## 5 Discussion  
Thus, if we compare the results between the epoxy bonded specimens TGIB-fw and TGIB-gf with annealed float glass, we can see that the results are quite comparable. AF glass shows a very brittle behaviour, that is, the relationship between stress and specific deformation is linear-elastic until the tensile strength of the material is reached, followed by an immediate loss of load-bearing capacity or failure. In a TGIB, this effect is seen when annealed float glass is used as a crack bridge that develops at the point of maximum tensile stress concentration and then grows in the appropriate direction as a function of subsequent stress distributions. Annealed float glass is more ductile because the appearance of cracks also predicts ultimate failure. TGIB-gf with this type of glass and epoxy adhesive shows an average 1 kN higher force value during the first crack formation compared to TGIB-fw. However, the behaviour of both groups of specimens during the test was similar. We can now conclude that the behaviour pattern of TGIBs with annealed float glass is linear until the first crack occurs. This fact must be taken into account when calculating the stiffness. It was expected that the bending stiffness would be higher for TGIB-gf, and it is. This \begin{table}
\begin{tabular}{c c c c c} \hline \hline  & \multicolumn{2}{c}{**Experimental Tests**} & \multicolumn{2}{c}{**Gamma Method**} \\  & \(\mathbf{Y}\)**—TGIB-fw** & \(\mathbf{Y}\)**—TGIB-gf** & \(\mathbf{Y}\)**—TGIB-fw** & \(\mathbf{Y}\)**—TGIB-gf** \\ \hline Silicone & 0.577 & 0.720 & 0.794 & 0.681 \\ Acrylate & 0.932 & 0.907 & 0.989 & 0.981 \\ Epoxy & 0.922 & 0.898 & 0.999 & 0.999 \\ \hline \hline \end{tabular}
\end{table} 
Table 13: Comparison of results of measurements for TGIB. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Specimen** & \(\mathbf{F_{cr}}\) = \(\mathbf{F_{max}}\) [kN] & \(\mathbf{u_{cr}}\) = \(\mathbf{u_{max}}\) [mm] & **EI [MNN2]** \\ \hline TGIB-fw\_S\_FT & 19.4 & 48.0 & 0.594 \\ TGIB-gf\_S\_HSG & 19.8 & 41 & 0.879 \\ TGIB-fw\_A\_FT & 26.7 & 42.7 & 0.898 \\ TGIB-gf\_A\_HSG & 25.2 & 40.6 & 1.133 \\ TGIB-fw\_E\_FT & 23.4 & 37.9 & 0.889 \\ TGIB-gf\_E\_HSG & 25.5 & 40.2 & 1.156 \\ \hline \hline \end{tabular}
\end{table} 
Table 12: Comparison of results of measurements for TGIB-fw with fully tempered glass (FT) and TGIB-gf with heat-strengthened float glass (HSG), E—epoxy, S–silicone, A—acrylate). cross section basically offers higher stiffness, while TGIB-fw offers better behaviour against possible temperature variations. This is not possible with TGIB-gf. A comparison of the results of TGIB-fw shows that the specimens bonded with epoxy adhesive have the highest bending stiffness. Epoxy is also the stiffest adhesive compared to the silicone and acrylic adhesives used, so we were not surprised by the results. The specimens bonded with silicone adhesive, which is also the most elastic of the three adhesives, had the lowest stiffness. A correspondingly high stiffness was also achieved with acrylate, indicating that the acrylate used is one of the stiffer ones. Based on the above, it can be confirmed that the stiffness and load bearing capacity of TGIB depend on the type of glass web used. An exact comparison between fully tempered glass and heat-strengthened float glass is not possible, mainly because of differences in the bending strength of the glass. The bending strength of toughened glass was 50 N/mm\({}^{2}\) higher. They have in common that the first crack was the end of the story. Both types of tempered glass are extremely fragile and fail without warning. We equated the first crack with failure. However, it can be seen that the fracture forces for the test specimens bonded with acrylate were highest for TGIB-fw with 26.7 kN and lowest for silicone, with an average of 19.4 kN. For TGIB-gf and HS glass, it was observed that the fracture forces for epoxy and acrylate are practically identical at 25 kN.