16 May 2016
By Nick Jones
Few architects have graced the pages of Concrete Quarterly more over the past decade than Zaha Hadid, who died suddenly in March. But then few architects have done more to push concrete to the limits, showing what often seemed like a wilful disregard both for the laws of gravity and the sound sleep of structural engineers.
The first Hadid project that the magazine covered in detail was the extraordinary Phaeno Science Centre in Wolfsburg, Germany (CQ 208). The writer, Margo Cole, had the tricky task of describing a building that even the project team struggled to find the words for. Hadid’s concept was of a main exhibition floor space that “melted down” into 10 reinforced-concrete structural “cones”. Except the term “cones” wasn’t quite right. Each was of a different geometric shape (which naturally changed as they rose), and with surfaces inclined at 45˚ they blurred the boundary between walls and floor. Even the term structural was a little imprecise, as they relied on the floor slab for restraint. Paul Scott, project engineer for Adams Kara Taylor (AKT), told Cole: “Structurally they are not quite one thing, and not quite another. I suppose they are part arch and part beam, but we had to get away from the traditional idea of thinking of it in terms of structural elements and naming them.”
Twelve years on, the project can be read as a landmark in getting the construction industry to work in three dimensions – a process that continues with the growth of BIM. Hadid and AKT basically had to rethink many of the rules of construction, from the design of double-curved forms, to the way this information was presented to contractors, to the materials used to create them. (In this case, the complex cone shapes and grid of reinforcement required the pioneering use of a self-compacting concrete.)
These are themes that resurfaced in virtually all of the Hadid projects that CQ has covered subsequently. In the past two years alone, it has marvelled at the structural gymnastics of the Issam Fares Institute in Beirut (CQ 249), where an improbable proportion of the concrete building hangs off an astonishing 21m cantilever; the Messner Mountain Museum (CQ 254), which brought curved in-situ concrete to an Alpine peak; and the sinuous Investcorp Building at St Antony’s College, Oxford (CQ 253), where almost every surface curves in two or three dimensions.
But there was more to Hadid’s work than pyrotechnics. The other theme that emerges throughout CQ’s articles is the care taken over the quality of the concrete. Nowhere is this more evident than at her two Stirling Prize winners: the Maxxi museum in Rome (CQ 230) and the London Aquatics Centre (CQ 241). At Maxxi, the architects demanded an exacting homogeneity and fine surface texture for the long and winding fair-faced concrete walls that define the interiors. Again, self-compacting concrete was specified to flow around the dense areas of reinforcement, ensuring that the complex forms remained free from air bubbles (after much experimentation a modified mix was developed to control shrinkage in the dry Roman atmosphere).
Likewise at the Aquatics Centre, the specification process was meticulous, with various mixes tested to meet not only Hadid’s visual requirements but also the rigid sustainability criteria of the organisers. The specialist formwork, manufactured from phenolic ply, was shipped in from Germany. It was, wrote CQ’s Tony Whitehead, “something akin to a giant toy construction set of formwork”.
Where the in-situ concrete finish could not be assured, Hadid’s architects have always been similarly ambitious in the use of precast. At Pierresvives, a mighty departmental HQ in Montpellier (CQ 242), more than 1,100 precast cladding elements cantilever from the frame, giving the required flawless finish, but also necessitating a structural redesign from the original exposed frame to take account of the weight. There was nothing simple about this precast design: about 155 elements required specially manufactured double-sided moulds.
The results were always amazingly photogenic. The Phaeno Science Centre, the Maxxi Museum, the Aquatics Centre, Pierresvives and Issam Fares all made the CQ cover. Probably the only reason that the Investcorp Building didn’t was to avoid accusations of favouritism. There will doubtless be others from the practice that Hadid built. In fact, the recently opened ferry port in Salerno, with its oyster-like concrete shell, must be a contender for the next issue…