A Decision Support Tool for the Valuation of Variations on Civil Engineering Projects

Abstract

The valuation of variations has been recognised as a prime cause of conflict and dispute in construction management. Such disputes often concern the prices and/or rates to be applied to the varied works. Previous research has identified the subjectivity of the decision-maker in interpreting the valuation rules to be the major problem, particularly with regard to defining the work conditions and/or characteristics during a variation event. Findings of a survey, conducted to elicit the views and perceptions of experienced practitioners towards interpreting the valuation rules are presented. The development of a decision-making tool based on a robust framework for valuing variations in civil engineering projects is described. The tool was developed by analysing changes in various decision attributes. The result of the changes was then mapped to relevant sets developed using fuzzy-logic principles. Various operators were used to perform the fuzzy-aggregation operation. The modelling technique was demonstrated to be reliable in replicating the decision-making process performed by experienced practitioners. As such is considered a suitable aid for decision-making involved in valuing variations on civil engineering works. The results of the analysis reported here have suggested the fuzzy-logic as an appropriate tool to model human decision-making, particularly in valuing variations on civil engineering works. This is considered an essential progress of the current study in modelling human decision-making process, particularly since there are so many unknown aspects associated with such a process. The modelling technique successfully developed here is then used as the main algorithm for decision-making in the subsequently developed Knowledge Based System (KBS) which is intended to assist practitioners minimise conflict and dispute arising from the valuation of variations.