Longest 3D printed concrete pedestrian bridge begins to take form

The world’s longest 3D printed concrete pedestrian bridge, co-commissioned by Rijkswaterstaat (Dutch Directorate-General for Public Works and Water Management), is being built in Dukenburg in the city of Nijmegen, Netherlands, and printed in Eindhoven, where the 3D printing facility of BAM and Weber Beamix is located. Summum Engineering was responsible for the parametric modeling, in order to elaborate and rationalize the freeform geometry, designed by Michiel van der Kley.

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.

The longest 3D printed bridge in the world, soon be installed in Nijmegen, is now in full swing and four more bridges for North Holland are in the pipeline at Weber Beamix. Sometimes it may seem that 3D printing is used only mainly for aesthetic display projects but the truth that is increasingly emerging is that printed objects have been finding their way to more practical applications, and a very large market is rapidly developing, all over the world, with huge projects now underway all over Europe, in the US, in Africa, in the Middle East, in China and in Australia.

Digital design and construction are 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. A first test bridge was produced by TU/e, and the final bridge will be printed and assembled by BAM, using the joint printing facility set up with Weber Beamix.

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.

This 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.