## 3 Testing Set-Up and Data Acquisition
### Experiments to Measure Vertical Displacement  
#### 3.2.1 Specimen Information  
The proposed method was also employed to measure the vertical displacement of PC test specimens [23]. The test specimens were constructed to simulate the progressive collapse of the PC structures frequently used in Korea. In this study, precast concrete simple supported connection (PC-P) and precast concrete continuous supported connection (PC-C) were selected with the same design parameter: a center-to-center span of 3000 mm, a net span of 2600 mm, a story height of 2000 mm, beam dimensions of 300 mm in width and 300 mm in depth, column dimensions of 400 mm in width and 300 mm in depth, and a bracket length of 200 mm. Figure 9(a) illustrates the details of PC-C with a continuous joint. PC-C is a continuously supported connection specimen that is connected between precast concrete elements, and there is no intended relative movement or rotation between the elements. The green line is a continuous bar, and the purple line is a hook bar used to connect the beam and column. These connections are used to transfer both vertical and horizontal loads between the connected elements and are typically found in structural systems where rigidity and load transfer efficiency are important. In PC beams, the bottom rebar ratio was \(\rho=0.51\%\) (2-D16  
Figure 8: Drift ratio from Wall A: (**a**) using LVDT and (**b**) using LiDAR. Figure 9: Drift ratio from Wall B: (**a**) using LVDT and (**b**) using LiDAR. rebars). As a connection detail, the bottom rebars in PC beams were extended outward to provide anchorage, with the required bar development length (i.e., \(\mathrm{ld}=350\) mm). A single \(\varphi\)15.2 strand (i.e., diameter of \(\mathrm{db}=15.2\) mm and cross-sectional area of As = 138.7 mm\({}^{2}\)) was positioned at a depth of 240 mm to apply the prestressing force. A prestressing jacking force of Pep =205 kN (80% of the tensile strength of the tendon, fpu = 1860 MPa) was applied via pretension before pouring the concrete. The prestressing tendon was cut when the compressive strength of the concrete reached 30 MPa. The PC beam was placed on the PC column bracket and fixed by bolting with two D19 dowel bars (with a diameter of \(\mathrm{db}=19.1\) mm and cross-sectional area of As = 286.5 mm\({}^{2}\)) extended from the bracket. The dowel bars were anchored into the PC column with a development length of 300 mm. Non-shrink mortar was used to fill the anchor holes of the dowel bars and the gaps between the PC beams and PC columns. Once the PC beams were positioned on the PC column bracket, the continuous top rebars of the topping were installed. The top bar ratio was \(\rho^{\prime}=1.02\%\). The topping concrete was cast into the area encompassing the net span and the beam-column joint. At the mid-span of the beam, the nominal flexural strength for the positive moment (\(\mathrm{M}_{\mathrm{n}}^{+}\)) was calculated as 130 kN-m. At the both ends of the beam, the nominal flexural strength was calculated as 78 kN-m for the positive moment (\(\mathrm{M}_{\mathrm{n}}^{-}\)), and 135 kN-m for the negative moment, ignoring the effect of the prestressing force. Figure 10: The details of PC specimens. (**a**) PC-C specimen; (**b**) PC-P specimen. Figure 10b illustrates the specific characteristics of PC\(-\)P with a pinned joint. PC-P is a simply supported connection specimen that is connected between two precast concrete elements where one element is supported by the other in a manner that allows for relative movement between them. The rebar details in PC beam and PC column were the same as those in PC-C, except that the bottom and top rebars (represented by the green and purple lines) were not continuous at the beam-column joint. The top and bottom bars of the PC beam were anchored at the ends of the PC beam using headed bars. Further, topping concrete was only poured in the net span region. In the topping concrete, the top bar ratio was 0.51%.