Weight of brick wall in KN

[tony1851]

Good point, but I've got a book on my desk at work called Structural Mechanics...

You've spoiled my evening! I was rather hopeful that I'd got him on that one

 

[^woody^]

You've spoiled my evening! I was rather hopeful that I'd got him on that one

Haha ... you'll have to get up much earlier for that, sunshine

 

[RonnyRaygun]

Good point, but I've got a book on my desk at work called Structural Mechanics...

You've spoiled my evening! I was rather hopeful that I'd got him on that one

Sorry "Statics" is a much better description I agree...

 

[emphasis303]

Thank you for all your replies especially jeds.

Can anyone tell me the assumed loads for a roof in Kn m2, with redland 49 roof tiles and 4x2 rafters at 400 centres and 100mm of pir insulation between the rafters.

Thank you

 

[RonnyRaygun]

Thank you for all your replies especially jeds.

Can anyone tell me the assumed loads for a roof in Kn m2, with redland 49 roof tiles and 4x2 rafters at 400 centres and 100mm of pir insulation between the rafters.

Thank you

Including plasterboard and skim, it's going to be around 1.0kN/m2,
That is the flat load, so you have to allow for the slope by dividing it by cos θ (if measuring from plans, that is).

 

[jeds]

Don't forget live load, which will be 0.75 or 1.00kN/m² depending on where you are in the Country. Also loft load at 0.25 if there is one.

 

[emphasis303]

Thanks for your replies

So assuming we have 45 kn m2 for the roof load and 45 kn m2 for the live load, 90 kn m2 divided by Cos 0 would be 57.3 in radians? Which divided by 2 again to distinguish the live and dead loads would be 28.65 kn m2.

Is this correct?

Once again thank you

 

[tony1851]

Thanks for your replies

So assuming we have 45 kn m2 for the roof load and 45 kn m2 for the live load,

Is your roof made of 6" thick steel plate?!! and is it supporting a foundry?!!!

Just joking, but you may have got the decimal points in the wrong place, as well as 'quintupling' (if there is such a word) the dead load.

A tiled roof would typically be around 1.0 kN/m2,and the live load 0.75 to 1.0 kN/m2.

 

[RonnyRaygun]

Thanks for your replies

So assuming we have 45 kn m2 for the roof load and 45 kn m2 for the live load, 90 kn m2 divided by Cos 0 would be 57.3 in radians? Which divided by 2 again to distinguish the live and dead loads would be 28.65 kn m2.

Is this correct?

Once again thank you

WTF?!

I have no idea what you are on about now!

What exactly is it you are trying to find out?

Basically your roof will weight about 100kg per square metre, with another 75kg per square metre for the imposed load, which is usually an allowance for snow.

 

[^woody^]

That's the trouble when trying to calculate a beam without knowning what it all means

 

[tony1851]

There's no show without Punch.

 

[emphasis303]

Sorry I shouldn't of written in m2 it should of been kn.

If my roof is 9x5m long, that's 45m2 Now if my roofs dead load is 1 kn m2 that means my roofs weight is 45 kn

Now if the live load is 1 kn m2 that makes the toal live load 45kn.

Therefore the total loads being imposed are 90kn

Apologies for the confusion.

 

[RonnyRaygun]

Sorry I shouldn't of written in m2 it should of been kn.

If my roof is 9x5m long, that's 45m2 Now if my roofs dead load is 1 kn m2 that means my roofs weight is 45 kn

Now if the live load is 1 kn m2 that makes the total live load 45kn.

Therefore the total loads being imposed are 90kn

Apologies for the confusion.

Have you allowed for the slope in that calculation?

 

[emphasis303]

To calculate for the pitch of the roof I should divide my loads by cos 0 right?

When I did that for my total loads it came to 57.3 in radians but I'm guessing that was wrong? Would the load be reduced or should it increase?

 

[RonnyRaygun]

To calculate for the pitch of the roof I should divide my loads by cos 0 right?

When I did that for my total loads it came to 57.3 in radians but I'm guessing that was wrong? Would the load be reduced or should it increase?

If you are measuring from the plan then divide by cos theta, so if your roof pitch is, for example, 45 degrees, and it's 5 metres from eaves to ridge (on plan), then 5/cos45° gives an overall length of 7.07m.
So your total weight is based on 7.07m, not 5.00m, geddit?

But (this is important) the imposed load is a plan load anyway, so only do the above calc for the dead load.

Your calc is (assuming 5m is the sloped dimension):
DL = 1.00kN/m2 x 9m x (5/cos (pitch of roof))m
LL = 1.00kN/m2 x 9m x 5m

It might only be 0.75kN/m2 for imposed load, depending on location and elevation.

If you are trying to design steelwork or masonry, you also need to allow your safety factors of 1.4 for dead loads, and 1.6 for imposed loads.