RESEARCH AND EXPERIMENTATION
The use of 3D printing in building construction has been a subject of research at Centrale Lille for several years. The focus has been on two aspects: the industrialization of building sites and their modernization. Bouygues Construction has teamed up with the school in this research with the aim of incorporating operational solutions in its building activities. In 2015, a thesis on 3D printing in building construction, the first in France, was done at Centrale Lille with support from Bouygues Construction’s R&D department.
Meanwhile, a patented technique called BâtiPrint3D has been developed at the Université de Nantes. Bouygues Construction then carried out a demonstration project with the printing of the Yhnova house, which got under way on September 14, 2017. The robot’s metal arm deposits beads of polyurethane, building up two layers to create the formwork into which the concrete is poured. These foam layers will also serve as insulation for the house. With this process, 55 linear meters of wall are printed in just 54 hours. “We learned a great deal in this trial project that will be useful in developing future building methods,” says Bruno Linéatte, an R&D manager at Bouygues Construction who specializes in construction techniques. In the Inno’Shape project at Lille, a different technology, one developed by the Dutch start-up Cybe, has been used. The printer head at the end of the robot arm deposits layers of concrete fed to it by a pump. In 3D printing, a computer program controls the machines and determines the trajectories in the pouring process.
Yhnova. It is a perfect name for this 95-m2 residential housing unit, the first to be built anywhere with 3D printing technology while complying with building regulations. Inaugurated on March 21, it was constructed in a joint project by the Université de Nantes, Bouygues Bâtiment Grand Ouest, and its customer Nantes Métropole Habitat. More than 800 people came to see it.
Another 3D printing initiative, Inno’Shape, is under way at Lille. There, the objective is to print individual homes using a robot. This project is being carried out in cooperation with the Construction 4.0 chair at the engineering school Centrale Lille, a partnership initiated in early 2015 by Bouygues Construction to explore how digital technologies can modernize construction methods.
GREATER SAFETY AND FLEXIBILITY
The other advantage is the much greater freedom in creating forms. “Making a curved wall is no more complicated for a printer than making a straight wall. The wide variety of forms obtainable is something new for architects,” says Laure Ducoulombier, manager of the Construction 4.0 chair for Bouygues Construction. The 3D printing projects are still in the trial stages, and adjustments will be needed. Once development of the technologies is further along, it will be possible to boost productivity by cutting both the time and cost of building. Longer term, the materials used in the printing process will become more environmentally friendly, with quantities limited to just what is required. “Robots are one solution to make our construction projects faster, cleaner, and safer,” says Linéatte.
The printing techniques tested at Nantes and Lille are complementary. Yhnova is a promising technology intended mainly for the construction of external walls and newly designed, low-cost housing units.
With Inno’Shape, on the other hand, hyper-personalized architectural designs with complex forms are possible. The next step for Bouygues Construction is to develop a way to pinpoint the parts of a building for which 3D printing would be preferable to conventional construction methods.