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Tottenham Hotspur Stadium - Licence To Stand
- Thread starter Jordinho
- Start date
SteveAWOL
Erik Thorstvedt
If the depth of those turf trays aren’t a factor in our continuing injury woes then perhaps having the Millennium Bridge of football pitches might be contributing…
How Tottenham Hotspur Stadium built a sliding football pitch in three pieces
Ingenia focuses on all aspects of engineering. Our articles showcase a wide range of engineering and technology innovation, from robotics and data to the latest in renewable energy and medical technologies.
www.ingenia.org.uk
Flexible but stable
With something of this size raised off solid ground, there was a danger that it could behave very differently from standard football pitches. Running on a large steel structure suspended above the ground will cause it to bounce, so the team faced the challenge of making sure the whole structure did not turn into a giant trampoline. A bouncy pitch could affect the way that players move or jump for a header, how goalkeepers leap to make a save, or the way the ball bounces, and would have interfered with the whole game. The team fitted a series of accelerometers around a football field during a game to monitor vibrations and find out how a normal pitch behaved. Engineers also tested a movable pitch at the University of Phoenix Stadium in Glendale, Arizona, during a match between Real Madrid and LA Galaxy to work out what the optimal resonant frequency should be. Widening the main structural beams allowed the engineers to tune the pitch to the right frequency, so that it feels like solid ground.While the structure needed to be solid, it also had to be flexible. Changes in temperature could cause the steel frames to expand and contract, meaning the pitch can grow or shrink by up to 45 millimetres in all directions. To cope with this constantly changing size, engineers designed the 598 wheels that support the pitch sections so that they do not slip off the rails as it moves. Each section of pitch runs on three rails, and the wheels on the central rail have a flange on both sides to keep the trays running in a straight line. However, the wheels running down the outer rails have no flange, allowing them to move left and right across the rail as the weather conditions shift.
And playing regularly on a pitch that’s torn asunder every time there’s an event (see that there were 13 such occasions last year) can’t be helping either…
Joining the pitch
The whole pitch weighs over 9,000 tonnes, more than the Eiffel Tower in Paris. Each of the three sections need to fit together seamlessly so that fans watching football games, and footballers taking part, cannot tell that matches are happening on trays mounted 1.6 metres above solid ground. Ensuring the accuracy required to get this kind of join along the entire 118-metre-long edge was one of the most difficult aspects of the project for the engineering team. Each section, composed of 33 metal trays welded together from 16-millimetre-thick steel plates, needs to line up perfectly when brought together.The team discovered that the best way of ensuring a reliable and repeatable joint was to have the trays ‘touch’ via a three-ply rubber strip running down the entire length of each section of pitch, just beneath the turf. Alternatives included a plastic mesh that would allow the roots to knit through over time. The engineers at SCX also tested how best to pull the pitch apart again as, when the sections are joined, the grass can become entangled as roots and leaves grow. The team initially used a device similar to a pizza cutter to slice between the sections, but it left noticeable damage when the pitch was reassembled later. Instead, it found that the best approach was to simply let the turf tear naturally as the sections pulled apart, allowing it to split along its own weak points.
Bedfordspurs
Paul Gascoigne
What i was told on the tour was it’s a shallow depthIf the depth of those turf trays aren’t a factor in our continuing injury woes then perhaps having the Millennium Bridge of football pitches might be contributing…
How Tottenham Hotspur Stadium built a sliding football pitch in three pieces
Ingenia focuses on all aspects of engineering. Our articles showcase a wide range of engineering and technology innovation, from robotics and data to the latest in renewable energy and medical technologies.Flexible but stable
With something of this size raised off solid ground, there was a danger that it could behave very differently from standard football pitches. Running on a large steel structure suspended above the ground will cause it to bounce, so the team faced the challenge of making sure the whole structure did not turn into a giant trampoline. A bouncy pitch could affect the way that players move or jump for a header, how goalkeepers leap to make a save, or the way the ball bounces, and would have interfered with the whole game. The team fitted a series of accelerometers around a football field during a game to monitor vibrations and find out how a normal pitch behaved. Engineers also tested a movable pitch at the University of Phoenix Stadium in Glendale, Arizona, during a match between Real Madrid and LA Galaxy to work out what the optimal resonant frequency should be. Widening the main structural beams allowed the engineers to tune the pitch to the right frequency, so that it feels like solid ground.
While the structure needed to be solid, it also had to be flexible. Changes in temperature could cause the steel frames to expand and contract, meaning the pitch can grow or shrink by up to 45 millimetres in all directions. To cope with this constantly changing size, engineers designed the 598 wheels that support the pitch sections so that they do not slip off the rails as it moves. Each section of pitch runs on three rails, and the wheels on the central rail have a flange on both sides to keep the trays running in a straight line. However, the wheels running down the outer rails have no flange, allowing them to move left and right across the rail as the weather conditions shift.
And playing regularly on a pitch that’s torn asunder every time there’s an event (see that there were 13 such occasions last year) can’t be helping either…
Joining the pitch
The whole pitch weighs over 9,000 tonnes, more than the Eiffel Tower in Paris. Each of the three sections need to fit together seamlessly so that fans watching football games, and footballers taking part, cannot tell that matches are happening on trays mounted 1.6 metres above solid ground. Ensuring the accuracy required to get this kind of join along the entire 118-metre-long edge was one of the most difficult aspects of the project for the engineering team. Each section, composed of 33 metal trays welded together from 16-millimetre-thick steel plates, needs to line up perfectly when brought together.
The team discovered that the best way of ensuring a reliable and repeatable joint was to have the trays ‘touch’ via a three-ply rubber strip running down the entire length of each section of pitch, just beneath the turf. Alternatives included a plastic mesh that would allow the roots to knit through over time. The engineers at SCX also tested how best to pull the pitch apart again as, when the sections are joined, the grass can become entangled as roots and leaves grow. The team initially used a device similar to a pizza cutter to slice between the sections, but it left noticeable damage when the pitch was reassembled later. Instead, it found that the best approach was to simply let the turf tear naturally as the sections pulled apart, allowing it to split along its own weak points.
The NFL players complain it’s very very hard (different pitch I know)
And I’m sure @Kandi1977 contact at BODO said the grass couch was so fast and possibly hard (can’t remember) that it was quicker than their plastic pitch
SirPercyHotspur
John Scales
ricky2tricky4city
Barry Daines
We've been playing on it since 2019.If the depth of those turf trays aren’t a factor in our continuing injury woes then perhaps having the Millennium Bridge of football pitches might be contributing…
How Tottenham Hotspur Stadium built a sliding football pitch in three pieces
Ingenia focuses on all aspects of engineering. Our articles showcase a wide range of engineering and technology innovation, from robotics and data to the latest in renewable energy and medical technologies.Flexible but stable
With something of this size raised off solid ground, there was a danger that it could behave very differently from standard football pitches. Running on a large steel structure suspended above the ground will cause it to bounce, so the team faced the challenge of making sure the whole structure did not turn into a giant trampoline. A bouncy pitch could affect the way that players move or jump for a header, how goalkeepers leap to make a save, or the way the ball bounces, and would have interfered with the whole game. The team fitted a series of accelerometers around a football field during a game to monitor vibrations and find out how a normal pitch behaved. Engineers also tested a movable pitch at the University of Phoenix Stadium in Glendale, Arizona, during a match between Real Madrid and LA Galaxy to work out what the optimal resonant frequency should be. Widening the main structural beams allowed the engineers to tune the pitch to the right frequency, so that it feels like solid ground.
While the structure needed to be solid, it also had to be flexible. Changes in temperature could cause the steel frames to expand and contract, meaning the pitch can grow or shrink by up to 45 millimetres in all directions. To cope with this constantly changing size, engineers designed the 598 wheels that support the pitch sections so that they do not slip off the rails as it moves. Each section of pitch runs on three rails, and the wheels on the central rail have a flange on both sides to keep the trays running in a straight line. However, the wheels running down the outer rails have no flange, allowing them to move left and right across the rail as the weather conditions shift.
And playing regularly on a pitch that’s torn asunder every time there’s an event (see that there were 13 such occasions last year) can’t be helping either…
Joining the pitch
The whole pitch weighs over 9,000 tonnes, more than the Eiffel Tower in Paris. Each of the three sections need to fit together seamlessly so that fans watching football games, and footballers taking part, cannot tell that matches are happening on trays mounted 1.6 metres above solid ground. Ensuring the accuracy required to get this kind of join along the entire 118-metre-long edge was one of the most difficult aspects of the project for the engineering team. Each section, composed of 33 metal trays welded together from 16-millimetre-thick steel plates, needs to line up perfectly when brought together.
The team discovered that the best way of ensuring a reliable and repeatable joint was to have the trays ‘touch’ via a three-ply rubber strip running down the entire length of each section of pitch, just beneath the turf. Alternatives included a plastic mesh that would allow the roots to knit through over time. The engineers at SCX also tested how best to pull the pitch apart again as, when the sections are joined, the grass can become entangled as roots and leaves grow. The team initially used a device similar to a pizza cutter to slice between the sections, but it left noticeable damage when the pitch was reassembled later. Instead, it found that the best approach was to simply let the turf tear naturally as the sections pulled apart, allowing it to split along its own weak points.
So it's probably not the pitch that makes 2024 2025 different?
SteveAWOL
Erik Thorstvedt
Most of the sliding pitches used across the world are in one section whilst ours is in 33 individual trays which split apart every time there’s an event, so perhaps that is a factor (the designers mention trying to mitigate against the trays vibrating underfoot in that interview plus the pitch getting divided up like a pizza every few weeks for events so maybe those joins aren’t knitting as well as hoped) which shall become apparent when further studies are done.
Wish that I’d paid more attention during the Mechanical modules of my Engineering degree so that I could’ve volunteered my services
MartyFunkhouser
Terry Dyson
Thats literally made me laugh out loud, well played
I guarantee there are hundreds of variations what are natural grass pitches in the countries that have variations of properties under the top. I played 2 years at Grays Athletic which was a quarry, clay and stone under about 2 inches of decent/ish soil. I bet there are variations of the same everywhere in the world.
I suspect the level of edge players are asked to play at is more impactful than the pitch, the level of athleticism is being pushed, players are less robust, being asked to do more, hamstrings going all over the shop. I lean towards a friend who is in the science theory that there is a fine line between being an athlete and being built for durability.
We are having it bad, but we ain't the only ones, its spread across the sport
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SteveAWOL
Erik Thorstvedt
Perhaps the linkages between the turf trays have an inferior tolerance than anticipated when they tested them at our training ground and moving 3000 tonnes dozens of times over the years has lead to some unforeseen buckling which is now in some small way contributing to these injuries.
Considering how unusual a design WHL’s moveable pitch is then it could be suffering some teething problems, similar to how Sir Norman Foster’s Millennium Bridge required many years of modifications before it functioned as he designed and is still undergoing engineering studies decades it opened.
Revised Cause Identified for London's Wobbling Millennium Bridge After Two Decades
Report says adjusted paces, not mass synchronization of walkers, caused negative lateral damping that shut down footbridge in 2000.
www.enr.com
SteveAWOL
Erik Thorstvedt
We’ve spent well over £2billion on transfer fees plus wages since moving into the new gaff and yet we’re once again languishing in bottom 6 of PL… perhaps you don’t always get what you pay for and the designers behind that innovative retractable pitch are no more competent than our Directors of Football…
Gazza Dazzla
Rafael Van Der Vaart
Once again?
1 season in the last 25(?) seasons we’ve been in the bottom 6 (1 in 6 since moving into the new stadium)
Edit: and in that 1 season we won a European trophy and quite clearly sacked off the league.
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SteveAWOL
Erik Thorstvedt
We’re currently 5th from bottom and over the past 2.5 seasons we’ve picked up the 15th most points in EPL…
Gazza Dazzla
Rafael Van Der Vaart
we moved into the new stadium in 2019 and we’ve finished 4, 6, 7, 4, 8, 5, 17 (We were actually a bit better in the period prior)
so to say we are “once again languishing in the bottom 6” is a bit disingenuous…
SteveAWOL
Erik Thorstvedt
We didn’t have a crippling injury crisis until 2.5 seasons ago… maybe there’s a correlation with the tray runners becoming worn or some other issue with the design of that removable pitch and perhaps it’s merely a coincidence but I have so little faith in our board of directors (who’ve been criticised by multiple managers) that I simply don’t trust them to have properly scrutinised this issue. No more than I trust them to appoint a manager who’ll bring back the glory days next season or finally carry out that painful rebuild which Pochettino warned us about just after we moved into nWHL.
Gazza Dazzla
Rafael Van Der Vaart
You said yourself we’ve spent the best part of 2bn, it didn’t take a genius to think we needed new players, the club tried (hampered by the Ndombeke, Sess, Lo celso, Clarke window by the way), but failed to replace like for like. As almost every club has over the years, Utd, Goons, Pool, etc.