Surfside condominium collapse

On June 24, 2021, at approximately 1:22 a.m. EDT, Champlain Towers South, a 12-story beachfront condominium in the Miami suburb of Surfside, Florida, United States, partially collapsed, causing the deaths of 98 people. Four people were rescued from the rubble, but one of them died of injuries shortly after arriving at the hospital. Eleven others were injured. Approximately 35 were rescued the same day from the un-collapsed portion of the building, which was demolished ten days later.

A contributing factor under investigation is long-term degradation of reinforced concrete structural support in the basement-level parking garage under the pool deck, due to water penetration and corrosion of the reinforcing steel. The problems had been reported in 2018 and noted as "much worse" in April 2021. A $15 million program of remedial works had been approved before the collapse, but the main structural work had not started. Other possible factors include land subsidence, insufficient reinforcing steel, and corruption during construction. The National Institute of Standards and Technology (NIST) is investigating almost two dozen potential causes for the collapse. It is likely they will determine several factors happened simultaneously to cause the collapse.

The Champlain Towers South collapse ties with the Knickerbocker Theatre collapse as the third-deadliest non-deliberate structural engineering failure in United States history. The deadliest is the Hyatt Regency walkway collapse and the second deadliest is the collapse of the Pemberton Mill.

The residential condominium building, Champlain Towers South, was located at 8777 Collins Avenue (Florida State Road A1A) in the town of Surfside, just north of Miami Beach, Florida. Champlain Towers South (completed in 1981) was part of a three-building complex along with Champlain Towers North (completed in 1982), and Champlain Towers East (built between the North and South buildings in 1994). All three were L-shaped structures with 12 stories, but as of 2021, the South building contained the most units at 136 including a rooftop penthouse, varying in size from 1,200 to 4,500 sq ft (110 to 420 m²) and from one to four bedrooms. The penthouse was a controversial part of Champlain Towers South's design, as an exemption was needed to exceed Surfside's height limit. The penthouses were also not part of the original building permits.

William M. Friedman & Associates Architects, Inc., was the architect for the project's 1979 contract drawings. Breiterman Jurado & Associates, consulting engineers, were responsible for engineering aspects and the 1979 contract drawings, with Breiterman and associates covering structural items and Jurado and associates covering electrical and mechanical.

The project was the first new construction in Surfside following a moratorium on new development imposed by Miami-Dade County due to water and sewer infrastructure problems in Surfside during the 1970s. In 1979, developers paid the city $200,000 (equivalent to $866,000 in 2024) to fund the replacement of the sewer system and secure approval for the construction of the condos.

The pool deck of Champlain Towers South suddenly suffered a partial collapse at about 1:14 a.m, followed by the progressive collapse of the central section and eastern wing of the building at 1:22 a.m. EDT on June 24, 2021. The collapse of the building lasted less than 12 seconds. Surveillance video footage indicates that a large north-central section of the building abruptly collapsed first. This isolated and destabilized part of the northeast corner of the building, which also collapsed approximately nine seconds later. Of the 136 units in the building, at least half were destroyed.

The collapse killed 98 people.