Abstract
Historic Unreinforced Masonry (URM) structures are enduring symbols of cultural and architectural heritage, yetthey remain highly vulnerable to seismic activity. Conventional retrofitting approaches often disrupt the intrinsicaesthetics of these structures and struggle to meet the stringent standards of minimal intervention, compatibilityand reversibility, which are essential for preserving their historical integrity. This proof-of-concept study introducesa novel solution that harnesses the capabilities of wire arc additive manufacturing (WAAM), also knownas wire-arc directed energy deposition (DED-Arc), to 3D print custom-fit steel reinforcing meshes, which can beembedded within the mortar joints of masonry walls. By integrating the 3D-printed reinforcing mesh, thestructural performance and ductility of URM walls are substantially enhanced, while preserving the originalappearance and historical significance of the facade. To ensure precise replication of the mortar profile, 3D laserscanning is employed to map its geometry, which is used as input in the execution of the 3D printing process. Thepresent study is the first experimental demonstration of this novel retrofitting method, providing proof ofimplementation and structural effectiveness. The structural performance of URM walls was examined (before andafter the application of the proposed strengthening technique) by means of diagonal shear tests. The resultsdemonstrate that the interlocking mechanism between the masonry units and the 3D-printed steel mesh enablessignificant improvements in both the in-plane load-carrying capacity and the ductility of the walls.
NETL
NSTL
Elsevier