The Social Security Administration needs a new National Computer Center. The existing one near Baltimore is more than 30 years old and in perilous shape — so much so that the Social Security Advisory Board said it’s in danger of catastrophic failure, which could delay disability and seniors’ benefits from being paid on time. Now Congress wants to know why SSA only let them know last fall that the building needs replaced as soon as possible. And that explanation is a simple one, said Mary Glenn-Croft, deputy commissioner for budget, finance and management for SSA. By 2006, the SSA had…