Obayashi Corporation has constructed a shell-like bench (7m-wide, 5m-deep, and 2.5m-high) composed of curved surfaces only, without using steel bars and formwork, by a 3D printer with cement-based materials at its Technical Research Institute in Kiyose, Tokyo. This is one of the largest 3D printed structures in Japan.

First, special mortar is continuously extruded from a nozzle attached to a large robotic arm and laminated at 3cm-wide and 5mm-thick to produce a frame to replace the formwork. Next, the UFC (Ultra-High-Strength Fiber-Reinforced Concrete) called "SLIM-Crete®", which does not require rebar reinforcement, is poured into the frame to integrate into a piece. Watch the video to see how the shell-like bench with a complex shape, yet high strength and light weight, was completed.

(Video playback time: 3minutes, 02seconds)

Obayashi Corporation will continue to develop new technologies to increase the freedom and possibilities of design and to provide society with buildings that can be used safely and securely.