Universal column, universal beam and RSJ differences?

[DIYedboy]

Would I be right in assuming that these are all the same thing ie an H section metal beam?

 

[Jackrae]

Not the same but all H-sections. The I values (moment of inertia) varies with the design and hence the application. Columns are designed to support vertical loading down their longitudinal axis (down their length) and are generally squareish in section (width and depth similar) to resist twisting. Whereas beams are designed to support loading across their axis and as such are generally much deeper than they are wide to resist bending.

RSJs can be used as columns but they need to be much larger than the equivalent column (deeper) to get the equivalent width to do the same job and columns can be used as beams but again they need to be much larger (wider) to get the equivalent depth. In both cases they end up wasting metal (money) to perform a task they are not ideally designed for.

 

[^woody^]

You would be right in assuming that they all look the same. That's it

 

[DIYedboy]

Jeez, nothing is simple is it?, so if I was walking down the road and there laying before me was three H section beams, would I be able to look at them and say ' that's a beam, that's a column' etc or must we rely on the metal stockist telling us?

 

[^woody^]

Columns are square, RSJ's have rounded fillets and sloping flanges, anything else is a UB

 

[DIYedboy]

Many thanks for your help, out of interest, if I had to fit a 'goal post' beam frame into a 9 inch solid wall, how am I supposed to attach the uprights to the brickwork?

 

[^woody^]

Whoever designed the goal posts should design the method of fixing

But generally it is intended that the goalposts take the load and not pass it to the structure via ties

 

[RonnyRaygun]

Just to confuse you a bit more, BS4 (the British Standard for Structural Sections) lists UBs (Universal Beams), UCs (Universal Columns), and Joists.

RSJ stands for Rolled Steel Joist. All of the above are rolled steel sections, but only one of them is a joist. You can also get welded sections and cold formed sections.

Many people use the term RSJ to cover the above three types of section, although it is not an official term used by the BSI.

 

[tony1851]

But generally it is intended that the goalposts take the load and not pass it to the structure via ties

The purpose of the 'goal post' frame is not just to carry the vertical loading, but also to provide lateral stability under wind load.

Therefore, some degree of connection is required between the vertical columns and the adjacent walls, otherwise there wouldn't be any point in having the columns in the first place.

 

[RonnyRaygun]

Many thanks for your help, out of interest, if I had to fit a 'goal post' beam frame into a 9 inch solid wall, how am I supposed to attach the uprights to the brickwork?

Resin anchors through the flange into the wall. Although if the brickwork is particularly old and crumbly we sometimes specify solid blocks of concrete cast into the wall, into which the resin anchors can then be fixed.

 

[Darren Davey]

Hi. I am new to fabrication and I am working with RSJs.
I was working on an upgrade for a structure and was confused with the measured size on the drawing which conflicted with the RSJ being supplied.

My question is:
Why does the designation (i.e. 254x254x132) and the actual size (276.3x261.3) differ? I would have expected them to be the same.
I have done a lot of searching and found no answer, hopefully you can help with this one.

 

[freddiemercurystwin]

The 254x254 is the nominal size of the beam and the 132 is the weight in kg per m and that weight per m varies depending on the specification of the beam.

So a 254x254x107 is 107 kg per m.

http://www.rainhamsteel.co.uk/products/universalcolumns.asp

 

[jeds]

My question is:
Why does the designation (i.e. 254x254x132) and the actual size (276.3x261.3) differ?

Section designation is something to do with machine tooling during the manufacturing process. The rolling machine is set up to produce 254x254 sections but it can be adjusted to produce any one of 5 weights within that group, all slightly different dimensions.

 

[tony1851]

The flange thickness varies, but the fillet depth (internal depth between the flanges), is the same for any one nominal size of UC.

 

[RonnyRaygun]

It's all to do with the size of the rollers at the mill. The internal dimensions have to stay the same while the thickness of the flanges and web vary.