The Council shall, by ordinance, establish and maintain a retirement system to provide for the retirement of officers and employees of the city who become superannuated or totally and permanently disabled; said retirement system to become effective April 1, 1955. The objective of the retirement system is to create a sound and efficient means of providing pensions, in addition to social security benefits, for the officers and employees of the city to the end that economy and efficiency in public service may be effected and an orderly method of retirement be provided without hardship and prejudice to employees who have become superannuated or incapacitated. The terms and conditions of the ordinance shall be within the discretion of the Council, except as provided in this chapter.