Surfside Condo’s pool deck was “severely underpowered,” researchers say

The Surfside, Florida apartment that collapsed two years ago had a pool deck that was “severely lacking in strength,” and the structure failed to meet both building codes and original design parameters in some areas, federal investigators have found.

Concerns about the polar deck have surfaced repeatedly since the Champlain Towers South collapse in June 2021, which killed 98 people, but a federal team’s preliminary analysis shows the magnitude of the problems discovered so far.

Investigators still have many months of work ahead of them before reaching a conclusion about the cause of the outage. But new documents released on Thursday suggest they have focused on a possible pool deck failure that could have triggered the collapse of the mid-rise residential tower.

Researchers at the National Institute of Standards and Technology, which is leading the study, have described it as one of the most complex probes ever undertaken, in part because there was no clear cause.

Investigators interviewed witnesses, reviewed historical records, tested the building’s materials, and modeled its structural soundness. They have looked at the original design and construction of the 40 year old tower, as well as all renovations and repairs; they also investigated the possible effects of corrosion, subsidence and vibration on nearby structures. Officials say they don’t expect to complete their final report until May 2025.

The collapse in the early morning hours of June 24, 2021 came with little warning. Some witnesses reported that the pool deck fell first, crushing vehicles in the parking garage below, and structural engineers said a failure there could have destabilized the columns under most of the building. Much of the tower collapsed into rubble within minutes, before many residents realized something was wrong.

In summaries of their preliminary findings ahead of a hearing on Thursday, the researchers wrote that the pool deck design was not sufficiently rigid at and between many of the supporting columns. The researchers found that those problems were serious in many places.

But the pool deck had other problems. The steel reinforcement in the concrete slabs of the pool deck was dug deeper into the concrete than in the original designs. Planters that were heavier and more elaborate than originally designed had been added to parts of the pool deck, adding weight to an already underdesigned system. Investigators also looked at the layers of sand and pavers that were later added to the top of the deck, and for signs of corrosion in some parts of the deck’s steel reinforcement.

All of those problems, the researchers said, caused the structure to have “critically low” margins to protect against failure. There are signs that the polar deck showed suffering — cracks in a planter and sagging concrete slabs — well before the collapse, the researchers wrote.

The research team said it was not yet ready to make recommendations, but it planned to consider new guidance on building practices, building codes, document retention requirements and ways to assess the safety of existing buildings.

Built in 1981, the building had many of the problems previously reported, not only with the pool deck, but with corroded columns, design flaws, and improper steel rebar. Three years before the tragedy, an engineer had warned of “major structural damage” to the complex, and a multimillion-dollar repair project was about to get underway when the collapse occurred.