Load bearing length of RSJ

[r_c]

We have a couple of RSJs in our new extension. They are connected like a T. The ends of the T are on something call pads (a special concrete block). Is my understanding correct that they RSJ must have at least 150mm of length that is bearing on these concrete pads?

You can see the pad in the lower arrow.

2016-08-07 09.31.57

• r_c
• 7 Aug 2016

 

[tomfe]

No, it's down to what the SE report has the bearings being.
How much have you got and what did the report say?

 

[r_c]

what did the report say?

Img012-upload

• r_c
• 8 Aug 2016

I don't know why i didn't look earlier. Well in fact all the RSJs are less than 150mm over the 3 pads. One of them is only about 95mm. What happens now?

 

[^woody^]

That drawing makes no sense. The drawing is of steel beams, but the text says to use a standard steel lintel - IG L1/s.

Bearings don't need to be 150mm anyway.

 

[r_c]

the text says to use a standard steel lintel - IG L1/s

So that's what IG L1/s means! Thank you. OK, in that case it refers to the lintel above the bifolds, which are about 4m wide. (I should probably say that this is currently the only sheet that I have seen from the structural engineer.)

Bearings don't need to be 150mm anyway.

Why state it then?

 

[^woody^]

All literature for lintels, and designs will state an end bearing, and that will typically be of 150 mm.

This allows a factor for safety and error, but normal loading can typically mean that 100mm is sufficient. The engineer has probably stated 150 as that is in the lintel literature, so he does not have to prove it by calculation.

It can be a lazy way to specify.

But ultimately it will depend on the end loading and the bearing capacity for the lintel over the span.

 

[r_c]

I think I know what is going on here. This page of the report just shows B1 connecting to B2, and then goes on to talk about the steel lintel for the bifolds. Obviously I need to see the rest of the report as the earlier pages will have more detail on B1 and B2. Thank you woody.