Sealed proposals shall be deposited at the Administration Building, Bellefield Entrance Lobby, 341 South Bellefield Avenue, Pittsburgh, Pa., 15213, on October 1, 2024, until 2:00 P.M., local prevailing time for:. Service & Maintenance Contracts at Various Schools, Facilities and Properties:. Chillers and Refrigeration Systems Service, Maintenance and Repairs. Concrete Maintenance.