## 1 Introduction
of the Interface (mm2)**} & \multirow{2}{*}{**Number of Bars, \(n\)**} & \multirow{2}{*}{**Parameter (mm)**} & \multirow{2}{*}{**Reinf. Ratio, (mm)**} & \multirow{2}{*}{**Strength of (58)**} & \multirow{2}{*}{**Type of (58)**} & \multirow{2}{*}{**Anchor. (53)**} \\  & & & & & & & & & **Anchor. (53)** \\  & & & & & & & & & **Anchor. More specifically, in the studies by [PERSON] and [PERSON] [5], [PERSON] and [PERSON] [10], and [PERSON] et al. [11], interfaces were subjected to monotonic loading, whereas in those of [PERSON] et al. [12; 13], [PERSON] et al. [4], [PERSON] and [PERSON] [14], [PERSON] et al. [15], [PERSON] et al. [16], and [PERSON] [17], the interfaces were subjected to cyclic loading. The test setups used by several researchers can be categorized as follows: push-off setup [5]; modified push-off, for the application of cyclic loading [4; 12; 14; 16], push-through [11; 15]; topping on a base [10; 13]; and wall specimens subjected to diagonal compression [17]. Irrespective of other parameters adopted in the experimental campaigns, such as roughness, reinforcing steel ratio, etc., all researchers have reached the conclusions that (i) the external \begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Paper**} & \multirow{2}{*}{**Number of Tests**} & \multirow{2}{*}{**Interface (m)**} & \multirow{2}{*}{**Dimension. of the Interface (m)**} & \multirow{2}{*}{**Number of Bars, \(n\)**} & \multirow{2}{*}{**Diameter (\(\mathbf{d_{b}}\)**} & \multirow{2}{*}{**Reinf. Ratio, \(\boldsymbol{\rho}^{(1)}\) (\%)**} & \multirow{2}{*}{**[PERSON]. (MFA)**} & \multirow{2}{*}{**Type of Anchor. (\(\mathbf{\alpha}\)/p)**} \\  & & & & & & & & & **Enchor. (\(\mathbf{\alpha}\)/p)** \\  & & & & & & & & & **Enchor. (\(\mathbf{\alpha}\)/p)** \\  & & & & & & & & & **Enchor. (\(\mathbf{\alpha}\)/p)** \\ \hline
[4] & 2 Mon. & Rough, & & 0 (4) & & & & & & & 0.0 (6) \\  & 14 Cyclic & Sandblasting & & & 3 (8) & & 19 (12) & & & & & 2.4 (1) \\  & & & 6 (4) & & & & & 2.06 (4) & & & 8 d (12) \\ \hline
[14] & 8 Cyclic & \begin{tabular}{c} Very smooth, \\ grease (3) \\ Shear keys (5) \\ \end{tabular} & 225 \(\times\) 860 & 2 & 22 & 0.39 & 380.0 & \
\begin{tabular}{c} By \\ bond/29.6 d\({}_{b}\) \\ \end{tabular} &
\begin{tabular}{c} 0.0 (3) \\ 7.8 (3) \\ \(-1.1\) (2) \\ \end{tabular} \\ \hline
[15] & 6 Mon. & Steel element, & & 254 \(\times\) 711 & 4 & 19 & 0.31 & 413.4 & \
\begin{tabular}{c} Welded- \\ Headed \\ Studs/6.7 d\({}_{b}\) \\ \end{tabular} &
\begin{tabular}{c} 0.0 (1) \\ \(-0.35\) (1) \\ \end{tabular} \\ \hline
[16] & 8 Cyclic & Smooth & 200 \(\times\) 1700 & 5 & 16 & 0.30 & 401.0 & \
\begin{tabular}{c} Adhesive \\ mortar/ \\ 10.0 d\({}_{b}\) \\ \end{tabular} &
\begin{tabular}{c} 0.0 (4) \\ \(0.62\) (2) \\ \(1.12\) (2) \\ \end{tabular} \\ \hline
[17] & 2 Mon. & \begin{tabular}{c} Rough, \\ exposed \\ aggregates \\ \end{tabular} & \begin{tabular}{c} \(90\times 400\) (2) \\ \(120\times 400\) (11) \\ \end{tabular} & 8 & \begin{tabular}{c} 6 (2) \\ \(8\) (11) \\ \end{tabular} & \begin{tabular}{c} 0.47 (2) \\ \(8\) (11) \\ \end{tabular} & \begin{tabular}{c} 521.0 (2) \\ \(1.12\) (2) \\ \end{tabular} & \
\begin{tabular}{c} By bond/ \\ 3546.0 (11) \\ \end{tabular} &
\begin{tabular}{c} 0.0 (3) \\ \(33\) (3.4 d\({}_{b}\) \\ \(25.0\) d\({}_{b}\) (11) \\ \end{tabular} \\ \hline \hline \end{tabular}
\end{table} 
Table 1: _Cont._  
Figure 1: (a) Geometry of the specimens with three cast-in bars crossing the interface. (b) Geometry of the specimens with three post-installed bars crossing the interface (dimensions in meters). Photo of the artificially roughened interface area \(\mathrm{A_{c}}\) after drilling the holes for the installation of the interface reinforcement (n bars). compressive stress results in higher interface resistance, and (ii) the external stress should be added to the clamping stress provided by the interface reinforcement for the calculation of the resistance.