New forms - Vector Foiltec

GAME-CHANGING ROOF:
DUNEDIN’S RUGBY WORLD CUP STADIUM
✸ ARENA SPACES TO ACTIVATE FANS AND BRANDS
✸ SYNTHETIC TURF LIFECYCLE ✸ CASHLESS ACCESS
✸ ARENA IN A PALACE ✸ STADIA & ARENA 2012
OCTOBER
2011
WWW.SAM.UK.COM

Venue design and construction – roofs
Roof revolution
New architectural forms and new materials are leading to stadiums which better
match the needs of owners and spectators, as cost goes down and comfort goes up.
When it comes to customer
comfort, what’s more important
than the stadium roof? It keeps
the rain, wind and sun off the
seating areas so that spectators can enjoy the
entertainment. It protects the rest of the
stadium fabric and it can be an iconic structure
for those walking up or watching an aerial shot
on TV. First things first: the roof should be safe.
Stadium roof collapses this year are a warning
to the industry: at FC Twente’s De Grolsch Veste
stadium (one death, 16 injured) and at
Wollongong’s WIN Stadium, where (according
to local newspaper reports) a recently installed
roof buckled under gale-force winds.
History suggests that where roofs are
specified, they are enclosing more and more of
the stadium. The ’dome arenas’ showed the
way during the 1990s. Built by Mitsubishi
Heavy Industries in Japan, domes housed
ballparks (Tokyo and Fukuoka Domes) with
retractable seating and pitching mounds to
allow other events to take place, such as cycling
and concerts. Mitsubishi’s technology included
the bicycle racing banks, stage equipment and
rigging machinery as well as the retractable
roof drive equipment.
When the Waldstadion in Frankfurt was
finally redeveloped for the 2006 World Cup, its
signature roof was constructed from a cablesuspended
ring of fibreglass, similar to
stadiums in Hamburg and Berlin, but this time
around 80,000ft 2 of the inner roof was
removable. An inner network of tensioned
cables also suspended a cube with LED screens.
BC Pavilion Corporation (PavCo) in
Vancouver has specified a new roof as part of
Right: Forsyth Barr Stadium, Dunedin. The
roof and natural turf combination is the
result of extensive research. Copyright
reproduced courtesy of Vector Foiltec.
32 STADIUM & ARENA MANAGEMENT www.sam.uk.com October 2011

the rejuvenation of the BC Place stadium that
was previously covered by an air-supported
structure. PavCo has quoted energy cost savings
of $350,000 or 25% per year and maintenance
cost savings of $100,000 per year. The roof is
suspended from 36 masts, each 50 metres in
length and weighing approximately 240
tonnes. The retractable centre portion of the
roof is made of flexible Tenara fabric. The outer
permanently-fixed portion of the roof is made
of PTFE coated fibreglass, and covers all of the
seating in all weather conditions.
Architects have employed materials such as
fibreglass to design very different looking roofs.
Stadiums in South Africa, for the FIFA World Cup,
and in Poland for Euro 2012 are just some of
the latest examples. Texlon, Vector Foiltec’s
invention which employs ETFE (ethylene
tetrafluoroethylene) for cladding, looked very
interesting for some stadium design work that
architect Populous was carrying out for rugby
stadiums in New Zealand in preparation for the
Rugby World Cup.
Texlon allows natural light to penetrate and
it therefore held out the hope of growing
natural grass under a roof. The client’s team of
experts wanted to know more. Angus Macleod,
engineer at Vector Foiltec, explains: ”We
designed and built a fully enclosed test rig with
walls and a roof and tested various grasses.”
Real rugby players and a mechanical scrum
were used to see how the turf held up.
Although the turf was lush and grew faster
under the Texlon ETFE than outside, it was
determined that the roots needed the help of a
Desso Grassmaster system.
The upshot of this early work is that
Populous, in association with local firm Jasmax,
designed the Forsyth Barr Stadium as the
world’s first fully covered stadium with a natural
grass pitch. It has 20,000 permanent seats, and
11,000 temporary for the World Cup. The design
and engineering of the roof allows optimal
solar light transmission while natural ventilation
is provided by raised facades. The supporting
structure spans 105 meters with an internal
roof clearance of 37 metres. Five trusses stretch
from the north stand to a transfer truss above
the metal deck roof of the south stand as the
main support.
The roof cladding is made up of inflated
cushions of Texlon, which first found
international acclaim when used on the 2001
Eden Project, a series of gardens under domes
in Cornwall, England. There are now 1,000
projects worldwide using this technology,
which was subsequently supplied by Vector
Foiltec for use in St Jacobs Stadium in Basel and
the Olympic Aquatics Centre in Beijing.
”In Carisbrook, spectators stood and froze,”
says Macleod, referring to the previous
incarnation of the stadium. ”It was lowering
attendance at games. Stadium design is about
winning people back from in front of their TVs
October 2011 www.sam.uk.com STADIUM & ARENA MANAGEMENT 33

in their lounges, so we have to create a nice
atmosphere and a comfortable experience.”
Anyone who viewed games at the stadium in
the recent Rugby World Cup will have noticed
the fans jumping up and down in their
shirtsleeves and drinking cold beer in what is
the middle of winter in New Zealand.
Texlon is about big numbers – 100,000m 2 on
the water cube – and small – weighing one
kilogram per square metre. Forsyth Barr
Stadium has 20,500m 2 in the roof and Eden
Park, Auckland, has used 10,000m 2 in the
façade which is part of its new south stand.
Macleod says the material’s lifespan is as yet
unknown. After 20 years of maintenance,
Vector Foiltec has detected no change in its
optical or mechanical properties.
The material is smooth and so dirt washes
off easily and the cushions, which are five
metres by 20 metres, won’t pop out of their
framework in the event of an earthquake. If a
cushion were to be damaged, the lightweight
material would float to the ground. It has low
embodied energy. Macleod assures that,
although Texlon ETFE uses some fossil fuels in
its production, it’s a byproduct of a mining
process and doesn’t leave any harmful waste. It
is also recyclable. If a building one day pulls
down the Texlon ETFE – it hasn’t happened yet
– the material can be taken back by Vector
Foiltec, melted down and re-used.
”It’s very exciting,” sums up Macleod. ”You
can grow natural turf pitches under a Texlon
ETFE roof. Couple that with the material being
lightweight and easy to adapt architecturally
and you have to ask ’why not?’ It could be a
revolution in stadium design and I’m told it’s the
cheapest stadium in New Zealand judged by
NZ$ per square foot.”
”The permanent roof means Forsyth Barr is
a true hybrid between a highly efficient, well
functioning football/rugby stadium and an
entertainment venue,” says Richard Breslin,
Populous Senior Principal and Project Director of
Forsyth Barr stadium. ”Research by many
people has created this final concept of a
natural grass pitch growing under a permanent
roof structure. The fans are protected from the
elements and the action goes on whatever the
weather.” Breslin also thinks the rectangular
design will change the way we view the live
game: ”The angled seating pitch and enclosed
roof will mean spectators are closer to the
action than ever before and the atmosphere
will be fantastic. I was there recently, and even
though there was no game on, the sense of
enclosure made the hairs stand up on the back
of my neck.”
Populous Associate Principal, Ron Van Sluijs,
Project Architect of Forsyth Barr stadium during
its design phase, says: ”The new roof means
Top and middle: Forsyth Barr Stadium kicked off with games in the Rugby World Cup. It
will prove its multi-purpose credentials in December with a first concert.
Bottom: Eden Park, also a Rugby World Cup venue, has a new façade made from Texlon
ETFE. Photos copyright reproduced courtesy of Vector Foiltec.
34 STADIUM & ARENA MANAGEMENT www.sam.uk.com October 2011

Innovative
Stadia Architecture
Vector Foiltec is revolutionising sport and stadia
design with the world’s first permanently covered
natural turf pitch, the Forsyth Barr Stadium.
International market leader and pioneer of Texlon ®
ETFE, Vector Foiltec boasts 30 years of experience
at the forefront of specialist design and ETFE
technology. We offer our clients a complete service
with unprecedented expertise.
Our extensive portfolio includes The National
Aquatic Centre, Beijing, The Khan Shatyr
Entertainment Centre, Kazakhstan, Eden Park
Stadium, New Zealand, and St. Jakob Stadium,
Basel.
www.vector-foiltec.com
4
1
5
1 National Swimming Center
Beijing (CN), 2007
2 Stadion St. Jakob-Park
Basel (CH), 2009
© Andreas Braun
3 Eden Park Stadium
Auckland (NZ), 2010
© Julian Apse
4 2022 Showcase Stadium
Doha (QA), 2010
5 Eden Park Stadium
Auckland (NZ), 2010
Forsyth Barr Stadium
Dunedin (NZ), 2011
2
3

we can maintain a constant temperature and
grow a stronger grass which will not become
boggy because it will never rain, snow, or hail
inside the stadium during a game at Forsyth
Barr. This roof material allows for 90% of
sunlight to still reach the pitch, along with UV
light and fresh air.”
Project Architect during the construction
phase at Forsyth Barr, Populous Associate
Jochem Veerman adds that the sectional profile
of the stadium was carefully designed to
maximise solar penetration onto the field as
well as the natural ventilation:
”The ETFE covers the roof and parts of the
façades. The stands on the northern end are
lower to allow maximum sunlight onto the
pitch and the end facades are raised five
metres so the stadium is open at these points,
allowing natural ventilation of the grass, and to
ensure spectators do not feel enclosed. There
are also ventilation slots at a high level to
ensure air circulates properly.”
New forms
Thinking about the real needs of stadium
spectators can result in interesting architectural
forms, according to Mott Macdonald Divisional
Director Leon Higgins.
Roof design in hot countries, such as the
Middle East, needs new thinking, he says: ”They
don’t need an umbrella, they need a sun
shade.” FIFA’s guidelines designate a roof to the
edge of the seating but this isn’t always
appropriate. Mott Macdonald Associate Paul
Officer encourages architects to take a rational
approach: ”It is sometimes more appropriate to
relax the compliance with the guidelines and
focus more on designing for
the actual environmental conditions at the site.”
Future-proofing customer comfort
Mott Macdonald’s engineers consult on many
stadium projects around the world. The company
is currently working with Pattern Architects’
Dipesh Patel, who has introduced a profile roof
that provides complete shading at kick-off time in
the afternoon in August for stadiums in the Middle
East. This has resulted in a different, assymetrical
form. Often this form is used to save money but
Patel’s design is about achieving the right
conditions for the environment.
Patel explains that his design came about
on a job which started out as a moving roof. ”To
keep the aperture small enough to have a
moving roof, you really struggle with getting
enough daylight through.” The debate around
the roof design included using artificial turf and
the use of different roof materials.
”It’s essentially a parasol – that’s the best
way to describe it,” says Patel. ”It provides a
balance of shading for spectators, but enough
light during the rest of the day for the grass to
grow. We’ve looked at several materials and
settled on a polycarbonate and PVC sandwich,
and that’s more about what it looks like. It’s
effectively solid, which is good for the people
underneath.”
Officer points out that the moving roof on
Wembley is principally about getting light to
the pitch, a problem that hasn’t been
completely solved by translucent materials. He
suggests that Patel’s parasol is a less brutal
approach to solving the shading versus grassgrowing
conundrum. ”Moving roofs are big and
heavy and expensive. You need a lot of
steelwork to take the load which is
concentrated on two lines where the rails are
located. At Wembley we kept it down a bit by
spreading the load around more panels.”
Patel thinks that the ”firework roof
structure” still has its place but that architects
Holding things together: High Torque
Jubilee Clips (made by L Robinson & Co) on
the roof of the new Forsyth Barr Stadium,
Dunedin, New Zealand. Auto Agencies
(New Zealand distributor) supplied 208
clips at short notice to the roof contractors.
take a more holistic approach than a decade
ago. ”A roof can still be iconic and striking, but
through its overall form rather than the finery of
the diagram.” For simple grandstand shapes,
the cantilever is generally the most costeffective
of the self-supporting structures. Patel
agrees that these structures are cost-driven and
that it’s difficult to scale down the forms
possible in larger stadiums, such as those he
used to design City of Manchester Stadium, to
smaller capacity venues.
Vector Foiltec supplied Texlon to the showcase stadium built by the Qatar 2022 bid committee for the FIFA World Cup. The bid required
looking into a future of comfortable and energy efficient stadiums hosting athletes and fans in summer. A combined team of architects,
engineers and environmental services at Arup managed the project and Edwin Shirley Staging constructed the prototype. Vector Foiltec
worked with David Dexter Associates structural engineers to clad
Photo: copyright reproduced courtesy of Vector Foiltec.
the moving roof and two opening/closing façades.
”The cladding is Texlon ETFE combined with tensile fabric shading
and the design is all about controlling heat gain out and in,” says
Stephen Jones, Design Director at Vector Foiltec.
The principle is to open at night to cool the seating areas and base
of the walls, closing in the day to keep out the heat. Jones explains
that the Texlon ETFE is light and therefore doesn’t put big load or
energy demands on the engineering needed to move the roof and
façade structures.
The stadium met Arup’s performance criteria and Qatar won the bid
so the project succeeded in various ways.
”We learned valuable lessons about value engineering our
solution,” says Jones. ”I hope that Texlon ETFE is deemed applicable
for this kind of stadium application.”
36 STADIUM & ARENA MANAGEMENT www.sam.uk.com October 2011