Bending rebar mesh - help!

[maxdavie]

Hello, 

 

So, I have a groundworker that hasn't fully engaged with the engineer's foundation design before taking on the job! 

Our foundation is a raft slab with an edge thickening. 

 

Following my SE's advice, I've had a bunch of U bars pre-fab'd off site. 

I think the rebar cage designers expected him to have the means to bend some mesh on site, but he doesn't know how to do it. 

 

Does anyone know how to bend a sheet of A393 mesh in two places - see pic below. 

Any help would be amazingly appreciated! 

 

[Jenki]

Personally never seen it like this, (I'm not a structural Eng.)  usually its a square / rectangle ring beam tied to the mesh, can't see the angled portion offering anything that a square section  wouldn't.  I'd be gong back the SE to ask for it to be square.

 

EDIT:

 

you can pick up square 'rings' pretty much of the shelf and make the ring beams by adding rebar lengths. no reason for as simple design to have bespoke rebar IMHO,

Edited July 28, 2022 by Jenki
additional info

[Conor]

That looks like an awkward detail. 

 

It would be normal to extend the mesh right to the edge of the slab, and have the the additional mesh at the bottom of the ring beam as shown.

 

Go back to the SE and ask for an easier to build option. Failing that, simply cut the mesh and tie / weld after set in position (faff).

[maxdavie]

I'm an architect and (though I've never overseen a foundation being built on site) I know that this is a standard raft slab detail. It must be buildable. I imagine there's some kit needed or my SE failed to mention that you'll need to have the mesh bent off site

[markc]

Most mesh suppliers should be able to bend that detail, it can also be done on site manually but it’s a pain to do (fork bender and work along the mash one rod at a time bending a few degrees each pass)

[Mr Punter]

I guess you could get some H10 bars bent to the shape and allow for a 500mm lap to the mesh, then tie further H10s at right angles at 200 ctrs.  It looks like you will only need about 6.

[maxdavie]

I'm thinking, why on earth were the rebar U-bars we had pre-fabbed off site not just this shape so no mesh-bending was necessary! 

I'll relate the folk bending method to my groundworker, but I'm not sure he'll know what I'm talking about! 

[saveasteading]

That is not normal. I would cut the mesh into flats and link them with bent bars, which you can bend on site  if necessary.

 

Actually no...I would extend both top layers of mesh to the full width, and build a cage to form the edge beam, made of stirrups which link top and bottom.

[George]

1 hour ago, saveasteading said:

That is not normal. I would cut the mesh into flats and link them with bent bars, which you can bend on site  if necessary.

 

Actually no...I would extend both top layers of mesh to the full width, and build a cage to form the edge beam, made of stirrups which link top and bottom.

 

Almost that. The red square links should extend to the top face (the lower mesh just gets snipped when it clashes).

 

The concrete chamfer on the underside is just fill, it isn't really necessary in domestic scale loading for a structural role.