Quote:
Originally Posted by Calgarian
This is crazy to me, strip and pad footings are good for up to 5 or 6 storeys here, but a house needs a 20m friction pile in Winnipeg. Saskatchewan is slightly better from my limited experience, but still requires heavy use of piles.
What do you guys do for tower foundations here, friction piles under a raft slab?
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20m - hopefully you meant 20-feet...
But yes for a house a friction pile (16" dia.) would typically be between 20 and 30 feet long, depending on the load and if it's subject to frost.
Bigger buildings are mostly on driven pre-cast concrete piles.
That's usually good for residential midrises (up to 10 storeys).
Beyond that or for really heavy loads, like Biff said, it's rock-socket caissons drilled into the bedrock. The sky is the limit for that type of foundation.
Raft slabs make me nervous (i.e. like what's under the Bow)...it's like wedging sandbags along the base of a post and calling it a day. Obviously it works, but it's not something familiar around these parts.