This lecture introduces the course of structural mechanics for civil engineers at EPFL, covering key principles such as high-fidelity modeling of steel structures, performance steel materials, stability, and nonlinear finite element modeling. The instructor, Prof. Dr. Dimitrios Lignos, reviews course logistics, learning objectives, and assessment methods. The lecture delves into the history of structural mechanics, the structured solution process for statics and mechanics of materials, and the motivation behind studying structural mechanics. Various structural supports like rollers, pins, sliding supports, and fixed supports are explained. The lecture also covers internal forces, stress resultants, and provides examples to illustrate concepts.