Decision Support System for Contractor Selection in Integrated Project Delivery (IPD): A Low Carbon, Sustainability-Oriented Model for Urban Infrastructure Projects

As cities pursue smarter, more resilient infrastructure, conventional contractor selection focuses narrowly on cost, which often neglects holistic sustainability. This study addresses a critical gap by introducing a novel, sustainability-oriented contractor evaluation model within Integrated Project Delivery (IPD). While IPD enables early collaboration, its integration with structured sustainability metrics remains underutilized. We develop a Multi-Criteria Decision-Making (MCDM) framework that operationalizes the three pillars of sustainability, economic, social, and environmental sustainability, with the inclusion of the technical pillar through an expanded environmental, social, and economic model incorporating sub-criteria such as constructability, workforce competence, collaborative readiness, etc. The innovative inclusion of technical sustainability deepens contractor assessment and enhances alignment with smart urban priorities. The model is embedded in a custom Decision Support System (DSS), combining Fuzzy AHP for weighting and Fuzzy VIKOR for ranking. A real-world IPD scenario, which is a proposed multi-purpose banquet facility, illustrates the tool’s functionality. Nine experts evaluated four contractors across 16 sub-criteria, with the results reflecting structured, priority-weighted decision logic. The DSS offers a transparent, replicable framework for aligning procurement with smart city goals. Its novelty lies in advancing sustainability through sustainability-oriented contractor selection, supporting policymakers, project teams, and cities in meeting integrated infrastructure objectives.