concrete lintels which way up?

[george [dicegeorge]]

I bought two concrete lintels today,
2.4m x 100mm x 65mm
on top of which i plan to build a double brick wall.

If I put them with the 100mm sides horizontal
then the bricks will fit neatly on top,
But if the 100m sides were vertical
it feels to me that they'd be stronger.

advice please...

[george]

[Phil]

The pretensioned reinforcing steel in the lintels is off-centre and is
intended to be fitted closer to the bottom edge (the edge in tension).

[george [dicegeorge]]

look at them the measurements are 35-30 and 55-45
to the centres on the 65mm and 100mm sides.

But shall i put them horizontal,
or vertical with a gap between
or buy a third lintel and put them vertical?
[george]

[Phil]

They are only designed to go one way up - you need to find out where the
reinforcing is fitted (look at the ends & you may see two raised
'bumps') and point this to the bottom.

[Phil L]

they are 65mm for a reason, and that is so that it covers the same thickness
as one course of brick, also, the 100mm edge is the same width as a brick,
so it's fairly straightforward, without examining the reinforcing which way
they go on the wall

[newshound]

Or check with a magnet. The short side will be vertical. TBH the only
time I used one I didn't realise about the reinforcing and it worked OK.
I *think* you will find that you lay the bricks on the "poured" surface
(because the other three are potentially visible).

[harry]

> (because the other three are potentially visible).- Hide quoted text -
>
> - Show quoted text -

They are made in long lengths and cut up. You can see the wire rope in
the cut end.

[harry]

On May 15, 2:12 pm, "george [dicegeorge]" <dicegeo...@hotmail.com>
wrote:

They are designed to fit long axis horizontal. They are pre-
stressed.
They only support the triangle of blockwork on top.
The strength is all in the steel wire rope inside. It is high tensile
steel.
Usually the wire is in the centre. If it is offset, put it towards
the bottom.

Don't worry. I never heard of one of these breaking.

[Tony Bryer]

On Tue, 15 May 2012 14:12:09 +0100 George [dicegeorge] wrote :
> If I put them with the 100mm sides horizontal
> then the bricks will fit neatly on top,
> But if the 100m sides were vertical
> it feels to me that they'd be stronger.

No, as others have said, the 100mm side should be horizontal.
There's not a huge amount of strength in the lintel on its own.
They're designed to work in conjunction with brickwork over, the
lintel providing the tension and the brickwork the compression
zone.

See http://www.robeslee.co.uk/typea.htm

Lintel on its own, 1.2m span, SWL 3.86kN/m, with 2 courses of
brickwork over 9.50; 5 courses 20.21

--
Tony Bryer, Greentram: 'Software to build on',
Melbourne, Australia www.greentram.com

[george [dicegeorge]]

On 15/05/12 23:18, Tony Bryer wrote:
> On Tue, 15 May 2012 14:12:09 +0100 George [dicegeorge] wrote :
>> If I put them with the 100mm sides horizontal
>> then the bricks will fit neatly on top,
>> But if the 100m sides were vertical
>> it feels to me that they'd be stronger.
>
> No, as others have said, the 100mm side should be horizontal.
> There's not a huge amount of strength in the lintel on its own.
> They're designed to work in conjunction with brickwork over, the
> lintel providing the tension and the brickwork the compression
> zone.
>
> See http://www.robeslee.co.uk/typea.htm
>
> Lintel on its own, 1.2m span, SWL 3.86kN/m, with 2 courses of
> brickwork over 9.50; 5 courses 20.21
>

i didnt realise that -
maybe i should use steel,
maybe get building control
maybe get a surveyor...

but i haven't planned exactly what i'm going to do on top of it...

thanks.
[george]