Story at a glance:

  • This Bali School has led by example, emphasizing sustainable education since 2008.
  • The Green School’s newest and largest structure is The Arc—made entirely of bamboo.
  • IBUKU designed The Arc after being inspired by the belly of a whale.

The campus of the Green School in Bali is dense and green, with structures made from natural materials using both ancient techniques and modern technology. At the center of an open field, bordered by palm trees, stands the school’s largest and newest structure—The Arc.

Standing underneath the Arc’s gracefully sloped roof you feel like you’re in the belly of a whale, staring up at detailed weavings and large arches. The Arc spans more than 60 feet across and reaches 45 feet tall. The structure is built entirely with bamboo; its weaving arches are not only aesthetically beautiful but an impressive feat of engineering.

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The Arc’s design was inspired by a mammal’s ribcage. The structure’s long arches are held in place by tensioned anticlastic gridshells. Photo by Tommaso Riva

Architecture firm IBUKU has designed the Green School’s buildings since the school opened in 2008, and they’ve built a world-renowned reputation for their innovative ways of working with natural materials. The Arc itself mimics shapes found in nature since the beginning of time, while also being a new type of building entirely.

When Green School founders Cynthia and John Hardy first conceived of the project, they too dreamt of building something new—a campus made from bamboo. More than a decade later, as the school prospered, the founders set out to build the largest assembly space on-campus.

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The Arc was not only designed as a gym for children to use but also as an event space. The design team wanted to make a building that the entire community would enjoy being in together. Photo by Tommaso Riva

The design concept stems first from its purpose as not just a place to meet, but as a school gymnasium. The vertical height clearance was non-negotiable as it was vital to meet local code requirements and to play sports unobstructed. The architects needed to have adequate natural light and airflow while also providing a sense of enclosure to the space. The arch of the bamboo inside reflects the path of a ball when being thrown through the air.

In its earliest stages, the simple solution was to use a roof over curved trusses. But the design team refused to settle for something so straightforward. Trusses were more likely to challenge height requirements and disrupt the feeling of unity they set out to achieve. Instead, the final design is made using a series of anticlastic gridshells to bind intersecting arches and create the carefully calculated shape.

“The gridshells use shape stiffness to form the roof enclosure and provide buckling resistance to the parabolic arches,” says Neil Thomas, the project’s structural engineer. “The two systems together create a unique and highly efficient structure, able to flex under load and allow the structure to redistribute weight, easing localized forces on the arches.

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The Arc, designed by IBUKU. Photo by Tommaso Riva


Drawing courtesy of IBUKU

Project Credits

Project: The Arc at Green School
Architect: IBUKU
Location: Bali, Indonesia
Completion: 2021
Size: 8,180 square feet
Structural Engineer: Atelier One
Concept: Jörg Stamm

As a material, bamboo creates infinite variability when high precision engineering is applied. IBUKU and the Green School invested a lot of time and research answering every question they could think of before moving on to the engineering stage. The structural engineer, Atelier One, was in constant collaboration throughout multiple rounds of structural testing.

“The concepted structure for The Arc is totally unprecedented. Embarking on a design never before executed required some bravery and optimism,” says Rowland Sauls, the project’s architect. “The IBUKU architects started with modeling all the possibilities of what the building could be before exacting the shape and feeling.”

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Aerial image of The Arc. Drone photo by Sasha de Laage

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The multipurpose building was engineered to survive catastrophic events like storms and earthquakes. Photo by Tommaso Riva

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Photo by Tommaso Riva

The Arc is a great example of how broadly natural materials can be used when combined with modern design and construction. This structure shows us how organic materials can be reimagined for their strengths to fit today’s architecture needs. As many across the globe are pushing for sustainable alternatives, the IBUKU team hopes this project can be a reference point for design teams in the future.