The medieval cathedrals used external reinforcements (“flying buttresses”) extensively-they seem not to be used today.
the Presidentail Palce (Brazila) used external supports (link:File:Palacio da Alvorada Exterior.JPG - Wikipedia); are there any other buildings that use them?
I like the look- why aren’t they used more extensively?
Seriously, Cowboys Stadium.
I don’t think either of those are flying buttresses. They’re just arches that building is built onto.
I suppose a case could be made for it, but it seems like a stretch to me.
I would imagine we don’t use them because we have better building materials and techniques then we did hundreds of years ago.
They were often used to support vertical stone walls, but now that we build with steel and concrete footings and pay a lot of attention to wind/snow load/seismic activity we don’t need the supports on the outside constantly holding the wall in place.
I’d imagine we would still need them if we still wanted to build massively tall buildings (for the time) out of rocks and didn’t want them to fall or rack.
Moved to GQ from Cafe Society.
Seriously, no.
Flying buttresses were needed because stone walls can only be built so tall. (Without making the walls so thick that they eliminate interior space.) The advantage of steel beam construction is that the walls can be made much thinner and allow for larger - and more profitable - interior space. The structural elements can be exposed, as was done for Cowboys Stadium, but they are still interior and integral. Buttresses were exterior.
There’s a bit more to it. The roofs and ceilings of cathedrals were made up of arches spanning from one wall to the other. That sort of roof puts an outward pressure on the walls. (Imagine leaning two playing cards together. The bottoms will splay apart unless you hold them in place with something.) Buttresses were built against the walls to keep them from falling outwards. After a while, someone realized that only the outer part of the buttress was needed, so the inner part was left out and the flying buttress was born.
Part of the reason we don’t need them anymore is because we don’t build arched, stone roofs much. You can span the same distance with a beam or truss which doesn’t put that outward force on the tops of the walls.
I would classify those supports on Cowboy stadium to be flying buttresses. They’re just not made of stone. I have used buttressed glass walls like this one before.
But the load is transferred all the way to the ground (not counting the concrete footing), whereas with a flying buttress, the wall pushes against the flyer which transfers the weight to the vertical concrete buttress and that takes it to the ground.
If the Cowboys Stadium is using flying buttresses…what are they holding up? I presume what we see in that picture is more or less what the other side looks like and that those parts are continuous. That is, they arch from one side to the other and the structure is hung from them, not leaning on them. The pressure is pushing the arches downward, not outward.
Looking at wiki on arches, it appears that (at least some of them) they are based on Gothic flying buttresses.
St. Coleman’s Cathedral in Cobh, Ireland, is only about a century old, and so takes advantage of basically-modern construction techniques, but still has flying buttresses because the architects wanted to make it look like the old medieval cathedrals.
If the arches did not go all the way to the ground then the weight of the roof would sit on the curtain walls and bow them outward.
Medieval problem: While stone is a very durable construction material, it has no strength in tension. So if a wall has tendency to bow out, you need to support it from outside.
Modern solution: Steel is also very good construction material, and is even better in tension than in compression. So if a wall has tendency to bow out, you can anchor it on the inside from the other wall.
I can see both sides of this argument - you’re right, except that the curtain walls are not part of the arch, whereas with a traditional flying buttress, they would be.
In other words, a flying buttress is an arch where the wall itself forms a compressive component of the arch.