# Study of Innovative Connector for Steel-Concrete Composite Structures
## 3 Results
### Material Properties  
The following results were obtained from the static tensile test of the steel:  
* The yield strength of each samples marked \(\mathrm{R_{e}}\) in accordance with EN ISO 6892-1 [28];
* Nominal yield strength marked \(\mathrm{f_{y}}\) (according to EN 1994-1-1 [20]), which was taken as the mean value from experimental tests;  
Figure 6: Samples for push-out tests. Figure 7: Arrangement of the dial gauges on the sample for the push-out test: (**a**) scheme; and (**b**) sample photo. * Tensile strength of each sample marked R\({}_{\text{m}}\) according to [28];
* Nominal ultimate tensile strength marked f\({}_{\text{u}}\) according to [20], which was taken as the average value from experimental tests. The results for the HEA 160 I-beam material used for the shear test specimens of the fasteners are shown in Table 4. The HEA 160 material meets the requirements of S235 JR steel grade, as the average yield strength and tensile strength of 275 MPa and 405 MPa, respectively, meet the requirements of EN 10025-2 [27], which define the minimum yield strength for steel grade S235 at the level of 235 MPa and tensile strength in the range of 350-510 MPa. The material test results for the 1.00 and 1.25 mm thick corrugated sheets used to make the test specimens of the fasteners as well as for the composite beam are shown in Table 5. The average yield strength of the 1.0 mm and 1.25 mm metal sheet are, respectively, 300 and 304 MPa and they are higher than the required 280 MPa according to EN 10346 [26]. On the other hand, the average tensile strength of 1.0 mm and 1.25 mm thick sheets is 379 and 382 MPa, respectively, and is higher than the 360 MPa required by the standard [26]. Therefore, the material of metal sheet meets the requirements for steel grade S280 GD. Test results of the strength class of the concrete used for the construction of connectors are presented in Table 6. The average characteristic compressive strength f\({}_{\text{ck,cube}}\) for the tested concretes is 33.1 and 32.2 MPa. In accordance with EN 206+A2 [29], all tested samples met the requirements for the concrete class C20/25. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Purpose of Concrete** & **Sample No.** &
\begin{tabular}{c} **Characteristic Compressive** \\ **Strength f\({}_{\text{ck,cube}}\) MPa** \\ \end{tabular} \\ \hline \multirow{3}{*}{Used for preliminary test} & K11 & 33.0 \\  & K12 & 32.0 \\ \cline{1-1}  & K13 & 34.2 \\  & Average \(\overline{x}\): & 33.1 \\ \hline \multirow{3}{*}{Used for main tests} & K21 & 31.9 \\ \cline{1-1}  & K22 & 32.6 \\ \cline{1-1}  & K23 & 32.1 \\ \cline{1-1}  & Average \(\overline{x}\): & 32.2 \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Test results of concrete class used for preliminary and main samples. \begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Sample No.**} & \begin{tabular}{c} **Yield Strength R\({}_{\text{e}}\)**, \\ **MPa** \\ \end{tabular} & \
\begin{tabular}{c} **Tensile Strength R\({}_{\text{m}}\)**, \\ **MPa** \\ \end{tabular} &
\begin{tabular}{c} **Relative Elongation** \\ **A5, \%** \\ \end{tabular} \\ \hline \hline HEA 160.1 & 272 & 409 & 34.8 \\ HEA 160.2 & 249 & 386 & 35.6 \\ HEA 160.3 & 304 & 422 & 38.8 \\ Average \(\overline{x}\): & f\({}_{\text{y}}\) = 275 & f\({}_{\text{u}}\) = 405 & 36.4 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Results from static tensile tests of HEA 160 steel.