Experts Explain Buckling Steel Beams in Manhattan Skyscraper

Firefighters ordered an evacuation of a Midtown Manhattan skyscraper on Tuesday after steel columns on the 21st and 22nd floors began to buckle, raising concerns of a possible structural failure.

The evacuation was ordered quickly.

What officials observed

The FDNY said a call came in just before 8 a.m. EDT, prompting crews to inspect 235 East 42nd Street, a 37‑story tower near Grand Central Terminal. Responders found at least two steel columns bending on the 21st and 22nd floors and sagging floor slabs between the 21st and 26th levels.

Why columns can fail

Gregoy Deierlein, a professor of structural engineering at Stanford University, explained that buckling is a known risk when columns become weakened. “Imagine if you’re standing on the floor and you look over—the portion of the floor supported by that column would have dropped a little bit, so it’s going to look like a sagging floor,” he said.

Columns are designed to carry the building’s dead load plus a specified “live load” that accounts for occupants and movable items. During renovations, the live load can exceed expectations if construction materials are stored on site. “That could be a very concentrated live load, which could be enough load to overcome the column strength,” Deierlein noted.

Magued Iskaner, a civil‑engineering professor at NYU Tandon, said he would be “very surprised” if planners had ignored these calculations, but warned that hidden defects in a column could still go unnoticed. “All of these people could have done these things correctly, but the presumed capacity of a column is off simply because there was a latent defect that nobody knew about,” he added.

Doug Holmes, an engineering professor at Boston University, pointed to the joints that connect structural components as frequent failure points. “Where a significant amount of shearing forces are exerted—think a bolt shearing off—and in the buckling of columns,” he said, noting that corrosion or wear can exacerbate the problem.

The tower, formerly the New York City headquarters of Pfizer, is undergoing a $75 million conversion to luxury apartments with about 1,600 units planned. The project is a joint effort by David Werner Real Estate Investments and MetroLoft, both of which declined immediate comment. MetroLoft’s statement to the New York Times emphasized safety as a priority and clarified that no debris fell from the structure.

The incident resembles other cases where renovation projects unintentionally overload structural elements. In many past conversions, the added weight of construction stockpiles has triggered similar buckling, prompting owners to reassess load calculations. While the immediate danger appears limited to a small section of the tower, the episode highlights the importance of rigorous monitoring during major retrofits.

Engineers continue to evaluate whether the original design was insufficient, whether a hidden flaw existed, or whether the live load during renovation simply exceeded safe limits. The Department of Buildings’ investigation will likely inform future guidelines for high‑rise conversions in dense urban cores.