Structural channel

The structural channel, C-channel or parallel flange channel (PFC), is a type of (usually structural steel) beam, used primarily in building construction and civil engineering.

It is distinguished from I-beam or H-beam or W-beam type steel cross sections in that those have flanges on both sides of the web.

[1] The structural channel is not used as much in construction as symmetrical beams, in part because its bending axis is not centered on the width of the flanges.

If a load is applied equally across its top, the beam will tend to twist away from the web.

This may not be a weak point or problem for a particular design, but is a factor to be considered.