Alternatives to RHS column for steel

[Iknowcraig]

Hi all, I am working on an extension at the moment and have a large steel ready to go in to take out a length of wall (6M long). The structural engineer has specified 150x100x5 S355 RHS posts to support the steel. These seem pricey and S355 is harder to get hold of. I was wondering if there was an easy way to find alternatives to consider, such as brick piers, or other profiles like a UC or S235 option. The calcs provided are below if they helps, is there a simple calculator/piece of software I can put these into to view alternatives or do I need to go back to (and pay again) my engineer?

 

[tony1851]

Is the RHS specified to fit in with the thickness of the inner skin of the wall by chance? A 152 x 152 UC would be cheaper, and if necessary you can build the blockwork tight into the web.
Of course, brick piers would be cheaper still, though taking up a little more space. Most SEs seem to insist on designing goal post frames, when more often than not, correctly-designed brick piers are perfectly OK.

 

[Iknowcraig]

Is the RHS specified to fit in with the thickness of the inner skin of the wall by chance? A 152 x 152 UC would be cheaper, and if necessary you can build the blockwork tight into the web.
Of course, brick piers would be cheaper still, though taking up a little more space. Most SEs seem to insist on designing goal post frames, when more often than not, correctly-designed brick piers are perfectly OK.

Thanks yes it does seem they were trying to fit everything within the walls which is optimal, but we have already done up upstairs so will have the beam across the ceiling sticking down and boxed in, so another protrusion from brick piers wouldn’t make much difference and could save a chunk of money, any ideas how to prove if brick piers are sufficient or do I need to go back to the SE??

 

[tony1851]

I should not be surprised if your SE won't get involved if you ask him/her to consider brick piers instead; it just takes a little more number crunching but saves £££s on steel and fabrication. As long as the house has reasonable brick/blockwork walls at ground floor level so that lateral rigidity is maintained, the pier need not be too big.

This pic shows a 440 wide x 215 deep pier (extreme left) supporting a heavily-loaded 7.5m beam. It's made of a mix of dense block and concrete brick. Gives an idea of the size you'd be looking at.