Demonstration of Fabrication and Construction Technology for Integrated Large-Scale PCa Members Using Construction 3D Printers

JGC Global, an overseas EPC subsidiary of JGC Holdings Corporation, in collaboration with Taisei Corporation, has demonstrated a fabrication and construction technology for large-scale precast (PCa) members by using construction 3D printers to form integrated formwork for columns, beams, and slabs, as part of their efforts to digitize production processes.

In this demonstration conducted in Namie Town, Fukushima Prefecture, 3D printers were used to create permanent formwork. After placing reinforcing bars inside, concrete was poured, creating large, integrated PCa members. This initiative represents the first project executed based on the Japan Society of Civil Engineers' 'Technical Guidelines for Concrete Structures Using 3D-Printed Permanent Formwork' (published in July 2025).

In the construction industry, the severe shortage of skilled workers makes improving productivity a critical challenge. While the PCa method is widely used for labor and time efficiency, the increasing size and complexity of plant and infrastructure structures have made construction work and quality management more cumbersome due to the increased number of members.

To address this, the new technology enables the integrated production of column, beam, and slab PCa members—which were traditionally produced and joined separately—by using 3D-printed formwork. This significantly reduces the number of parts and joint assembly tasks. This enables labor savings and shorter construction schedules, with future targets of a 50% reduction in labor and a 15% reduction in costs. Furthermore, the simplified process reduces high-altitude and manual work, contributing to better construction efficiency and safety.

JGC Global has previously introduced large-scale gantry-type cement-based 3D printers from Denmark's COBOD International A/S for domestic and international demonstrations. Meanwhile, Taisei Corporation has accumulated know-how in materials and construction technology through the development of its 'T-3DP' construction 3D printing technology. This demonstration integrated the large-scale printing equipment with high-performance printing materials to realize the integrated production and construction of large-scale PCa members at full scale.

It was confirmed that quality equivalent to or higher than conventional methods can be ensured even when combining equipment and materials developed by different companies. This result marks a major step toward the practical application of large-scale PCa members utilizing construction 3D printers.

[Features of the Technology]
- Improved construction efficiency and safety through integrated modeling: Reduces the number of members and assembly tasks, decreasing manual and high-altitude work.
- Improved productivity through near-site printing: Near-site production eliminates transport restrictions and helps lower costs by utilizing locally sourced materials.
- High applicability to large, complex structures: Highly flexible for complex structures, such as plant support frames where piping and peripherals cause interference.

The demonstration confirmed that the designed shapes and strengths could be achieved, verifying effects in shortening schedules and reducing workloads. Both companies plan to further advance and standardize this technology to promote its use in domestic and international construction projects, aiming to transform the entire construction production process.