Due to many uncontrollable and often unpredictable factors such as groundwater inflow rate, equipment availability and cost, weather, and various geological details, drilled shaft construction can become highly complex. Decisions on how best to install drilled shafts are made by foundation subcontractors however, the assistance of these experts is not always easily obtained. Thus, a decision support system called DS 2 has been developed to assist in the construction of drilled shafts. It is composed of three prototype expert systems that interface with spreadsheet, database, and graphics packages. It uses a heuristic, rule-based, backward-chaining system to analyze geological information, suggest a construction method, prepare a preliminary cost estimate, and suggest key specification items.