If no protests are filed as provided in this Article, or when such protests have been heard and overruled, the City Council may adopt a resolution finding and determining that the public convenience and necessity require the proposed improvement or acquisitions and that the Special Assessment Investigation Limitation and Majority Protest Act of 1931 shall not apply. Such resolution shall be adopted by no less than four-fifths vote of the City Council and its findings and determinations shall be final and conclusive. Upon adoption of the resolution of convenience and necessity, the City Council shall immediately have jurisdiction to adopt a resolution of intention pursuant to the improvement act under which the improvements or acquisitions are to be made.