###### Abstract
The difference from previous studies was the use of laminated 6 mm annealed float glass panes with a PVB film in between. The timber flanges had a cross section of 70 \(\times\) 100 mm. During testing, they also found that the load bearing capacity of a 3500 mm composite beam with polymer adhesive increased by up to 85% after the first crack. They also observed fewer cracks in the beam than previous researchers, mainly due to the use of a more rigid adhesive. The Portuguese researchers were also among the first to study the adhesives that hold timber-glass composites together. They divided them into three groups, namely: rigid adhesives--extremely high strength and stiffness (e.g., acrylate, epoxy), medium-stiff adhesives--balanced strength and elasticity (e.g., polyurethane) and elastic adhesives--extreme elasticity and low strength (e.g., silicone and some polyurethanes). Finally, they recommended silicone as the most suitable adhesive for bonding timber-glass composite beams because of its elasticity. They also recommended that the higher elasticity and associated lower stiffness of adhesives warrants thorough investigation, especially when adhesives are used in load-bearing structures. In such a composite, the timber provides the ductility, and the glass provides the resistance and stiffness. Research on I-beams made of timber and glass continued, and in 2008-2011 the research results of Swedish researchers [PERSON] et al. were presented [7]. A slightly different model than the previous ones was performed. All beams were 3850 mm long and 240 mm high. The beams were made of laminated veneer lumber (LVL) with dimensions of 45 \(\times\) 60 mm. The special feature of this beam cross-section was the groove into which they glued a glass web using different adhesives. Two different groove widths of 13 mm and 15 mm were tested. Two different edge finishes for the glass web were also tested. For comparison purposes, the beam was made with a silicone adhesive. A similar concept of the beam, as seen in the work of Swedish researchers, was published by [PERSON] and [PERSON] in 2013 [8]. The Polish researchers used an 8 mm thick annealed float glass web and 55 mm \(\times\) 75 mm timber flanges. The length and height of the test specimens were 1800 mm \(\times\) 300 mm. [PERSON] et al. [9; 10] published another study in 2013 that will serve as a comparison to our experiments. This study will be presented in more detail later in the article. Over the years, more research has been done on TGIB [11; 12; 13; 14; 15; 16; 17; 18; 19; 20; 21; 22; 23; 24; 25; 26; 27; 28; 29; 30]. From all these studies, two main types of TGIBs can be derived, namely, TGIBs with flanges directly attached to the glass web, and TGIBs with grooves in the flanges. In this paper, a detailed comparison between our TGIBs with flanges directly attached to the glass web (TGIB-fw) and TGIBs with grooves in the flanges (TGIB-gf) from the researcher [PERSON] et al. was presented. In TGIB-fw, the glass web was not fully integrated into the timber flange, which allowed for greater temperature expansion between the two materials. It was expected that the ductility of such elements is higher, but probably also has a lower bending stiffness and load-bearing capacity, which we aimed to demonstrate in this study. The main novelty of this study lies in the connection of the glass web to the timber flanges and the comparison with another connection method--TGIB-gf, in particular the study of [PERSON] et al. [10], where a slightly lower ductility was expected. The temperature effect was not considered in the study. First, the theoretical background was given, then basic data of both cross sections were compared, and then the design of the specimens included in the experimental analysis was analysed. Both concepts were evaluated using the load-displacement diagrams obtained from the bending tests and finally the results and recommendations were presented.