The Engineer’s Recalculation Summer 1978

You are advising William LeMessurier, structural engineer of the Citicorp Center tower in New York.

The 59-storey tower, completed in 1977, stands on four giant columns placed at the middle of each side rather than at the corners. Prompted by questions about the design, LeMessurier has rechecked his work and found that winds striking the building at an angle would put far more stress on some joints than calculated, and that those joints were bolted rather than welded.

Known information

His analysis suggests a storm strong enough to cause failure has about a one-in-16 chance of striking in any given year.
The hurricane season is approaching.
Disclosing the error could damage his reputation and lead to lawsuits and insurance problems.
The joints could be strengthened by welding thick steel plates over them, but the work would take months in an occupied building.
No one else appears to have noticed the problem.

Reveal what happened (spoilers: decide first)

Fact

What actually happened

LeMessurier told the building’s owners and oversaw emergency repairs. (Alert the owners and repair it)

LeMessurier informed Citicorp, and during the summer and autumn of 1978 workers welded two-inch-thick steel plates over the building’s bolted joints, mostly at night. Emergency evacuation plans were drawn up in case of a major storm. The repairs were completed without public alarm, and the story did not become widely known until a 1995 article in The New Yorker.

Important

Possible consequences · Analysis and speculation, not fact

Keeping silent would have left the building exposed to a rare but plausible storm; whether a failure would actually have occurred is unknowable, which is part of why the case is still debated.

History does not reveal what would definitely have happened under the other choice. Many factors could have changed the outcome.

Context · Why it was decided this way

The episode is widely taught in engineering ethics courses as an example of an engineer taking responsibility for an error. The questions that prompted the recheck came from an engineering student, Diane Hartley.

Later research, including a book by author Michael M. Greenburg, has given a more complicated picture, noting that the repairs were deliberately kept from the public and the press at the time. Views differ on whether that secrecy was justified to avoid panic.