## 5 Experimental Investigations
### Transverse Load-Bearing Behavior of Cross-Beams for Construction State
#### 5.1.4 Measurements  
The applied loads were simultaneously measured via load cells mounted at the hollow piston jacks (Eberspacher GmbH, Esslingen, Germany) and load cells (HBM GmbH, Telgte, Germany) at each support. The uplift forces were calculated based on strain gauge measurements on the tension rods. To quantify the contribution of the protruding reinforcement during the tests, two strain gauges (HBM GmbH) at each protruding bar, right above the supporting area, were applied. Surface deformations during testing were measured using digital image correlation (Aramis 4M, resolution 2352/1728 pixels, GOM, measurement frequency 1/4 Hz). Linear variable differential transformers (LVDTs) were positioned underneath the specimens to measure the deflections during the tests (Solartrron BS50 100 mm (Solartrron Metrology, West Sussex, UK), maximum relative error of indication \(<\pm\)1%, measurement frequency 5 Hz). In addition, concrete strain gauges (HBM GmbH) were applied in the compression zone above the support areas. These were located 50 mm above the bottom edge of the beam. \begin{table}
\begin{tabular}{c c} \hline Component & \(m\) \\ \hline Sand 0/4 & 858 \\ Fine gravel 4/16 & 828 \\ CEM I 52.5R & 374 \\ Limestone powder & 178 \\ Water & 182 \\ Superplasticizer & 7 \\ \hline \(\Sigma\) & 2427 \\ \hline \end{tabular}
\end{table} 
Table 1: Composition of normal-strength concrete for 1 m\({}^{3}\) (amounts in kg/m\({}^{3}\)). \begin{table}
\begin{tabular}{c c c c c c} \hline \multirow{2}{*}{**Specimen**} & \(f_{\text{cm,cyl}}^{a}\) & \(f_{\text{cm,cube}}\) & \(f_{\text{cm}}^{a*}\) & \(E_{\text{cm}}^{a*}\) \\  & in N/mm\({}^{2}\) & in N/mm\({}^{2}\) & in N/mm\({}^{2}\) & in N/mm\({}^{2}\) \\ \hline S100 AL95/S100 AL295 & \(67.0\pm 1.76\)\% & \(81.7\pm 1.76\)\% & \(5.28\pm 1.76\)\% & 41,360 \(\pm\) 1.76\% \\ S200 AL95/S200 AL295 & \(63.7\pm 2.05\)\% & \(77.6\pm 2.05\)\% & \(5.04\pm 2.05\)\% & 40,571 \(\pm\) 2.05\% \\ \hline \end{tabular} \({}^{*}\) calculated based on \(f_{\text{cm,cube}}\) acc. to [32]/** calculated based on \(f_{\text{cm,cyl}}\) acc. to Eurocode 2 [31].  
\end{table} 
Table 2: Material properties of concrete. \begin{table}
\begin{tabular}{c c c c c c} \hline \multirow{2}{*}{**Type**} & \(A_{\text{s}}\) & \(f_{\text{ym}}\) & \(f_{\text{mm}}\) & \(A_{\text{gtm}}\) & \(E_{\text{sm}}\) \\  & in mm\({}^{2}\) & in N/mm\({}^{2}\) & in N/mm\({}^{2}\) & in \% & in N/mm\({}^{2}\) \\ \hline \(\mathcal{O}26\)-B550B & 535.10 & \(574.00\pm\) & \(677.00\pm\) & \multirow{2}{*}{\(9.30\pm 12.37\)\%} & 204,600 \(\pm\) \\  & & 0.62\% & 0.10\% & & 3.68\% \\ \hline \end{tabular}
\end{table} 
Table 3: Material properties of protruding bending reinforcements of \(\mathcal{O}26\) mm. Figure 18 shows the crack pattern of all four tests at maximum load \(F_{\text{max}}\) above the support. As can be seen, an ordinary bending crack pattern was obtained in each test. From these results, it can be concluded that the transfer of bond stresses between the protruding bending reinforcement and the concrete worked properly with the help of the additional loop reinforcement. The influence of the selected parameters (a) the spacing \(s\) and (b) the anchorage length \(h_{\text{b}}\) of the additional loops did not have a significant effect on the results, as can be seen in Figure 16. Even with the configuration that has the lowest loop reinforcement ratio (\(s=200\) mm; \(h_{\text{b}}=95\) mm), the flexural reinforcement could be fully utilized. A detailed structural analysis according to Eurocode 2 [31] for the construction stages of the deck slab for a fictitious project is presented in [34]. In that analysis, the cross-beam of the deck slab element must withstand a design bending moment of 120 kNm during the erection of the deck slab including all safety factors. In this case, it is a 3.10 m long cantilever on which the dead weight of the deck slab element, the top concrete layer and construction traffic loads were applied. The mean bending moment resistance (S100 AL95, S200 AL95 and S200 AL295) was 465 kNm.