In a building project, the structure needs to be strong, durable, and not too expensive. In this film, we take you through some fundamental construction principles — common techniques and methods used to build strong structures efficiently. You’ll learn that the frame-and-shell method is a great way to create lightweight structures that are still strong, that concrete is reinforced with steel to increase its strength, and that triangular shapes are great at creating stable structures. Finally, the film explains how the arch is a shape that distributes weight, commonly used when building bridges and viaducts. These well-established techniques are used to construct everything from boats and cars to huge skyscrapers.