An integrated lean-digital framework for optimizing civil- engineering supply chains: mixed-methods evidence from multi-project case analyses

All around, civil engineering megaprojects are still struggling with budget overruns, schedule slippage,and disjointed supply-chain coordination. This paper conducts an embedded, multiple-case study ofpublicly recorded projects spanning Asia, Africa and the Middle East. Using a pragmatist mixed-methodsapproach, we thematically coded secondary reports, audits and peer-reviewed case narratives;descriptive statistics were used to investigate related cost- and time-performance data. Convergenttriangulation found four common levers distinguishing better performers, early strategic alignmentamong stakeholders, proactive scenario-based risk management and digitally enabled transparencythrough (BIM) and (IoT) twins. Collaborative contracting cultures such as Integrated Project Delivery.Projects using these levers reduced lead-time variation by as much as 17% and cost overruns by 4–6percentage points. Building on these ideas, we suggest an Integrated Lean-Digital Frameworkcascading through Strategic Alignment, Collaborative & Digital Integration, OperationalExecution and Continuous Improvement & Sustainability. Though reliance on secondary datareduces statistical generalizability, deliberate case selection and cross-source triangulation improvetransferability, therefore offering a consistent path to fight fragmentation. This synthesisoffers practical advice for managers and politicians.