The popularity of log houses has been on the rise in numerous regions worldwide. In the context of log construction, the stability of log walls is notably influenced by the friction existing between the layers of logs and the openings designated for windows and doors. This study endeavors to comprehensively evaluate the lateral resistance of log walls through an extensive parametric analysis utilizing finite element (FE) methods. To construct a robust dataset, a total of 71 distinct samples were generated employing FE analysis, where the shuffled frog-leaping algorithm (SFLA) was incorporated in conjunction with a feed-forward (FF) neural network. Within this framework, the accuracy of the SFLA-based informational model was juxtaposed against that of an artificial neural network (ANN) coupled with particle swarm optimization (PSO), genetic algorithm (GA), and statistical models including multiple linear regression (MLR).
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Log houses were introduced to Canada through European newsletters. The renewed interest in wood as a construction material, driven by concerns about climate change, has led to increased attention towards this construction technology in various regions around the world. Contemporary log construction incorporates larger windows and door openings, featuring a diverse range of layouts and aspect ratios. The structural integrity of a log house relies on several factors, including wall dimensions, the arrangement of openings, and the methods employed to support the logs around these openings, as openings are known to lessen the structural strength of log walls (Bedon, Rinaldin, et al., 2015). Schematics of typical log walls with and without window and door openings are provided in Figure 1.
During the last three decades, several researchers have focused on investigating the lateral performance of log walls under various loading conditions employing experimental (Branco & Araújo, 2010; De Araujo et al., 2016; Eakintumas et al., 2022; Sciomenta et al., 2018), and numerical modeling methods (Kalantari et al., 2021; Kalantari & Hafeez, 2021; Kandethanthri & Hafeez, 2023; Rinaldin et al., 2013). The authors also explored the resistance of such a wall system under lateral (Bedon, Rinaldin, et al., 2015; Bedon & Fragiacomo, 2017; Heimeshoff & Kneidl, 1990, 1992) and fire loads (Bedon & Fragiacomo, 2019). Further, Scott et al., 2005, reported on the effects of foundation anchorage systems on the wall system's structural behavior (Scott et al., 2005).
Timber is characterized as an anisotropic material, exhibiting greater strength along the axis parallel to its fiber direction, whereas its capacity to withstand loads orthogonal to the fiber direction is comparatively diminished. The load transfer phenomenon in the log wall is different than the conventional wood frame wall. Unlike a conventional wood shear wall, the transmission of load to the foundation transpires via compressive stress perpendicular to the grain. The wall’s vertical stability is ensured through strategically placed notches and diverse corner styles. Horizontal load-bearing resistance is facilitated by the frictional force and the interlocking mechanism inherent to the logs’ arrangement (Hahney, 2000).
The structural integrity of log walls, in the context of resisting lateral forces, is primarily achieved through mechanisms that are ingeniously integrated into their construction. It has been recognized that the friction generated by the weight of the logs pressing against one another plays a crucial role in this context (Branco & Araújo, 2012). This natural resistance is significantly enhanced by the architectural design of interlocking corners, where logs are precisely notched and joined together, allowing for the effective distribution of lateral loads across the structure. Furthermore, the addition of mechanical fasteners such as screws, bolts, and wooden dowels has been identified as a modern technique to secure the logs more tightly, thereby providing an additional layer of stability against lateral pressures (Graham Drew. A. et al., 2010). This amalgamation of traditional craftsmanship and contemporary engineering not only augments the aesthetic allure of log structures but also substantially elevates their capacity to withstand environmental forces. Hence, the deliberate application of these construction principles signifies a pivotal enhancement in the field of log wall construction, ensuring their enduring resilience and safety.