“The life expectancy of the bridges cannot be determined at this time, as the actual construction of the foundations is unknown,” says a report by TranSystems, a consultant the county hired to review the extent of the bridge damage.

To Stearns and other critics, including County Commissioner Juan C. Zapata, who requested the report, that assessment raised alarms.

“If it’s unknown, why don’t we just wait ’til we know?” Zapata said. “We know more about the atmosphere in Mars than what’s in the substructure of that bridge.”

If the foundations’ lifespan is in doubt, the county should consider temporarily reinforcing the bridge and building an entirely new one, says Stearns, a Sony Open attorney who says he has been campaigning for a new bridge on his own and not on behalf of the tournament. He has created a website, SaveRickenbacker.com.

He’s not the only one questioning the plan. Of the five firms that initially qualified to bid for the project, two of them — Condotte America and the de Moya Group — dropped out. That’s not unusual.

But in an email obtained by The Miami Herald, Andres G. Mendoza, Condotte’s executive vice president, told colleagues that “satisfying the requirements of the project proved to be difficult.”

The bid parameters and county staffers’ answers to questions about the project “were too risky to jeopardize the reputation of my company,” he wrote. “Should the County issue a modified and reasonable criteria package, I would not hesitate in teaming with you all once again.” Mendoza did not respond to Herald requests for comment.

Two other engineers from firms associated with the bids — who spoke to The Herald on condition of anonymity because participants are banned by county rules from discussing bid details before they are made public — said they too have misgivings.

One called the county’s 300-day repair schedule “impractical and impossible” and the proposed fix “poorly thought out.” The other called it “a horrible project for the county.”

Gimenez has dismissed complaints from critics who decline to be identified, noting that county engineers and their consultant have signed their names to their reports.

Of the three firms still in the running for the project — GLF Construction, Kiewit Infrastructure and Munilla Construction Management — one also questioned the county’s proposed schedule for the project.

GLF Construction wrote in its technical bid that while the timeframe would work for the bridge repairs, expanding the bridge for cyclists and pedestrians may take longer because it requires new pilings and lanes that may not qualify for emergency permits.

“[B]ased on our extensive knowledge of the regulatory process, environmental permits and the scope of the additional work, the widening portions of the project cannot be designed, permitted and constructed within the 300 calendar days,” the bid says.

Stearns, for his part, wants the county to bolt steel plates to the bridge’s corroded beams — a fix referred to as bracing — to reinforce the structure and give Miami-Dade time to build a new one. According to the county, a new bridge could take seven to 10 years to complete.

Under regular circumstances, the report from Miami-Dade’s consultant said, bracing could cost $7.8 million and last 15 to 20 years, but that estimate came with serious caveats. The bracing would address only severely damaged locations of the bridge, leaving the rest of the structure to continue to deteriorate, causing new problems in “as little as five years” — likely before a new bridge could be completed.