Wooden roof “Grand Ring” at Osaka-Kansai Expo reaches major construction milestone

(Construction) – Japanese construction company Takenaka Corporation announced on June 7th that the symbolic “the Grand Ring” in Pavilion World West Section, under construction at the Osaka-Kansai Expo 2025 site in Yumeshima, Osaka, has reached its topping-out stage.

This section spans approximately 700 meters of the total 2-kilometer circumference and is being constructed by a joint venture of Takenaka Corporation, Nankai Tatsumura Construction, and Takenaka Civil Engineering & Construction. Initially aiming for topping-out in early August, the project achieved this milestone two months ahead of schedule by leveraging digital technologies such as BIM from design through to timber production, on-site delivery, and construction.

Wooden roof “Grand Ring” at Osaka-Kansai Expo reaches major construction milestone

During the planning phase, models created with 3D printers and BIM software were utilized to select the optimal construction method. To enhance efficiency in production preparation, an “Open BIM” approach was employed, integrating BIM software used in each phase and by each trade. This optimized the traditional Japanese “Nuki” construction technique used for the Grand Ring, minimizing wood indentation at joints and enhancing the rigidity and strength of the core structural components.

In the manufacturing phase, BIM data was input into saws and drills for timber processing, improving production accuracy through simulated machining. This automation of processes from cutting to precise drilling of components reduced production time and labor requirements. The wooden room in this section aims for completion by the end of February 2025. (2024/06/10)