An I-beam, also known as an H-beam, W-beam, or universal beam, is a structural element shaped like the letter "I" used primarily for load-bearing in construction. Consisting of a vertical web and horizontal flanges, it efficiently resists bending and supports heavy loads in buildings, bridges, and industrial frameworks.

Design Efficiency: The I-shape concentrates material at the top and bottom flanges to resist high stress (bending) while keeping the center web thin, reducing weight without sacrificing strength.

Types & Terminology: Often referred to as W-Beam (wide flange), H-Beam (heavier), or S-beam (standard American).

Dimensions: Classified by depth and weight per foot (e.g., 

 is 12-inches deep and 20 pounds/foot).

Usage: Commonly used in residential/commercial steel building frames, bridges, and as supporting columns.

Materials: Typically made from structural steel, though aluminum alloys are also used.