To the extent that such have not been heretofore exercised or discharged, all rights, powers, duties and liabilities of the Alabama Building Corporation created by Act No. 477 of the 1951 Legislature, page 845, Acts of 1951, approved August 17, 1951, are hereby continued in full force and effect until such have been fully exercised and discharged. At such time as all of the rights, powers, duties and liabilities of the said Alabama Building Corporation have been exercised or discharged, including specifically the payment or discharge of all bonds or other securities issued by such corporation, the said corporation shall perform the acts of dissolution prescribed by Section 18 of said act, and thereupon the said corporation shall cease to exist.