The onset of this failure early that morning looked something like this.
There are many unanswered questions around why this condo building collapsed in Miami, Florida.
However there is also a lot that we do know. This event requires respect for those left
impacted and traumatized. The aim of this video is to provide better understanding to lessen
the uncertainty and confusion. Let us examine the video footage and eyewitness clues we have so far.
The building was located on a barrier island in a north Miami town called Surfside. The
Champlain Towers South was a 12-story apartment building and had a prime position just 400 feet
from the sea. A single level underground parking garage covered the entire site.
The parking floor was just 2 1/2 feet above sea level. At about 1:22 am on Thursday the
24th of June 2021 the ocean-facing portion collapsed. It happened with little warning.
70 Apartments were destroyed completely and 11 partially. 55 On the west remained standing.
This video was filmed from across the road looking into the basement. A sprinkler pipe was cut by the
fallen slab and was gushing water. Concrete rubble was visible lying on the garage floor.
The lights were out in the collapsed portion. The visible column is one of the 4 tower columns
that gave way and was still intact. The top of the column was out of view so we cannot know
if it had been damaged when the slab pulled away. There was nothing to suggest a foundation problem.
The rubble lay under a section of the pool deck where there were large planters and a raised
step level. The rubble positions are not certain from the single camera viewpoint nor is it clear
how far the rubble pile extended. The pool slab fell roughly 7 minutes before the tower collapsed.
This footage is from a year earlier. It shows the poor state of the garage ceiling,
which is the underside of the ground level concrete slab. There is evidence of widespread
water penetration into the concrete from long-term failed waterproofing.
Corrosion of the steel reinforcement would be aggravated by the aggressive salty environment.
The zone of water damage is indicated relative to the planters.
These are the apartments that we know of that were alerted by building noises.
It is tragic that there was not a longer warning time so all occupants could get out safely.
This ground level family started hearing noises half an hour before the collapse.
The mother described what sounded like construction noise.
Her apartment was right next to the fallen rubble in the basement and her external wall included the
primary failure columns. Shortly before the main collapse she heard what sounded like walls falling
and went to discuss it with the lobby attendant this is the view from the lobby.
She saw the garage had collapsed. Her daughter saw the ceiling cracked in the shower.
The family escaped to safety just in time. This sixth floor resident also got out safely.
She was halfway down the surviving stairs when the building fell.
This resident was on her balcony and described the pool sinking to
her husband on the phone moments before the phone call was cut.
The first point of failure of the pool and parking area as well as its timeline is not certain.
The sequence animated here is an estimate. We know the parking area dropped before the tower.
This was confirmed by the son of the ground floor apartment who explained that the cars
had dropped into the garage below with car alarms going off before he ran out.
This distinct line in the slab is a construction joint. It is where the
concrete poured on a particular day ends and left the neat fracture visible in the photos.
It is possible it may in time be proven to be the trigger point.
The cctv footage suggests the tower failed in this sequence.
When the deck slab pulled away from critical columns a portion of the column was ripped out.
The beams under the planters caused rotation and buckling of the columns.
It was only a matter of time before they caved in. Each adjacent point
of strength yielded like a rapid sequence of dominoes, helped on by seismic shock.
The concrete shear wall to the second staircase,
which briefly kept the ocean section standing, was last to fall and landed on top of the rubble pile.
Building codes require strict safety factors and engineers go to great lengths to make buildings
very robust by including multiple layers of redundancy. Buildings should still stay standing
with multiple element failures. For this reason structural failure of buildings is thankfully
exceptionally rare. Whether the structural design had any blatant shortcomings,
will be part of thorough examination. But considering this building stood firm
for 40 years, it seems likely the structure was compromised more recently by unattended
corrosion. The lack of warning in this collapse was shocking. The failed pool deck should not have
mortally damaged the tower columns and will be an important part of this investigation.
Concrete fails slowly and with much commotion, which is why it makes for great structure.
But if the steel is corroded and weakened by long-term neglect,
the failure would be more sudden which is what is seen in this case. Crrosion resulting
in delamination of the top layer steel in the pool area slab seems an important factor here.
One month later this is all that remains of the site. The standing portion was brought down
in a controlled demolition and carted away with everything else. We will have to wait for answers,
but in the interim I hope this video was useful to you. The 1979 building plans were used in this
modeling and analysis. The download link to these is in the description below. Thanks for watching