I was describing a "family" of very similar flooring systems.
Some use trusses embedded in a concrete base to carry the "fillers" before the concrete was cast to tie everything together and top the system that usually had wire mesh or light steel.
The other common systems in the same "family" used slender, usually prestressed, beams also made or cut for the spans that support the fillers.
Both systems are supported prior to concrete placement, so the system of separate elements acts as a unit after curing and the supports are removed.
isshvaaag -
You are right the truss system is very common in Spain. Our sister company (I worked for the managing partner company) made special block fillers for projects in southern Spain and also worked closely with several other Spanish manufacturers and I got "dragged"(LOL) into providing technical assistance and visited many projects from Seville to Valencia and south to the coast. I never saw "gypsum" used in the construction, but it could possibly used in some way. For the residential units we built in Marbella, we used a high slump concrete to insure full bond between the beams/trusses and the fillers (pumped with small portable pumps) and cycled the placement in a group of units and followed immediately with a stiffer layer of concrete after the first layer had consolidated somewhat, but still was able to be vibrated into the first layer. This is very similar to the usual masonry grouting methods that allow the wet materials where the excess moisture is absorbed by the drier materials (fillers and possibly beams) to increase density and bond before a final layer to final lift/layer is completed. Timing of the layers was critical, especially in the hot Spanish sun during the hot season. - It was not a fully engineered process since most floor filler systems internationally are based on engineering and tradition, common sense backed with past performance. Visiting Spain at least 4 times (4-5 days) a year for 15 years was a perk for being the only engineer available that enjoyed the country and people that could meet with engineers, contractors, accounting firms and be a return courier, so I always scheduled my trips over a week-end so allow me to go to see "Toro" on Sunday. Fortunately, a later job allowed me to return to Spain frequently to see old friends and keep reasonably current on changes and compare the systems that were used in northern and eastern parts of Europe.
Dick
Engineer and international traveler interested in construction techniques, problems and proper design.