|The report said the structure's original design flaws included faulty wind-load calculations, weak steel framing and vulnerable joints. Federal researchers said their analysis, unlike Cover-All's, accounted for "internal wind pressure due to the presence of vents and multiple doors."
They also questioned the company's claim, made in design documents, that the building's fabric provided structural support.
And 2008 reinforcements to the building "had a minimal effect," they said. "The most critical members were not reinforced."