At the first regular meeting in December following the general election in every even-numbered year, the council shall meet in the usual place for holding meetings and the newly elected council members shall assume the duties of their office. Thereafter the council shall meet at such time and place as it may prescribe by ordinance, but not less frequently than twice each month in cities of the first class. The mayor, any two council members, or the city manager may call special meetings of the council upon at least six hours' written notice. The meetings of the council and sessions of committees of the council shall be public. A majority of the members shall constitute a quorum, but a majority vote of all the members elected shall be required to pass any measure or elect to any office.