The design problem was in the CHEVRONS – 4:20/27:47
The Design Flaw That Almost Wiped Out an NYC Skyscraper – http://www.slate.com/blogs/the_eye/2014/04/17/the_citicorp_tower_design_flaw_that_could_have_wiped_out_the_skyscraper.html
The Design Flaw That Almost Wiped Out an NYC Skyscraper – http://www.slate.com/blogs/the_eye/2014/04/17/the_citicorp_tower_design_flaw_that_could_have_wiped_out_the_skyscraper.html