12 x 12 RSJ

pete6296

Hi,
I am full of questions.
I had to purchase a 12 x 12 inch rsj to span an opening of 3.4 metres leading into a sunroom so the total length was 4m.
It will be placed 10 courses high, at the 13th course will be 8 inch hollowcore spanning horizontally over steel at a span of 4.5m.
Is 300mm(1foot) on both sides of rsj adequate to sit on external blockwork, the weight of this rsj is extreme.
Your thoughts!
Thanks,
Peter

archtech

300mm of bearing either side should be ok however, you should rest the rsj on a padstone rather than bearing the rsj on standard blockwork.

gally74

this is a question you should be asking your engineer

pete6296

Thanks archtech, where would i source a padstone and what size should i put in.
Thanks,
Pete

pete6296

I was interested to see the opinion of other people, the engineer recommended 300mm but i thought it was a little skimpy.
Thanks

archtech

Your engineer would be specifying the minimum size required. Depending on if your casting one or buying one it may be more cost efficient to use a large one.

Might be worth your while contacting some suppliers.

Mellor

archtech wrote: »

Your engineer would be specifying the minimum size required. Depending on if your casting one or buying one it may be more cost efficient to use a large one.

Might be worth your while contacting some suppliers.

How exactly would be be cost efficient to use a larger one?
Surely the price is related to the size for standard padstones.


To the OP, if the engineer says 300, then 300 is fine. This is standard enough for domestic loading. But a padstone is a must.

archtech

Mellor wrote: »

How exactly would be be cost efficient to use a larger one?
Surely the price is related to the size for standard padstones.


To the OP, if the engineer says 300, then 300 is fine. This is standard enough for domestic loading. But a padstone is a must.

The engineer has specified a 300 however the shortest available from the supplier in the link is 450. My point is it may cost less for the op to buy the 450 one rather than insisting of getting a 300 specially made just because his engineer specified a 300.

gally74

look im a mechanical engineer myself

if you go 450 mm how are you going to cover it up,

at 300 a normal 100, 100 cav, 100 block will be as wide.

Mellor

archtech wrote: »

The engineer has specified a 300 however the shortest available from the supplier in the link is 450. My point is it may cost less for the op to buy the 450 one rather than insisting of getting a 300 specially made just because his engineer specified a 300.

Check the link again. The last one is a 300mm padstone. this is a standard size.

gally74 wrote: »

look im a mechanical engineer myself
if you go 450 mm how are you going to cover it up,
at 300 a normal 100, 100 cav, 100 block will be as wide.

Em, The stone goes the other way. 450 is the lenght (or 900, or 300 as specified here),
215 wide on a 215 wall, or 300 on a wider wall. 300 cavity walls are not built internally.

pete6296

Hi,
This steel is on an external wall, 300mm in thickness in total.
Pete

Mellor

It shouldn't be on the external wall. Well specifically on the external leaf.
So depending on the junction you should either build a stub wall inside the external wall to hold it, or continue the 300 wall inside. I was continuing the 300 wall inside, i'd make it solid not cavity.

The exact way to do it depends on the shape and direction of the junction, engineer should provide a detail.