If, after hearing any objections, the Council shall determine to proceed with the improvement, it shall so determine by resolution. Such resolution shall include the determination of the necessity for the improvement, set forth the nature hereof, designate the limits of the special assessment district to be affected, describe the lands to be assessed, determine the part or proportion of the cost to be paid by the lands especially benefited thereby, and the part or proportion, if any, to be paid by the City at large, determine the number of installments in which the said assessment may be paid and the rate of interest, not exceeding six percent, to be charged if the payment of any balance is to be deferred, and shall order the City Manager to prepare plans, profiles and specifications for the work to be done. If there are any objections in writing filed with the City Clerk prior to the said hearing, the passage of such resolution shall require the concurrence of two-thirds of the Council members elected.