It's a style of building that was very popular doing the boom in Silicon Valley during the 80's and early 90's. Construction crews would pour the walls into molds, let them dry, and then literally tilt them up and put a roof on them.

It was weird to drive through parts of the Silicon Valley (e.g., North 1st St.) finding buildings had been tilted up in what had been flat land the week before.

Quite a few of those buildings are empty now.

Blank linked the word to http://www.tiltup.com/ (maybe after initial reader confusion) to provide context.

Looks to me like the miles and miles of low-rise office parks in Silicon Valley include lots of 'tilt-up' concrete-slab construction.