In levying special assessments to pay any part of the cost of any public work or improvement, the Council shall not exceed any limitation as to the amount thereof which may be prescribed by the general laws of the State applicable to municipalities and in force at the time it is determined by the Council that any such work shall be done or improvement made. Unless for special reasons which shall be stated in the ordinance levying an assessment or made pursuant to contract, no such ordinance shall be passed, or assessment levied or money borrowed, until bids for the labor and material have been received and the approximate cost of the improvement determined.