Engineer suggests corrosion might be to blame for Champlain Towers South partial collapse

Engineer Asher Cohen says the condo’s builders didn’t have access to modern construction technology

Engineer Asher Cohen says the condo’s builders didn’t have access to modern construction technology.

JACKSONVILLE, Fla. – The federal government is sending a team of scientists and engineers to Surfside, Florida, to find out if Thursday’s deadly condo collapse should result in a broader investigation that could have implications for building codes nationwide.

The six scientists and engineers dispatched to South Florida are from the National Institute of Standards and Technology, the same government agency tasked with investigating structural failures at the World Trade Center following the 9/11 attacks.

On Friday, News4Jax spoke with Asher Cohen, a forensic engineer with U.S. Forensic, who said one of the potential causes at the top of his list would be saltwater corrosion of both concrete and rebar, two staples when it comes to construction.

“It’s something that we have to absolutely consider,” Cohen told News4Jax. “It’s not even a stretch to put this at the top of the list. It’s not like it’s something new.”

The Champlain Towers South Condominium, which was set to undergo its 40-year inspection, was built in the early 1980s, according to published reports. Back then, Cohen said, builders didn’t have access to the same type of materials used in modern construction.

These days, he said, there are different chemicals and substances that are used to reinforce concrete and steel that will protect building materials from the elements, such as saltwater, and help them stand up to the test of time.

“They add mixtures to concrete to stop corrosion to some extent, but not eliminate it outright,” he said. “Obviously the rebar itself, coated rebar, steel rebar, galvanized rebar, has been used, as well as other types of alloys that protect it from corrosion.”

Thursday morning’s collapse left at least four people dead and dozens more missing or unaccounted for.

Cohen said saltwater can seep into concrete through existing cracks in the building. Over time, he said, the chlorides corrode areas that can’t be seen. He described the result as spalling, which happens when the steel inside the concrete expands.

“We can see this usually when it starts happening, and it gives us a warning,” he said. “We see a crack, maybe we see some corrosion staining, a red type of staining. Or on the underside of that slab, as the corroded steel starts to expand, it causes spalling and actually blows the concrete out. And this happens over many, many years.”

Cohen told News4Jax he has confidence that the engineers who were preparing for the building’s 40-year inspection didn’t notice any evidence signaling a catastrophic failure of this magnitude. He hopes when the cause of the collapse is identified, Florida’s building codes will be upgraded.

“Sadly, in the history of humanity, we have learned from most failure,” he said. “And it’s just a tragedy human lives were lost. We’ll learn from this and get better. I’m sure there will be new legislation, rules, regulations, to make sure it doesn’t happen again.”

About the Author:

Tarik anchors the 4, 5:30 and 6:30 p.m. weekday newscasts and reports with the I-TEAM.