BIM processes and workflows using the example of the subway extension in Stockholm

Three major technical and economic factors of the “Yellow Line” project of the Stockholm subway network justify the decision to apply a BIM-oriented design: (1) Early optimization and risk minimization for cost and time and active counteraction to the loss of information throughout the entire lifecycle of the project, (2) all technical aspects are to be incorporated in the design simultaneously and from early stage onwards, (3) numerous surface and subsurface structures, including tunnels under operation and in vicinity of the new line lead to a complex geometrical layout and geotechnical influences on each of these structures are to be minimized. Commercial 3D/BIM products have proven to be developed for application in surface structure design and new methods had to be established to cope with high quality tunnel modelling, coordination and tunnelling challenges. This publication is addressing the experience and solutions made during the design: Choice of appropriate modelling tools, applied methodology for a structured design process in a multidisciplinary and manifold work environment, accounting to highly complex geologically-geotechnical data, seamless transfer of the model data to numerical analysis tools. The advantages and disadvantages of using BIM methodology are discussed and recommendations with regard to future development are presented.