The construction industry faces problems in interoperability. Information is not easily interpreted nor accessed by participants. The insufficient level of interoperability occurs due to fragmentation between disciplines in the construction industry. To enhance interoperability, Building Information Modeling (BIM) formed a collaborative model that connects team members. However, the different disciplines continue to share information that cannot be directly used by others. This situation is present between designers and cost engineers. Despite working in a 5D BIM model that considers cost information, fragmentation between these disciplines persisted. Costs do not guide the design and they are computed after the model matures. Furthermore, the detachment of design and cost estimation processes led to the segregation of information in BIM. Addressing the problem of fragmentation between processes, the research aims at investigating the main question: How can design and cost estimation be effectively integrated using 5D BIM?
To answer the research question, several steps were performed. From the case study research, the following issues on fragmentation and BIM application are identified: [1] unsteady involvement of the cost engineer in the design, [2] limited influence of the cost engineer on the design, [3] model complexity, [4] incompatibility of model information and cost estimation, [5] absence of standardized and uniform information representation, and [6] resistance of clients and practitioners to the application of BIM/5D BIM.
By countering these issues, the “Integrated Design – Cost Estimation 5D BIM Process” is designed to answer the research question. The integration between design and cost estimation via 5D BIM focuses on cost driving components which are components influencing costs. Accordingly, these components are considered as key for communication, discussions between designers and cost engineers, and model development. Focusing on cost driving components, the process balances the information in the model. The information in the model is checked for compatibility with the estimate’s accuracy. Furthermore, the process proposes the consideration of the cost engineer’s perspective in the design. Then, 5D BIM is incorporated in the designed process by standardizing information and following the semi-automated approach for cost computation.
To assess the effectiveness of the integration addressed in the research question, a pilot case is performed to test the process in a running project. From the observations, it is concluded that the process provided a standard representation of objects, enhanced the communication between the designer and cost engineer, and involved the cost engineer earlier in the design. Furthermore, the pilot case led to the conclusion on barriers to BIM implementation. These include: the cultural change from individual effort to collaboration, lack of support from the management and client, inadequate planning for BIM application, and the inexperience in applying 5D BIM. These factors limited the successful implementation to reach effective integration. Despite the limited integration achieved in the pilot case, project participants and interviewed BIM experts ensured that the process leads to effective integration. However, it is crucial to respond to the noted barriers to have effective integration between designers and cost engineers via 5D BIM.