C- U- channel shaped beams/ Differences?

[Yt.]

Hi, i'm trying to get the difference between C- U- or channels shapes. It's reasonable to me that both U- and C- may be called channels. But providers often call U- and C- to the same beam and codes state distinctions.

Are there implication about hot rolled or cold-formed? (saying one is cold formed and the other rolled)

I also have seen square and round corners at web/flange junction

which are the expected differences?

thanks

 

[DaveAtkins]

I don't believe you can get hot rolled cee shapes (I am talking about a cee shape with lips). A hot rolled channel will normally be u-shaped.

Cold formed cee shapes will have the lips, because otherwise local buckling of the flanges greatly reduces the strength of the member.

DaveAtkins

 

[racookpe1978]

A C-shape (also CH in some books) is a designated, specifically controlled structural steel shape with outside square corners, 3x flat and perpendicular sides, hot-rolled to controlled structural dimensions and alignment in a series of patterns that are designated (US convention) by: nominal height of the web and weight per foot of the member. ALL dimensions are controlled during the hot-rolling: height of web, thickness of web and flanges at midpoint, angle of the two legs (usually 2.5 degrees) and shape of the end of the two legs.

A "U" shape is usually trimmed from a square tube steel with uniform and equal leg and web thicknesses, and a height based on the original square tube steel height. Each edge of each leg is usually ground off square and burrs removed. The corner is as it originally was from the original tube steel: rounded inside and outside.

 

[Yt.]

Thanks Dave, I'm aware of stability issues of flanges and i agree with you. A hot rolled stiffener would be nonsense. But C-Beam also could be unstiffened according to AISC.


My problem is that i'm trying to specify a C beam and started to look for available commercial dimensions at local site in order to check their resistance. I want to work with the cheaper C cold-formed channel that withstand stresses, and by seeing local providers i noticed they call "C-shape U beam" to the same member. So i'm trying to deduce which kind of beam they are based on the pictures at websites

I'm assuming that square corners should be hot rolled. but i haven't found a clear difference between U- and C-beams (if there is one)

 

[Yt.]

Thanks racookpe!