The county board shall require bidders to bid upon plans and specifications on bidding blanks prepared by the Director-State Engineer or such other officer who may have charge of such matters in this state, to be furnished by Director-State Engineer free of charge, which shall be adopted by the county board; Provided, if the county board should adopt plans and specifications which infringe on any patent right granted under and by virtue of the laws of the United States, the county board shall endorse on the plans and specifications the name of the owner of such patent right or the name of the party entitled to receive royalties therefor, and the amount of royalties received by the owner or party entitled thereto; and the board may accept the lowest responsible bid and award the contract accordingly or reject any and all bids submitted for such work. Upon the rejection of any bid or bids by the board, it shall have the power and authority to purchase the necessary bridge material and employ the necessary labor to construct and repair bridges to be built by the county within one year; the purpose being that the county board shall be vested with power and authority to purchase the necessary material and employ the necessary labor, to construct and repair the bridges of the county within one year; Provided, however, nothing herein contained shall prevent any person or corporation from submitting to the Director-State Engineer plans and specifications for his consideration.