Learning Curves: A Thin Shell Concrete Structure for the Next Generation

The winners of the 13th Architizer A+Awards have been announced! Looking ahead to next season? Stay up to date by subscribing to our A+Awards Newsletter.

Some of the most notable architectural roof structures are those of Felix Candela. Specifically, the hyperbolic paraboloid became the staple of his designs, allowing him to push the boundaries of structural reinforcement and the properties of concrete. The Spanish emigre was obsessed with geometry, structure and concrete experimentation, with the Los Manantiales restaurant in the Xochimilco area of Mexico City and the Cosmic Rays Pavilion for the National Autonomous University of Mexico being some of his most renowned designs.

Candela’s breakthrough was attributed mainly to the unexplored properties of concrete when it followed the logic of the hyperbolic paraboloid. It was a research output that eventually led to many impressive structural designs, where concrete in a dome or shell-like shape became incredibly efficient and resilient, laying the foundations for later advancements in parametric design. Additionally, Candela’s designs elevated the architectural field in multiple ways. To achieve such outstanding structures, the amount of material costs and site labor required became a point of both innovation and contention, as his thin-shell structures drastically reduced the need for excessive material while demanding precise craftsmanship and specialized on-site labor. At a time when labor was cheap and steel was expensive, he proved that striking, thin concrete can cover a large span of space for as little as 50¢ per square foot, without sticking to the “standard rules” of making.

HAKEBRY1, Planta embotelladora de Bacardí-Instalaciones industriales de Ludwig Mies van der Rohe y Félix Candela, CC BY-SA 4.0

Now, many years later, the Bloomingdale International School in Vijayawada evokes memories of Candela’s thin concrete structures as it tests the transformative power of parametric architecture, celebrating structural expression and adopting a cost-conscious approach without sacrificing quality or wonder. The remarkable design clinched the Popular Choice Vote for the Architecture +Small Projects category in the 13th Architizer A+Awards.

The structure essentially follows the site’s topography, “becoming a form of the landscape in itself,” and connecting the new pre-school building with an existing structure and unifying the two under the new roof. It also creates a delightful transition between the inside and the outside, bringing the built form in sync with the landscape and forming visually mediated paths throughout the school campus.

Cocoon, Pre-primary Extension, Bloomingdale International School by andblack design studio, Vijayawada, India | Popular Choice Winner,  Architecture +Small Projects, 13th Architizer A+Awards

Contrary to Candela’s dense paper calculations, the roof’s form has been conceptualized using an array of computational tools that deviate from the traditional geometric form of the hyperbolic paraboloid. Instead, the required curvature has been attained by varying curve heights at pre-calculated junctions. From the inside, the structural core is an impressive sight in itself. Comprised of prefabricated metal sections, the supports were constructed through various techniques that involved directing built-up beams along the X and Y axes, upon which ferrocement was later cast.

To increase its overall tensile strength, ferrocement was integrated with prefabricated metallic circular hollow sections, which provided a striking contrast to the exterior’s “green” surface. Specifically, the curved ferrocement roof was then covered in turf, giving the appearance of a green carpet floating above the raw landscape. Still, the most groundbreaking aspect of such design is its economic conscience. By adopting efficient construction processes and using readily available materials and fabrication methods, the structure is realized at a remarkably low cost without compromising on structural performance or aesthetic impact.

Cocoon, Pre-primary Extension, Bloomingdale International School by andblack design studio, Vijayawada, India | Architecture +Small Projects, 13th Architizer A+Awards

This deliberate balance between form, function, and economy not only places the Bloomingdale International School project at the forefront of architectural innovation, but it also pays homage to Candela’s work, reframing it for the 21st century. Today, constraints such as material or labor (major challenges during Candela’s time) are redefined through new pressures on climate sensitivity, technology, and an overall need for social awareness. This school provides a playful exploratory environment through the making of a structure that holds — apart from the actual space — a strong, participatory narrative.

In parallel, by placing emphasis on sustainability, ferrocement not only enables the desired curvature and lightness in construction but also its relatively low carbon footprint, long lifespan, and easy sourcing elevate the curved roof into a structure with a deeper ecological mindfulness. Additionally, considering the city’s hot local climate, the added turf adds to the overall building insulation, reducing heat, filtering dust, and promoting passive cooling strategies.

Cocoon, Pre-primary Extension, Bloomingdale International School by andblack design studio, Vijayawada, India | Popular Choice Winner, Architecture +Small Projects, 13th Architizer A+Awards

Noahedits, Pabellón de Rayos Cósmicos 2, CC BY-SA 4.0

In truth, the Bloomingdale International School’s new pre-primary wing revisits the Spanish architects’ revolutionary design ideas and construction methods, not through imitation but rather through reinterpretation. To be more precise, it is this spirit of “hacking” the hyperbolic paraboloid — not as a fixed form but as a flexible system of thinking — that ultimately elevates the project. It delves into the principles of expressive form, economy, craft, and sustainability, which, when aligned with contemporary tools and contextual awareness, are able to push the boundaries of what architecture can actually achieve – not only for landmark buildings, but for the everyday environments that shape our earliest experiences.

The winners of the 13th Architizer A+Awards have been announced! Looking ahead to next season? Stay up to date by subscribing to our A+Awards Newsletter.

Featured Image: Cocoon, Pre-primary Extension, Bloomingdale International School by andblack design studio, Vijayawada, India | Popular Choice Winner, Architecture + Small Projects, 13th Architizer A+Awards

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