PSI - Issue 70

Milena Carolina Derlam et al. / Procedia Structural Integrity 70 (2025) 3–10

7

of the rigid beam, designed to support the panel, was fully constrained at the designated reference point. Fig. 2 illustrates the boundary conditions implemented in Abaqus CAE (2024). Nonlinear Static General analyses were performed, which are appropriate for simulations aimed at capturing structural responses under applied loads. The analysis involved evaluating the relationship between lateral load and horizontal displacement of the top track, using FE models with screw spacings of 75, 100, and 150 mm. All other settings remained unchanged, adhering to the default standards established by the system.

U1=UR2=UR3=0

U1=U2=U3=0 UR1=UR2=UR3=0

Fig. 2. Boundary and loading conditions applied to the framing components.

To incorporate geometric imperfections into the models, a buckling analysis of the samples was carried out using the software's automated simulation feature, enabling the prediction of lowest load at which a structure may lose stability due to local or distortional imperfections. The two lowest eigenmodes, based on the buckling mode with the lowest critical stress, were combined and incorporated into the model, with imperfection amplitude defined following the methodology of Schafer and Peköz (1998), adopting 50% of the cumulative distribution function of imperfection magnitudes, thus enabling a comprehensive assessment of stress distribution, strength, displacements, and stiffness. 3. Results and Discussion The structural behaviour of shear walls within the LSF system, sheathed with OSB panels on both sides and subjected to different screw spacing configurations, was evaluated using the FEM in Abaqus CAE (2024) to assess the impact of screw spacing on the overall strength and stiffness of the system. The ultimate displacement was defined as the point at which the load dropped by 20% from its peak value, in accordance with the recommendations of AISC 341-16 (AISC, 2016) and FEMA 350 (FEMA, 2000). As shown in Fig. 3, all models exhibited a significant load drop beyond the peak, and the data clearly indicate that reducing screw spacing enhances both the strength and stiffness of LSF shear walls. The “Model 75”, which had the smallest spacing, exhibited the highest maximum load capacity of 39.265 kN and the greatest initial stiffness of 1.383 kN/mm. In contrast, the “Model 150”, with the widest spacing, demonstrated lower strength at 29.539 kN and reduced stiffness of 0.628 kN/mm. The “Model 75” stands out, delivering the best overall performance, as the screw spacing increases to 100 mm and 150 mm, there is a reduction of 3.8% and 24.8% in maximum load, an increase of 55.5% and 58.8% in maximum displacement, and a corresponding reduction of 38.8% and 54.6% in stiffness. This behaviour can be attributed to the increased number of connections, which enhances load transfer between the components, thereby reducing excessive displacements and mitigating the risk of premature failure due to profile buckling. Moreover, decreasing screw spacing leads to a higher load-bearing capacity of the panel and, consequently, greater overall stiffness and structural integrity. Conversely, increasing the distance between connectors diminishes the efficiency of energy transfer and dissipation through the fastener connections between the sheathing and the substructure. This reduction in interaction results in a lower stress distribution across the panel and, consequently, a smaller effective tensioned area in the board, as shown in Fig. 4, resulting in premature failure of the profiles due to local and distortional buckling, which compromises the structural integrity of the panel.