PSI - Issue 81

Denys Mykhailovskyi et al. / Procedia Structural Integrity 81 (2026) 333–338

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Fig. 1. Cross-section and reinforcement layout of the CLT panel with rebar spacing: 1) 40 cm; 2) 30 cm; 3) 20 cm; 4) 10 cm

To ensure structural stability, boundary conditions were applied. The nodes at the left support region were restrained from horizontal and vertical displacements. Additionally, to prevent rotation about the vertical axis, two edge nodes were fixed. A uniformly distributed load of q s =10kN/m 2 was applied to the panel surface (Fig. 2). After applying the load, the numerical calculations were performed.

Fig. 2. Structural loading scheme of the CLT panel

3. Results and discussion The results of the numerical simulation performed in the LIRA-SAPR software package are presented in Fig. 3, which shows the isofields of vertical displacements and longitudinal stresses in the timber. A comparison between the reinforced and unreinforced panels indicates a significant reduction in deflection – from 13.2 mm to 7.35 mm. When comparing reinforced panels with different reinforcement spacing, the deflection values remain nearly unchanged: 7.35 mm for a 10 cm spacing and 7.41 mm for a 40 cm spacing. Thus, it can be concluded that the reinforcement spacing has only a minor influence on the overall deflection of CLT panels. Similarly, reinforcement leads to a reduction in longitudinal stresses in the timber. The maximum longitudinal stress in the unreinforced panel was 7.49 MPa, while in the reinforced cases it was approximately 4.19 MPa. The influence of reinforcement spacing on stress distribution is negligible: with a 10 cm spacing, the maximum stress was 4.12 MPa, whereas with a 40 cm spacing it was 4.19 MPa. In contrast to the behaviour observed for deflections and longitudinal stresses, reinforcement spacing has a significant effect on shear stresses (Fig. 4). The figures clearly demonstrate the development of shear stress concentrations around the reinforcing bars. For 10 cm spacing, the maximum shear stress was 0.079 MPa, whereas for 40 cm it increased to 0.272 MPa. Based on these observations, the most favourable spacing is the smallest one; however, fabrication complexity must also be considered. Reducing reinforcement spacing increases the number of grooves required in the panel, leading to additional labour effort. Taking this into account, a spacing of 20 cm – approximately twice the panel thickness – can be considered optimal, as it does not lead to critical increases in shear stresses and remains reasonable from a fabrication perspective. The numerical results obtained for all panels are summarised in Table 2.