The I beam consists of two horizontal planes, known as flanges, connected by one vertical component, or the web. The shape of the flanges and the web create an “I” or an “H” cross-section. Most I beams use structural steel, but some are made from aluminum. Infra-metal constructions, such as carbon structural steel and high-strength low-alloy structural steel, have different applications – such as building framing, bridges, and general structural purposes.