words Justin McGuirk
The “siamese towers” are actually just one building, designed by the young Chilean architect Alejandro Aravena for the Catholic University of Chile in Santiago.
Officially known by the acronym CITEDUC, the building houses the university’s centre for digital research and technology. Although the 38-year-old Aravena was asked by the head of the university to design a glass tower, the structure’s volume wasn’t large enough to produce anything very tower-like, so he split the top of the building to give the impression of two towers. “It’s like Siamese sisters that share a body but not a head,” says Aravena.
In certain lights, the two segments appear to be different colours. In fact, the outer skin is made of uniformly clear glass, but one side uses a plain aluminium frame and the other side black aluminium so that the glass takes on different hues.
Beneath the glass is a concrete shell. This box within a box was cheaper to build than a single, energy-efficient glass structure, but to counteract the heating effects of using ordinary glass there are two holes in the ceiling of the outer skin. These act like chimneys, sucking out the hot air before it can enter the inner shell.
At the base of the tower is a landscape-like arrangement of ramps made from old timber railway sleepers. Deceptively, these ramps are the roofs of the classrooms, which are partially underground, while the tower is used for administrative offices.
“Educational architecture is going to change now that we have computers: instead of light we want shade,” says Aravena, referring to the way sunlight reflects off computer screens. To make up for the underground classrooms, the timber slopes are meant to encourage a more ancient form of outdoor tutelage and discussion. “Once you have a sloped surface it becomes a bench, like the Palio in Siena,” says Aravena.
However, the sloped roofs at the base and the top of the tower also serve to offset the effects of earthquakes, since Chile is one of the most seismic countries in the world.