Van Wezel flooding highlights repurposing engineering study

Flooding from Hurricane Milton has supplied added perspective to the Purple Ribbon Committee’s task of making a recommendation to repurpose the Van Wezel Performing Arts Hall. 

The timing of storm surge flooding from Sarasota Bay from Hurricane Milton that permeated the lower, non-public levels of the building and into the Grand Foyer has given Karins Engineering a case study as it continues to prepare its report on the structural stability of the building for a potential variety of future uses.

David Karins updated the committee on his company’s work to assess the viability for long-term use absent any improvements needed for the short-term should a new Sarasota Performing Arts Hall be built, nor what the Van Wezel’s future use should be. However, water intrusion damage that has been estimated at costing $7 million to $10 million to mitigate may cast the long-term investment value into question.

“We can look at it and say, ‘Okay, we're going to spend $80 million to save the building from an event that might happen five times in a millennium, or might happen five times in a decade,’ Karins told the committee. “You just don't know. Ultimately, we'll make recommendations, but it will be out of our hands on what's the best way to go.”

Karins’ comment was only a for-instance. For now, there has been no figure attached to whatever work the Van Wezel might need for future use. That will come in a final report that will be used as the basis for the committee’s recommendation to the City Commission. What is known for certain, though, is the sea-level building just feet from the edge of Sarasota Bay with significant utility functions located below the water table leave it vulnerable to storm surge.

Preliminary assessments are the building is on solid footing. The roof took only minor damage from the eye of Category 3 hurricane passing overhead, and its dead and active weight load capacities are sufficient for most alternative uses short of a monster truck rally.

Committee member David Rovine asked Karins to describe the scope of his firm’s work, “because part of our mission is to consider alternate uses of the building,” he said. “On the other hand, regardless of what happens with the new theater, this theater has to function as a theater for X amount of years so that Sarasota doesn't fall out of the routing of all the shows that are critical to come to the theater.”

He asked Karins whether the report will consider protecting the building for three to five years to function as it does today and for however it may, or may not, be repurposed.

“Our primary charge is preserving the building for whatever might be inside of it,” Karins said. “The other part is what's the functionality of the building? So we're looking at how does it function for what it does, and the consultants are having a little bit of creative fun saying what could it also be. But that's really not in the core of what we've been hired to do. 

“Once we're done with our work, we'll tell you this can be done to preserve it for 10 or 50 or however many years you want to.”

That analysis will include long-term recurring costs of maintenance and strategies to protect the Van Wezel from future flood events. Those can include installation of resilient materials, which would be required under FEMA policy should the cost of any retrofitting exceed 50% of the value of the building. 

If so, FEMA requires:

• Elevating the structure to above flood level.
• Using flood-resistant materials.
• Proper flood venting.
• Replacing structural elements like bearing walls, tie beams, and trusses.
• Replacing interior finish elements like tiling, linoleum, stone, or carpet.
• Replacing utility and service equipment such as HVAC.

“We're looking at evaluating how the building compares to the current design philosophies and codes for flood,” Karins said. “It is a non-conforming building in that it is not elevated to minimum flood requirements or dry waterproofed to mitigate water getting into the building. And it's certainly not designed to be wet floodproof, which means you let the water run through the building and it doesn't hurt anything.”

Karins described Milton as the perfect storm to imperil the Van Wezel in that the wind came from the north, elevating the storm surge in Sarasota Bay to 6.5 feet. The sun-driven three-foot waves on top of that moved thousand-pond boulders into the Van Wezel Parking lot and pushed water into a ramp down to kitchen doors where it penetrated the building.

The intrusion, Van Wezel Executive Director Mary Bensel told the committee earlier in the meeting, did not enter the Grand Foyer through the multiple glass doors that overlook the bay. 

The path, wind direction and storm surge of Milton was unique to Sarasota, something that may never happen again or could happen next year. 

Helene was an example of a still water flood, the effect of storm surge plus astronomical tide that raises the water level gradually. Because of the wind direction and speed, Milton exacerbated the storm surge with a wave flood.

“The main issue with Milton was that the breakwater wasn't stout enough to absorb the wave energy,” Karins said. “One thing that we're working on a recommendation for is looking at putting in a more substantial energy absorption device. If we're going to be designing mitigation for still water floods, we have to get rid of the waves, and that's going to be a pretty heavy lift.”