Unless the traditional acquisition approach of design-bid-build established under sections
1101 to
1104 of title
40 is used or another acquisition procedure authorized by law is used, the head of an executive agency shall use the two-phase selection procedures authorized in this section for entering into a contract for the design and construction of a public building, facility, or work when a determination is made under subsection (b) of this section that the procedures are appropriate for use.