The meeting with the engineer Monica Antinori gave us the opportunity to explore important issues, such as the approach of young engineers to the use of steel, with particular reference to the experience of the staff of Expo’s Planning Office, the impermanence of the pavilions imposed by the rules of BIE and the solutions adopted in this regard for the works of the Exposition, the strategic choices of the various designers in order to meet the need for speedy construction, ending with a question that everyone will ask at least once: what will happen to the pavilions once Expo is over?
Tell us about the use of steel in the various works of Expo.
Based on BIE’s rules, Expo is obliged to have temporary pavilions. This condition has naturally guided professionals in the choice of material. Moreover, the fact that they must be swiftly dismantled and constructed with material that can easily be used saw the conscious choice of steel predominate. Indeed, the TCP, Pavilion Zero, Expocentre, the Awnings, some covers of the squares of the clusters and most of the participants’ pavilions are in steel.
However, steel was not only used for the temporary pavilions. Steel was also used for the permanent buildings, almost icons of Expo, such as the roof of the Theatre (OAT), the PEM and PEF footbridges, some parts of Palazzo Italia and other minor works.
Tell us some of the details connected to steel and Expo.
I find myself with an embarrassment of riches! I was lucky enough to be able to observe both the works of Expo and those of the participating countries from close up. Without going into the purely technical merit, I can reveal that there are projects that are really worthy of note where avant-garde choices have been made regarding the structures: foundations made of screwed piles in steel that enable the speedy recovery of the entire foundations at the end of the event; pavilions founded directly on well-compacted land with surface foundations in steel with derisory amounts of digging. The recover and making safe of Cascina Triulza with (hidden) structures in steel; use of high-resistance material to lighten the structures; pavilions entirely "dry" constructed in less than a week; use of corrugated sheets as cladding. I’ll stop there, there’s too much to relate!
The speed of the construction of the Self Built and Corporate pavilions in good time for the start of Expo 2015 is one of the constraints by which the projects have been assessed and finalised.
How was this aspect tackled by the various countries?
I have to say that this was one of the constraints that not all the designers were able to tackle in the same way. I can say that most of the projects took into serious consideration the issue of a material that would enable quick, safe construction from the very early stages of the concept. The participants developed strategic choices that came down strongly on structural steel. Some chose wood, others combined wood and steel. Some used prefabricated elements in concrete while others constructed their Pavilion with composite structures. I would have expected a much greater use of dry construction. However, this construction type was also adopted in subsequent stages of the project, including by some of those projects that had not planned to do so at the start.