Activity-based vs. Object-based Scheduling in Construction: A Phenomenological Study of the potential shift of Construction Scheduling Process

Construction activities scheduling can be seen as the backbone process of any construction project to ensure its successful delivery. A sound construction project schedule allows informed decisions, appropriate actions and improved management of actions. Construction planning is based on activity scheduling and many tools and applications have been developed to manage durations, resources and risks. However, this is time-consuming, error-prone and insufficiently coordinated because of the continual acquisition and updating of data needed to keep the plan relevant. To help this, 4D BIM technology is seen as revolutionary digital solution which can automate much of the effort as well as producing better output and to operate this in real time. This move to 4D BIM technologies for planning puts more emphasis on the objects in the 3D model and these become the drivers of the schedule. This study aims to unpack the difference between activity based and object-based emphasis in construction project planning so that the full advantages of 4D BIM technologies can be met. In-depth narratives from planners and 4D Modeller for one of the contractors in the UK are used to capture the potential complexities resulting from using object-based scheduling. These narratives highlight the gains and shortfalls of this scheduling process, while analytically comparing it to activity-based scheduling. Analysis suggests that the phenomenological shift in scheduling practice from using 4D BIM can have inappropriate outcomes. This has deep implications on both the future development of 4D BIM technologies and construction scheduling process.