Longest 3D-printed steel bridge
MX3D Bridge
8.718 metre(s)
Netherlands (Amsterdam)

The longest 3D-printed steel bridge is the MX3D Bridge, which spans the Oudezijds Achterburgwal, a canal in the De Wallen district of Amsterdam, Netherlands. The bridge, which was formally opened by Queen Máxima of the Netherlands on 15 July 2021, was made using robotic 3D printing technology by Dutch engineering firm MX3D and has a span of 8.718 m (28 ft 7 in).

The MX3D Bridge was designed by Joris Laarman Lab with engineering support from Arup, and built by MX3D at their facility in Amsterdam. The 3D printing process saw the bridge built up, layer by layer, using commercial off-the-shelf robotic welding systems controlled by MX3D's custom software. As a result, the bridge is a single continuous piece of metal, with no joints or separate sections. Structural testing carried out by researchers from Imperial University London and the University of Twente demonstrated that the 6 tonne structure was able to support a weight of 19.5 tonnes – well above its design load.

The idea for the bridge came from MX3D, who in 2015 decided to test their technology by building a bridge over one of Amsterdam's many canals. The robots started work in March 2017, and finished construction around a year later. However, delays relating to permits and necessary reinforcement of the existing canal walls (as well as COVID related shutdowns) delayed the installation of the bridge until 2021.

During the wait for the bridge's installation, MX3D worked with its academic partners to fit the bridge with a network of sensors that track the load, patterns of strain and many other parameters. It is hoped that this "smart bridge" technology will not only allow engineers to better understand the structural performance of this 3D printed design, but also to learn more about patterns of activity and movement in the area.