Originally Posted by glowrock
The problem with many people here on SSP is that they don't consider the COSTS of what they propose, for instance an insistance on underground parking next to a major river with an aquifer located not far below ground level with a capacity of 5,000+ vehicles...
My guess would be a minimum of $100 million for that kind of underground parking capacity, perhaps even higher.
Dunno about Pittsburgh, and construction costs and soil conditions are pretty local, but as a Seattle (sort of) construction guy I'd guess $200,000,000.
I haven't read the next few pages yet, so forgive any duplication. But there are several ways of creating a dry site during construction, and keeping the water out after. Parking garages deep under heavy groundwater are nothing new. It's a cost issue. As for keeping the water out during floods, the building perimeter plus an emergency watertight door system should be plenty. Alternatively, a small berm around the entire garage, with a ramp or two over it, would be a cheap option, though probably less secure.