Developing a bi-parameter bidding model integrating price and sustainable construction practices

The existing contractor selection models, and specifically the lowest bidder model, do not encourage contractors to adopt sustainable construction practices. This article proposes a new bidding model that incorporates sustainable construction practices. The proposed A + S model takes into consideration the bid price (A) and the monetary value for the use of sustainable construction practices (S). The (S) parameter is taken as a negative value to act as an incentive rather than a deterrent. Twenty sustainable construction practices were identified. A survey was conducted to measure the importance of each practice. The Analytic Hierarchy Process (AHP) was used to calculate the weight of each practice. The top five sustainable practices were eliminate toxics, air & dust control, project management, health & safety and quality management. The average monetary value of the selected sustainable construction practices, relative to construction cost, was 20%. The proposed model encourages contractors to implement sustainable construction practices to improve their chances in winning bids.