## 1 Introduction
### Methodology: Test Setup, Load Application, and Measurement Setup  
The test setup required to create the static system described in Section 2.1 is shown in Figure 5.  
In a first step, the test specimen was vertically prestressed at the three locations of the diaphragms. This was carried out by using double-C steel beams on the top and bottom of the beam, through which threaded rods were passed, tensioned, and anchored. This step was necessary to avoid gaps between the steel beams and the specimen during torsional loading--applying in particular to the load application area, where a preload of up to 250 kN was generated by means of hydraulic presses. Next, the prepared test specimen was placed onto load cells (see Sections B-B and C-C), which, in turn, were placed on steel beams. As the restraint was to be created in the center of the girder (i.e., Section B-B), the load cells and steel beams were placed as far out as possible, in order to increase the lever arm and, thus, reduce the occurring forces. To generate the restraint, the test specimens were anchored against the strong floor of the test area (Section B-B), where the middle diaphragm (representing the pier segment of the new construction method) was situated. This was also carried out with threaded rods, which were passed through the double-C beams and anchored to the floor of the testing area. The rods were then prestressed to 350 kN by means of hydraulic presses. This not only created the restraint needed to take on the torsional load, but also simulated the vertical forces from the anchorage of the post-tensioning tendons that would arise in a real bridge project. The force was chosen so that, scaled to the size of the test body, it corresponded to the deviation forces of the post-tensioning tendons of a bridge project designed alternatively with the new method. To prevent tipping, threaded rods were also attached to the unloaded ends of the test specimens (Section C-C); however, these were only tensioned by hand to 60 kN, resulting in a small torsional moment transmitted to the unloaded area of the beam. As this torsional moment was of small magnitude and no torsional cracks occurred in this area, any influence on the following torsion test could be excluded. To apply the torsional \begin{table}
\begin{tabular}{c c c c c c} \hline
**Concrete** & **Concrete Age** & **\(f_{cm,cube}\) (N/mm\({}^{2}\))** & \(f_{cm,cyld}\) (N/mm\({}^{2}\))** & \(f_{cm}\) (N/mm\({}^{2}\))** & **Associated** \\  & & & & & **Components** \\ \hline
1 & 41 & 61.2 (\(\pm\)1.0\%) & 49.5 (\(\pm\)1.5\%) & 3.32 (\(\pm\)8.1\%) & TS\({}_{\text{Ref}}\): webs \\
2 & 30 & 60.8 (\(\pm\)2.7\%) & 50.2 (\(\pm\)4.7\%) & 2.91 (\(\pm\)10.6\%) & TS\({}_{\text{Ref}}\): bottom slab \\
3 & 28 & 74.5 (\(\pm\)3.7\%) & 64.3 (\(\pm\)5.3\%) & 3.19 (\(\pm\)8.4\%) & TS\({}_{\text{Ref}}\): deck slab \\
4 & 44 & 62.5 (\(\pm\)1.8\%) & 52.3 (\(\pm\)2.0\%) & 3.23 (\(\pm\)9.6\%) & TS\({}_{\text{joint}}\): webs \\
5 & 40 & 65.8 (\(\pm\)0.2\%) & 55.1 (\(\pm\)2.7\%) & 3.59 (\(\pm\)5.8\%) & TS\({}_{\text{joint}}\): bottom slab \\
6 & 38 & 80.9 (\(\pm\)6.7\%) & 64.7 (\(\pm\)3.2\%) & 3.59 (\(\pm\)7.9\%) & TS\({}_{\text{joint}}\): deck slab \\ \hline \end{tabular}
\end{table} 
Table 1: Material properties of the different components of the two test specimens. load (Figure 5a,b: Section A-A; Figure 6a), a press was first placed between the lower steel girder and the bottom of the testing area. This press was hydraulically coupled with another press, which was placed on the opposite side of the cross-section at the top of the steel girder, so that exactly the same pressure--and, thus, force--was applied at all times. The activation of the two presses created a torsional moment that twisted the girder around its axis. Large bending of the threaded rod was prevented by a calotte in the press assembly. As the torsional load increased, the lower press tended to slide laterally outwards.