Production and Cost Estimating for Trailing Suction Hopper Dredge

Abstract

Major dredging projects in the United States are typically contracted out by the government using a competitive bidding process. A method for accurately estimating the total cost associated with performing the dredging work is essential for both government solicitation and the bidding contractors. This thesis presents a method to determine production rate for trailing suction hopper dredges when minimal information is known about both the site to be dredged and the hopper dredge being used. The calculated production rate is then combined with financial inputs to estimate a total dredging cost and project duration.

The production and cost estimation is incorporated into a publically available program designed on Microsoft Excel. The program utilizes fluid transport fundamentals, dimensionless pump curve analysis, and overflow loss assumptions to create a highly customizable program across a wide range of hopper dredge project types. In addition, the program allows a user to reduce or expand the scope of cost estimating depending on project requirements.

Results for the program were found to satisfactorily estimate total project costs and dredging operation costs for eight major dredging projects between 2013 and 2015. Through the utilization of default hopper specifications and project specific site characteristics the program generated a mean absolute percent difference of 21% for the total project costs and 20% for the dredging operation costs alone.