OK, reading the info from the google book link above, it looks to me that hollow floor is synonymous with suspended floor. The actual method of construction really kind of describes how we in the Northeast US would build a traditional wood floor on joists over a foundation.
The Figure 1.2 shows a frame for a wood floor slightly elevated over the concrete slab. Some builders would do this in order to put a wood floor in a basement or over a slab. You can't put the wood flooring directly on the concrete - too much moisture.
This puzzled me too.