<![CDATA[Background: Foundation design changes triggered by differing site conditions can alter quantities, activity logic, durations, and costs in design-build projects. Objective: This study evaluates how integrating Building Information Modeling (BIM), the Critical Path Method (CPM), and Earned Value Management (EVM) supports time- and cost-based assessment of a foundation design change in the Pelindo Office Tower project. Methods: A descriptive case-study design was applied using contract records, working drawings, schedule and cost data, and project documentation. Autodesk Revit 2024 was used to generate three-dimensional models and perform Quantity Take-Offs (QTOs); Microsoft Project 2019 was used to identify zero-float activities and calculate performance indicators; and Autodesk Navisworks Manage 2024 was used to visualize four-dimensional and five-dimensional sequences. Contract conditions were compared with the research model. Results: The design change increased the number of pile locations from 738 to 746 and the total pile length by 1.08%; however, the modeled duration decreased from 87 to 67.31 days, representing a 19.69-day (22.63%) reduction in duration. The research-model budget was IDR 16,919,996,110, which was IDR 570,693,850 (3.26%) below the initial contract value. This budget difference was associated with resequenced activities, optimized use of the Hydraulic Static Pile Driver, reduced waiting time, and lower time-related indirect costs. This difference should be distinguished from the EVM cost variance reported within the research model and should not be attributed to software integration alone. Conclusion: The framework improves traceability from design quantities to critical-path logic and earned-value indicators, supporting more informed decision-making under design uncertainty.]]>
