Given that a significant fraction of buildings and architectural heritage in Europe’s historical centers are masonry structures, the selection of proper diagnosis, technological surveys, non-destructive testing, and interpretations of crack and decay patterns is paramount for a risk assessment of possible damage. Identifying the possible crack patterns, discontinuities, and associated brittle failure mechanisms within unreinforced masonry under seismic and gravity actions allows for reliable retrofitting interventions. Traditional and modern materials and strengthening techniques create a wide range of compatible, removable, and sustainable conservation strategies. Steel/timber tie-rods are mainly used to support the horizontal thrust of arches, vaults, and roofs and are particularly suitable for better connecting structural elements, e.g., masonry walls and floors. Composite reinforcing systems using carbon, glass fibers, and thin mortar layers can improve tensile resistance, ultimate strength, and displacement capacity to avoid brittle shear failures. This study overviews masonry structural diagnostics and compares traditional and advanced strengthening techniques of masonry walls, arches, vaults, and columns. Several research results in automatic surface crack detection for unreinforced masonry (URM) walls are presented considering crack detection based on machine learning and deep learning algorithms. In addition, the kinematic and static principles of Limit Analysis within the rigid no-tension model framework are presented. The manuscript sets a practical perspective, providing an inclusive list of papers describing the essential latest research in this field; thus, this paper is useful for researchers and practitioners in masonry structures.

Many existing structures require seismic retrofitting based on the latest findings and standards. Most of the works presented in the literature have considered the effect of different retrofitting solutions on the seismic behavior of the structures. Therefore, a comprehensive comparison of these techniques is needed to select the most effective one. Hence, in this paper, we present a comparative study of the most useful retrofitting techniques of RC structures, using the recent and updated versions of the standards and design codes. The merits and weaknesses of the most useful retrofit techniques and the available approaches are presented and demonstrated, which utilizes SeismoStruct and SeismoBuild. A 2-story RC building with the lack of transversal and longitudinal reinforcements is retrofitted by some techniques such as RC jacketing, RC walls, and FRP wrapping. The structural response of the retrofitted buildings is compared with the initial one. The comparison of the results shows that using RC walls at the perimeter of the existing buildings is the most efficient way in reducing demand capacity ratio (DCR) of other structural members, maximum roof displacements, and building fundamental period. The results of the pushover analysis of the buildings retrofitted by RC jackets and RC walls indicate a significant increase in the capacity curves.