For inquiries about requests for bids and proposals for contractor and consultant services, call 412-350-5914. Resources. Construction contractors interested in performing construction contracts with the department must first complete the Vendor Registration process.View Public Works' open solicitations, and learn more about how to register as a supplier and submit a bid or proposal. Bids may be uploaded to the Authority's online submission site; the link is accessible via the HACP website and within the IFB. DUNS, SAM and CAGE Registrations Required to Bid on Federally Funded Projects.