July 30, 2017 § Leave a comment
Technically on vacation, but part of the travels this month include college visits for my son, who by happy coincidence has Dartmouth on his shortlist.
Hanover, New Hampshire is an unlikely answer to the question of which American city has more Nervi projects than any other, thanks to a progressive campus leadership that commissioned two sports arenas from him in the 1960s and 1970s. Leverone Field House, finished in 1965, was covered extensively in Aesthetics and Technology in Building, but his second arena, the Rupert Thompson Ice Arena, has never received as much attention. But as a pair they’re fascinating as a comparison of Nervi’s techniques, literally across the street from one another.
Leverone Field House reflects an evolution of Nervi’s Turin Exposition Hall–it’s a shallow-vaulted, thin-shell roof supported by ranks of beautifully simple buttresses at its base. You can see the three-part buttress to the left in the photo, with a diagonal that takes most of the vault’s thrust, a vertical that resolves a portion of the gravity load, and the cantilevered roof that also acts as a horizontal beam, forcing the roof to hold its shape between buttresses. The main facade has vertical wind braces that are shaped to reflect that they’re primarily bending elements, designed to hold the curtain wall on to the end arch and to its foundations. A similar system would have stayed the enormous glass facades of the Reynolds Aluminum project, which Nervi had designed a few years prior.
Inside, though, the roof is a very different system than the one at Turin. Instead of that hall’s folded plate construction, Leverone adopted the diamond-shaped lamella pattern of Nervi’s 1939 Orbetello Hangars and the ferrocemento formwork he’d perfected in Rome’s Palazetto dello Sport in 1957. The result is a fine grain imprinted on a long span, but also an incredibly lightweight concrete roof–the diagonal ribs form both the gravity and the lateral system for the roof, and they ‘trick’ the roof into behaving like a shell with the depth of the ribs, while removing most of the roof’s weight by scooping out the dead weight of the diamond-shaped voids. It’s a simpler roof than Turin, and the geometry is one-dimensional, so it’s missing the dramatic spirals of the Palazetto. But it’s still a masterful space (even with all the accouterments of a college athletics facility hanging from it…)
The Thompson Arena (1973-75) wasn’t quite as open as the field house (long story), but its most dramatic elements are on its exterior–these twisting, curving buttresses that collect the thrusts and gravity loads of this arena’s roof into point supports at ground level. These are trademark Nervi ruled surfaces, using a technique of twisted boards that he’d first worked with on his collaboration with Marcel Breuer at UNESCO in Paris. Here, the buttresses are paired as they are at the edges of the Scope Arena in Norfolk, which was built from 1968-71. The concrete on Thompson is similarly flawless–we looked but couldn’t find the nail holes that would have held the twisted boards in place, which are readily apparent on Nervi’s earlier ruled surfaces. The interior is a similar lamella-patterned set of ribs formed with ferrocemento formwork, but the difference between Laverne’s simple buttresses and these is dramatic.
Both of the Dartmouth buildings are covered well in Alberto Bologna’s book on Nervi’s work in America–in terms of innovation they’re important primarily for the fact that they translated some of Nervi’s most innovative techniques into an American market. These didn’t prove as economical as they had back home, and the fact that Nervi built only a handful of major projects in the U.S. shows in part how tied to Italy’s unique labor market and material economics.
For me, though, these were vital projects. Growing up, my grandparents lived just outside of Hanover, and on rainy days while I was staying with them a trip to run around inside Leverone was often on the agenda. Formative experience, definitely–I’ve said more than once that the Nervi book (due in November, 2017!) is something like forty years in the making…
July 7, 2017 § Leave a comment
Reading early reports of a massive fire in downtown Oakland at a construction site where 6 stories of apartments were being built. While there’s no word on the cause yet, a quick Google Maps street view…
…shows that as of March the building was up a couple of stories. While the lower level (designed to be retail storefronts) are all obviously reinforced concrete, the upper stories are all lightweight timber with foam insulation. Those would all get sprinklered, one assumes, but the material itself is not only not fire-resistant, it’s actually flammable. Hard to tell from the street, but this view doesn’t show anything like fire walls being constructed to separate elements of the whole-block-long site from one another, which would mean that once it starts, there’s not much to start a fire from racing through the light frame construction.
So, all perfectly legal, but a reminder that, as at Grenfell Tower, the gradual retreat in code-world from fire-resistant materials in multi-story buildings isn’t a slam dunk. Sprinklers save lives, and the latest thoughts on timber high rises all assume heavy, ‘slow burning’ construction instead of the lightweight stuff here. Still, a sobering reminder that what buildings are made out of can make a huge difference in how they perform in emergencies…