WATCH: Slicing apart Union Terminal

Posted at 12:48 AM, Feb 25, 2016
and last updated 2016-02-25 01:18:25-05

CINCINNATI -- How do you even begin to renovate a building that's 83 years old, wasn't built exactly to specification and has undergone at least three major changes?

Lasers. That's how.

Hamilton County voters approved a temporary sales tax in 2014 to fund massive repairs to Union Terminal. The quarter-cent sales tax increase, which expires after five years, is expected to raise $170 million to fund massive repairs to the art deco train station that houses the Cincinnati Museum Center.

But before anybody can start fixing it, they've got to know what they're dealing with. And that's why the building's history is so important.

Watch a video that slices the building into cross sections:

Construction on Union Terminal started in 1929, which wasn't a great year to start construction on much of anything. The Great Depression put a strain on pretty much everybody's financing, so, instead of being a train terminal in the classical style, architects turned to the more economical art deco style we all know and love today.

More adjustments were made during construction, meaning there were "notable differences between the blueprints and the finished building," according to Museum Center spokesman Cody Hefner.

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“It may be a bit of a surprise to some, but not all buildings are actually built according to the original plans and specifications," Turner Construction project executive Bob Grace said. "Union Terminal is no exception."

The whole complex originally had 22 distinct buildings, requiring nearly 225,000 cubic yards of concrete, 100,500 square yards of paving, 8,250,000 bricks, and 45,421 net tons of steel to build.

Inside the rotunda, Christmas 1945

Cincinnati, ever behind the times, finished its train terminal just as air travel was taking off. It got a good amount of use in World War II, as men left to serve their country. But, by the late 1950s, the Union Terminal Company was already looking for other uses for the massive building.

In 1972, passenger train traffic had ceased, and most of Union Terminal's concourse was demolished a short time later to make way for larger freight in the train yard.

More alterations came in 1980, when Union Terminal briefly became a shopping mall. Just four years later, most tenants had moved out.

Then in 1990, the Cincinnati Museum Center moved in, and Union Terminal had even more changes to house the new exhibits and artifacts.

Which brings us to today's work to fix the crumbling behemoth.

To save architects and engineers time, Cincinnati's Truescan 3D spent three months setting up and processing 2,000 individual laser scan stations throughout the inside and outside of Union Terminal.

Each scan produced up to 100 million data points; the building's iconic rotunda and concourse alone resulted in a total of 4.3 billion data points.

In all, more than 600,000 square feet of building measurement data was collected, resulting in more than two terabytes of data.

The laser measurements are accurate to 1/16 of an inch and include detail on Union Terminal's mechanical systems, structural components and architectural components, Hefner said.

From the laser scans, Truescan3D created highly accurate 3D renderings of the building, to help GBBN Architects and Turner Construction with their renovation work.

Click here to see a panorama of the steel structure.

Click here for a panorama of Union Terminal's iconic rotunda.