## 2 Materials and Methods  
The preliminary design had the purpose of sizing up the frame profiles' cross sections (assumed to be the same for all the frame's profiles) and to evaluate the fastening bars' diameters and positions. The concept of the object of study is described in detail in a published paper [26] and depicted in Figure 1A; the essential information for the scope of the paper is reported in this section. The basic requirements were the following: 1) in-plane retrofitting of the transversal walls of traditional solid brick masonry had to be carried out, 2) the retrofit frames had to be placed on one side of each wall, and 3) a diagonal braced frame pattern, with wall-frame fastenings consisting of threaded steel bars passing through the whole thickness of the masonry, had to be used. A wall thickness of 25 cm was accounted for, as well as a wooden floor deck and truss roof covered with tiles, and typical loads for housing (Table 1). The measures indicated in Figure 1 and in the third column of Table 1 are divided by two to obtain the mass of the half-scale structure. According to EC8 SS3.2.2.5 [27], the base shear load \(F_{b}\) given by the building's mass was calculated, taking the structure's period \(T_{1}\) = 0.17 s, behavior coefficient \(q\) = 1, soil type C (\(T_{B}\) = 0.2 s) and design acceleration \(a_{g}\) = 0.2 g into account. Finally, \(F_{b}\), equal to 50.325 kN, was assumed to be the load on the retrofit frames, equally shared by the transverse walls and distributed linearly along the height. Assuming that the earthquake direction was parallel to the X axis, the middle internal wall subjected to in-plane shear force is the detailed object of study (Figure 1A). A linear FE analysis of the frame under the calculated loading put out a maximum compressive load of 11.5 kN (Figure 1B); this was the design load assumed in the choice of the pultruded profiles for the retrofit. As for the type of material, Glass Fiber Reinforced Polymer (GFRP) was selected due to its wide diffusion as a structural material for pultruded profiles; the main properties of the GFRP, provided by the producer, are listed in Table 2. To make frame-wall connections as simple as possible, C-shaped profiles were chosen and the same cross-section was kept for both the vertical and the diagonal element. The convenient size of the cross-section was determined after the assumption of frame collapse by the buckling of the compressed diagonal. Accounting for a free deflection length of 700 mm, it was found that a \(60\times 60\times 5\) mm C-shaped profile had a much higher critical load than the design value of 11.5 kN. Nonetheless, the profile had to be large enough to be perforated and cut to the purpose. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Elements** & **Quantity** & **Dimensions 1:1 (m)** & **Unit Mass** & **Total Mass 1:2 (kg)** \\ \hline Wooden trusses & 5 & \(0.15\times 0.15\), total length 14.04 & 650 kg/m\({}^{3}\) & 148 \\ Wooden lintels & 9 & \(0.1\times 0.1\), total length 10.00 & 650 kg/m\({}^{3}\) & 73 \\ Clay tiles and tablets & 1 & roof surface \(2.68\times 10\times 2\) pitches & 70 kg/m\({}^{2}\) & 469 \\ Floor (dead and live load) & 1 & \(10\times 5\) & 660 kg/m\({}^{2}\) & 3960 \\ External walls & 2 & \((10+4.8)\times 4.8\times 0.25\), 30\% holes & 1550 kg/m\({}^{3}\) & 4530 \\ Internal wall & 1 & \(4.8\times 4.8\times 0.25\), 15\% holes & 1550 kg/m\({}^{3}\) & 897 \\ \multicolumn{3}{c}{Total mass of the whole building} & 10077 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Calculation of the building mass. Figure 1: **(A)** Typical low-rise traditional building and retrofit system with Pultruded Fiber Reinforced Polymer frames; **(B)** half-scale retrofit frame: static scheme and axial force diagram; **(C)** physical model of the research. The basic concept of the physical model--before its practical realization--was established as depicted in Figure 1C, similar to the frame proposed by [PERSON] et al. in [28].