Development of Mitigation Cost Estimates for Unstable Soil and Rock Slopes Based on Slope Condition

Following the adoption of Transportation Asset Management principles for bridges and pavements, some state transportation departments are realizing the opportunities for extending the same principles to manage their geotechnical assets, such as unstable rock and soil slopes. The asset inventory and detailed rating information can be used to consistently describe the condition of sites across the department’s transportation system. If conceptual mitigations are developed for a sufficient number of inventoried sites, then correlations can be developed between asset condition and conceptual mitigation cost. These cost correlations can in turn be used in programmatic-level planning. As part of the Geotechnical Asset Management (GAM) Program currently under development by the Alaska Department of Transportation and Public Facilities (AKDOT), preexisting detailed condition rating and conceptual mitigation cost datasets were obtained from the Montana Department of Transportation (MDT) and Washington State Department of Transportation (WSDOT) for unstable rock and soil slopes, respectively. These datasets were used to develop Condition State – Mitigation Cost correlations that AKDOT could apply in the initial phases of high-level planning for programmed work to be done in a transportation corridor. Use of these datasets allows AKDOT to model mitigation costs and reinvestment levels based on deterioration rates and develop initial cost correlations that can be improved upon as AKDOT’s own GAM program matures.