Every contractor for the making of any such improvement shall be required to enter into a good and sufficient bond for the performance of his contract and containing such other conditions as may be proposed. Such bonds shall run to the city of Aberdeen and shall be payable to said city and may be consolidated with the bond required by statute to be given for public improvements running to the state of Washington for the protection of laborers, mechanics, subcontractors and material men, and in case it is so consolidated, shall run to the city of Aberdeen and be filed with the city clerk of said city. The penalty of such bond shall be in such sum as shall be specified in the contract, not less than fifty (50) percent of the contract price, and unless the surety on such bond is a licensed surety company authorized to do business under the laws of the state of Washington, such bond must be signed by not less than two individuals qualified to become surety upon bail and the sufficiency of such surety must be approved by the city council.