If the construction of such sidewalks, curbs or gutters is done by contract after advertisement for bids, such advertisement for bids and contract may be for sidewalks, curbs or gutters in front of one or more lots or parcels of land as the council shall determine. Any contractor to whom a contract is let for the construction of sidewalks, curbs,or gutters shall before commencing work execute and deliver to the city a good and sufficient bond in a sum not less than double the amount of the contract, which bond shall be conditioned on the faithful performance of all work done by him under such contract and shall further guarantee the maintenance and durability of said work for a period of not less than three (3) years, which bond shall be approved by the mayor. (Ord. 416, 1-3-1994)