## 5 Discussion  
A summary of the experimental results obtained from the pull-out tests is presented in Table 8. It is noted that the average values presented in the table were calculated for each type of anchor, regardless of the specific failure mode, since the main purpose was to draw comparisons between the three different anchoring systems. This generalization is acceptable, bearing in mind that masonry properties usually present a significant scatter, and similar loads may lead to different failure modes. Therefore, by comparing the average capacity for the three systems, it was observed that chemical anchors performed better in terms of resistance, followed by the cementitious grout type, and, finally, by the mechanical fasteners. In particular, the average load obtained for chemical anchors was 14% higher than that of the grout, and more than twice the average value obtained for mechanical anchors. Although the difference, with respect to the mechanical fasteners, is reasonably large, it must be recalled that the effective embedment length of mechanical fasteners was lower, i.e., \(h_{ef}=85\) mm instead of \(h_{ef}=150\) mm for adhesive anchors. By normalizing the results by a factor 150/85, the tensile and shear components are \(N_{p}^{*}=17.75\) kN and \(V_{p}^{*}=7.55\) kN, respectively, which are closer to the values obtained for the chemical and grout anchors. Nonetheless, the performance of adhesive fasteners is still superior, in addition to allowing longer effective embedment lengths. It is further noticed that the introduction of a shear component led to an overall reduction in the tensile capacity for all the anchoring systems. Table 9 provides a comparison between the results obtained from the pull-out tests and the values estimated from the analytical formulas presented in Section 2. Considering the predictive formulas for the tensile loading cases (horizontal actuator), the average estimated value for chemical anchors was comparable to the average resistance obtained from the pull-out tests. Conversely, the experimental values for cementitious grout and mechanical anchors were 100% above and 26% below the estimated values, respectively. The higher value estimated for mechanical anchors is especially problematic, since the formulation seems to overestimate the performance of the system. For the cases with combined tension and shear (inclined actuator), the predictive formulas for the tensile component did not match the experimentally observed values. In particular, the performance of chemical and grout anchors was underestimated by around 61% and 45%, respectively, whereas the capacity of the mechanical fasteners was overestimated by 34%. With respect to the shear component, the analytical formulas were appropriate for the mechanical anchors but largely overestimated the resistance of the adhesive cases. \begin{table}
\begin{tabular}{c c c c} \hline
**Wall** & **Type of Anchor** & \(N_{p}\)**(kN)** & \(V_{p}\)**(kN)** \\ \hline BW\_1 & Mechanical & 12.55 & - \\ BW\_5 & Mechanical & 12.88 & - \\ BW\_9 & Mechanical & 7.42 & 4.29 \\ BW\_10 & Mechanical & 7.40 & 4.28 \\ Average value of mechanical anchors (CoV in \%) & 10.06 (30.4) & 4.28 (0.2) \\ BW\_2 & Chemical & 27.00 & - \\ BW\_6 & Chemical & 23.11 & - \\ BW\_11 & Chemical & 18.20 & 10.51 \\ BW\_12 & Chemical & 16.74 & 9.67 \\ Average value of chemical anchors (CoV in \%) & 21.26 (22.1) & 10.09 (5.9) \\ BW\_3 & Grout & 26.29 & - \\ BW\_4 & Grout & 17.06 & - \\ BW\_7 & Grout & 14.22 & 8.21 \\ BW\_8 & Grout & 17.20 & 9.93 \\ Average value of grout anchors (CoV in \%) & 18.69 (28.1) & 9.07 (13.4) \\ \hline \end{tabular}
\end{table} 
Table 8: Summary of \(N_{p}\) and \(V_{p}\) values obtained from the pull-out tests. The comparison between experimental and analytical values indicates that the analytical formulation originally developed for concrete substrates cannot be directly extrapolated to brick masonry cases, and specific predictive formulas should be developed.