Except as provided in Article 9 (commencing with Section 33410) and in Section 33449, this part does not authorize an agency to construct any of the buildings for residential, commercial, industrial, or other use contemplated by the redevelopment plan, except that, in addition to its powers under Section 33445, an agency may construct foundations, platforms, and other like structural forms necessary for the provision or utilization of air rights sites for buildings to be used for residential, commercial industrial, or other uses contemplated by the redevelopment plan.