ISMB or I-Channel Beam (Indian Standard Medium Beam) is a structural steel beam with an I-shaped cross-section. These beams are widely used in construction for load-bearing applications, including roof structures, floor systems, and framing systems.

It consists of two horizontal plates called flanges and one vertical plate called the web. This design provides high load-bearing capacity while minimizing weight, making it one of the most widely used sections in construction and engineering projects.