What are the differences regarding the way they expand due to heat?
In: 5
No difference in heat expansion. This is longitudinal and proportional to the length and temperature. Beam shape and weight don’t affect this unless you try to restrain it (normally a bad idea) in which case heavier beams will put more force into the restraints before failing in some way.
[“I shaped beams” fall into two categories – one is an older one with narrow flanges and sloped inside flanges (in the US called an S beam) and the other has slightly wider flanges and square inside flanges, called a W section in the US.](https://www.kloecknermetals.com/wp-content/uploads/2022/03/h-beam-w-beam-s-beam.png)
Outside of fairly niche applications you almost only see W sections being used, and I’ll assume these are what you mean by I shaped beams. Europe has other naming standards but the same types.
For the same weight beam an I beam tends to be better in bending because its deeper. This makes it stiffer and gives it more capacity in bending and shear, but makes it more vulnerable to buckling. This weakness can be countered by providing restraints to the beam.
H-shaped beams tend to be better in compression. The wider and more square ratio of height to width of the shape gives it more resistance against bucking (compared to a taller and narrower I beam the same weight). H shaped sections are most commonly used as columns and in big trusses, where the main loads are compression forces.
You can use I shapes as columns and H shapes as beams, but normally there’s some fairly unusual design consideration that would drive that.
In construction they call them w sections because they have a wide flange. They come in all different sizes and shapes but if you take an I beam and turn it on it’s side it’s an h. They make the flange and the web(the middle part of the beam) different widths and thickness based on the properties needed for the design. Different ones are stronger in different aspects
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