Cost Estimating Methods for RC Structures by Quantity Takeoff and Quantity Prediction in the Design Development Stage

抄録

The cost estimating methods for reinforced concrete structures based 3D design can be categorized into quantity takeoff (estimation) and quantity prediction in the design development stage. The main estimating elements are concrete and formwork that can be considered in a quantity takeoff, whereas the quantity prediction element is the reinforcing bars in the design development stage.
This study proposes a cost estimation system that applies automatic quantity takeoff and quantity prediction with parameters. Firstly, the logic of a quantity takeoff calculates the quantity of formwork with the object information. The Standard Method of Measurement (SMM) automatically estimates the quantity of formwork upon receiving physical shape information from the 3D-object. Secondly, the logic of quantity prediction estimates the quantity of reinforcing bars with data mining tools such as the Decision Tree Model (DTM) and Case Based Reasoning (CBR). To predict the quantity of reinforcing bars, Information Gains (IG) of design attributes are evaluated, and then the valid attributes are selected as the parameters. The Parameters can statistically classify the quantity of reinforcing bars by generating decision tree nodes.