“We have reinforced all the column bases,” principal architect George Heinlein said. “If somebody does get past that first line and up against the building — if they were to carry a bomb in a backpack or something like that and set it off — we have resistance at the base of the building.”

Heinlein said the National Football League increased security requirements after the terrorist attacks of Sept. 11, 2001. The secured perimeter will double as a plaza for ticketed fans, according to Heinlein and Mark Lamping, the executive supervising the construction.