TAMPA — Without warning, a 9-ton concrete panel broke off the David A. Straz Jr. Center for the Performing Arts last month and fell 30 feet into a flower bed.
The panel — about 25 feet long, 5 feet high and 1 foot thick — fell from the third level of the 27-year-old city-owned building about 2 p.m. Dec. 12. It came loose from the west side of the building, facing the Hillsborough River, and landed outside the lobby for the Carol Morsani Hall.
No one was hurt, but the falling panel sliced lengthwise down the trunk of a palm tree and broke a ground-floor plate glass window.
"A freakish happenstance," said Straz Center chief operating officer Lorrin Shepard, who said the center had no indication the panel was at risk of coming loose.
Nothing similar had happened before.
"It was shocking because there was nothing we could relate it to," Straz Center president and CEO Judith Lisi said Tuesday. Over the course of a year, "we have a few hundred thousand people here. I just thank God — thank God a million times — that it was at that time of day and it was a flower bed."
The panel was not necessary to the structural integrity of the building. It did not support or protect any other part of the building but was a more decorative or ornamental element.
After an inspection that day by engineers from the Tampa office of Walter P. Moore and Associates, the patio and the neighboring part of the lobby inside the building were cordoned off.
By about 4 p.m. that day, engineers told the center's administration that the building was safe for two shows to go on that night, including the Radio City Christmas Spectacular starring the Rockettes.
Had the engineers said otherwise, Lisi said, the shows would have been canceled.
"It's safety first here," she said. The center routinely works with insurers on inspections to ensure that rigging suspended inside its performance halls is safe and secure.
The patio next to the flower bed where the panel landed remained cordoned off until about a week and a half ago while the panel was removed and steel cables were used to secure the remaining ones to the building as a precaution and temporary measure.
In a 10-page report, the engineering firm said the panel was attached at its four corners to two short wall-like structures, known as corbels, that protrude from the building. Suspended several feet from the wall, they are known as flying panels.
One of the corbels, on the north, had "weathered concrete at certain locations along its cracked surface," leading engineers to believe that that connection most likely gave way first.
"We believe the existing flying panels in the immediate area are now secure," engineers Richard Temple and Stephen Blumenbaum wrote Dec. 17. "We recommend a visual observation of all the panels on the building take place as soon as possible, and that permanent connections be designed and installed."
The engineers raised the idea of using X-ray imaging or taking cores from the concrete to be analyzed.
"Such measures could provide more thorough and accurate documentation of the existing conditions, particularly because we are not aware of any drawings documenting this area," they wrote.
In the long run, they recommend adding permanent connections to those already in place, possibly through the use of steel clips. Similar clips are already used to secure some pre-cast concrete panels on the center's roof.
The Straz Center has paid $35,000 to $40,000 so far to clean up, secure, study and install the cable reinforcements to the remaining panels. It also has filed a claim with City Hall because the building is owned and insured by the city of Tampa.
So far, Lisi and city officials say, no decisions have been made about what the city's insurance could cover, who would pay any deductible, or other similar issues.
"I don't think a determination has been made about what we do moving forward," City Attorney Julia Mandell said. "We want to be good partners with them."
Under the city's lease with the Straz Center, a nonprofit organization, the center pays the city $100 a year in rent, Mandell said.
In addition, the city this year allocated $586,750 to the Straz Center. Its five-year capital projects plan includes $275,000 for Straz Center improvements, with funds coming from special events fees paid at the William F. Poe Parking Garage.
While the city owns the building, Mandell said the city doesn't have any obligation to repair or perform maintenance on it.
"Basic maintenance," Lisi said. "This, I would say, is beyond regular maintenance and upkeep" and arises from conditions that go back to "when the building was constructed."
When it opened in 1987, a year behind schedule, the center was celebrated as the largest performing arts complex south of Washington, D.C.'s, Kennedy Center.
In 1988, the contractor on the project, Great Southwest Corp., sued the city, claiming the center's design caused a delay and $17.8 million in cost overruns.
(To pay for the center's construction, patrons of the arts raised $21.5 million privately and the city issued $38.5 million in general-revenue bonds.)
In 1991, the city and Great Southwest settled the case for $3.2 million. That came on top of $6.2 million the city's insurance company paid the contractor.
The center originally was known as the Tampa Bay Performing Arts Center, but was renamed for banker and philanthropist David A. Straz Jr. as the result of a gift in 2009 that the Tampa Bay Times reported was probably around $25 million.