Thread rod used as rebar.

[Alistair_Heaton]

I am building using aerated concrete blocks and ceiling plates. I will admit it's a DIY workshop/bar building

There is a 6 meter by 15 meter floor of ceiling/floor plates which are 600 mm width x 215mm thick x 6000mm long. I want to tie them together to form a shear diaphragm.

The design manual also says to use circular reinforcement to stop cracking between panels 10mm dia.

I can't get hold of corrosion resistant rebar plus will have issues getting it welded together if I get hold of ZN plated.

I can get hold of plated ZN threaded 3m lengths of bar 8,10,12mm dia.

How stupid is using 12mm threaded ZN rod joined by ZN hex nuts instead of black iron/steel rebar?

Locally they are telling me to just use black iron but my research says this a big no no with aerated concrete as it sucks moisture like a sponge, and you will have corrosion issues in 5 years if you do.

I haven't been a practising Engineer in over 20 years and never worked with concrete practically even when I was practising and this aerated foam autoclaved concrete is a steep learning curve designing and building with it. It has huge advantages compared to normal building materials but has some huge minus issues with this water migration and movement internally.

 

[Lomarandil]

These are post-installed in some fashion?

I'd allow it.

I wouldn't count on a standard hex nut to connect two 3m rods in any meaningful fashion though. If that's your plan to align things, no problem. But not to create a 15m diaphragm.

 

[Alistair_Heaton]

20mm groove cut into the top of the plates then rebar goes in and you fill it with mortar.

There is a 34mm layer before the re bar grid for the top of panel you sink it into that. That upper grid is to do self support while the plates are getting lifted in.

I haven't included it in the structural calcs for the building side of things of the walls etc, but I will be using them for the tension bottom member of a roof truss but the steel grid will deal with that.

When I say hex nut the things am on about are hex continuation nuts DIN 6335 steel galvanised. They are M12 normal size and about 50mm long. I went for M12 rod instead of 10mm rebar to give the joints more metal. In the grand scope of the project the cost increase is more than covered in reduced labour costs and mucking about.

I might add a local structural engineer has signed my calcs off for building permit. But he is as clueless as me with this aerated stuff.

Design manual is here is your interested. Its a bit like building with lego to be honest. The normal way here is to use hollow concrete blocks then put vertical rebar in and then pump concrete in to make it solid. I want the thermal properties of this stuff plus the one-day installation of the ceiling/floor plates. Plus it will make life way easier putting the rafter roof in.

The numbers I can find is 24 MPa tensile strength and I have 2.4 kN/m ultimate roof load (dead and live together) and that's without rebar.

https://bauroc.ch/uploads/sites/19/2019/06/bauroc-manual-EN.pdf

 

[Tomfh]

I’d be happy with this detail too. 50mm long nuts are fine.

Id have gone with smaller dia rods to reduce disruption to the cover zone, but M12 should work too.

 

[Alistair_Heaton]

Going to put 245x45 impregnated wood as the rafter footing. That will be attached to the load wall under the plates with 600mm length of same rod in 4 places at the ends of 2 3600mm lintels.

And every 600mm two 403 shear screws down to half plate thickness.