# Tensile Capacity of Adhesive Anchors in Damaged Masonry
## 5 Conclusions  
This research allows to draw the following conclusions:  
* The existing European assessment and design of post-installed adhesive anchors in masonry [13; 14] do not cover seismic loading conditions nor the influence of masonry cracking and damage on the anchor performance. Anchor products, in fact, are required to be tested only in uncracked, undamaged conditions. Depending on the level of damage of the base material, however, adhesive anchors undergoing cyclic actions (e.g., seismic events) can exhibit poor performances.
* There seems to be a clear correlation between the crack width, measured on the surface at or nearby the anchor location, and its maximum recorded load capacity. Furthermore, when damage is limited (e.g., crack width below 1.0 mm) the characteristic pull-out strength evaluated on the basis of the test results is still considerably high and reaches around 75% of the expected characteristic resistance valid for uncracked conditions.
* Only a rather weak correlation was found between anchor stiffness and crack width. This may be related to the fact that cracks were measured on the surface without considering damage (incl. crack propagation) inside the masonry, which is expected to affect the anchor stiffness rather than its peak load, especially for smaller crack widths.
* The location of the anchor within the wall is crucial. Anchors along the diagonal (most stressed area) exhibited lower strength compared to all others. Overall, anchors exhibited good performance when highly stressed areas (associated to crack widths well beyond 0.5 mm) were avoided. For anchors installed in these areas, the peak loads were still significant (minimum load 3 kN at a crack width of 2.5 mm), but their displacements were not compatible with practical applications.  
Summing up, the installation of anchors in masonry elements expected to undergo seismic actions should be preceded by a detailed analysis of the expected stress state of the base material to avoid areas where large cracks are foreseen and where a reliable performance of the connection might not be guaranteed. On the other hand, the adhesive anchors installed in areas with limited damage could still show relatively good strengths. This latter conclusion, however, is no substitution for requiring specific cyclic tests under crack influence in the future to guarantee a reliable and adequate anchor performance for seismic-relevant applications.  
Conceptualization, S.C.; methodology, S.C. and N.V.; software, S.C. and N.V.; validation, S.C. and N.V.; formal analysis, S.C. and N.V.; investigation, N.V.; resources, S.C.; data curation, S.C. and N.V.; writing--original draft preparation, S.C. and N.V.; writing--review and editing, S.C. and N.V.; visualization, N.V.; supervision, S.C.; project administration, S.C.; funding acquisition, S.C. All authors have read and agreed to the published version of the manuscript. This research received no external funding. Not applicable. Not applicable.  
While opinions, findings, and conclusions are those of the authors, we would like to thank [PERSON] for his insights, expertise, and suggestions throughout the preparation and review of this article, together with the technical staff of the Materials and Structures Testing Laboratory of Politecnico di Milano (particularly, [PERSON] and [PERSON]) for their assistance during the experimental work.  
The authors declare no conflict of interest.