Basement Slab design 2

[Iasonasx]

Looking for suggestions on what I can refer to on this. I had no luck finding something specific in the ACI 318-14. I am somewhat concerned actually about the possibility of moisture pressure, especially when it rains and water pushes through a basement. The specific one has this so-called "French Drain." The plan is to deepen the basement and insulate it to work like the reverse of a pool, essentially keeping all the water out even if the water reaches above the level of the basement floor, without lifting the building.
Thanks

 

[DaveAtkins]

You should design the slab for the hydrostatic uplift, using a load factor of 1.6. You will probably need to reinforce the slab more heavily than a typical slab-on-grade, as it will be spanning from wall to wall--sort of like an upside down flat plate.

DaveAtkins

 

[Canuck65]

French drains will not do you any good when the static water level is above the basement floor. French drains also need somewhere to drain. If they drain into an interior sump pit, then your basement will flood when the static water level is above the basement floor. When constructed new, foundation slabs and foundation walls are constructed like a water tank, except with the waterproofing on the exterior and no sump pit. This will be very difficult to accomplish an equivalent if you are retrofitting and existing basement via underpinning. Negative pressure side waterproofing is not effective.

Buoyancy is an issue. Often we try to increase dead load of the floor to resist buoyancy, or sometimes we install helical piles that will resist uplift. There are many variables.