4D CAD models to support the coordination of construction activities between contractors

• Practice based study showing the utility of 4D CAD for co-builder coordination.
• 4D CAD helped to align construction engineering design.
• 4D CAD helped to align construction sequences.
• 4D CAD helped to coordinate construction operations.

Construction projects are characterized by the existence of a number of different co-building companies that together deliver a constructed product on site. The work tasks of all these different co-builders need to be aligned to allow for the efficient delivery of the product. To allow for smooth alignment, all co-builders work together in the planning phase to rule out unwanted conflicts between work activities. Despite these efforts, many projects still accrue costs forced by on-site conflicts that were not anticipated beforehand and require costly improvisation to be resolved. The potential of 4D CAD models to avoid costly on-site improvisation by providing possibilities to anticipate conflicts better in the planning phase has been widely acknowledged. However, little empirical evidence exists that illustrate these benefits. This paper provides such evidence by providing in-depth narratives of how 4D CAD models helped to foresee conflicts on a major railway station renovation project in the Netherlands. These narratives describe in detail how practitioners on the case study successfully used 4D CAD models to coordinate their construction engineering designs, their construction schedules, and their construction operations. With these findings, the paper contributes to 4D literature by providing empirical case-based evidence for the benefits of applying 4D CAD models to plan construction work.