BUCKLING AND PROGRESSIVE COLLAPSE OF DIAGRID SPACE STRUCTURES

The growing demand for sustainable, efficient and aesthetically innovative tall buildings has led to the development of advanced structural systems. Among these, diagrid structures have emerged as a prominent solution due to their geometric efficiency, structural performance and architectural flexibility. This thesis analyses the buckling behavior of spatial diagrid structures, focusing on their stability and resistance in the case of extreme situations, studied by means of a progressive collapse analysis to highlight the resilience of such structures. The following study involves the development of a model based on numerical analysis for the efficient and effective description of these behaviors. Thus, compared to existing methodologies based on the definition of the structure's shear and bending stiffness, and on finite element models, the proposed approach is based on the direct calculation of the structure's stiffness matrix. This methodology is named Matrix-Based Method (MBM) and was used as the foundation for the preliminary design of the structures to be analyzed. The relevant numerical procedure was implemented in a MATLAB code. In addition, the proposed model was validated using a FEM-based analysis, comparing the results obtained with theoretical predictions to ensure its accuracy and reliability. The results highlight the crucial role of stability analysis in the design of diagrid structures, demonstrating their ability to withstand significant compressive and tensile forces while maintaining structural integrity even under extreme conditions, in order to demonstrate the importance of geometry-based optimization to improve the performance of diagrid systems. This thesis contributes to the field of structural engineering by providing an effective tool for the preliminary design and analysis of spatial diagrid structures, offering insights into their stability, efficiency and application potential in modern tall building architecture. The results provide a basis for future research and practical applications in the design of innovative and resilient buildings.