Quote:
Originally Posted by LouisVanDerWright
Actually I'm pretty sure they didn't actually lose any SF and just increased the height of the building slightly. I think that accounts for the descrepancy between the 1150ish number we had originally heard and the final height just below 1,200 we wound up with. There was an engineering article posted a while ago that discussed how the blow thru wasn't in the original design until wind testing determined that they had to do something to resist the sway of such a narrow, slab like, structure. The same article also discussed the interesting unique linked double core of this building which has also been used as slight against this design. Turns out that unique sheer wall configuration was also a result of the massing of the structure and need to locate the core on either side of the street and not because of the frustums as was hypothosized by the anti-Gang contingent here on SSP.
Basically the conclusion of the article was that all the fancy cores, sheer walls, and dampering has nothing to do with the frustum form and everything to do with the extremely narrow, slab like, massing of the building which is basically outside of the architects control given the site constraints and the height of the building.
|
Yes, a lot of us read the same engineering article. You are correct, that the frustums had little or no direct effect at all on the structural engineering to prevent sway. However, the tower/frustum design and the goal of maintaining the smooth, 'crystal'-like gemstone effect, did have an effect in the sense that it eliminated the option of locating significant structure at the outer edges of the three towers (to prevent sway) vis a vis a 'tube'-like vertical cantilever (Sears) or even an exoskeleton that would have freed up the exterior of the building for increased views rather than relying on 4' thick concrete shear walls...
There are numerous structural solutions to a tower of this size and shape. In fact I have seen earlier designs from others for this exact program, client, and 3 tower design that employed radically different designs structurally. I am not trying to criticize the innovative structural solutions here, I think they did a remarkable job given the function-follows-form nature of the design...