# Behaviour Analysis of Beam-Type Timber and Timber-Concrete Composite Panels  
[PERSON]  
1 Institute of Civil Engineering, Riga Technical University, LV-1048 Riga, Latvia; [EMAIL_ADDRESS] (E.B. ); [EMAIL_ADDRESS] (A.P. ); [EMAIL_ADDRESS] (R.O. )1 Institute of High-Performance Materials and Structures, Riga Technical University, LV-1048 Riga, Latvia; [EMAIL_ADDRESS] (3)Institute of Sustainable Building Materials and Engineering Systems, Riga Technical University, LV-1048 Riga, Latvia; [EMAIL_ADDRESS] (4)Correspondence: [EMAIL_ADDRESS]  
[PERSON]  
1 Institute of Civil Engineering, Riga Technical University, LV-1048 Riga, Latvia; [EMAIL_ADDRESS] (E.B. ); [EMAIL_ADDRESS] (A.P. ); [EMAIL_ADDRESS] (R.O. )1 Institute of Civil Engineering, Riga Technical University, LV-1048 Riga, Latvia; [EMAIL_ADDRESS] (A.P. ); raimonds.ozolins@ftu. glued laminated timber (GLT), cross-laminated timber (CLT), and laminated veneer lumber (LVL) [1; 13; 14]. European and North American markets have seen a rapidly growing popularity and demand for CLT (cross-laminated timber) boards [15; 16]. This is also evidenced by companies traditionally producing components and solutions for reinforced concrete structures, such as Peikko Group Corporation and Hilti Corporation, which are increasingly focusing on CLT and the development of innovative connection components and solutions for CLT. A CLT solution for buildings for load-bearing structures is convenient as the material is easy to handle, easy and quick to assemble, with relatively low self-weight (compared to traditional precast concrete), and gives a more aesthetic architectural appearance to the interior. In Northern European countries such as Sweden and Norway, CLT is already quite widely used for both multi-storey residential and public buildings, whereas in Latvia, it is not yet as widely used. As the popularity and demand for CLT material increase, so does the ambition for its application. To increase the load-bearing capacity of CLT panels, ribbed CLT panels are appearing in practice, and the calculation and production are offered by the Finnish company Stora Enso Oyj, Helsinki, Finland. CLT panels supplied by the longitudinal glued laminated timber (GLT) ribs are characterised by increased stiffness and load-carrying capacity in comparison with the plain CLT panels. So, adding the longitudinal timber ribs (Figure 1) can be considered as a possible way to increase the load-carrying capacity of the CLT panels. As the use of CLT and other timber structural systems in roofs and floors increases, so does the need to enhance their load-carrying capacity. Combining timber with materials that have superior mechanical properties, such as concrete, can improve the load-carrying capacity of timber structures [17; 18; 19; 20]. Timber-concrete composites (TCCs) represent one such solution. When the concrete layer's thickness exceeds one-third of the composite member's depth, the principal steel reinforcement is added if the concrete's bottom part is tensioned. However, TCC members with fully compressed concrete layers are of particular interest as they rationally utilise concrete's compressive strength without needing principal reinforcement. Traditional steel reinforcement increases concrete layer thickness and CO\({}_{2}\) emissions, presenting additional costs and environmental impacts. Dispersed synthetic reinforcement fibres can enhance concrete ductility and maintain structural integrity upon collapse without significantly affecting concrete strength [21]. This study evaluates the potential to increase the load-carrying capacity of beam-type timber and TCC panels by adding GLT ribs. It assesses the effectiveness of structural materials, the behaviour of timber and TCC panels, the influence of synthetic reinforcement on TCC panels, and methods to reduce the brittleness of adhesive timber-to-concrete connections, particularly using the stone chip bonding method [22; 23] and mechanical  
Figure 1: CLT beam-type panel with glued laminated timber longitudinal ribs. fasteners [24].