At the first regular meeting in December following the general election in every even-numbered year, the city council in a city under the city manager plan of government shall meet in the usual place for holding meetings and the newly elected city council members shall assume the duties of their office. Thereafter the city 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 city council members, or the city manager may call special meetings of the city council upon at least six hours' written notice. The meetings of the city council and sessions of committees of the city council shall be public. A majority of the city council members shall constitute a quorum, but a majority vote of all the city council members elected shall be required to pass any measure or elect to any office.