Exchange of parametric bridge models using a neutral data format

Parametric modeling is a well-established methodology in the field of mechanical engineering. It allows the creation of flexible geometric models using parameters for dimensions and makes it possible to define numeric relationships between these parameters by means of mathematical formulas and define geometric-topological constraints between geometric entities. The result is a flexible geometric model which can be steered through the manipulation of its primary parameters. In contrast to explicit geometric models with fixed dimensions, a parametric model can capture the design intent and represent domain knowledge. The use of parametric modeling techniques is particularly beneficial for designing bridges. This is due to the fact that the geometric design of bridges is mainly determined by external constraints resulting from the size and the layout of both the overlying and the undercrossing carriageway. This reduces the effort required for reworking when changes are made, while simultaneously providing a high degree of reusability for the model in other, similar projects, resulting in significantly increased efficiency in the bridge design process. Due to the strong fragmentation of the AEC (Architecture, Engineering and Construction) industry, the data exchange between the different participants in a construction project is of crucial importance. The use of neutral, open data formats has proved to be the most suitable approach to realize this data exchange. However, currently existing neutral data formats do not allow for an exchange of parametric geometry. To overcome these technical limitations, this paper introduces an extension to the IFC-Bridge format, thus providing a means of interchanging parametric bridge models. This article describes in detail the necessary entities introduced to define parameters and capture dimensional and geometric constraints. The suitability of the developed extensions is proved by presenting the successful transfer of parametric bridge models between two parametric design systems as well as from a design system to a structural analysis system