The raising of the center section of the timber roof of the gymnastics venue for the 2020 Tokyo Olympics took place Wednesday, with the under-construction interior opened to the media.

The second of five sections of the Ariake Gymnastics Center roof that was raised is 70 meters wide and weighs 200 tons, one of the world's largest timber roofs. Once completed, the overall roof will be around 120 meters long and 90 meters wide.

Expected to be completed by October next year, the facility features domestic wood as a primary material. Aspects of Japanese culture and traditional building methods are incorporated in its design and construction, said games organizers.

The Ariake Gymnastics Center will be converted into a convention and exhibition center after the Games and be retained until 2030.

The semi-temporary venue is located in Ariake, in the Olympic hub close to the Olympic and Paralympic village. The structure will have a capacity for 12,000 spectators.

It will also be the home of the boccia events for the 2020 Paralympics.

The raising of the roof was good news for games organizers after the revelation last month that Olympic venues are among the nearly 1,000 buildings using earthquake shock absorbers produced by KYB Corp., which admitted cheating quality inspection data for more than a decade.

The Olympics Aquatics Center and Ariake Arena, which will host volleyball and wheelchair basketball, use KYB products -- although the infrastructure ministry said there was no risk that the affected buildings could collapse, even if they were hit by a quake at the top of Japan's seismic intensity scale.