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GRIDSHELLS
- A NEW TIMBER FORM IN THE MAKING
It
is a sky blue summer open day at the Weald and Downland Museum,
in Singleton, West Sussex. Crowds flock around the various traditional
craft attractions, which, along with one of the largest collections
in the country of renovated historical buildings, comprise the
museums stock in trade. Up in the woods in the museums’
southerly corner a sizeable contingent of visitors are clumped
together, looking admiringly at the uncovered roof of the latest
building at the centre. This is no medieval, Elizabethan or Regency
house. It is a great weave of whirling timber laths, making three
lattice-shaped shell domes, which will become the roof of this
latest, only too contemporary addition to the museum. This is
the Weald and Downland Museum’s brand new gridshell building,
which in the last year has won praise from press and public alike.
Image
Stuart Keegan and Elaine Duigenan
On
this summer day the cladding is yet to be added. The structure
looks like a beautiful ship’s hull turned reverse side-up,
but still naked as you can see the criss-crossing timber laths
running in great long curves, some 30 metres, side to side. One
year on the building has been completed, the cladding is in place,
and after a big launch the gridshell is a stand-out showcase of
what can be achieved with the emerging synergies of computer modelling
power, related developments in glue and timber technologies, and
a dedicated team of expert carpenters and sympathetic architects.
By
the gridshell there is a viewing stand and there Cullinan’s
project architect, Steve Johnson, and one of the projects engineers,
Ollie Kelly, are describing to all comers exactly what they think
they have been doing in designing the building. At one of these
wall-to-wall tours an elderly man pipes up. He worked with Barnes
Wallace during the war, and the wooden lattice design of the skins
for the Wellington and Lancaster bombers is exactly the same.
The knowledge has been around for decades, but why the transfer
to architecture never happened remains something of a mystery.
What
are gridshells though? They are, at core, lattice shell structures,
shellshapes pocked with diamond lozenge holes. Because of their
shell properties they are phenomenally strong, and don't require
internal supports. They are usually made out of steel, aluminum
and concrete the recent British Museum courtyard roof is a contemporary
example of a steel version. Today however a number of gridshells
have emerged around the country, all made of wood, and all in
a very short period of time. They are very different. The Weald
and Downland building has the highest profile, amassing sheafs
of press-cuttings, as well as being narrowly pipped at the post
for the coveted annual Stirling Architecture Prize.
The
history of timber gridshell engineering actually reaches much
further back. At the turn of the last century German and French
engineers began putting onto paper nascent gridshell plans for
agricultural buildings. From there the design was adapted for
first World War zeppelins, and in World War ll became the aforementioned
body design of Wallace Barnes' famous Lancaster bombers. But the
real year zero for gridshell is 1975, when the eminent German
Architect, Frei Otto, unveiled the first real gridshell building
in Mannheim. Originally a temporary horticultural exhibition hall,
today this set piece of wood engineering futurism is a listed
building. A member of the Ove Arup's original engineering team
described it as one of the most advanced buildings of the twentieth
century. Since then? Well, not very much. In the interim years
since 1975 two buildings have emerged in Japan, one out of timber,
the other from bamboo. Japan's submission at the Hanover 2000
Expo was also a gridshell, very similar in shape to Weald and
Downland, but twice the size, constructed from cardboard tubes.
Whether it truly constitutes a gridshell building is something
of a moot point, since it has already been dismantled.
Image
Stuart Keegan and Elaine Duigenan
The
history of gridshell building is intimately connected to Frei
Otto’s Mannheim building. A generation of engineers, mostly
initially connected to Ove Arup’s, received exposure and
experience there, which is now, over thirty years later, bearing
direct intergenerational fruit, and feeding through to this new
wave of timber design. Until Frei Otto and Arup at Mannheim, the
Wallace Barnes gridshell knowledge hadn’t effectively jumped
tracks into architecture. Originally, Otto had uncovered the possibilities
of gridshells by observing the biological structure of double-curved
coral, a textbook example of nature as a strategy for design.
The entire Arup timber team, including Ted Happold, Michael Dickson,
Ian Liddell, and Chris Williams defected to form Buro Happold,
bringing with them their timber expertise to Britain.
A
related stream of influence has been the work of Florian Beigel,
who today runs the Architectural Research Unit at North London
University School of Architecture. Beigel moved to Britain in
the early seventies, who also worked with Frei Otto on another
of the renowned German's gridshells, the Munich tent structure.
The tent structure was a cable grid structure, in contrast to
Mannheim's compression structure. When he came to Britain in 1970,
Beigel brought the gridshell concept with him. In 1974, along
with his students, he constructed a series of four gridshell structures
on Highbury Fields as experimental exercises. From there he tried
to get funding support from Arup's and then Happold's to continue
the research, just when the two big engineering companies were
first beginning to research tension structures, but to no avail.
The Highbury Fields' gridshells are documented in one booklet
publication by the Stuttgart Institute for Lightweight Structures
(document IL13). Beigel, in conversation, though not directly
involved in gridshell design for a number of years, remains absorbed
by its simple elegance to this day. Despite being double-curvature
in form, the use of laths makes for a very simple element. Usually
the use of the double-curvature form is difficult and the manufacturing
expensive. "I still find the elegance of the idea very fascinating",
Beigel says. With wood there was, for the first time, a way of
making the square of the form into a parallelogram. His last direct
involvement in the form was in 1992 when he was centrally involved
in plans for a gridshell theatre and arts centre in Brentwood,
Essex, It never got any further however, unfortunately. Were it
to have, the beginnings of this gridshell movement might have
been earlier off the starting block. By this time, the mid nineties,
the influence of the Mannheim building on the two Ted's, Cullinan
and Happold, was already water under the bridge. Today, Beigel
points out the Weald and Downland gridshell is exactly the same
shape as the structures he and his students were playing around
with on the playing fields near-on thirty years ago. (see, www.aru.unl.ac.uk)
To
some extent it is the influence of all Frei Otto’s architectural
and engineering colleagues settling in Britain, which has been
a primary inspiration for the different gridshells, which have
emerged during this millennium time. This summer, the opening
of Weald and Downland gridshell became a springboard, so to speak,
for other buildings with unusually singular development in wood
construction. The Weald and Downland gridshell makes a geographic
midpoint in a short triadic necklace of related buildings; Frei
Otto's '90's Hooke Park Workshop to the west in Dorset, and to
the east, the smaller adapted Flimwell Woodland Centre chestnut
modular gridshell. Even if Hooke Park is not a gridshell, there
are similarities which make it persuasively belonginning to the
same family. There is also a fourth family member - a northern
relative – the hand built completely low tech Pishwanton
or Lothian gridshell, designed by the Anthroposophical architect
Christopher Day. Pishwanton brings another, accessibly small-scale
dimension to the growing band of wood grid dings, (should read
gridshell buildings) suggesting that gridshells can also come
in many varieties, small and perfectly formed, as well as large-scale.Both
the Weald and Downland, and Flimwell structures provide something
a testament to a new 'hands-on/hi tech' building paradigm; the
convergence of developments in wood and related materials technology,
and the new capacity for modeling which have been inaugurated
by computers, and also incorporating the skills of the crafts
tradition. Add to this the shell properties of the building and
the lightweight properties of the material, and it all dovetails
into the emergent tradition of 'lightness': becoming a fitting
example of how wood can be a suitable candidate in the search
for extra-light materials and structures.
As
to the future, how will this putative gridshell movement look
a dozen years down the line? There are hopeful signs that these
buildings are the forerunners of a larger emergent movement with
the possibility that a number of further timber gridshells will
be constrcuted. Cambridge Botanical Gardens are considering an
ambitious gridshell project, while not far away, in Chelmsford,
a chestnut modular gridshell is on an architectural practices
computers’ screens for a park and ride project. What could
be happening is this growing band of buildings, are, bit by bit,
pulling a genuinely exciting, elegantly ecological and twenty-first
century form into material existence. With a public tuned towards
the curvatures of organic form, partially by way of the grand
millennium projects, alongside an ongoing and growing research
and knowledge base, a possible critical mass may be on the cusp.
So, the next steps in a very specific strand of an architecture
with organic form, using organic materials, is, at the beginning
of the new century, in the early stages of development, as this
specific gridshell example demonstrates, examples which will hopefully
multiply. That the Weald and Downland gridshell is kickstarting
an interest in the double-curvature rectilinear forms which comprise
their skeleton, and is building an ongoing momentum as described
above. The sections below outline the three principal gridshell
examples in this country, albeit one is an adapted modular gridshell.
All of these were under construction at approximately the same
time, the millennium years between 1998 and 2002.
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