What's the buzz? It's the Hive!
The UK Pavilion at Expo Milan 2015 won both public and critical acclaim, attracting over 5 million visitors and taking the prestigious Gold medal for architecture and landscape --and at its core stood the 'Hive'. Here is the remarkable story behind the sculpture's evolution and completion
Simmonds Studio is a very small consulting engineering company that specialises in the unusual combination of lightweight tensile structures and complex geometrical sculpture projects. The underlying link between the two and the mild obsession of the practice is the design of expressive 'complex' structural forms that are a product of physics and practical fabrication techniques.
After a decade of designing similar structures at Arup, Tristan Simmonds MIED founded Simmonds Studio in 2009, in order to work much more closely on projects with artists and designers and fabricators. The studios first project was Drift with acclaimed artist Antony Gormley in Singapore--a suspended 16t 40m long sculpted polyhedral lattice of 1,6000 hand welded stainless bars--which set the precedent for the studios approach to design and its working process.
Then, on the 8 May 2014, the team of award-winning artist Wolfgang Buttress, Simmonds Studio and BDP landscape architects won the competition to design the UK Pavilion at Expo Milan 2015. The expo opened on the 1 May 2015 and the UK Pavilion received both public and critical acclaim. It attracted over 3 million visitors and subsequently won the prestigious Gold medal for architecture and landscape. It was also on budget.
Here, then, is the story behind this extraordinary achievement ...
The 2015 Expo's theme was 'Feeding the Planet' and the budget for the UK pavilion was 6m [pounds sterling]. Wolfgang Buttress' concept for the pavilion was centred on the honey bee, in order to raise awareness of its essential contribution to our environment and its current unprecedented decline.
The overall concept for the Expo pavilion site was simply a British wild flower meadow with a large Hive sculpture that would act as an iconic centrepiece, providing a destination and a space for performances and events. A secondary building structure would provide accommodation for a cafe/bar, offices and a meeting space for business delegates.
Buttress intended the Hive to be aesthetically similar to a series of his sculptures called Space. These were cubes of layered acrylic with spherical Internal voids. The Hive structural scheme developed as horizontal layers of profile cut plates forming a radial hexagonal grid, with small solid bars linking the layers together in alternating triangulated space-frame and Vierendeel arrangements to produce a vertical hexagonal pattern of brace elements. Also, the hexagonal grid at each layer was rotated on plan to give the structure a twist. This twisting lattice was then trimmed externally to a 14m cube and trimmed internally with a sphere to provide the central void.
BEE HIVE GEOMETRY As Tristan Simmonds recounts: "Inspired by the evolved nature of bee hive geometry, we considered that, to build a complex biological-looking structure consisting of potentially many thousands of parts, we would need to adopt a blologlcal/evolutionary approach to the design process and set the following requirements:
* An underlying repeating 'macro' geometry throughout the structure to parallel the repetitive geometry of a beehive and to help keep the overall description of the geometry relatively simple
* Variation at the 'micro' level. The structural optimisation of Individual element sizes to produce a filigree, 'efficient' structure, but rationalised to a limited family of section sizes
* An automated system for generation, analysis, checking and information production, because we expected the design would have to adapt significantly during the project (which proved correct).
The Hive was initially developed as a stainless steel (316) structure with design and cost input from fabricator Sheetfabs. "Stainless has the obvious aesthetic and corrosion benefits, but also allowed the potentially complex connection nodes to be resolved with a simple TIG welded detail, a fabrication process similar to that we had developed for the Gormley Drift sculpture in Singapore--ie, simple construction, but lots of It. Lengthy contract negotiations meant that design meetings with the appointed contractor Stage One did not start until the end of June 2014, only three months before we estimated fabrication needed to begin and five months before starting on site.
"From the first meeting, It quickly transpired that, in order meet the tight deadline, Stage One Intended to carry out all fabrication themselves and required the Hive to be made from aluminium and simplified to be on budget."
NEW SET OF CONSTRAINTS
The use of aluminium imposed a new set of constraints entirely concerning material properties, connections and fabrication techniques, and so the Hive was redesigned from scratch and underwent many subsequent design changes over the following four months, as new structural, fabrication and cost constraints evolved.
"Fabrication of node component parts started in October 2014," Simmonds recalls. "In November, 1,500 CAD files were supplied to the contractor, along with numerical data for CNC fabrication of plates and tubes. Access to the site was granted in December with the fabrication and Installation of 60,000 mostly unique parts, with 169,000 individual components completed In early March 2015.
"The initial structural lattice design had up to 4 braces welded at a point and partly relied on Vierendeel action. However, the use of aluminium and the adoption of a bolted node connection (see below) meant that the braces had to be 'pinned' and the system heavily simplified to minimise the size and complexity of the node," he says.
"The final structural system consists of 31 stacked layers of alternating radial and circumferential trusses. The trusses are topologically planar, with nodes only connecting a maximum of two braces, allowing trusses to be pre-assembled as independent entitles. The aesthetically Important hexagonal grid pattern Is created from the combination of chord plates from adjacent radial and circumferential trusses. The adjacent truss chords overlap on alternating sections providing zones suitable for splice joints.
"Hexagonal cellular geometry is, unfortunately, inherently flexible and not the best choice for a structural geometry. The artist's geometry was rationalised to use a pair of repeating radial zig-zag centrelines for all radial truss chords.
This reduced the number components and straightened the radial structure significantly, Improving the structural stiffness, as well as the aesthetics, by giving the pattern a spiral twist. Alternating circumferential layers were subsequently expanded radially, in order to open out angles between braces, and the geometry was painstakingly parametrically tweaked to rationalise brace angles and thereby reduce the number of unique node geometries," he adds.
From layer 6 to layer 28 (of the 31 stacked layers), an internal void is created by trimming away the structure, forming a 9m diameter floor at level 6, with access via a 3m hole at one side. Trimming had to respect the capacity and stability of the stacked truss system to achieve an aesthetic and structural solution with a large enough floor area. Overall, the Hive went through several step changes and multiple iterations, and so 'adaption' was very much part of the design process. It was this fast adaptive/ iterative approach that retained the artistic and functional intent of the Hive through the development of the project, which, in turn, led to its success.
"Despite the level of compromise and changes to the design of all elements of the pavilion, the result was still remarkably close to the very first conceptual sketches by [Wolfgang] Buttress and by that measure we feel the project is a great success," concludes Simmonds. "Another important feature of the Hive's design and fundamental to its purpose for environmental awareness is that it is demountable and reusable."
Indeed, the Hive is now enjoying a new lease of life at London's Kew Gardens. If you have yet to go and see it up close, make your way there and marvel at this exquisite piece of work--a fitting tribute to, and celebration of, the now much compromised, much loved honey bee.
DESIGN FOR LIVING
Born in London, Tristan Simmonds CEng MIED studied structural engineering at the University of Bath and found inspiration in the lightweight structures of Sir Ted Happold, and the mathematical and computational techniques of Alistair Day and Chris Williams for the generation and optimisation of structural and aesthetic form (form-finding).
On graduation, he joined international consulting engineers Arup and worked there for 13 years, specialising in lightweight, tensile and complex geometrical structures. Whilst at Arup, he worked on many domestic and international projects, on secondment in Hong Kong and Japan, and was a founding member of the Arup Advanced Geometry Unit (AGU). In 2002, Simmonds designed the sculpture Marsyas for artist Anish Kapoor at the Tate Modern, London. The project was an innovative mix of digital development, engineering and art that has acted as a turning point in Simmonds' interest in design and working process.
He subsequently left Arup and founded Simmonds Studio in 2007, in order to focus on the digital design and engineering of complex sculptural projects and has since collaborated in design of many large sculptures for artists, including Antony Gormley and Wolfgang Buttress.
In addition to sculptural work, Simmonds also carries out the design of tensile fabric structures and long span roofs, often as a specialist sub-consultant for larger engineering companies and contractors. Recent projects have included involvement with the scheme design of the roofs of the velodrome and aquatic and tennis centres for the 2016 Rio Olympics, the roof of a stadium for Brussels and multiple large tensile structures In Qatar.
Simmonds has given talks on his work, assisted in design workshops in Europe and the USA, and also tutored at the Architectural Association in London.
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|Title Annotation:||STRUCTURAL AESTHETICS|
|Article Type:||Cover story|
|Date:||Sep 1, 2016|
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