## 3 Description of the Test Specimens and Test Setup
### Instrumentation Details  
Crane loads were measured using two axial load cells located between the crane hook and the shackle attached to the lifting cables. The applied concentrated loads in test scenarios 2 and 4 were measured using a load cell connected to the winch, as mentioned earlier. To measure the local deformation of the cage specimens during tests, two regions along the length of the cage were instrumented using six string potentiometers (string pot or SG for short), as shown in Figure 7. For the specimens with the internal stiffening \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**SpecimenScenario \#** & **1** & **2** & **3** & **4** & **5** & **6** & **7** \\ \hline Cage \#1 & C1-S1 & - & C1-S3 & - & - & C1-S6 & - \\ \hline Cage \#2 & C2-S1 & C2-S2 & C2-S3 & C2-S4 & C2-S5 & - & C2-S7 \\ \hline Cage \#3 & C3-S1 & C3-S2 & C3-S3 & C3-S4 & - & C3-S6 & C3-S7 \\ \hline Cage \#4 & C4-S1 & C4-S2 & C4-S3 & C4-S4 & - & C4-S6 & C4-S7 \\ \hline Cage \#5 & C5-S1 & C5-S2 & C5-S3 & C5-S4 & - & - & C5-S7 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Test matrix (C specifies the cage number, and S indicates the testing scenario. For example, C2-S3 stands for Cage #2, test scenario 3). Figure 6: Schematics of test scenarios: (**a**) scenario 1, (**b**) scenario 2, (**c**) scenario 3, (**d**) scenario 4, (**e**) scenario 5, (**f**) scenario 6, and (**g**) scenario 7.  
in this study is called 3D-target-tracking DIC [9], in which targets are installed on the test specimen and used to measure the deformation of the specimen during testing. The DIC measurement process includes two phases: calibration and measurement. The input data are images recorded before and after experiments [10]. In the calibration phase, 2D images are transformed into a 3D cartesian coordinate space using available photogrammetric methods [11]. In the measurement phase, the triangulation method [12] is used to process the calibrated data collected from the calibration phase to measure the movement of the targets attached to the specimen. Two high-speed cameras (IL5 QM4, Fastec Imaging) controlled by a LAN connection via the FasMotion 2021 software [13] were used for DIC measurements. The two cameras record videos at a 24-frames-per-second rate with a resolution of 2560 \(\times\) 2048 pixels in 8-bit grayscale. Two types of targets are tracked in 3D-target-tracking DIC: coded and un-coded targets. Un-coded (or artificial) targets act as independent sensors on the test specimens. These targets must be rigidly attached to the specimen to reflect the deformation of the specimen [14]. In our tests, the un-coded target was a 64 mm (2.5 in) diameter black circle inside a 128 mm (5 in) diameter white circle, which was glued to a fiberboard and mounted to the test specimen with a clamping hanger. Coded targets were numbered with specific patterns that could be identified by the software through their unique patterns. 3D coordinates were determined based on the positions of the coded targets. Coded targets need to be stationary during the calibration phase; hence, they were mostly attached to boxes and walls distributed within the field of view. About 20 coded targets were used in each test. Coded and un-coded targets are shown in Figure 9.  
Figure 9: (**a**) Position of targets with respect to different camera positions during the calibration process (green dots are coded targets, and yellow dots are un-coded targets); (**b**) coded and un-coded targets used in the tests. The calibration phase involved determining the cameras' positions and the location of the targets. Over 40 pictures were taken from different perspectives to capture the targets' positions. The distances between at least two coded targets were measured to define the dimensions of the point cloud, referred to as \"scale bars\". The calibration calculations were performed using the TRITOP point-tracking software (Version 6.3.1), which determined the point positions based on the positions of cameras and the orientations of images.