Built-up shapes are made up of any combination of plates, bars and rolled shapes which are riveted, bolted or welded together.

• A. Solid Shapes
• B. Reinforced Concrete
• C. Built-up Shapes
• D. Hollow Sections

Answer: (C)

Built-up shapes are cross-sections created by assembling multiple elements—plates, bars, and rolled shapes—and joining them together with rivets, bolts, or welds. This approach lets engineers tailor strength, stiffness, and overall geometry by combining readily available pieces into a larger or more complex form, rather than relying on a single solid piece. In practice, you might see flanges made from plates and a web from a rolled piece riveted or welded into a single, strong channel or box-like member. That assembly-and-join concept is what defines built-up shapes.

Solid shapes, by contrast, are a single piece with no assembled joints. Reinforced concrete combines concrete with steel reinforcement inside the member, not assembled steel components. Hollow sections are single, hollow cross-sections formed by rolling or extrusion, not built up from multiple plates or bars joined together.