By Keith Jones

MIAMI (CBSMiami) – After the rescue mission is complete, the investigation into what led to this catastrophe will begin.

CBS4’s Keith Jones looked into the history of the building and found there have been several reasons for concern throughout the years.

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“Nothing appeared either to the engineers or to any of the residents that suggests anything like this was imminent. Nothing,” said Ken Direktor.

Direktor is the attorney for the Champlain Towers South Condo Association, which is in charge of the buildings upkeep and maintenance.

He confirmed engineers were in the middle of the required 40-year recertification. The tower was completed in 1981. It’s a 12-story oceanfront condo in Surfside with 136 units The condo association hired an engineer to deal with structural and electrical changes for the recertification process.

Perhaps what residents didn’t know was the building was sinking, according to Dr. Shimon Wdowinski, from FIU’s department of earth and environment.

“We used data from ‘93 to ’99, so that was the data available for that study and we saw there was some pockets of subsidence in Miami Beach,” he explained.

Wdowinski studies subsidence, which is the movement of the surface downward.

His study included Surfside, and specifically the Champlain Towers South.

“Now, we saw subsidence in that particular building in Surfside, which was unusual, because we didn’t expect to see it over there,” he said.

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It was unusual because Surfside has a lot of limestone, which offers more support.

“In this particular case, we saw subsidence over there,” he said. “We reported about it.”

In HIS report, he noted the tower was built 41 years ago on reclaimed wetlands. It was sinking at a rate of 2mm a year for three decades, and that may have an impact on the structure.

When subsidence is present, structures can show cracking that worsens over time. That’s something the professor looked for.

“I looked at it from satellite imagery, but I didn’t see anything suspicious at the time,” he said.

The age of the tower, 40 years old, likely didn’t play a factor in the collapse, according to Atorod Azizinamini of FIU’s engineering department.

“So buildings built in 1981, we had lots of knowledge. So I wouldn’t say that age is a factor, not by itself,” he said.

Dr. Azizinamini said it’s likely a collection of failures that made for a catastrophic event.

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“They’re going to look at how the building was constructed. They’re going to take samples of the steel, concrete, signs of corrosion. They’re going to look at the foundation to see if there was settlement,” he said.