Stadium report reveals risks

The planned site for a baseball stadium shows potential for sinkholes, which is not surprising, says a city official.

By DEBORAH O'NEIL

© St. Petersburg Times, published February 2, 2001

CLEARWATER -- A study of the 32-acre site where the city and the Philadelphia Phillies want to build a $22-million baseball stadium shows sinkholes could develop there.

The report suggests the risk can be minimized with measures that city officials say could add to the cost of the project.

Overall, the geological analysis given to the city this week by Qore Inc. of Tampa contains no surprises, said Keith Ashby, Clearwater's general services administrator who is overseeing the new stadium.

"What we found is completely normal for the area," Ashby said. "A lot of buildings in Clearwater have been built on limestone that has strong parts to it and weak parts to it. The report tells me we can go forward, but we have to do due diligence and reinforce where necessary."

The site at the corner of Drew Street and Old Coachman Road was given to the city by St. Petersburg Junior College. In the 1950s and early 1960s, the land was used as a Pinellas County landfill. A separate study completed last year determined the land is free of environmental problems.

In the latest study, engineers spent eight days in January drilling into the ground to examine whether it was prone to sinkholes or had existing underground cavities and whether it could support a stadium.

Small cavities were found around the property; but there was only one cavity within the footprint of the stadium, in the southeast corner of the site. The 6-foot cavity is about 118 feet underground. Ashby said the more studies will be done of that area.

The study concluded that the site, like much of the surrounding area, has a limestone bedrock that is susceptible to the creation of cavities and sinkholes; therefore, anything built on it runs the risk of being affected by the ground sinking, according to the study.

"The possibility exists for sinkhole development at this site," the study says. "It is not possible to investigate or design to completely eliminate the possibility of future sinkhole related problems but with proper remedial measures the risk can be greatly reduced. In any event the owner must understand and accept this risk."

Ashby said sinkholes are a problem all over Tampa Bay.

"It's a question of how you deal with them, how big they are," he said. "What we have is nothing that scares us size-wise, and we have the capacity technologically to deal with them."

The solutions offered in the study are complex. They include reinforcing the ground by injecting a concretelike material into the cavities under high pressure to fill them and compress any soft soil.

Also, to avoid the decay of material in the landfill -- which could cause the land to shift -- some of the landfill could be excavated. Then, it would be refilled with a more compactible material.

Some preventive measures could be taken with the stadium itself by creating an underground foundation for it, according to the study. The stadium could be supported by steel pipes filled with concrete or large pilings buried underground.

No one knows yet what these measures will cost. It will be up to the Phillies to analyze and find the costs of the different alternatives, Ashby said. A Phillies representative could not be reached Thursday.

"I would think it's a fair statement to say there may be some increased cost," Ashby said. "If it is cost-prohibitive, we're not going to do it. If it's within the budget of the project, we'll do it."

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