I don't expect Salesforce towers to lean. These guys are building those as an ego trip. They have more money than god, and don't care how much they waste, so they can afford to pay for the Extra Stuff that overbuilds stability, etc. They don't care how much it costs. My best friend ran the plumbing for a significant percentage of those projects.
Every time I see the Salesforce Tower I'm incredibly disappointed at how fucking pedestrian it is. They could have really made a statement of design and instead went with sedate and boring.
...The park would be hard to account for, and they may have been pressured to reduce the estimated weight of it because of the exponentially increasing cost to build sufficient load bearing with linear increases in load.
With all due respect, I call poppycock. X amount of soil + top cover weighs this much. X amount of concrete weighs this much. X amount of people way this much.
Over build to ensure, and voila.
Also, having your engineers build to a lower weight because it's too hard to meet specs is (in my worthless opinion) the absolute last possibility. I hope like hell I'm wrong, but that would be seriously criminal malfeasance at least.
the faulty beam is supporting the park up above. maybe there shouldn't be a park on top of a transit hub? nobody thinks, let's keep it simple?
Weight is weight. Doesn't matter if it's a park or a parking structure or another 100 stories of concrete building.
There are thousands of structures in the world with vastly more weight on top.
Also, the leaning tower is a completely different issue. The material used has nothing at all to do with the stability of the high-rise being built with no solid foundation. There is no reason at all to delay construction on buildings in SF because of the MT issue...unless you're building a high-rise and you can't reach bedrock.
Never time to do it right, always time to do it twice.