The specifications of Sections 13.04.070 through 13.04.090 shall govern all new concrete work done within the limits of the streets and alleys of the city, whether such work is done by public or private contract, the common council reserving to itself the right to supervise and regulate the construction of all such work, except where the common council may by resolution direct that such work shall be done by authority of the board of county commissioners. (Prior code § 27-46)