Have a look to the assembling of the data center roof for the new Swiss National Supercomputing Centre (CSCS) in Lugano.
In the movie (see here below) you can see the positioning of the roof beams for the new machine room. Each roof beam is 35 meters long and weights 50 tons.The machine room will offer a surface of about 2’000 square meters without pillars to host the supercomputers.
The mobile crane used is the largest worldwide and can lift up to 1200 tons. The crane itself weights about 380 tons.