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A three-story parking garage used by hundreds daily in the heart of downtown is now closed due to structural safety issues — another expensive casualty of rusted innards caused by salt and water.
The Wentworth Garage — a 500-space downtown landing spot for tourists, hungry locals and College of Charleston students — is among 13 on the peninsula that an engineer warned the city and the college in 2018 were in need of more than $3 million in immediate repairs.
Those repairs didn’t happen, and problems at the Wentworth Garage worsened to the point that it was deemed unsafe to keep it open, officials said.
What’s more, all of the others had clear early signs of the wear and tear from salt and water that, without repairs, can lead to closure or collapse: Rusting steel, exposed rebar or cracked concrete.
“(Corrosion) is a very rapid acceleration once it starts … It might take 20 to 30 years to start but once it does, it might only take five or 10 years to affect the structural integrity of a building,” said Paul Vinik, a Florida-based engineer and corrosion expert.
The Wentworth Garage was built in 1982, making it the second-oldest city-supported parking deck in use. The oldest was built in 1979.
Engineers had initially estimated in 2018 that $11 million in repair work was needed to the network of garages by 2028. It’s unclear if — or by how much — that estimate has increased due to delays in maintenance.
By the time construction crews arrived to repair Wentworth in June 2022, they discovered corrosion of the structure’s steel support system had spread too far to keep the garage open. The garage, located on city-owned property, is owned by the College of Charleston. The city has overseen minor repairs through the years, but the college agreed in 2018 to take responsibility for the major rehab the garage needed.
Now the garage sits in limbo while the college determines whether the structure can be salvaged after decades of deterioration in the harsh coastal environment. Salt speeds up the rusting process, which can threaten a structure’s stability if left untreated.
The worst-case scenario played out in Florida two summers ago when the Champlain Towers condominium caved in, killing 98 people. The collapse sparked concerns about tall structures standing near the beach.
Ninety miles up the South Carolina coast from Charleston, the 22-story Renaissance Tower in Horry County remains unoccupied after an emergency evacuation in October triggered by dangerously damaged concrete and steel. The Post and Courier previously identified hundreds more high-rises close enough to the South Carolina coast to be at higher risk of damage as they age in places where where salt travels in the air and water.
Using the same method — mapping elevator permits in coastal storm surge zones — the paper found more than 60 parking garages along the coastline, clustered almost exclusively in Charleston and Myrtle Beach. They’re a mix of public decks and private ones for hotels or hospitals.
New wedges, which serve as anchors for steel supports, are compared to corroded wedges from the Wentworth Garage in an engineering firm’s report. Wiss, Janney, Elstner Associates Inc./Provided
More than a dozen are at least 30 years old, and two dozen more have stood for 20 years.
Experts say parking garages are particularly vulnerable because of their exposure to the elements.
“One aspect is the sheer surface area,” corrosion expert Vinik said. “A parking garage is usually many layers and its not enclosed.”
Often, the extent of the damage can be difficult to detect. Rust so severe that some connective pieces had disintegrated wasn’t apparent at Renaissance Tower until workers got a clear view inside its supports.
Wentworth shares a similar story, with workers finding conditions worse than they expected as they started other repair work.
And it was doomed from day one, built in a way now known to allow moisture intrusion and stability problems.
In a new report commissioned by the college and completed in September, engineering firm Wiss, Janney, Elstner Associates, or WJE, found that corrosion among the steel support system of the Wentworth garage was severe enough to warrant shutting the parking structure down. The inspection only looked at portions of the garage so the report called for a more detailed look at the structure before determining whether it is better to repair it or tear it down.
“Hopefully, they’re lucky. But if the stats so far are confirmed, then that becomes a more expensive job,” said Fabio Matta, a University of South Carolina associate engineering professor who reviewed the report at the request of The Post and Courier. “In theory, not all hope is lost. But it’s a serious situation.”
Images from an engineering firm’s report detail some of the damage to the Wentworth Garage. Saltwater has caused the steep support system of the garage to corrode and break through concrete. Wiss, Janney, Elstner Associates Inc./Provided
What went wrong at Wentworth
In 2018, the city of Charleston commissioned a report on all 12 city-owned garages in addition to the Wentworth Garage. Only one garage was reported in “good” condition. The rest fell somewhere between “poor” and “fair to good.” The report identified $7 million in repairs needed across all of the structures by the end of 2023 and an additional $4 million needed by 2028.
That hasn’t happened.
At another parking deck, the 20-year-old aquarium garage, cracks in the concrete and exposed rebar remain today. So do cracks and gaps around the elevator shafts that can allow salty, moist air and water to infiltrate the structure. Duct tape holds the elevator button panel to the wall on the fourth floor.
“The exposed steel is rusting, which will cause further deterioration,” the report notes of the garage that’s newer than all but two in the city’s inventory.
City Council set aside $3.45 million for immediate repairs across all the garages in the city’s 2020 budget, a figure that doesn’t include more than $1 million the college expects to spend on Wentworth.
But the city’s plans were put on hold because of the COVID-19 pandemic. The allocation was struck from the budget and then brought back in 2022.
The college’s plans came too late for Wentworth.
Each floor of the Wentworth garage is supported by 36 concrete beams that run the width of the building. Think of the slats on a bedframe that hold up a mattress. Inside each beam is a twisted rope of steel strands that anchors onto either side of the building, creating tension that helps support the floor above.
Engineers found that water seeping into the center of some of the concrete beams corroded the steel strands enough to leave them completely slack, rendering them useless. In the beam with the worst damage, five out of eight strands had corroded enough to go slack.
Although more work needs to be done to determine the extent of the damage, the presence of any corrosion at all is cause for alarm, Vinik said.
When the Wentworth garage was built, it was considered common knowledge in the construction community that concrete was impermeable, Vinik said. But that wasn’t true. Concrete, especially of the quality used at the time, was actually quite porous.
“(Concrete) is more closely related to a sponge, it absorbs moisture and water,” he said. “If that water contains salt and reaches the steel reinforcements, it causes them to corrode.”
While more modern building practices include better quality concrete, stainless steel and alternative materials, coastal communities need to be vigilant about the conditions of older structures, many of which are reaching a breaking point at the same time, Matta said.
Salt water corroded anchors that helped support the Wentworth parking garage. Wiss, Janney, Elstner Associates Inc./Provided
“It’s a daunting issue,” he said. “Previous generations did a lot of work to build infrastructure … perhaps, the new generations have to shift the focus on maintaining, and when they cannot maintain, rebuilding better using new technologies.”
When repair work began, crews alerted the College of Charleston about the extent of the corrosion.
“The garage has not collapsed and likely would not experience a collapse but due to the age and complexity of the structural issues, the College decided to close the structure permanently,” college spokesman Mike Robertson said.
While the garage has not collapsed, Matta said, the conditions listed in the report indicate at least part of it could.
“You don’t have to look at this problem in extremes, meaning will it collapse or will it stay up,” Matta said. “But what can happen is one beam goes down and causes damage and you just have to hope a car is not underneath it.”
Although funding for the city’s repairs is behind the recommended schedule outlined in the 2018 report, none of its garages is facing structural issues as severe as those that forced Wentworth to close, according to the city’s Capital Project’s Team.
A Coastal conundrum
The deadly collapse in Florida prompted a great deal of talk and action surrounding the safety of tall buildings, but parking garages are often left out of that discussion.
Florida lawmakers, for example, passed a bill that required all condos to be recertified after 30 years if they are three stories or taller. Condos within 3 miles of the coast will be recertified at 25 years. Once a condo reaches its recertification date, it must be reinspected every 10 years. That process includes taking a look at condo parking areas, but inspection requirements for standalone garages are rare across the U.S..
The hope is that inspections will prevent tragedy, but they will also save building owners money in the long run. A generally accepted rule of thumb with concrete, known as De Sitter’s Law of Fives, says that repairs cost five times more than maintenance, and rehabilitation costs five times more than repairs.
In South Carolina, buildings are not required to be reinspected once built and issued a certificate of occupancy. A bill to change that was recently refiled in the state legislature after failing to gain traction during the last session.
In Charleston, the city began conducting a survey in mid-December to determine how many buildings six stories or taller exist within the city’s boundaries, as well as which ones may need a structural inspection. While parking decks would not be included in that survey, city officials say those buildings are already on their radar and part of a long-term maintenance plan.
Officials in Horry County and the cities of Myrtle Beach, and North Myrtle Beach say they have no plans to conduct structural safety inspections on tall buildings or parking decks. They said it’s the responsibility of building owners to monitor structural integrity.
Briah Lumpkins contributed to this report.
