Structural engineering for an MEP engineer...

[Dan Benson]

Hi all,

Hoping this falls within the forum allowable questions!

Bit of background: I'm an MEP & building physics engineer and my partner and I have bought a house.

Previous owners removed an internal wall (see attached SE drawing) but the builder has only installed support 1, but rather than the spec'd 203x203 they've installed a 152x152. There's no support 2 to be found.
They didn't (unsurprisingly) get BC signoff, but we are looking to get this regularised and of course be confident the house won't come down.

Here's my questions:

1) I know we'll need to go to an SE for a formal calculation but I'd quite like to be able to do it myself (or understand the results) - any good resources for this specific structural problem? I've a masters in physics so hopefully don't need too much background.
2) It'd be great if this were a simple problem that someone could tell me off the bat are we going to need to install new structure i.e. are we safe?

 

[Enable]

It's not possible to give you the assurance you're looking for with the schematic you posted. It's not entirely clear what is being supported by these members or why you have CATNIC lintel for support 2. From a bit of googling seems like a pre-insulated steel member which suggests this is at the enclosure boundary but what loads are on it are unclear.

You need to:

a. Figure out where the load Support 2 was intended to pick up is going

b. Figure out the loads on all supports that are actually there

c. Analyze support 1 as simply supported and see if capacity exceeds your demand from (b) taking into account lateral torsional buckling. Not entirely sure of your British call-outs but a 152x152 UC23 ( ~ W150x18) has a max unbraced length of 1.5 meters. At 4.6 meters the moment capacity is ~ 45% of fully supported condition. Analyze any other member that is taking load in this arrangement (i.e. where load intended for support 2 went to)

d. Get a structural engineer to review this