ETH Zurich and Zaha Hadid Architects unveiled KnitCandela, a 3d knitted concrete pavilion transportable via suitcase. ETH Zurich, working in collaboration with Zaha Hadid Architects Computation and Design Group (ZHCODE) and Architecture Extrapolated (R-Ex) have designed KnitCandela, a thin, sinuous concrete shell built on ultralightweight knitted formwork that was carried to Mexico from Switzerland in a suitcase.
The “KnitCandela” prototype is a five-tone concrete structure that represents the first application of this technology at an architectural scale. The pavilion is on display at the Museo Universitario Arte Contemporaneo in Mexico City.
Text description provided by architects. Constructed at the Museo Universitario Arte Contemporáneo (MUAC) in Mexico City as part of Zaha Hadid Architects’ first exhibition in Latin America, KnitCandela is an experimental structure that pays homage to the Spanish-Mexican architect and engineer Félix Candela. KnitCandela reimagines his inventive concrete shell structures through the introduction of new computational design methods and innovative KnitCrete formwork technology.
The dynamic geometry of KnitCandela’s shell is inspired by the fluid forms of the colourful traditional dress of Jalisco, Mexico. While the structure’s local builders nicknamed the project ‘sarape’ (a striped scarf that originated in Mexico), KnitCandela’s form references his acclaimed restaurant at Xochimilco; a concept he further developed in several of his subsequent projects.
While Candela relied on combining hyperbolic paraboloid surfaces (“hypars”) to produce reusable formworks leading to a reduction of construction waste, KnitCrete allows for the realization of a much wider range of anticlastic geometries. With this cable-net and fabric formwork system, expressive, freeform concrete surfaces can now be constructed efficiently, without the need for complex moulds.
KnitCandela’s thin, double-curved concrete shell with a surface area of almost 50 sq.m. and weighing more than 5 tones, was applied on a KnitCrete formwork of only 55 kg. The knitted fabric of the formwork system was carried to Mexico from Switzerland in a suitcase.
The 50 sq.m. of textile shuttering of KnitCandela’s formwork is comprised of four long strips ranging from 15 m to 26 m in length. Each of the four strips is a seamless, double-layered textile produced as a single piece. Two layers of textile fulfil different tasks. The visible inside is an aesthetic surface that displays a colourful pattern and reveals traces of the supporting cable-net falsework system. The exterior surface fulfils technical requirements by including features for inserting, guiding and controlling the position of additional formwork elements.
The pockets created between the two layers as part of the spatial knitting process are inflated using standard modeling balloons. These inflated pockets become cavities in the cast concrete, forming a structurally efficient waffle shell without the need for a complex, wasteful formwork. Pockets located on this exterior side of the textile have different knit densities to control the inflated shape and openings for the insertion of the balloons, enabling cavities of different dimensions to be created with one standard balloon size.
The soft, colourful textile interior of KnitCandela’s shell and its hard, concrete exterior is visible from all viewing angles. The textile’s striped pattern expresses the knitting fabrication process and the radial symmetry of the shape. This patterning, along with the simultaneous visibility of the soft interior and the hard exterior of the shell enhances the visitor’s spatial experience and the curvatures of the KnitCandela’s form.