What size concrete slab can hold 90,000 lbs?

There are two ways to look at this:

1. A surface that needs to hold something like a 90,000lb vehicle rolling along. Or.
2. A 90,000lb concentrated load coming down such as a column.

For the first scenario, you need something like 8″-12″ thick reinforced concrete. Conditions below the slab generally define the difference.

For the second scenario, you probably don’t want the slab supporting this load. You really want a pad footing designed for this.