This lecture provides an introduction to the functioning of structures in architecture, covering topics such as forces, equilibrium, resistance, deformation, rigidity, and dimensioning. It explores various structural elements like cables, membranes, arches, vaults, domes, trusses, beams, and frames. The course emphasizes the importance of understanding, analyzing, designing, and dimensioning structural components in both 2D and 3D spaces. Practical exercises on i-structures are included, with corrections and grading criteria for successful completion.