Slab that failed at fallen Champlain Tower had been a problem for 25 years, records show

The pool deck at Champlain Towers South Condo, now at the center of a forensic investigation into the building’s deadly collapse, had been a problem for decades, a newly released 1996 construction permit for “concrete structural repair” shows.

Documents submitted to the town as part of permitting and construction show the deck slab, which makes up the ceiling of the underground garage, needed 500 feet of cracks sealed and a 20-square-foot slab replaced entirely just 15 years after the original construction of the building.

“The scope of work will be concrete structural repair in the parking garage,” wrote Rob Sommer, sales manager for Western Waterproofing Company of America to the Surfside Building Department in March 1996. “This type of repair entails removing loose concrete overhead, treating steel rebar with rust inhibitive coating and patching back with repair mortar. Also included in the garage will be urethane foam injection in ceiling cracks.”

Tong Le, the consulting engineer on the project, certified the $156,602 of structural concrete construction work and waterproofing in a Nov. 20, 1997, letter to the town.

“I performed inspection of different phases of the waterproofing of the deck and the repair of approximately … 20 square feet of spalls in the ceiling of the garage,” Le wrote. “The repair has been performed under our inspections from the beginning to completion.”

Le did not immediately return the Herald’s request for comment. Someone who answered the phone at the Pompano Beach office of Western Waterproofing Company of America said the company is not taking media inquiries on the 1996 repairs of Champlain Towers South.

“[The 1996 repairs] indicate that they were having problems with water infiltration, which is saltwater infiltration, all these years,” said Abieyuwa Aghayere, concrete expert and professor of structural engineering at Drexel University. Aghayere said the need for these kinds of repairs after only 15 years was “atypical.”

The pool deck above the garage has become a focal point for engineers investigating why the tower suddenly and catastrophically collapsed on June 24 after a video showed the garage ceiling partially caved in shortly before the rest of the building went down. Nearly 100 bodies had been pulled from the wreckage as of late Monday with other building occupants still missing and presumed dead. The failed slab in the video would have been located at the edge of the pool deck and the north part of the building, where a large planter serving as a base for palm trees and other foliage added increased weight to the slab.

In 2018, engineer Frank Morabito indicated a “major error” in the original construction or design of the pool deck and planters had prevented proper draining and caused “major structural damage” to the concrete slab below.

In his report, Morabito said previous repair work in the garage had been “ineffective.”

The 500 feet of cracks cited in the documents “seems like a lot,” according to Dawn Lehman, professor of structural engineering at the University of Washington. In comparison, 20 square feet of slab repairs seemed insignificant, Lehman said.

“I would have expected more. It suggests that they did not investigate the extent of the damaged concrete and instead only repaired what was visible,” she said.

Lehman pointed out other discrepancies between the original scope of work and the certification, including that the consulting engineer did not mention the rust-inhibitive coating for the rebar in his certification of the construction. Still, Lehman said the 1996 permit adds to the growing concern that the slab was a significant weak point in the building due to a long history of water intrusion and damage.

“This is a systematic issue for this building, which you can see they have been dealing with since the late ‘90s,” she said.

A pool contractor inspecting the underside of the pool just 36 hours before the collapse noted significant standing water in the basement garage below the pool deck slab. A former maintenance manager for Champlain South, William Espinosa, told Miami’s CBS4 that water in the garage had been a problem since at least 1995, a year before the building contracted Walter Hoffman of Western Waterproofing to repair damage to the slab and install waterproofing and drains.

“It was so much water, all the time, that the pumps never could keep up with it,” Espinosa told CBS4. He did not specify that the water was coming through a damaged slab, but rather said he thought most of it was coming up through the foundation.

In fall of 2020, Morabito’s team took core samples of the concrete near the planter showing that the slab thickness was 9.5 inches — consistent with the original building plans — but did not report the chloride content or strength, which experts said would be necessary to understanding if the slab was degraded.

Aghayere, from Drexel University, said that lack of detail on the strength of the concrete slab seems even more glaring in light of the 1996 repairs, though it’s unclear if Morabito’s firm knew the building’s full history.

Morabito has not made himself available for comment.

Because of the design of the building, which places a lot of stress on the concrete slabs above the columns supporting the tower, Aghayere said the cracking and spalling noted in 1996 would have drawn his attention.

The extent of the concrete damage should have prompted more probing questions as far back as 1996, he said.

“I would have asked myself, ‘What is the root cause of all this cracking? Why is it spalling? What’s going on?’” Aghayere said. “And I would have done what I call a biopsy of the slab.”

Records of the 1996 repairs don’t show whether there was any further exploration of the damaged concrete or rebar beyond what was visibly obvious. The drawings included with the documents also did not specify where the cracks or spalling in the concrete had been occurring.

“If there are cracks, you map out where they are … so a structural engineer can review it and ask themselves the question: ‘Are these cracks superficial or are these cracks structural that show the building is crying out for help?” Aghayere said.

This story was originally published July 13, 2021 at 1:33 PM.