Re:New Orleans levees passed their first major test
by 8note on Sunday September 05, 2021 @11:21PM
(#28429906)
Does having poor soil mean New Orleans buildings are designed better? Or does New Orleans suffer from both bad soil and designs?
Re:New Orleans levees passed their first major test
by beerandt on Monday September 06, 2021 @02:15AM
(#28430946)
It just means everything gets built on piles, so there's a lot of local experience.
I wouldn't say better, because there are/were multiple skyscrapers with chunks of facade falling off them. At least a couple are abandoned because they were built so bad.
But they're not sinking.
Re:New Orleans levees passed their first major test
by dylan604 on Sunday September 05, 2021 @06:06PM
(#28428253)
>or more typically until they hit the first layer of sand, which is stable.
I think this is the first time I have ever seen someone claim that a layer of sand is stable. But hey, NOLA is one of the craziest places, so sure, sand is stable there.
Re:New Orleans levees passed their first major test
by beerandt on Sunday September 05, 2021 @08:58PM
(#28429240)
We're not talking about a beach here.
Sand underground with overburden pressure is quite stable, to the point that piles driven to it are treated as bearing piles (supported primarily on the end/tip), not friction piles (supported on sides by friction).
It's non-cohesive, so doesn't shrink or swell, and once it's compacted/consolidated, it's fixed volume and quite stable.
The problem strata in New Orleans is the top 10-20' of soil. Mostly whatever's above the pumped-down, controlled, water table.
Piles only need to go that deep to suffice, or more typically until they hit the first layer of sand, which is stable. Literally every slab house built in New Orleans is built in these, because before this, everything was on blocks so it could constantly be raised and leveled.