The Effects of Building Information Modeling on Construction Site Productivity
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Construction experiences low productivity compared to other industries, largely attributed to poor planning and communication. Building Information Modeling (BIM) is a process that is used to resolve these problems by simulating physical space and expressing design intent graphically, providing a clearer image of design conflicts or constructability issues so that they are resolved before construction begins. Productivity rates increase as BIM practices are implemented because rework and idle time are reduced for laborers.
Case studies of projects utilizing BIM indicate field productivity gains from 5 to 40%, depending on how the process is managed. Although the amount of savings is guarded closely by those who measure and track the changes in their productivity rates and unknown to many contractors, there are indicators that reveal increased productivity. Key indicators of increased productivity are RFI reduction, amount of rework, schedule compliance, and change orders due to plan conflicts. Each of these affect the various stakeholders of a project to different degrees but the overall effect is a net savings for the owner ranging from a few percent for competitive bid projects to over 10% for integrated projects. BIM-enabled projects have 10% of the RFI that a typical project would have so that contractors realize an average savings of 9% in management time. Reduction of rework and idle time due to site conflicts savings for trade contractors are on the order of 9% of project costs. The abilities to prefabricate and automate site processes are also significant advantages of BIM usage experienced by trade contractors. The most significant savings are attributed to the clash detection process which eliminates conflicts in the field. These findings show that the strongest determinants of success on BIM projects in terms of site productivity are human factors rather than technical.