Failure Mechanism of Tree-Shape Support Structures under Static and Lateral Loading

Trees' consistent shape and robust structure can withstand massive loads, which has influenced numerous architects and design engineers. Tree shape support structures are considered one of the most suitable alternatives to long-span roof-truss systems. Limited research has been undertaken on the structural efficiency of the columns with geometric subdivisions. This study investigates the Y-shape tree column's failure mechanism and damage index under static and lateral load. The variables considered are the external moment, subdivision element angle (θ), and joint failure volume of material (V dj ), investigating buckling and yielding behaviour. SAP2000 and ABAQUS are used in numerical modelling. The results revealed that when sliced half into branches, a symmetric column (prone to local buckling) switches the failure behaviour from buckling/ yielding to joint failure. Furthermore, V dj has been found more in branches than stems, which increases with branch inclination (96.72% for θ =75 o ). Considering both static and lateral load simultaneously resulted in a slight reduction (less than 35 %) in total V dj but made the areas with high-stress asymmetric, making the support structure unfunctional comparatively at lesser load. The sliced column behaved like a single beam/column element for pure lateral load. To brace tree-shaped structures, this study recommends using a triangular wedge by welding the erected branches together just above the joint with the stem, increasing the overall affected joint area and making it resilient by reducing the stress intensity. Yet numerous areas need more exploration, such as integrating nonlinear behaviour and using a multilayer multi-material system utilizing high-fidelity modelling approaches.