FE-modelling of glulam connection in a pre-tensioned glulam truss : Detailed Finite element modelling of the connection between primary beam and compression stud in a sub-tensioned glulam roof truss

Abstract: After the collapse of the roof structure in Tarfalahallen 2020, great attention has been focused on instability of sub-tensioned glulam roof trusses. Investigations were launched to find the reason for the collapse and the cause was instability in the roof truss that supported the roof. As a result, several similar glulam roof trusses in Sweden have been investigated and reinforced to avoid the fate of Tarfalahallen.Inexperience with instability, negligent design procedure and faulty assumptions is an underlying issue with this type of structure. Complex structures can be difficult to analyze without suitable assumptions which means sophisticated method must be used. Proper analysis must be done before construction.To perform this sophisticated analysis, an engineer can use the finite element method to perform global stability analysis. Simple and computationally cheap models can produce meaningful insight, but in most cases the user must be experienced to understand the implications of the results that the finite element method can produce. There is therefore a need for a more detailed, realistic model that can capture failure and motion and visualize it for the user. This thesis has created such a model in the FE-software Abaqus/Standard.By using a wide variety of elements and element sizes a detailed geometry of the connection between primary beam and compression stud, the behavior of the structural components has been analyzed throughout the loading period of the structure. The critical buckling mode was identified, and the complex non-linear interaction of the connection was tracked when buckling occurs.The thesis can be used as a guideline of how to create a FE-model that captures the intricate behavior of the connection between primary beam and compression stud and be used as the groundwork for more complex models in the future.