O.C.G.A. § 32-10-68

All contracts of the authority for the construction of any project authorized by this article shall be let to the reliable bidder submitting the lowest sealed bid upon plans and specifications approved by the department, except as otherwise provided for projects authorized under any provisions of Code Sections 32-2-78 through 32-2-81. The procedures for letting such bids shall conform to those prescribed for the department in Code Sections 32-2-64 through 32-2-72 and 32-2-78 through 32-2-81.