Design-bid-build is the most common project delivery method in commercial and residential construction. The owner hires the architect to develop drawings and specifications. After design is complete (or near complete), the owner solicits competitive bids from GCs based on the finished documents. The lowest qualified bid typically wins, and that GC executes a fixed-price contract for the work as drawn.
DBB is preferred when the owner wants maximum price competition and has the time to wait through full design before construction starts. The trade-off: GCs have no input on constructability during design, change orders are common when the drawings have errors, and the schedule is sequential rather than overlapping. Compared to design-build and CMAR, DBB usually produces the lowest hard cost but the longest total project duration and the most adversarial owner-contractor relationship.