Authorities in Miami-Dade County, Florida have identified 97 people who died in the partial collapse of a 12-storey condominium building in the town of Surfside on 24 June, and believe one still to be missing, as the site was largely cleared of debris last week.
People of all ages including elderly couples and a one-year-old child died as a result of the collapse of the Champlain Towers South condominium in the small hours, sparking a frantic search that over nearly a month moved from rescue to the recovery of bodies.
The search was interrupted on 4 July when demolition crews used explosives to bring down the standing remnants of the building, deemed unsafe as a tropical storm approached.Â
Clues as to the whereabouts of the person still missing are now being sought in debris from the building that has been relocated to a secure site near the airport, where it is being stored as evidence in the investigation into the collapse.
"Thanks to the diligent and incredibly thorough work of our first responders and debris handling teams, the building collapse site has been mostly cleared and debris relocated to the evidentiary debris collection site near the airport," said Miami-Dade County Mayor Daniella Levine Cava on 21 July.Â
Some 145 survivors are living in temporary accommodation.
The county said teams are working around the clock to ensure all recovered personal property and family heirlooms are tagged for return.
The National Institute of Standards and Technology (NIST) began a full technical investigation of the collapse on 30 June.
It said it has collected more than 200 building elements including columns, beams and pieces of concrete slab, which are under the protection of Miami-Dade Police, and are tagged with RFID chips for cataloguing.
A NIST engineer evaluates the strength and quality of a concrete column using Ultrasonic Pulse Velocity (Credit: NIST)
NIST engineers are evaluating the condition of concrete elements using Ultrasonic Pulse Velocity testing, which sends a pulse through the concrete.
They have also installed accelerometers in the collapsed building’s twin, Champlain Towers North, to measure its vibrations, along with a seismometer to measure ground vibrations, in order to validate computer modeling of the south tower.
NIST said its investigation could lead to recommended changes to building codes in Florida, where there are millions of high-rise condominium units, many of them ageing structures near the ocean.
Image: View of the Champlain Towers South condominium site. NIST positioned cameras on a neighbouring balcony to record the locations of items being preserved for study (Credit: NIST)