Building Technologies
Thin Shell Concrete
What is it?
Thin shell concrete is an application of concrete that is dependent upon the dead weight of the material itself to form load paths - that the material thin conforms to. It's materiality is embedded in it's name - and it's form resembles a thin shell, not unlike the walls of an egg.
How does it work?
Thin shell concrete is a load bearing shell of concrete in which the vector-lines of the structure are essentially the same as the shape of the building itself. Remarkably simple in form as well as application - shell concrete's simplicity makes it excellent in seismically active areas.
During the building of the Lost Manantiales Restaurant in Mexico City, workers created the criss-crossing shell shape of the structures, called a "hypar", using wood and thatch
Due to the severe sloping of the roofs using this material - wet concrete cannot be fully relied upon to get the job done. Thus - wet concrete is initially used to cover the wire mesh formwork and, upon almost drying, a drier mix is caked onto the form work and allowed to also dry. After it is mostly dry, more concrete is applied over spaces that need to be covered - and the form work is removed.
Aesthetic considerations
Shelled concrete, most notably, gives a presence of weightlessness and therefore airiness in a space. This is juxtaposed with concrete's monolithic nature. La Purisima chapel in Mexico demonstrates how the concrete's form gives the church a cavernous spaciousness - perfect for sacred and reflective architecture.
Not only one of the most famous applications of concrete but of modern architecture, the Sydney Opera House uses shelled concrete in a thicker form. The combination of the massing with the clerestory windows made for a world-famous space.
Another famous application, and perhaps one of the most "mid century modern" public space in the country - Eero Saarinen's TWA Flight Center uses shell concrete to create a 'space-age' space that focuses the public eye down towards the landing strip - glorifying the airplane. The organic curves makes the space feel at once large and intimate.