Quote:
Originally Posted by jhausner
Unfortunately you can believe it all you want but you're still wrong. Comparing Vancouver near False Creek geologically to most of South Delta is a bit silly sorry. If you base your knowledge of building codes on a "new VANCOUVER house thread." then there's not much else I can say. Not that long ago in this very thread I made a point about bring real life facts to a discussion if you want to sell your point as being factual and not purely "because I think so" opinion.
*shrug* I mean clearly the reason why the high rises in New Westminster along the Fraser River don't have underground parking is entirely because the rail yards are ugly. Clearly.
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Here we go again.
Building Codes do not dictate above ground / underground construction. If anything, that would be something a municipal government would try to do through their zoning by-law. Delta is one municipality that i have never worked with on a project. But I have with Richmond, New Westminster and the City of Vancouver. I mention them for their relevance to the TFN / South Delta situation. There is underground construction in Richmond, though not much. Why? Purely about cost. Foundations in Richmond are financially challenging enough. Talk to a geotechnical and structural engineer about it: you need to generate a lot of friction in the ground (friction piles) beneath a structure to survive an earthquake. And in contradiction to that, you need your structural bearing components to have 'access' to sufficient void space to evacuate water driven by the increased pressures that come with liquefaction. And, there is always the issue of waterproofing any spaces below ground and below the water table . . . which may be the same thing. Projects in Richmond are nowhere near big and profitable to allow for all of this in their budget / pro-forma.
They have taken care of all of these issues on a few projects in Vancouver. Vancouver House, though its excavation may be below the False Creek tideline, it is in solid ground. I don't see any special measures in the photos to deal with ground water. The towers between Main and Quebec Streets beside False Creek are a different matter. They are on the crappy fill of the False Creek Flats. While its not analagous, they are similar in many ways. For them, the excavated within a coffer dam, and then built a giant raft foundation, like a tub, in which the underground floors and tower foundations were constructed. That cost a lot.
There is an interesting case in New Westminster. The foundations for the Stewardson Way overpasses use giant hollow friction piles (steel, I think) which are perforated. Inside those, the constructed concrete post which transfer their load to the friction piles at the bottom. The posts are smaller than the inside diameter of the steel piles. The space between was carefully filled with crushed rock, such that the posts get the support they need, and the water has a place to go so the soil drains fast enough to either prevent or minimize the degree of liquefaction. That's a situation similar to Richmond and the rest of the delta.
The only reason New West has all that parking above ground, ruining its streetscapes, is money. The developers will do anything to save the costs of going underground. And the City is so stupid, that they allow themselves to be bullied because they fear no one would build there if they didn't allow it. So it is worked out, project by project, through development permit negotiations, in which the City gets a bit from the developers for their self-respect, and the developers end up with exactly what they, in private, targeted in the first place. Ta Da!
Please, no fights this time jhausner.