RSJ Bearing

[Magrah]

I know the min RJS bearing (in this case for a new window) is 150mm. However the whole cut for the window ended up 3cm's wider than needed. I.e. 2.1m RJS and window 1.8, but due to tolerances its been cut bigger and a little to big on one side. This has meant the bearing on one side is only 120mm , it has a couple of pieces of slate underneath whihc extend beyond. What can I do, bit tricky to build up 3cms of brick work, was going to cement up the gap up to the RSJ, any other ideas?

Thanks!

 

[Static]

Reducing the bearing will depend on the brick quality its bearing onto.. is there a padstone?
What size RSJ, what loading etc etc.. more info.. photos maybe

Was it SE designed.. if so they should be first point of contact.. may not be a critical beam

 

[Magrah]

Hi, thanks for the reply. Yes there is a padstone and the brick underneath is 3cms short. The brick is the original for the house whihc was built in the 1930's. The RSJ is a Birtley 2100l x 203w x 240h. I should be able to post photos tomorrow.

Yes SE designed and is a critical beam as a further RSJ will be spanning from it (hence the quite hefty beam needed for a normal window!).

 

[Static]

Best to check with the SE then its a quick check for the reduced bearing..

Chances are the 30mm will be lost equally both sides so 15mm less bearing each side..

 

[PrenticeBoyofDerry]

that's what I would do, even the bearing out either side to 135mm, but check it out with SE.

 

[Magrah]

I think its a little late for that!

The window has gone in and the RSJ is set, one side is 150mm the other 120mm. The RSJ was set before the window! I am just hoping that BC do not say that it will all have to come out. If that was the case then not easy to get a longer RSJ as its special order. Would have to support the steel take the existing padstone out and replace / move it tight to the window or take a section of the brickwork out and re brick it tight to the window and place the padstone on top.

 

[Static]

Your choice.. you basically invalidate any insurance the engineer provides for the beam design by installing it to alternate measurements without informing them..

For the sake of a 5 min phone call i think your being a little silly..

 

[Magrah]

Hi Static, sorry i'll be speaking to the structural engineer regardless.

Thanks for the advice, I was just trying to guage if the 120mm would be acceptable. It must be a common issue.

 

[Static]

Thats ok, i wouldnt say its that common especially for more critical beams where the site dimensions would be check before the steels even arrive on site so any amendments can be accomodated at the fabricators..

It is however quite a simple check calc to see if the bearing works with the padstone/wall.. for all you know the beam was actually designed for 100mm bearing and this is all just hot air..

 

[Magrah]

Contacted both the SE and Lintel Co yesterday, Lintel Co said

'We recommend using 150mm end bearing either side and the figures we publish for our lintels are with this end bearing. However, you can use a minimum end bearing off 100mm either side but this will reduce the lintels capabilities.'

The lintel can take a UDL of 100kn but we are only loading it at 43kn so should be ok. But will wait for SE to get final say so.

Thanks for all your help.

 

[Magrah]

Just to confirm the SE got back to me and said its fine, phew! Just hope BC agrees!

 

[Static]

Just to confirm the SE got back to me and said its fine, phew! Just hope BC agrees!

See all is good.. BC will be fine.. The SE takes the responsibility away from them..

 

[noseall]

See all is good.. BC will be fine.. The SE takes the responsibility away from them..

Almost true!

His calc's will do the talking.

If B.C. engineers decide there is an anomaly then they will be bounced straight back to the S.E.