Except as otherwise provided in this chapter, purchases and contracts for supplies, services, equipment and construction projects, which are equal to or in excess of the bid requirement amount specified by council resolution, shall be by written contract with the lowest responsible bidder pursuant to the procedures prescribed in this article. (Ord. 1435 § 1 (part), 2003: Ord. 954 § 2 (part), 1983: prior code § 2952.1)