2011: The year of structural engineering
Felix Mara, technical editor
Forty-two years after the publication of Reyner Banham’s The Architecture of the Well-tempered Environment, the UK architectural profession has finally got to grips with building services.
Although structural engineering is much more complex than it at first appears, many architects still find it more approachable because it uses scale drawings and is concerned with form – as well as performance, metrics and specification, which are the main focus of building services. Nevertheless, environmental performance and impact are now subject to much closer scrutiny and building services are often the largest elements in project cost breakdowns.
Despite this shift towards greater collaboration between architects and services engineers, structural engineering was back in the limelight in 2011. We saw practical completion of nearly all of the buildings for the London 2012 Olympic and Paralympic Games, a remarkable test-bed for structural ideas. Most of these were engineering-driven building types and many were not heated.
Also, with risk-averse design-and-build procurement favoured by the Olympic Delivery Authority and many other clients, architects were discouraged from specifying named products, bespoke design and prototyping. Structural engineering enjoys more freedom under this type of regime. Unless replicated for bulk building programmes, structures are usually bespoke. Also, although many clients could not afford to build in 2011, those with sufficient funds, having exploited fierce competition, completed large projects.
So this year’s structural engineering renaissance is unsurprising, especially in view of contractors’ need to use structural design to minimise their overheads by accelerating projects and the demand for buildings which were spectacles, without being unfashionably wilful. If it was structural engineering, it wasn’t vulgar. ‘We’re back where we were 15-20 years ago,’ says Buro Happold principal Wolf Mangelsdorf.
The year’s highlights break down into various approaches to collaboration between architects and structural engineers. At one extreme there was the uncompromisingly functionalist approach close to the hearts of Rogers Stirk Harbour + Partners and Expedition Engineering, whose Las Arenas (AJ 09.06.11) transformed a bullring in Barcelona into a mixed development. Faced with the problem of retaining unstable external walls, lowering the ground floor, improving access and supporting new floors, they audaciously picked up the perimeter envelope on an inverted crown of V-piers and inserted a stabilising inner ring of structure rising to parapet level. The structural works add much-needed visual excitement.
At The Shard in London, Renzo Piano Architects and WSP Group tackle the challenge of building the EU’s tallest structure by providing perimeter columns that are steel up to level 40, then concrete up to level 87. The steel columns accommodate high servicing requirements in the offices, whereas the concrete perimeter columns and slabs in the hotel are more compact.
‘This strategy gained three extra floors,’ says WSP technical director John Parker. ‘It also meant we didn’t need a tuned mass damper, because the concrete had enough inherent damping to absorb wind vibration.’
At the other end of the scale, Canterbury’s Marlowe Theatre (AJ 06.10.11), by Keith Williams Architects and Buro Happold, is much more opaque and contrived, with concealed cantilevers and transfer structures providing column-free spaces. This is structural engineering as the servant of architecture.
The mannered facade of London’s 7-15 Baker Street mixed development (AJ 07.07.11), by Squire and Partners with Scott Wilson and Taylor + Boyd, takes this to extremes. It’s hard to know which elements are structural or where the structure is. The striking external steelwork lattice of the London residential development neo Bankside (AJ 17.03.11), by Rogers Stirk Harbour + Partners and John Robertson Architects, with the Waterman Group, is in similar territory. It provides lateral bracing but, perhaps with some modifications, this could have been achieved by the internal cores alone – it’s arguably more bum-fluff than bracing. The diagonal bracing members of KPF and Arup’s Heron Tower offices in the City of London (AJ 14.07.11) are also facade-animators, although they do free up views from the atria behind the un-braced central section, albeit at the cost of excessive visual weight.
Though you might expect that the laurels were deserved by the most single-minded, some of the more sophisticated collaborations of 2011 involved hybrid approaches. Foster + Partners and Buro Happold’s McLaren Production Centre in Woking balanced structural rationale with architectural qualities, providing a calm interior with 21m x 18m bays, chosen for optimum flexibility, and column clusters around vertical risers. The eclectic Garsington Opera (AJ 08.09.11), by Snell Associates and Momentum, is also notable for the way it reconciles a feather-light demountable structure with a disciplined approach to architectural and acoustic design.
Interest in the environmental impact of structures continued, addressing concerns with pollution, energy resources and CO2 emissions. ‘Engineered timber has taken a leap forward this year,’ says Andrew Weir, director of Expedition, whose Olympic Velodrome (AJ 24.02.11), designed with Hopkins Architects, set out to address structural, practical and environmental challenges but also achieved architectural distinction and finesse, which would not have been possible without the ingenious engineering of its assemblage of ring trusses, gutters, trussed ribs and timber cassette-supporting cables.
Some, like Rogers Stirk Harbour + Partners and Expedition at Las Arenas, made environmentally intelligent contributions by retrofitting instead of demolishing. As part of a broad environmental strategy, several London 2012 Games projects were designed to be dismantled and recycled, either fully, like Wilkinson Eyre and KSS Design Group’s Basketball Arena (AJ 18.08.11), or partially, as in the case of Populous and Buro Happold’s Olympic Stadium (AJ 07.04.11), Heneghan Peng and AKTII’s Olympic Footbridge and Zaha Hadid and Arup’s Aquatics Centre. These last two also combine structural engineering with art, an approach taken to its extreme by the ArcelorMittal Orbit at the Olympic Park, by Anish Kapoor and Cecil Balmond with Ushida Findlay Architects and Arup, who challenged the orthodoxy that all towers should be pyramidal by proposing a non-rectilinear structure that is strengthened by gigantic loops of steelwork. Zaha Hadid and Buro Happold’s Riverside Museum in Glasgow (AJ 09.06.11), which uses trussed folded roof plates to span the full length of the building, resting on mullions at either end, was the ultimate hybrid of art-architecture-structural engineering.
These are just some highlights of an extraordinary year for collaboration between architects and structural engineers and there is a long list of individuals and specialist subcontractors whose role was crucial. The year also saw structural engineers improve collaboration with other project team members through BIM. ‘It’s here to stay,’ says Mott MacDonald divisional director Steve Gregson. Many also staunchly resisted financial pressure. ‘To us, lower fees mean you need to invest in designing harder to enhance project value and opportunity, not sitting back and doing the minimum,’ says aktii’s Gerry O’Brien.