Spie batignolles is experimenting with 3D printing of concrete materials for construction sites to produce prefabricated elements with high applicability. In collaboration with XtreeE, a start-up specializing in 3D printing for construction, Spie batignolles carried out its first experiments in additive manufacturing in concrete.
“We are convinced of the interest of the 3D printing technique for developing small concrete elements, the traditional production of which is generally time-consuming. These techniques will improve the working conditions of our employees on the site, our productivity and ultimately our performance, ” explained Frédéric Gaurat, Technical Director at Spie batignolles.
The company is aware that 3D printing is emerging in the building sector, however it is mainly confined at this stage to the construction of small detached houses or the printing of non-structural decorative elements. These applications are not yet seen as capable of driving real organizational changes in the construction industry, a sector heavily faced with a labor shortage.
Spie batignolles is now set on developing the use of construction 3D printing at its sites, with the desire to go further. The firm Spie set the goal of using 3D concrete printing on replicable elements incorporated into the structure, an area where this technique presents an interesting alternative to traditional methods.
Two examples of direct application of this new construction method include the formwork of complex beam nodes and the production of reservation boxes.
The nodes of beams on columns (see image at the top of this page) concentrate significant loads on small surfaces. In the design of certain complex floors, the final geometry of these nodes is very often unique: 3 or 4 beams, of different width, height and angle, must be joined together on the same post. In the traditional method, the realization of the formwork for these elements consumes single-use materials and labor hours, it needs to be carried out in several phases, and could be a source of critical low-quality parts.
Based on this observation, the technical direction of Spie batignolles set out to find a solution to address all these challenges. In partnership with XtreeE, Spie batignolles designed, printed and then implemented the formwork for a beam node, incorporated into the structure, with a complex geometric shape, allowing the beams to be joined on the column in a single phase.
“The first prototype produced at scale on a node of three consequent beams enabled us to validate the process. This test met a majority of our requirements with very conclusive results. It encourages us to continue our developments in order to make this process even more efficient and to extend it to several projects from 2021,” explained Gaurat.
In this project, the teams industrialized the formwork beam node “off-site”. The use of the digital model linked to 3D printing allowed the technical department to very quickly produce a unique complex part which simplified the realization of the work on site.
The reservation boxes are one of the most basic formworks in a construction site. Traditionally made of wood, they are used to provide for the passage of the various electrical networks, HVAC and plumbing after casting the concrete walls. Although essential, their implementation does not require any particular technical expertise but still results in significant labor time.
Spie batignolles and XtreeE have succeeded in printing reservation boxes in just 24 hours by using Ductal concrete, which has the advantage of drying very quickly and solidifying very strongly. The boxes were thus incorporated into the finished work and did not need to be removed. The tests carried out on-site made it possible to validate this application of 3D printing.
In this second case, Spie batignolles industrialized “off-site” the production of series reservation boxes. Thanks to BIM, reservations were optimized (number, standardization of dimensions) and the fact that they were 3D printed made it possible to do away with many tasks such as making the wooden box, removing formwork at height after pouring, or even disposing of the wood – made to be non-reusable – in dumpsters.
In these 2 application examples of 3D printing, the final objective was to industrialize the act of building from design to implementation on the site, striving for better performance. This new construction method leads to adapting the “tailor-made” or “large series” from the digital model. Each time, this process makes it possible to gain in terms of safety (less work at height), quality (finished element incorporated in the structure), time and economic performance.
With the design of these first constructive elements resulting from 3D printing, Spie batignolles is now fully committed to the era of construction 4.0 and continues to work on new developments bringing together the characteristics of recurrence, resistance, durability and safety.
“This new construction method opens up important perspectives and will participate in a profound transformation of our construction trades towards increasing industrialization, as its strengths are undeniable in terms of profitability, quality of construction, execution time and safety,” concluded Gaurat.