Letting of contracts. All contracts to be let for the construction, alteration, improvement, repair, enlargement, demolition or removal of any buildings or other facilities, or for materials or supplies to be furnished, where the amount thereof is in excess of $10,000.00, shall be let to the lowest responsible bidder, or bidders, on open competitive bidding after public advertisement published once at least three weeks prior to the opening of bids, in a secular English language newspaper of general circulation in the county where the Authority is located. Nothing contained in this Section shall be construed to prohibit the Board of Commissioners from placing additional advertisements in recognized trade journals. Advertisements for bids shall describe the character of the proposed contract in sufficient detail to enable the bidders thereon to know what their obligation will be, either in the advertisement itself, or by reference to detailed plans and specifications on file in the office of the Railroad Terminal Authority at the time of the publication of the first announcement. Such advertisement shall also state the date, time, and place assigned for the opening of bids and no bids shall be received at any time subsequent to the time indicated in said advertisement. The Board of Commissioners may reject any and all bids received and readvertise for bids. All bids shall be open to public inspection in the office of the Railroad Terminal Authority for a period of at least 48 hours before award is made. The successful bidder for such work shall enter into contracts furnished and prescribed by the Board of Commissioners and in addition to any other bonds required under this Act the successful bidder shall execute and give bond, payable to and to be approved by the Authority, with a corporate surety authorized to do business under the laws of the State of Illinois, in an amount to be determined by the Board of Commissioners, conditioned upon the payment of all labor furnished and materials supplied in the prosecution of the contracted work. If the bidder whose bid has been accepted shall neglect or refuse to accept the contract within five (5) days after written notice that the same has been awarded to him, or if he accepts but does not execute the contract and give the proper security, the Authority may accept the next lowest bidder, or readvertise and relet in the manner above provided. In case any work shall be abandoned by any contractor the Authority may, if the best interests of the Authority be thereby served, adopt on behalf of the Authority all sub-contracts made by such contractor for such work and all such sub-contractors shall be bound by such adoption if made; or the Authority shall, in the manner provided herein, readvertise and relet the work specified in the original contract exclusive of so much thereof as shall be accepted. Every contract when made and entered into, as herein provided for, shall be executed in duplicate, one copy of which shall be held by the Authority, and filed in its records, and one copy of which shall be given to the contractor.