"complex building" is a perfectly correct and usable part of a sentence in written English.
You could use it to describe a large structure with many parts, e.g. "The complex building had over 300 rooms on 8 levels."
The most complex building, the Taj Hotel, with its many passageways, took the longest to clear.
His hero was in New York, struggling with his UN complex building.
The mass of a complex building is differently composed from every point of view.
"Beauvais is the largest, most complex building ever to be scanned," said Stephen Murray, the Columbia architectural historian in charge of the project.
He also denied any responsibility for the budget overspend and said the construction costs per seat were comparable to other complex building projects.
HUNTERDON COUNTY FLEMINGTON County Utilities Authority, April 25 at 2 45 p.m. Hunterdon County Main Street Complex, Building 1, 71 Main Street.
"This is a complex building, but we wanted it to feel natural and relaxed as well as easy to get around.
This is a richly complex building, a thing of compound curves, stainless steel fronds, leaves and petals, wrapped over and around an intriguingly customised steel frame, the whole caboodle occupying an entire city block.
Sure, the release of Little Big Planet brought homebrew game development possibilities to the mainstream, but designers-to-be must own a PlayStation 3, the game, substantial time and the controller skills to use the complex building system to create a platform game reality.
A It's a very complex building because: A) the sheer size of it; B) where it sits, which is basically on a postage-stamp location and it goes straight up; and C) there's so much happening around and under it, including the PATH, the subway and the retail.
Complex building configurations must be schematised to their main dimensions.
