This famous New Yorker article, published two decades after the problem was found and fixed, explained what happened and how they fixed it.
[…] in the spirit of intellectual play, he wanted to see if they were just as strong in winds hitting from forty-five degrees. His new calculations surprised him. In four of the eight chevrons in each tier, a quartering wind increased the swain by forty per cent. Under normal circumstances, the wind braces would have absorbed the extra load without so much as a tremor. But the circumstances were not normal. A few weeks before, during a meeting in his office, LeMessurier had learned of a crucial change in the way the braces were joined.
A good story about a guy that screwed up and admitted it rather than tried to cover it up.