Two structural support beams on the 21st floor of a 37-story under-construction building in Manhattan started buckling Tuesday morning, triggering a mass evacuation, street closures and a large emergency response, officials say.
The FDNY said it got a call around 8 a.m. about bricks falling from the building at 235 East 42nd Street, between Second and Third avenues. The NYPD says it got a 911 call about the incident less than 15 minutes later.
When cops got to the scene, the NYPD says officers were told that construction workers on the 21st floor of the commercial building saw the columns beginning to collapse.
Raw footage from inside, taken by a construction worker, showed crumbling steel beams on the 21st floor.
Per NYCBC (up until maybe soon), you have to provide window access to a various list of rooms, which is why residential skyscrapers are usually shaped differently than commercial skyscrapers. To make it fit code, they would have needed to remove beams and columns to fit in the required air shaft which would provide the windows needed.
A few things that could have gone wrong off the top of my head but is not a complete list:
The demolition procedure had issues/wasn’t followed. That should include allowed construction loads on each floor. That only one floor saw buckling could be a sign that it was overloaded with debris.
Someone messed up the calculations. The two possible issues could have been either that the slenderness of some elements were miscalculated or there was a major storm that hit the area recently, and the building in the condition it was in didn’t have the necessary lateral resistance it needed.
That said, neither the developer or the contractor would have a vested interest in removing more than the bare minimum allowed. And, while steel is recyclable, it is usually far cheaper to leave it in place