An Engineering Challenge

[Parm]

leave it to a structural engineer / architect team to sort out.

 

[cumbriasteve]

OP, a number of members have taken their time to offer helpful suggestions and ideas, I would like to think you plan to return to the thread with how the task was achieved otherwise I don't really see the purpose of it.

 

[Swift&Bold]

In fairness this was posted as "Just for fun for some ideas" so a structural engineer isn't necessary in this case, I'm assuming as a 'Live project' that this has already been done and that the OP is just interested in what other peoples' approach would have been....no harm in that we see similar posts regularly.
It would be reasonable and proper etiquette to receive some response or feedback though.

 

[8ob]

Ok two injuneerin drawings/solutions ( not to scale ) that wont put outward pressure on the walls.

 

[Mee]

Either cast a re-inforced concrete ring beam around the top of the walls or fabricate a perimeter in steel to tie the top of the walls together and resist the spreading action of the roof.

Without knowing the dimensions it all guess work, but i would go with a universal beam around all four sides of building sitting in the centre of the 6 foot wall.
Bolted together then roofing steel work siting on top of UB.

And the two correct answers in this particular job were Dee J and Workshop Chris.

It is having a ring beam made from UC on its side around the centre of the walls, these will be sat on their sides and bolted together and have a series of holes and slots in them; they will be bolted through the walls using stainless steel bar and chemical anchor, with isolating washers at the steels to prevent electrolytic reaction between dissimilar materials. The roof trusses will be attached to raised mountings welded to the sides of the UC to allow the concrete ring beam to be cast.

This will be shuttered and a concrete ring beam cast around it, the slots are there to allow the poured concrete to go through, and for the vibrators to work in it to compact it, obviously the UC will act as reinforcing.

 

[MrFluffy]

The problem with that approach is the stone walls buckle in the midway point with crush load even if they resist the spreading effect , so while a ring at the top + the likes of a mansard truss ties the tops, it doesn't make them any more resistant to bellying out midway over longer time periods. They're literally piles of stones with bits of cowpoo, mud and straw between the stones that squeeze out over time and resettle with the load until one day something reaches a critical point and the wall falls over one day during heavy rain or something as happened to one here on another outbuilding.
Portal frame is a nice solution, but its expensive, hence the poured pillars approach at chez fluffy.

 

[Mee]

OP, a number of members have taken their time to offer helpful suggestions and ideas, I would like to think you plan to return to the thread with how the task was achieved otherwise I don't really see the purpose of it.

How about giving me time to post Steve, if people give feedback and Ideas I will respond. Many other people take much longer to respond.

In fairness this was posted as "Just for fun for some ideas" so a structural engineer isn't necessary in this case, I'm assuming as a 'Live project' that this has already been done and that the OP is just interested in what other peoples' approach would have been....no harm in that we see similar posts regularly.

Thank you Sip-Free, it was a little fun and you are correct, it is a live project and the steel is currently being fitted and bolted down and is currently being undertaken as we speak.

 

[Mee]

Attach a large balloon to the roof and fill it with enough helium to fully support the weight of the roof.

And that was the funniest suggestion of the topic, how much helium have you got.

 

[daleyd]

there is no right answer and obviously no wrong answer

Ahem .....

And the two correct answers in this particular job were

 

[reb78]

Any pics of the actual job for interest?

 

[8ob]

Ahem .....

That makes my answers wrong in their own right then , rightly or wrongly .




Bob

 

[PhillipM]

And that was the funniest suggestion of the topic, how much helium have you got.

There are a fair few stadium/factory roofs supported by positive air pressure in the building courtesy of a great big blower fan....although to keep a normal roof up they might have to be enough pressure so that when someone opens a door your eyeballs bulge out.

 

[Shox Dr]

There are a fair few stadium/factory roofs supported by positive air pressure in the building courtesy of a great big blower fan....although to keep a normal roof up they might have to be enough pressure so that when someone opens a door your eyeballs bulge out.

They had that problem in Total Recall

 

[PhillipM]

They had that problem in Total Recall

I didn't recall that bit.

 

[slim_boy_fat]

Any pics of the actual job for interest?

Are you having a giraffe?

 

[Parm]

leave it to a structural engineer / architect team to sort out.

How come part of my post has been deleted?

OP did say it's a bit of fun and I only mentioned information provided by the member himself

A little unfair that OP with his track record has lit the touch paper and then vanished

 

[The_Yellow_Ardvark]

There is a BS approved way of fitting a roof to the building the OP mentions. I spoke to some one today and there reply was along the lines of.
"Any one in the trade who has done the correct research knows about it.

He was not impressed about the OP first post, he did think it had a familiar ring to it.

Ony one who wants to know can PM me.

 

[Swift&Bold]

.........A little unfair that OP with his track record has lit the touch paper and then vanished

?? He replied earlier this afternoon.

 

[PhillipM]

he did think it had a familiar ring to it.

Was it a reinforced concrete ring?

 

[Farside]

This is merely for fun and for people to make suggestions, there is no right answer and obviously no wrong answer, so what would you do and how would you approach, and resolve this minor problem?

This is a live project which is currently part way through.

This is an industrial building which is two storeys high, with a pitched roof and loft to give it three storeys, and we have to make a roof for it and erect it.
The walls are cut stone and 6' thick and are structurally sound, but we cannot place roof trusses directly onto the stone as the weight would cause a "blow out" which is the weight of the roof forcing the top stones out and the roof collapsing, and we cannot use tie bars as the roof space has to remain open.

How would you approach it and what is your solution?

I'd simply copy the design of my own concrete shed, built in 1949.
Two stories high, walls made of block and mass concrete, about 12" thick. Building is 45ft x 24ft.
The roof is a pitched structure, totally open inside, and the only tie bar across it is one steel bar about two feet above the base level of the roof. This bar is approx 6" x 1/2" x 24ft, laid on edge.
It's kept the roof and walls together for 68 years, so it's working ok.