimental campaign and of a FEM study on the application of steel bars and two types of repointing material are also included. Such studies have proved that the proposed technique is able to apply a confinement action to the masonry and reduce the dilation caused by high compressive stresses.