By Dan Klepal
The Cincinnati Enquirer

The big bang or the big ball?

That's the question facing construction managers building Great American Ball Park, who have to decide in the coming weeks how to destroy Cinergy Field - either in an imploded heap, using nitroglycerin, or piece by piece, using a wrecking ball.

Mike Sieving, construction executive for Hamilton County, said they are closer than ever to picking implosion, and the decision could be made in the next two weeks. If the 33-year-old stadium is wrecked by explosive charges, it will happen at 8 a.m. Dec.29 and surly will become a huge event drawing thousands of people.

"Basically, we're down to two issues: making sure the contractor has all the insurance in place ($30 million worth) and getting the final reports back from our engineers and geo-technical engineers on what they believe the impact of the implosion would be," Sieving said. "We believe the permitting process is going pretty well. The agencies have been very favorable and supportive in all the meetings we've had.

"There is still detail work that has to be done, but they haven't found any poison bullets yet."

Here's how the implosion would work:

The stadium would be stripped to its load-bearing walls. All seats, walls, floor tiles, pipes and canopy would be removed before the implosion happens.

Then between 1,200 and 1,500 1-pound explosive charges would be placed in the stadium's concrete support columns, each with about a quarter-second delay. The charges would be wrapped in fabric material and chain-link fence to reduce the amount of flying debris.

The explosions would start in the northwest corner of the stadium and move in a counter-clockwise rotation, with the inner most columns being blown first - bottom to top - and moving outward. That sequence would force the stadium to fall inward.

In all, it would take about 38 seconds to reduce the stadium to rubble.

The trick is doing all that without causing damage to the new stadium next door, the Roebling Suspension Bridge, Fort Washington Way or any of the other nearby buildings.

Mike O'Rourke, president of demolition contractor O'Rourke Wrecking Co. of Cincinnati, has said he is confident implosion would be safe.

"The stadium lends itself to explosives, as opposed to a high-rise building, which would fall much faster in a much smaller area," O'Rourke said. "In this case, because the (stadium's) footprint is so large and the charges delayed, the force is spread out farther and there is much less vibration."

Construction managers are actually more concerned about the rush of air the falling concrete giant will create than any flying debris or vibrations from the explosions. But even that seems manageable to project manager Arnie Rosenberg, of Parsons Brinckerhoff.

"We believe implosion is a reasonable approach," Rosenberg said. "We're knocking each of the bowling pins down one by one and getting closer to a final decision."

Early tests indicated only 25 percent of the allowable level of vibrations would be caused by the event. Still, the county is waiting on the report from its geo-technical consultants and seismologists.

"That is what they predict will happen, and we can translate that into a seismic value that we can then relate to building structural forces," Sieving said. "They've done that, and now they're analyzing it. We've also involved our structural engineers - the guys who have a long-term interest in Cincinnati - along with our geo-tech people who have done test borings.

"They'll boil all that together in a pot of soup and make a recommendation to me."

There are distinct advantages to implosion:

Not exposing workers to extreme heights for extended periods of time to cut steel.

Reducing the demolition schedule from 12 months to nine months.

Reducing inconveniences, such as dust and noise, by bringing down the stadium in a heap, instead of piece by piece.

Implosion would cost about $5.7 million, as opposed to the $4.5 million original contract for a conventional demolition. But taxpayers would save money in the long run by allowing other projects to proceed more quickly.