This work-in-progress shot shows a bit of a surprise: These racks are being installed on epoxy-painted concrete floors, which protects against electrostatic discharge. What happened to raised floors? When you eliminate air cooling and under-floor cables, you also remove the need for space under the floor.
One major benefit to putting racks directly on the epoxied concrete floor is the ability to access overhead cables and other infrastructure without removing tiles or shifting equipment.
The only part of this facility with a raised access floor -- entirely for airflow -- is the second floor, where office and conference spaces reside.