This lecture focuses on the principles of static equilibrium in structural design. It begins with the introduction of basic concepts such as forces, their characteristics, and the importance of understanding how they interact within a structure. The instructor discusses the historical context of static equilibrium, referencing Simon Stevin's work from 1634. Key topics include the identification of tension and compression in structural elements, the significance of force diagrams, and the application of Robert Henry Bow's notation for analyzing forces. The lecture emphasizes the geometric relationships between forces and structural elements, illustrating how the positioning of supports can minimize material use and environmental impact. Through various examples, the instructor explains how to model forces and their effects on structures, ensuring that students grasp the foundational concepts necessary for effective structural design. The session concludes with a recap of the main ideas and an invitation for students to engage with practical exercises to reinforce their understanding of static equilibrium.