Rsj bearing help???

Recently had an rsj installed as dinning wall has been removed. Rsj sits on internal skin on a pass time, but only has 80mm bearing on each side? Will this be okay??

Thanks in advance

 

Jbg123, good evening.

Any chance of expanding on this please? is it a concrete pad?

What sort of span does the RSJ cover? and what are the RSJs dimensions?

Ken

 

Yes on a concrete padstone
Span is 2850mm
178x102x19 ub

Thanks

 

Your builder has used a 3.0m beam -I would've thought either 100mm or 150mm is usually the minimum (cant remember which)

 

Although you would usually look for a 100 bearing, 80mm will be OK for the loading normally found in a domestic setting.

 

Your BCO may want to see some calcs for an 80mm bearing, 150 is standard.

 

100mm is standard for steel beams.

 

The crushing strength of the average concrete padstone is around 50 N/mm²; when safety factors are taken into acount, this is reduced to around 20 N/mm².
If the beam is 102mm wide, and the bearing is 80mm, that gives a contact area of approximately 8,000 mm², so that the maximum load allowed on the padstone surface would be 20 x 8,000 N = approx 160 KN.
This is way, way above the load that will show in the SEs' calculations for the beam; it is not a problem.
There are other factors to be taken into account when using a short bearing, but in practice they would not apply in a domestic situation where the loads are relatively low.

 

Its quite amazing really -it always looks so dodgy when you see a biggish steel with just 100mm bearing -I can see the logic in the maths though.

 

I'll chip in with the ubiquitous "what do the design calculations say"?

Or are you printing out a thread from DIYnot and submitting it to the council for approval?

 

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