Officials said Thursday that decision likely will cost many millions of dollars more because some of the foundations are too short and narrow and must be fixed or replaced.

Officials with the Tampa- Hillsborough County Expressway Authority said this week that the foundations are fundamentally flawed and blamed URS Corp., the company that designed the foundations and served as the authority's general engineering consultant.

Figg Engineering, which designed the elevated lanes, wanted the piers to be sunken about 5 to 10 feet deeper. URS said the extra depth was not needed.

``They said that was over-designing and told us they didn't need to be that long,'' said authority spokeswoman PerryDawn Brown. She said the decision saved $1.8 million.

But an independent consultant determined that many of the foundations, if not all, must be reinforced or replaced.

Authority Executive Director Pat McCue said Wednesday that it could cost as much as $70 million to replace the 193 piers already built. He said Thursday that it is not likely they will all need replacing.

Until additional soil and load tests are done, the authority won't be certain how many need to be fixed and how many should be replaced.

McCue said he had to limit his comments because of potential lawsuits.

He said the authority is preparing a letter notifying URS of its concerns. It could be sent today. URS will have seven days to respond.

URS has declined to comment, citing potential litigation. An independent foundation expert, hired after one pier sank 11 feet in April and another dropped 1.3 inches in July, detected the design flaw.

Reporter Tom Brennan can be reached at (813) 657-4528.