Development Of The National BIM Standard (NBIMS) For Precast/Prestressed Concrete

Part 1 of the National BIM Standard (NBIMS) lays out the generic guidelines for developing specialized model views, defined in terms of industry foundation classes (IFC), for various exchanges. These model views are typically applicable to specific design or construction processes, or specific construction technologies. Various efforts have begun to develop such specialized model views. One of these pioneering projects has completed a model view definition for the planning, design, documentation, construction and fabrication phases of precast/prestressed concrete construction. In doing so our team had to deal with a range of issues stemming from the breadth and depth of the information exchanges. This paper presents the challenges experienced in compiling a BIM standard for precast/prestressed concrete. We discuss acquiring exchange requirements (ERs) from a diverse set of industry participants, rationalizing and formalizing them into information delivery manual (IDM), and finally developing model view definitions (MVDs) with specific IFC implementations that respond to the initial requirements. The model views are defined using information “concepts”. Each concept is then detailed with IFC 2x4 entities and relationships, which rigorously define how the concepts are to be implemented in ISO STEP EXPRESS-language functions. We propose several approaches for dealing with the breadth and the depth of information exchanges during the IDM and MVD development that allow for logical breakdown of the processes and the data types. Additionally we examine specific challenges that pertain to the fabrication and construction of precast concrete. We generalize the lessons learned in three different categories according to the NBIMS process phases: requirements development, model view definitions and implementation specifications.