How is a controlled demolition of another side of a building safe for any possible survivors in the side that originally collapsed?



My heart goes out to the victims and their family members in Surfside, FL. I feel like there’s a simple explanation but I’m not understanding how the demolition of the other side of the condo building didn’t seal a possible survivors’s death with more concrete and rubble falling?

In: Engineering

Knock the remaining building down in the other direction so they can remove the ruble without risk of the remaining building falling on top of emergency workers searching for survivors.

Nobody is still alive in the rubble anyway. Hate to be a pessimist but it’s just so unlikely.

Thats what the controlled means.

When a demolition is “controlled” it means how it falls and where it falls is controlled.

When you have half a building standing, you effectively block off a wide area to get excavator to. because ideally, you want a full surround to maximize digging potential.

Then theres also the increased risk. HALF the building already collapsed. Who knows when the other half will collapse? if it collapsed on the rubble or worse, on the rescue machinery, now you have a bigger problem and more people trapped.

There were multiple factors involved.

First, you have an unstable side of the building still standing. That posed a huge risk to everyone in the area, including the rescuers.

Second, a hurricane (Elsa) was coming in. This could have toppled the rest of the building easily, killing many more people.

Those in charge made the decision to demolish the rest of the building in a controlled manner. People experienced in building demolition can drop a building in an exact way so that it falls how they want it to. For this job, they needed very experienced people, because the building was damaged. And if you watched it, you saw them bring it down just as planned.

The debris from bringing it down carefully did not go onto the other pile. Some dust did, but no real debris. Bringing it down protected lives that may have been lost if it just fell on its own. I know the people working there are alive, so that’s why they decided to protect them.

You have to balance the risks involved.

Demolishing the remaining side of the structure will create risks to anyone still alive in the fallen side – rubble still being supported on the existing structure may shift, or vibrations from the work may cause the pile to settle further.

The question is whether delaying the demolition will provide you a better chance of saving any remaining trapped people, or whether leaving the structure standing will create risk for the rescuers still working.

Demolish the structure in a controlled fashion now and there is a chance someone that is still alive and trapped dies.
Leave the structure standing and there is a chance it will collapse itself in an uncontrolled fashion and kill rescuers.

It isn’t a fun decision to make, but someone needs to do it. At first there is a better chance of finding survivors and so rescuers will take the risk, but as time goes on the chance of finding survivors drops you have to reconsider that risk.

It is especially notable here because they are also considering the potential effects of a tropical storm and the damage it could cause, which has perhaps brought the demolition forwards to try and prevent it collapsing uncontrolled in the storm.