Construction of a decision support system for determining daily work quantities in the port construction cost estimation standard

Abstract

The Port Construction Cost Estimation Standard is a practical document that includes decision-making procedures for arriving at appropriate values through the organization of site conditions, the selection of construction methods, and the confirmation of required estimation conditions. In the design stage, determining daily work quantities is difficult for less experienced engineers, because it is not always clear which decision path should be followed and under what conditions a value can be finalized, creating a risk of adopting values despite insufficient conditions. In this study, focusing on backfilling material placement, we developed a decision support system that determines daily work quantities through the sequential stages of construction method identification, Q-formula selection, coefficient determination, capacity value selection, and final value calculation. At each stage, the system returns one of four states—proceed, ask, stop, and candidate—thereby explicitly handling suspension and confirmation requests under insufficient conditions. In addition, the system distinguishes intermediate values from final values and enables traceability to the original PDF document as evidence. The evaluation confirmed the system’s ability to stop under insufficient conditions, propagate upstream decisions to downstream stages, distinguish intermediate values from final values, explicitly present the final value, and ensure traceability to the original source document.