In the case of public works contracts, other than those entered into pursuant to the small works roster process, bids filed shall be accompanied with a certified check, cash, cashier’s check or bid bond payable to the city in an amount of five percent of the estimated cost of the work. If a bid is accepted, then all checks or bid bonds shall be returned to the bidders, except that of the accepted bidder, which shall be retained until a contract is entered into. If the bidder fails to enter into such contract in accordance with his bid within 20 days from the date upon which he or she is notified that he or she is the successful bidder, the check, cash or bond shall be forfeited to the city, to the credit of the fund from which the contract was to be paid. [Ord. 1998-04-016; Ord. 8884 § 7(A), 1980].