June 12, 2008 - Today we launch a new feature that dissects and describes newsworthy feats and phenomena.

To casual observers, the Trump International Hotel & Tower may resemble many a skyscraper in the making. But in reality, the 92-story building encompasses two worlds--a 339-room hotel with its restaurant and bar in one, and a 486-unit condominium construction site atop the hotel in the other.

"As far as we know, it's the largest building under construction while part of it is open," says Pauline Saliga, director of the Chicago-based Society of Architectural Historians. "The Blue Cross-Blue Shield building [now being expanded] is another example, but Trump Tower is enormous." The 31-story MoMo building at State and Randolph Streets--future home to the Joffrey Ballet and current site of a Loehmann's store--also illustrates this trend.

Here's how Trump Tower, scheduled for a spring 2009 completion, keeps adding floors with its doors wide open.

Make no little plans. Before groundbreaking, Donald Trump knew he wanted to open his hotel before the condos on floors 29-89, largely to offset construction debt. "So we went through a huge list of items we'd have to solve or be aware of," says Tower architect Adrian Smith. Those ran from erecting ultra-secure scaffolding at the hotel entrance to keeping phone and electrical lines for the hotel separate from unfinished residences.

Smith also had to plan for building lobbies early rather than later in the game: "Typically, lobby levels are the last to be completed."

The ground floor. Separating hotel guests and hard hats minimizes disturbance. With up to 700 workers on site, "You have to set boundaries," says Trump construction supervisor Pat Leech. "Hotel guests come through the front, and the construction crew comes in through a separate entrance. They never really see each other."

Silence stories. You only need two stories between construction and open building floors to minimize noise, Smith says. Trump Tower went further; when the hotel's first five floors opened Jan. 30, the nearest construction was on the 62nd floor. That's 40-plus stories away, says Trump vice president T. Colm O'Callaghan: "There was a big gap between us and the heavy lifting, and that worked in our favor."

With workers on the 79th floor as of mid-May, Trump's cranes and hammers leave no sonic trace in the new Rebar lounge and bar, which seats 125, or the 14th-floor indoor pool, even with its reverberant tile. Incline your ear and you won't hear a thing, or see telltale ripples on the water from heavy equipment. There's no evidence of building motion or shock, either; O'Callaghan points out that those conditions, if they existed, would create disruptions in the hotel spa's relaxation rooms.

Cream of the cranes. From the hotel's Sixteen restaurant, you'll see cranes hoisting heavy loads just inches from the still-closed outdoor balcony--but you won't hear them. Leech uses German Liebherr cranes, which he compares to driving a Mercedes. Each can haul 15 tons, and it only takes two of these finely tuned, quiet machines to cover Trump Tower's footprint. Plus, they're positioned on the opposite side of the building's hotel entrance (as are the equipment hoists) to remain unobtrusive.

Crowning achievement. Smith predicts the lessons learned from opening Trump under construction will have an impact on Chicago skyscraper projects for decades. Now designing four buildings surpassing 100 stories in the Middle East, "I'm talking to developers to make sure they're occupied before they are finished--and I'm bringing my experience from Trump to all of them," Smith said.

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