Surfside, Florida, in 2017. Champlain Towers South is located farthest to the left in the row of condominium towers on the shore.
Adobe Stock Surfside, Florida, in 2017. Champlain Towers South is located farthest to the left in the row of condominium towers on the shore.

Rescue work has been ongoing for the past six days at the Champlain Towers South condominium building in Surfside, Florida, which partially collapsed at 1:30 a.m. June 24.

Presently, 11 people are known to have died in or as a result of the collapse, according to the latest reports. About 35 people had been rescued from the uncollapsed portion of the building, two had been rescued from the rubble, and 150 people remain unaccounted for. Florida Gov. Ron DeSantis and Miami-Dade County mayor Daniella Levine Cava both declared a state of emergency in Miami-Dade County related to the event.

More than 80 rescue units have responded to the emergency, but the nature of the collapse and fires inside the wreckage have made rescue work difficult.

“The condo building in Florida experienced what’s called a ‘progressive collapse,’ which is similar to what happened to the World Trade Center,” says Robert Frosch, professor of civil engineering and senior associate dean of engineering for facilities and operations at Purdue University. “When a floor collapses, the weight of that slab doubles the weight of the floor below it. This type of failure is extremely rare. We have provisions in the building code to minimize the risk of this type of failure.”

Leading up to the collapse, the building had been undergoing preparations for its 40-year recertification as required under Miami-Dade County law. The city of Surfside has curated public documents related to Champlain Towers South, including architectural drawings, repair plans and permits, and engineering reports, on its official website.

Champlain Towers South was designed by William M. Friedman & Associates Architects and Breiterman Jurado & Associates Consulting Engineers in 1979, according to a 2018 inspection report by engineer Frank Morabito. It was developed by Champlain Towers South Associates, led by Canadian property developer Nathan Reiber, in 1981, and was the first in a complex of three buildings, including Champlain Towers North, built in 1982, and Champlain Towers East, built in 1994, according to the Miami Herald.

In his report, Morabito stated that the waterproofing under the pool deck had “reached the end of its usable life,” causing “major structural damage” to the concrete structural slab underneath. He noted that as the concrete slab was not sloped, water that penetrated the waterproofing would sit there until it evaporated—a “major error in the development of the original contract documents.”

The pool sat directly above the parking garage, which Morabito found to have “abundant cracking and spalling … in the concrete columns, beams, and walls,” as well as patches of “exposed, deteriorating rebar.” Morabito recommended the complete removal and replacement of the waterproofing structure, as well as repairs to the concrete slab.

Morabito’s estimated cost of repairs was $9 million, and an itemized bill sent to residents in April put the total current cost of repairs at $15 million. Repairs to the building’s roof had been completed just before the collapse, and permits exist for repairs to its electrical systems and stucco exterior. Work had not been started on the pool or parking garage.

“Collapses like these are fortunately highly unusual and extremely rare. However, it is imperative to identify the root cause of failures when they do occur, and to ensure that proactive steps are taken to prevent future incidents,” said Tom Smith, executive director of the American Society of Civil Engineers, in a statement on the tragedy. “ASCE fully supports the need for continued engineering assessments to pinpoint the cause of the collapse, and we stand ready to support official investigations with technical expertise.”

The Surfside website also offers additional community information and resources, including resources for donations, a family reunification hotline, and traffic alerts for the surrounding area.

“We are saddened by the tragic news coming out of Surfside, Florida, regarding the fatal partial building collapse,” Smith says. “Safety is the top priority of every civil engineer, and protecting public health and safety is core to our mission at ASCE. We share our deepest condolences to all of those affected by this tragedy.”