This means that you'll be able to search for NAICS codes directly (if that's your jam). We'll do the math; let's make better data on public procurement together.
Possible NAICS Codes
237310 – Highway, Street, and Bridge Construction
236220 – Commercial and Institutional Building Construction
237990 – Other Heavy and Civil Engineering Construction
115310 – Support Activities for Forestry
238990 – All Other Specialty Trade Contractors
238110 – Poured Concrete Foundation and Structure Contractors