Bridge Project

This project, also dubbed “The Bridge Project”, is an initiative of Rijkswaterstaat, Michiel van der Kley in collaboration with Eindhoven University of Technology (TU/e), and an effort to innovate, apply new techniques in the building environment, specifically the 3D printing of concrete, and to find new ways to collaborate. While looking for a location, Nijmegen seemed an ideal place, following the city’s position as Green Capital of Europe in 2018, and their wish to have an eye-catching and iconic memento of that year. Rijkswaterstaat believes it is not only building a bridge, but building the future as well, turning 3D concrete printing from innovation to proven technology.

Design

Digital design and construction is expected to lead to new concepts for building, with lower risks and better conditions. 3D-printing technology has the potential for more affordable, faster, durable and freeform methods of construction. Rijkswaterstaat and Michiel van der Kley were intent on exploring designs that are almost impossible to make with traditional techniques involving formworks, to find out whether or not 3D printing allows for much greater design freedom, and other benefits as well. The possibilities of freeform construction with 3D printing also lead to new challenges, such as the approach to structural safety, the method of analysis for such shapes, and determining the input for the 3D printer. In order to elaborate and rationalize the freeform design, Summum Engineering was commissioned by the structural engineers, Witteveen+Bos, to create a parametric model.

A first parametric model was developed to generate endless geometries, similar to the designer’s intent, to either revise the design or to create other bridges for different site conditions. A second parametric model took the initial shape, conformed it to structural constraints set by the engineers, segmented it based on printing specifications from TU/e, and then generated the bridge’s internal geometry.Three types of outputs were determined: first, exterior surfaces of the segmented bridge as input to the Revit-model and 2D drawings by Witteveen+Bos; second, meshes, including of the internal geometry, as input to their finite element calculations in DIANA; and, third, printing paths for the 3D printers of TU/e, and later BAM and Weber Beamix, based on their printing specifications. A first test bridge – a single span of the entire bridge design – was produced by TU/e for load testing.