CLT is created by rotating the direction of the fibers relative to the adjacent layers by approximately 90 degrees. It is made of engineered wood and widely used in construction in the USA, Canada, Europe, and Asia [12; 13; 14]. It should be noted that the cost of gulam and CLT is higher than steel or concrete, but they are still low-density materials that allow significant savings in transport and foundations. In addition, timber structures are usually transported half finished, which helps maintain cleanliness and saves time during assembly [15]. The number of timber buildings has continued to increase due to the lightweight and low carbon footprint of timber structures. Therefore, the use of structural timber products is expected to continue to increase accordingly. Consequently, issues concerning the strengthening of structural timber elements (e.g., repairing/upgrading existing timber buildings and strengthening prefabricated timber elements for multistorey structures) should be considered [16]. An important way to solve the above problems is to strengthen wooden elements using composite materials made of fiber-reinforced polymers (FRP). Numerous experimental, theoretical, and numerical studies can be found in the literature on the use of carbon,aramid, glass, basalt, hybrid, and steel in the form of bundles, strips, mats, cords, shapes, and rods to reinforce structural timber members [17; 18; 19; 20; 21; 22; 23; 24; 25; 26; 27; 28; 29]. Based on experimental studies, [PERSON] et al. [29] found that reinforcing composite glued beams (made of rubberwood) with a two-layer glass-fiber-reinforced polymer (GFRP) and a two-layer carbon fiber-reinforced polymer (CFRP) could increase flexural strength values by 40% and 51%, respectively. [PERSON] [10] produced a LVL (poplar)-GFRP composite, and glass fabrics and veneers were laid layer by layer. The MOE and modulus of rupture (MOR) of the LVL-GFRP composite were obtained from a three-point bending test. Based on experimental studies, the MOE and MOR of LVL- GFRP were 14% and 40% higher than poplar LVL, respectively. [PERSON] et al. [30] also investigated the water absorption and bending behavior of polar plywood, where glass fabrics were placed between the plywood layers. Based on experimental tests, it was found that the addition of glass fabrics reduced the water absorption (by 15-23%) of LVL and significantly increased the MOE (by 70-118%) and MOR (by 35-50%) of plywood towards the perpendicular direction. Also, it should be noted that, in addition to studies of timber beams reinforced with one type of FRP, there are studies of timber beams reinforced with synthetic hybrid FRP consisting of two or more types of synthetic fibers in one type of matrix. In their experimental research, [PERSON] et al. [31] used hybrid carbon, aramid, and glass fibers to reinforce wooden beams that had circular cross sections. The results showed that hybrid FRP with carbon, aramid, and glass fibers in a 2:1:1 ratio could achieve a stiffness increase of 69-115% in wooden beams. In [32], comprehensive research was conducted on the strengthening of timber beams using steel plates. Furthermore, the paper detailed how the application of plastic theory could be used to optimize the design of timber beams, ensuring their structural integrity and strength. Reinforcing timber beams with steel plates improved the behavior while also increasing the overall strength. [PERSON] et al. [33] investigated the effectiveness of timber plate strengthening of reinforced concrete (RC) beams that contained waste sawdust as a partial replacement for fine aggregate (sand). Initially, a wooden board was used, attached only with a layer of glue. Then, the wooden board was attached with a layer of glue and steel angles (2 and 11 angles). The results showed that despite the workability of the concrete, the ultimate load of the SD beam was lower than that of the control beam, with a slight difference of about 4%.