EXPERIMENTAL MODELING OF EXISTING MASONRY STRUCTURES STRENGTHENED WITH INNOVATIVE MATERIALS

This thesis deals with the experimental application and investigation of innovative techniques for the strengthening of existing masonry structures. A total of three experimental campaigns were conducted on the Department of Civil Architectural and Environmental Engineering of the University of Padua. The first campaign subject is application of an external post tensioning system to masonry arch bridges. The specimens reproduced in scale 1:2 existing masonry bridge geometries that can be found in the Italian railway network. The advantages of this technique are the ease of finding materials needed for the retrofitting and its potentially in increasing the load bearing capacity of the existing structure without increasing stiffness or mass. The second part of the thesis discuss the results of the second campaign, where masonry arch bridges were strengthened by means of FRCM (Fiber Reinforced Cementitious Matrix) applied to the intrados. This method permits to compensate the tensile strength lack of the masonry implementing an high tensile material that can increase the flexural capacity of the arch. Vertical eccentrical cyclical load is applied to these first experimental campaign. In the third phase the influence of Steel fiber-reinforced mortar (SFRM) coating applied to one side of existing masonry walls is discussed. The experimental campaign focuses on the benefit of this strengthening system to the in-plane shear capacity of the panels paying particular attention to the out of plane effects that can be generated in the resulting asymmetrical structure. Nine diagonal compressive tests were executed on unstrengthened and strengthened panel conditions. The results are presented as load-displacement or stress-strain curves, discussion of the collapse mechanism and comparison between the strengthened and unstrengthened case, highlighting the contribution of strengthening system in global and local mechanical behaviors.