I-beams, also known as H-beams or universal beams, are structural steel beams shaped like the letter "I." They are widely used in construction and engineering due to their high strength-to-weight ratio. The design allows them to efficiently support heavy loads while minimizing material use, making them ideal for buildings, bridges, and other structures. The vertical sections of an I-beam are called the "web," while the horizontal sections are known as the "flanges." This configuration provides stability and resistance to bending. I-beams are essential components in modern architecture and are often used in conjunction with other materials like concrete and steel reinforcement.