Jewel Changi Airport: Architecture of the Rain Vortex

Most searches for Jewel Changi Airport are about getting there, shopping or seeing the waterfall. This article is about something else: how the building is designed and engineered. Opened to the public in April 2019, Jewel sits on the site of a former open-air car park in front of Terminal 1, linking the terminals of Singapore’s Changi Airport. Its signature is a doughnut-shaped steel and glass dome enclosing a terraced indoor forest, with the Rain Vortex, an indoor waterfall about 40 metres tall, pouring from an opening in the roof.

We look at the design team, the toroidal gridshell roof, how its glass was selected for a tropical climate and an indoor garden, the engineering of the oculus and the Rain Vortex, and what the project shows about building complex structures around an operating airport.

The design team and the brief

The design was led by Safdie Architects under Moshe Safdie, whose earlier work in Singapore includes Marina Bay Sands. RSP Architects Planners & Engineers acted as executive architect and local structural engineer of record. BuroHappold Engineering was responsible for the structural and facade engineering of the roof enclosure, PWP Landscape Architecture designed the gardens, and WET Design engineered the Rain Vortex.

The brief combined an airport function, with check-in facilities, transport links and connections to the terminals, and a public destination of retail, dining and gardens. Safdie’s response was to wrap retail floors in a ring around a central garden valley, covered by a single glass roof, so that the garden and waterfall become the heart of the building rather than a decorative add-on. His broader approach to landscape and public space is discussed in our profile of Moshe Safdie.

A toroidal gridshell roof

The roof is a toroidal gridshell: a doughnut-shaped surface made of a single layer of straight steel members meeting at nodes, with triangular glass panels between them. BuroHappold’s project page describes a span of more than 200 metres at the widest point and more than 9,300 unique triangular glass panels. Every node and steel element is different, because the surface curves continuously and is not symmetrical.

A gridshell gains its strength from its curvature. Like a dome, it carries load mainly through forces within its surface rather than by bending, which allows a light, thin structure to span a very large space. Jewel’s roof also has to resist significant out-of-plane bending, so it is more than a pure membrane shell, and its stability against buckling was a central design check. The underlying principles are explained in our articles on shell structures and long-span structures.

How the roof is supported

The gridshell sits on a steel ring beam at the fifth level of the ring-shaped building that surrounds the garden. The ring beam rises at the entrances, forming arched openings into the garden. Inside the garden, the roof is supported at only a few intermittent points, so the interior is close to column-free. The ring beam collects thrust and vertical load from the shell and transfers it into the base building in a controlled way.

Nodes, fabrication and erection

Because no two nodes are alike, the connections were produced by computer-controlled machining. Specialist subcontractor MERO manufactured precision steel nodes with stubs set at the required angles, to which the straight steel members were connected. The geometry was coordinated in a single digital model, from analysis through to fabrication. The contractors erected the shell starting from the oculus and working outward in sections, rather than building inward from the perimeter, an approach adapted to the site and to the need to keep the airport running around the works.

Glass for a garden in the tropics

The glass is where architecture, engineering and horticulture meet. The indoor garden needs enough daylight to keep thousands of trees and shrubs healthy, but a glazed roof in Singapore’s equatorial climate also admits a great deal of solar heat. Too little light and the plants suffer; too much heat and the building cannot be cooled economically.

The design resolves this through the choice of glass and through fritting, a pattern printed on the glass that controls the amount of daylight and solar gain passing through different parts of the roof. The triangular panels were cut from standard rectangular sheets to keep waste down, and their fixings were designed to keep the roof profile slim, with gaskets and redundant waterproofing layers to keep tropical rainstorms out. For more on how glass carries load and resists weather in such assemblies, see our guide to structural glass.

The Rain Vortex and the oculus

The Rain Vortex falls about 40 metres from an oculus in the roof into a basin at the lower levels, and is widely described as the tallest indoor waterfall in the world. During heavy rain, rainwater collected on the roof is channelled to the oculus and feeds the waterfall; at other times recirculated water is used. In the evening the falling water becomes a surface for light and sound shows.

The oculus is not at the centre of the roof. It is offset to allow the airport’s Skytrain, which passes through the building, to clear it. That offset gives the roof a subtly irregular, elliptical geometry and complicates its structural behaviour. Around the oculus, the members of the shell are deepest where the compressive forces concentrate, while the inner zone around the opening behaves differently. The opening also has to carry the geometrically precise funnel that shapes the waterfall, which was developed with specialist water designers.

The garden as architecture

Beneath the roof, the Shiseido Forest Valley rises in terraces around the Rain Vortex, with walking trails, planted slopes and canopy-level spaces. The garden is not just decoration; it shapes how people move through the building and how the interior feels. It is one of the most ambitious examples of interior planting at this scale, and it illustrates the ideas explored in our guide to biophilic design, where natural elements are integrated into architecture to improve comfort and wellbeing.

Integrating the garden placed real demands on the structure: the terraces, soil and trees impose heavy loads, irrigation and drainage must be built into the structure, and the planting must be maintainable for decades within a glazed enclosure.

What Jewel Changi Airport teaches

The building shows how far contemporary engineering can take a single idea. A doughnut-shaped glass roof spanning more than 200 metres, with an off-centre opening for a waterfall and a railway passing beneath, required advanced analysis, digital fabrication and careful sequencing around a live airport. The glass had to serve plants and people at once, and the structure had to carry both a delicate envelope and a heavy landscape.

For readers interested in Singapore’s architecture, Jewel Changi Airport is a useful counterpoint to Marina Bay Sands: both are by Safdie’s practice, but one is about height and cantilever, the other about span, light and enclosure. In our consulting work, the lessons translate directly to more modest projects with glazed roofs, planted structures or irregular geometry: resolve the geometry early, design the glass for its climate and use, and treat landscape loads as seriously as any other structural load.

Frequently asked questions

Who designed Jewel Changi Airport?

Jewel was designed by Safdie Architects led by Moshe Safdie, with RSP as executive architect and local structural engineer, BuroHappold engineering the roof structure and facade, PWP Landscape Architecture designing the gardens and WET Design engineering the Rain Vortex.

How tall is the Rain Vortex?

The Rain Vortex falls about 40 metres from an oculus in the glass roof and is widely described as the tallest indoor waterfall in the world.

What kind of structure is the Jewel roof?

It is a toroidal steel and glass gridshell spanning more than 200 metres at its widest point, made of straight steel members meeting at unique machined nodes and supported on a ring beam with only a few intermittent supports in the garden.

Why is the oculus at Jewel off-centre?

The oculus was offset so that the airport’s Skytrain, which passes through the building, could clear the waterfall, which gives the roof a subtly elliptical geometry.

When did Jewel Changi Airport open?

Jewel opened to the public in April 2019, linking the terminals of Changi Airport on the site of a former open-air car park in front of Terminal 1.

Planning a glazed roof, long-span enclosure or heavily planted structure? Talk to our consultancy or get in touch.