Construction of bridges has always been an area of occupational interest since ages. Various designs and blueprints have been created by engineers to get their desired layout. What if there is no more the need for engineers to indulge in these construction activities? If this is the situation, will it not reduce the workload of generating designs and building the same, to a minimum?

This is demonstrated in the project initiated to build a bridge of length 12 meters across Amsterdam canal. MX3D, a start-up based in Amsterdam, has taken steps to 3D print this pedestrian bridge across the Oudezijds canal. Tim Geurtjens, the Chief Technology Officer of MX3D candidly describes the initial idea of making use of a frayed robot arm and placing a welder on it, such that this arm starts printing from either side, thus connecting the whole structure in the middle. Although this concept seemed quite simple, yet complications emerged.
As opposed to advanced 3D printing technologies such as Selective Laser Melting (SLM), or Direct Metal Laser Sintering (DMLS), the MX3D team decided to go with a simpler conventional method, i.e., welding. They inculcated the MIG welding technique which, as we know, makes use of molten metal for ensuring strong fusion. Although the idea of using this technique is worth-appraisal, the complexity of controlling this process had troubled them.

Similarly, to avoid corrosion related problems, the use of stainless steel was considered to be the ultimate solution. The use of steel further required the use of a coating on the surface to avoid corrosion. This, in turn, would subdue the fact that the bridge surface is made up of steel and is completely 3D printed.
As explained by Geurtjens, they invested in developing software related features, and different 3D printing strategies for different requirements such as for orientations such as vertical, horizontal, or spiral, for different pulse time, for the appropriate layer height, and other such specifications. Irrespective of this, certain conditions such as the dire necessity of having the supply room nearby, the importance of covering the welding machine and the robot from the weather conditions to avoid rusting, the need of having a logistics centre nearby, and the impending cost made the process very complicated. In order to address all these issues, they came up with a plan to set up their lab nearby, thus being able to continue with the fabrication of the bridge. Once built, the bridge can be subjected to various tests and situations which would then make it easy to be transported and put in public places.
The likelihood of developing voids during the printing process, and thus the generation of oxides on the bridge surface was another setback they faced with. To ensure the durability of the material, the whole structure was employed with sensors that monitor and analyse the overall performance of the bridge, even when the development process is in motion. These sensors take into account various factors such as displacement, strain, quality of the air, the temperature of the atmosphere, and others which permit rectifications to be done in real-time by regulating the changes as and when required.

All these advanced processes were carried out with the help of Autodesk which provides various cloud services for the synthesis of various data and processing of bridge’s information. The Alan Turing Institute has various qualified and experienced researchers which simultaneously work with MX3D in generating machine learning algorithms for the bridge to interpret its surrounding. With the development of a digital model of the bridge, strength analysis can be done easily. These physical tests then aid in comparing the theoretical situation with the real one, thus making it tailored to any known or unknown changes. This not only reduces the risk of faltering in any unwanted situation but also ensures the longevity of the bridge for the pedestrians under various conditions.
Thus, this autonomously manufactured bridge has been able to consolidate every single technological advancement in terms of 3D printing and thus has put forward promising challenges to those who state this to not being strong enough to be implemented. Measuring a type of deformation, or lacuna in the structural integrity of the bridge, in real-time has been made possible by the sensors and monitors used in the construction of the bridge, thus ensuring us to be less concerned with the functioning of this bridge to be built in Amsterdam.