Looking at the rising structure, I can't help but notice that its structural elements, particularly the columns, don't seem significantly different from those of other condominiums with fewer storeys. The columns appear relatively thin, and I'm curious about the engineering decisions that enable such a tall structure without apparent signs of increased structural demands.
I didn't work on this building specifically, but I have some experience with designing structures of supertall buildings.
this is still very much just coming out of the podium stage. Also, if you look in the pictures you'll see post tensioning cables that run up every few floors and add integrity to the building as well as everything tying back to the main core
That's part of it, the cables are to reduce axial tension, they would only change the size of the column if tension (i.e. reinforcement ratio) was governing size. They significantly assist the lateral load design.
Looks like they are using a lot of shear walls (stabilizing concrete walls). Maybe that deals with lateral forces and eliminates/reduces the need for megacolumns.
Pretty much, yeah, but then also add tension cables mentioned above.
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@cityspace,
I've been to this site, and the elements are massive compared to other buildings. It doesn't look like it in photos because everything is huge, but some of those beams are the size of bridge girders. However, at first glance, I'd agree that they aren't as large as I'd expect.
Materials can be a part of it, but that stuff has been around for a while and is expensive. See
UHPC (>120 MPa, about 4x traditional strength) and
GFRP Rebar (~1300 MPa, or 3.25x stronger than traditional), for examples.
The challenge in supertall design is creating an efficient system that doesn't require massive elements.
Upon closer inspection, I can see that the post-tensioned shear walls extend almost to the balconies, rather than just encompass the core. There's very few columns in the traditional sense, as they use so many full walls instead. If you were to compare the area and reinforcement of those walls to a handful of megacolumns, they'd probably be quite similar, which means the architect clearly would just rather have the structure hidden in the partitions than leverage the structure in the design (like 1 Bloor West).
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TL;DR: The elements are huge, they're probably using extra strong material, it's post-tensioned, and a distributed instead of localized system.