Portuguese National Pavillion
Construction Matters | Portuguese National Pavillion by Álvaro Siza
Summary
The Portuguese National Pavillion is a thin curve of concrete, a simple shape floating in space. The eye wants this curve to connect to its two supporting pillars but a visual break happens when there is a void in between these two masses. The void is the space highlighting this system - the cables holding up the curved concrete plane.
The cables holding up this concrete plane are slipped through the concrete like an elastic in a waistband. This action allows space for the concrete to expand and contract with the heat without stress, making the concrete less likely to crack. As we know, it's not if concrete cracks, it is when.
“The assumption may be true for the calculation of geometry and tension force in the cable, but simplicity vanishes when one considers the catalogue of disasters that could befall an exposed sheet of concrete over such a span.” This quote from the reading reminds the reader how many factors go into constructing a structure like this. Balmond also brings the reader into an in-person experience of the pavilion, writing about looking up at tons of concrete that could crush them.
Image by: GIOVANNI NARDI
Discussion Questions
In the reading, there is a brief discussion about Vault vs Sag. If the catenary were mirrored, the curve would have become an arch. This would not be sustainable at its current curvature and Balmond comments on the thickness of the concrete slab. What would change about this curve to make the pavilion an arch instead of a sag? Would the cables continue to be the connection point for the supporting pillars?
Flickr user Pedro Moura Pinheiro
Arch is over an opening, a vault is over a room
Horizontal force - thrust
The blank concrete sheet has an elegance of its own. What would change this elegance, and structure, if there were openings in the concrete sheet allowing light to hit the floor of the pavilion?
solid/void of the cable connection
Sun is very intense
If something were to happen that would ruin part of the concrete sheet, would the whole thing need to be redone, or is patchwork possible? If one of the cables broke, couldn’t a new cable be slipped in through the tube left in the concrete?
Release weight to do repairs and then add weight again
Resource
Balmond, Cecil, Christian Brensing, and Jannuzzi Smith. “Portuguese National Pavilion.” Essay. In Informal: Cecil Balmond, 309–44. Prestel, 2002.