A city of the metropolitan class, through its city council, is authorized and empowered to grant franchises for the nonexclusive use of bridges acquired under sections 14-1201 to 14-1252 to public utilities upon such terms, conditions, and for such consideration as such city may impose, whether incident to or part of the purchase of an existing bridge and rights of utilities in connection with such bridge, or otherwise, and to extend the duration or to amend the terms and conditions of such franchise. In the case of interstate bridges, any such grant shall be made by the city council by ordinance and no vote of the electors of the city shall be required. In no case shall such a grant be made by any bridge commission.