## 2 Experimental Specimen Test  
In this research, seven beam-column exterior reinforced concrete (RC) joints with a column dimension of 2000 mm \(\times\) 200 mm \(\times\) 200 mm and a beam dimension of 1250 mm \(\times\) 200 mm \(\times\) 250 mm. Type I ordinary Portland cement (OPC) obtained from Tasek 111 Corporation, Berhad, Malaysia, was used in the concrete mix design. The cement is in accordance with quality conforms 112 to EN 196. The concrete compressive strength was evaluated in accordance with the BS EN 12390-3:2009 standard [28]. Three specimens were tested for each RC beam-column joint. The average compressive strength of the cubes ranged between 41.1 MPa to 47.7 MPa. The steel reinforcement had an average tensile strength of 614.15 MPa, meeting the requirements of BS EN 10002-1:2001 standard [29]. Table 1 summarizes the reinforcement details for each RC beam-column joint. Figure 1 illustrates the reinforcement detail for each RC beam-column joint investigated. The additional shear link spacing and increased anchorage length in specimens BCJ-2 to BCJ-7 were arranged based on the ductility class medium (DCM) for low to moderate seismicity [30, 31, 32]. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{3}{*}{**Specimen**} & \multicolumn{5}{c}{**Detailing**} \\ \cline{2-7}  & \multicolumn{2}{c}{**Column**} & \multicolumn{2}{c}{**Beam**} & \multicolumn{2}{c}{**At Joint**} \\ \cline{2-7}  & \begin{tabular}{c} **Main** \\ **Bar** \\ \end{tabular} & \begin{tabular}{c} **Add. Shear** \\ **Link Spacing** \\ **(mm)** \\ \end{tabular} & \begin{tabular}{c} **Main** \\ **Bar** \\ \end{tabular} & \begin{tabular}{c} **Add. Shear** \\ **Link Spacing** \\ **(mm)** \\ \end{tabular} & \begin{tabular}{c} **Anchorage** \\ **Length** \\ **(mm)** \\ \end{tabular} & \multicolumn{1}{c}{**Remarks**} \\ \hline BCJ-1 & 4T12 & - & 4T12 & - & 250 & \begin{tabular}{c} Design based on British \\ Standard [33,34] \\ \end{tabular} \\ \hline BCJ-2 & 4T12 & \begin{tabular}{c} R8-75 \\ (600 *) \\ \end{tabular} & 4T12 & \begin{tabular}{c} R8-75 \\ (300) \\ \end{tabular} & 250 & \begin{tabular}{c} Strengthen at joint based on EC8 \\ (Low to moderate seismic) [30] \\ \end{tabular} \\ \hline BCJ-3 & 4T12 & \begin{tabular}{c} R8-75 \\ (850) \\ \end{tabular} & 4T12 & \
\begin{tabular}{c} R8-75 \\ (600) \\ \end{tabular} & 250 &
\begin{tabular}{c} Designed as in BCJ-2 with a 30\% \\ increased number of shear links \\ \end{tabular} \\ \hline \hline \end{tabular}
\end{table} 
Table 1: The designed detailing of specimens. Figure 2 illustrates the schematic drawing for the experimental test setup implemented. The ends of the RC beam-column were partially fixed. A 500 kN horizontal hydraulic actuator was attached to the top portion of the column. The bottom portion of the column was braced to the surface of a strong floor. An axial circular steel pin was attached to the strong floor and the end of the beam. The specimens were experimentally tested using displacement control mode with simulated earthquake loading under lateral cyclic loading [35]. The cyclic loading history is presented in Figure 3 and is in accordance with the ACI 374.2R-13 standard [36]. Each specimen was subjected initially to cyclic loading with a drift ratio (\(\Delta_{y}\)) of 0.25%. The drift ratio (\(\Delta_{y}\)) was then increased by 0.25% in each step until reaching a drift ratio (\(\Delta_{y}\)) of 3.00%, or specimen failure is observed. At each drift ratio (\(\Delta_{y}\)) level, the specimens were subjected to three cycles. The drift ratio (\(\Delta\)) was defined as \(l_{x}/H\), where \(l_{x}\) is the lateral movement and \(H\) is the column height [37]. Dinolite microscope camera was used to measure and analyze the crack width in every drift ratio (DR) level during testing, as recommended in earlier studies [38; 3  
Figure 1: _Cont_. Table 2 illustrates the parameters recorded before and after the experimental testing that was used as potential input parameters for machine learning models to accurately predict the cracking behavior.