N.Y.C. Admin. Code § 27-596: § 27-596 General.

The structural design of a member or assembly shall be deemed to be adequate if the design computations demonstrate conformance with the applicable standards noted in articles four through twelve of this subchapter. Where, because of practical difficulties, such computations cannot be executed, the structural design may be deemed adequate if the member or assembly is subjected to, and satisfactorily performs under, load tests in accordance with the provisions of subdivision (a) of section 27-599 of this article. Where there is a question as to the adequacy of a completed or partly completed construction, the provisions of sections 27-597, 27-598, and subdivision (b) of section 27-599 of this article shall apply.