Any officer or board charged with the general supervision of the erection and repair of the public buildings belonging to the state shall prepare or have prepared plans and specifications of the building to be erected or repaired, and such plans shall be prepared in such a manner that the completed building, landscaping, and parking facilities, including the cost of equipment and fixtures necessary therefor, or the completed repair cost shall not exceed the amount authorized for that purpose. Construction may be commenced after contracts are awarded, but the obligation of the state in any biennium under such contracts shall not exceed the amount appropriated for that purpose in such biennium. When contracts are submitted to public bidding and a certain item is specified by trade name, make, or catalog number, a bid for the furnishing of an alternate item, equal thereto in the opinion of the architects and officers or board involved and submitted within the time limits set for receipt of bids, shall not be rejected solely on the basis that such item was not approved prior to the submission of bids. No officer, board, architect, superintendent, or contractor shall change any plan for any public building, for which an appropriation is made by the Legislature, so as to exceed such appropriation, and any officer, board, architect, superintendent, or contractor who violates any of the provisions of this section and section 72-801 shall be deemed guilty of a Class II misdemeanor.