An i beam is a type of structural steel that is shaped like a capital "I". Generally, it has two horizontal and two vertical flanges, with the vertical flanges being equal in size. They are typically used in construction for support beams, as well as in bridges and other large civil engineering projects. They are also commonly used in construction for support columns, foundation beams, floor joists and various other industrial applications. I beams are extremely strong due to their unique design, which offers a rigid and solid support for a variety of structures. Additionally, I beams can often be factory-manufactured to specific sizes, making them attractive to architects and designers.