Just a thought.... Its the reinforcing steel design that does all the support work. The pre-cast concrete just holds the rebar in place.
As a construction managment group (on Google Earth map it is called 200 Villas), we built an 10 x 10 kilometer city from the gound up out of precast elements e.g. floors, walls and ceilings. It was like a gaint gigsaw puzzel. Took 4 years to design ( 4 US A&E contractors) and 5 - 6 years to build. 2 onsite precast plants, curing yards and a computer run concrete batch plant and a paver plant.
We had about 25 prime contractors, several hundred subcontractors and a 10,000 labor force man camp. The design elements were a power plant, water collection system and water treatment plant, sewage treatment plant, all underground utilities, all roads pavements and walkways included a 300 bed hospital, doctors and nurses quarters, family housing and schools, workers offices and command buildings, central mosque and airfield with hardend shelters and refueling systems,
For fun: Google Earth use coordinates: 27° 58' 55.07" N 45° 32' 40.64" East