Brighton i360 team visit Hollandia factory ahead of tower’s arrival

Tags

construction, David Marks, hollandia

A delegation from the Brighton i360 recently visited the workshop in Holland where the cans which will make up the 162 metre tower are being made.

Led by the i360’s chief executive Eleanor Harris and architects David Marks and Julia Barfield, the party spent a day at the specialist Hollandia factory in Rotterdam. 

There they were shown the 17 pieces of rolled steel, or cans, which are due to arrive in Brighton by sea on June 11.

Each can measures between six and 12 metres in height and together will form the shaft of the i360. They differ in size, with the taller cans going at the top of the tower and shorter cans, but with thicker walls, making up the lower sections.

John Roberts, the chief engineer at the i360, also made the trip – which was funded by the board and Marks Barfield, the architects behind the scheme.  He inspected each can individually and was delighted with the progress.

The cans will soon depart for British shores and should land in Brighton on June 11, when a 100 metre high crane will unload them from the boats onto the beach.

From there they will be fitted into place by a jacking tower. Rather than add each can to the top of the structure, the jacking tower allows the engineering team to build from the bottom up. Once the cans have arrived, the tower should take shape relatively quickly and the shaft should be completed by the end of September.

Eleanor Harris said: “This was the first time some of us had been to Hollandia and to see the cans up close was brilliant.

“Once they arrive in Brighton and start going up it will really give people a sense of the scale of the Brighton i360.”

David Marks and Julia Barfield were also behind the London Eye and remembered the excitement which greeted the structure being floated down the Thames.

And Eleanor Harris is anticipating a similar response to the arrival of the cans on Brighton seafront.

“We are expecting there to be a lot of interest when the cans arrive by sea,” she said.

“We already have a lot of people stopping to watch what is going on at the construction site when they walk by but the cans going up takes the construction to another level.

“Building the i360 a major feat of engineering. It really will be quite exciting to see the cans arrive and the tower start to take shape.”

For regular updates on the i360 construction and for further information about the beach landings event, follow @TheBrightoni360 on Twitter.

Prepare the basement and beach for the arrival of the tower!

Tags

Brighton, Brighton i360, construction, engineering

This summer, Brighton and Hove is going to change. On 11^th June, 17 huge pieces of rolled steel, the i360 tower cans, are due to arrive by barge onto the beach alongside the West Pier. Fences are going up and large bits of machinery are arriving… Holland, we are awaiting our exciting shipment!

Our tower cans are ready to leave Holland!

But first things first. We need to get ready…

Preparing the arches

Now that we have been granted listed building consent to rebuild the heavily corroded, structurally dilapidated arches behind our site, work has begun to turn them into part of our beach building.

We have moved the hoarding line on the upper promenade as a temporary measure. For a short while cyclists and pedestrians need to share the pathway. This works well on the beach footpath before 11am, when cyclists are allowed to use the lower promenade as long as everybody is mindful of other path users. Hopefully the same attention will be paid on the upper promenade but please do take care.

Preparing the basement

The 1st dig goes down 1.5 m

Those of you that have strolled along the beach footpath or cycled down the promenade, will have noticed the physical change in our site. It appears to be taking on a shape!

At the start of February we began to form the piles, the concrete ‘stilts’ that form the deep foundations of our building. Some of these piles interlock to form the basement wall. During March we put the capping beam on top – this is a solid layer that sits above the piles and transfers the load more evenly. The shape you can now see is the top of our basement!

Our high-performance crane will be here all summer

We have the layout, now we need the depth. The dig is done in two stages. The 1^st, which we are undertaking now, goes down to 1.5 m. We need to add temporary props to the structure at this point, which will stop the walls caving in as we dig.

To help us fit the props, we are using an 80 tonne crawler crane. Although it has only just arrived on site, the Hitachi SCX8000 is already playing a major role on site – shifting all the heavy kit that we will need to create the basement. The shiny red crane is also providing construction and environmental enthusiasts the chance to see a new breed of crane in action… the Hitachi SCX8000 has a high performance exhaust filter, cleaning the air using anti-pollution technology.  When tests were done in London, the air that came out of the exhaust was cleaner than the air the people of the city was breathing!

The temporary props will hold up the basement walls

At the end of the month we will start to dig down to the bottom. Digging 8.5m down into chalk on the seafront is no easy feat. We go below the tidal water level and so the engineer’s first challenge was to find a way to make the working area dry. Our plan is to drill down 16m and put ‘well point pumps’ in. These pumps allow us to remove all the water and keep the area dry while we work. Once we pour concrete in, the ground is effectively ‘plugged’ and we can remove the pumps.

A long reach excavator is due to arrive soon

With the water removed, we need to be able to shift the huge amount of shingle out of the basement. This is the 2^nd part of our big dig and a long reach excavator will be arriving on-site imminently.  This highly specialised piece of kit can reach out 16m and will allow us to remove all the shingle from the basement. The crawler crane will support the work, enabling us to lift things in and out of the newly formed space.

The steel will reinforce the concrete basement

As we dig, a steel cage is built within the basement. The rods are arriving on-site as individual pieces at the moment, but will be carefully linked together to form a mesh like structure to fit – much like they were for the helical cages used within the piles. The rods further strengthen the concrete when it is poured in at the end of May.

Preparing the beach

So where will the shingle from the basement go? Ever keen to reduce the need for landfill, we are reusing the shingle to create a ‘beach mat’ across the other side of the footpath from our site.  We need to reinforce the beach as this is where the 100m crane that builds the tower will sit. We will also store our 17 cans in this area, ready to be lifted over the path and positioned one-by-one.

We are busy preparing the beach for our platform

To get the shingle onto the site we are using a vacuum excavator truck. The truck will sit on a platform on the beach, attached to a pipe that runs under the footpath and on to our existing site. The shingle is deposited into the pipe and will literally be sucked through to the other side. A dumper truck on the beach will collect the shingle and deliver it across the beach, helping us create a flat platform.

To protect the existing beach, a geo-textile membrane is laid over the beach before we deposit any shingle on top.

Anyone who has ever walked down a shingle beach will know how the ground can give way beneath you on the steep slopes. To prevent this, gabions will shore the beach up at the far end of our platform. We will then add another layer of geo-textile membrane across the whole space so that we can deposit the layer of sand and stone needed to support timber mats.

Heras fencing surrounds the site for safety

There is still lots to do before June, but with the fences going up this week it is easier to get an idea of the working area. In the next few weeks we will be giving an update on how the beach landings will work and how we are going to celebrate the arrival of our space-age cans. Summer is going to be busy, so watch this space!

It’s in the can! A closer look at progress on the tower

Tags

construction, David Marks, hollandia, i360 tower, television crew

Many of you will have seen David Marks, the architect behind the i360, on BBC South East recently. David travelled with the BBC television crew to the Hollandia factory in Rotterdam for a first-hand look at the 17 tower cans due to arrive on Brighton beach this June.

We thought the news piece had a real impact. Having worked on a muddy site for many months, it was a real thrill to see the shiny steel cans in the factory and know that in less than 3 months they will be here! For those of you that missed the show, here are some more photos from the trip…

David and the crew were shown around the factory by Wim van’t Hof, Senior Project Manager and Works Director, Hollandia. The cans behind him have had their flanges attached, bolt holes drilled through and are currently being painted with a protective coating to withstand the elements.

The bolt holes have been drilled using CNC boring machines (above). The can above looks a rusty colour because it has not yet gone through the cleaning and painting process.

In most of the images the cans are hollow, but we spied a bar running across this one above. David reports that this is a temporary jig for centring the can to enable accurate setting out for the various cleats which will be welded inside the can to support ladders, platforms, counterweight guiderails, dampers, cable trays and everything else that needs to be supported inside.

Everything needs to be welded into place in Rotterdam, while the cans are in a factory-controlled environment. While David was there, the team were busy working on the counterweight guiderails which will be fixed inside the cans and will guide the counterweight up and down.

They also had the stainless steel abseil rail that will be fitted on top of the upper-most can at the top of the tower.

A lot of people are curious about how we will fit the first can into the ground and while they were at the factory, it became clear. We will use an anchor bolt frame (above) that is pre-assembled in Holland. It will be cast into the main foundation ready for us to bolt the first tower can down.

Although the pod is being built in France, some elements of  the mechanism need to be fitted into the tower cans before they arrive in Brighton. The bull wheels and counterweight guide-wheels (above) were shipped from Poma, our French team, to arrive in Rotterdam recently.

Here the counterweight is being pre-assembled in a temporary frame before being delivered to site.  The white ‘block’ above the Hollandia sign is made up of thick steel white painted ‘plates’ which are stacked up to form the counterweight.  The red bull-wheel is being lowered into the counterweight where it will carry the steel rope which will lift and lower the counterweight.

David and the BBC crew really got a sense of the scale of the tower, something that Brightonians will probably only begin to appreciate when the boats arrive in June. It was a fantastic trip and we hope the photos have got you as excited as we are about the tower build!

26 ways Brighton i360 will benefit the City

Tags

Benefits, Brighton, brighton biosphere, Community, conservation, engineering, environment, i360, i360 tower, jobs, sustainability

1. We will create 440 new jobs – An independent economic impact study concluded the i360 will generate 440 new full-time equivalent roles in the City.

Our tower will bring crowds and jobs to the seafront

2. We are the first tourism ‘living wage’ employer in the City – We believe that by paying a decent wage, we can attract the best people to work for us who will in turn deliver outstanding service to our guests.

3. We will bring an additional 350k visitors to the City – Who will travel to Brighton to visit the World’s tallest moving observation tower and the tallest observation tower outside London from the team who created the London Eye. All these extra visitors will all spend money in the City’s many shops, restaurants and hotels, generating more income and jobs in Brighton.

4. The Council will make £1m per annum from loan – The Council have acted as ‘middle men’ for a loan from the Public Works Loan Board and will earn £1m per annum profit at a time of economic cuts.  No council tax is being used.

Brighton Council need the revenue stream to help tackle the cuts

5. The city will get 1%  of ticket revenues – Every single year, we will pay 1% of our ticket revenues to the City for the community’s benefit – this payment will keep flowing even when we’ve repaid the loan.

6. Restoration of West Pier heritage – The i360 will restore the beautiful original 1866 West Pier toll booths and return them to their original position on Kings Road, as a tea rooms open to the public and our ticket office.

7. We are providing financial support to the West Pier Trust – This money supports the Trust’s heritage works, schools programme and plans to create a new Pier, ultimately securing their future

We are restoring parts of the West Pier

8. Free rides for school children – Every child attending a state school in Brighton will have the opportunity to visit the i360 at least once for free in their school career.

9. A great place to bring the kids – Did you know we’ll have a kids’ play zone in our beach building? There also will be fun activities during school holidays. We think the i360 will be a fantastic place to entertain the kids.

10. Inspiring the next generation – We hope to inspire the next generation of engineers and architects with the awe inspiring tower. We will develop free curriculum resources across the key stages in maths, design, technology and science.

Kids love to build – let’s harness that enthusiasm!

11. Discounts for local residents – We will offer a fantastic membership scheme for locals with discounts on our ‘rides’, Sky Bar, Brasserie, tea rooms and children’s soft play. Interested? Sign up here!

12. We are championing local companies – We want to harness all the amazing home-grown talent in Brighton and Sussex. We advertise all tenders locally and we are already working with a growing list of local suppliers.

Natural PR is just one of the local companies we are working with

13. We are creating a new benchmark in Sustainability – From harvesting rainwater to food composting and low energy appliances; our tower will even generate around 50% of its own energy needs on its descent! Pretty cool!

14. We are helping regenerate the seafront – We have kick started a regeneration of the Western seafront; more footfall West is of huge benefit to Preston Street and the many seafront traders to the West of the Palace Pier.

15. Working with charities – We will support many local charities once we open. We are already fundraising for Rockinghorse. Sponsor our CEO Eleanor Harris to dance the Charleston here.

Eleanor is one of 4 dancers set to raise money for the Rockinghorse Charity

16. A new City icon – We believe we are creating Brighton’s future heritage and a new icon for this progressive, exciting digital City, something to be proud of.

17. Supporting events and tourism across the City – We are forging positive partnerships with attractions, hotels and major city events. Our re-launched web site will promote all the wonderful things Brighton has to offer.

18. Showcase up and coming talent – We will host an exciting and ever changing programme of events such as live music, showcasing up and coming talent, something close to the heart of the City.

19. Open up the landscape of Sussex – From our glass viewing pod you will enjoy amazing views of the ‘UNESCO Biosphere Reserve, South Downs National Park and Sussex coastline in all its glory.

We are one of a handful of UNESCO Biospheres

20. Great beach-side venue to hang out and soak up that West Pier view – Even if you have a fear of heights, we hope you’ll come to visit. Good coffee, free Wi-Fi, delicious food, lovely views, fun events… a great new beach-side venue for locals to enjoy!

21. We’ll attract high spending overnight stays – Our unique Sky bar and destination Brasserie will make it worth extending a day trip into an overnight stay worth nearly 10 times as much to the local economy.

The Sky Bar is going to be the ‘top spot’ for evening drinks on the seafront

22. We’ll help Brighton remain competitive as a conference destination – Conference visitors can be entertained with a drinks reception in our glass viewing pod or in our beach-side hospitality rooms, helping Brighton attract conferences to the City.

23. Top spot for special events – We will host special events on Valentine’s Day, New Year’s Eve and during the Brighton Festival and Pride week. We can even change the lighting of the tower.‎ Rainbow tower?

Our pod lighting could change to match big events in the city – a pride rainbow in the sky!

24. Tallest moving place to get married – Imagine saying ‘I do’ at 450 feet and then descending to earth for a beach-side party in our beach building. Those wedding photos will be amazing!

Weddings at the top of Brighton!

25. Sustainable locally sourced food – Our Brasserie will serve fresh seasonal food from the South Downs, Sussex coastal waters. All from within the 26 miles you can see from the i360.

26. An incredible view – Why did we choose 26? Because from the top of our tower you can see for over 26 miles. On a clear day, views will stretch from Bexhill-on-Sea to Chichester.

Breathtaking views

Let the piling commence!

Tags

Brighton i360, engineering, piling

For the next month you may spot a rather large piece of machinery on site. With the sewer works behind us (or beneath us!), a new chapter has officially started! Ladies and gents the piling has commenced!

The full 25m rig – there are not many of these in the country

What is piling?

Piling is one way of building the deep foundations of a structure. You drill down deep into the ground and fill the space with concrete, steel or even timber. The hole is then filled with concrete. We are using two types of piles – secant and bearing.

What is the difference?

The first bearing pile is formed

Bearing piles are placed throughout the whole site and will act as stilts – holding the building securely in the chalk strata below the site. They are drilled at different depths depending on where on the beach they sit and what they are holding. Our bearing piles range from 13 to 20m and once drilled, will be topped off with piles caps and beams before the reinforced concrete ground floor slab is cast over the top.

Secant piles are used to create our basement wall. Rather than ‘hold up’ they need to ‘hold back’; the shingle would just collapse in if we were to dig our basement. The secant piles are 10m deep and interlock to hold the shingle back, allowing us to excavate the space.

How do you stop the hole collapsing?

The brush cleans off the auger as it draws up the shingle

We are using a continuous flight auger (CFA) pile, which means that as we drill down through the chalk, clay and shingle, we fill the space with concrete (which incidentally comes from a local Shoreham plant). A hose runs through the stem of the auger and pumps cement grout mix straight to the bottom. While the cement grout is pumped, the auger is slowly withdrawn, conveying the soil upward along the flights. A shaft of fluid cement grout is formed to ground level.

How will the basement walls interlock?

The channel is in place for the secant piles

The piles are scalloped and are either ‘male’ or ‘female’. We drill them in at different times and the scalloped nature means a male pile can interlock with a female. Females are drilled on Mondays and Tuesdays, males  on Wednesdays, Thursdays and Fridays.

Are they just concrete?

The male piles and baring piles are reinforced with helical cages

Female piles are straight concrete. The male piles and baring piles are different – they are reinforced with helical cages which are steel spirals that run through the pile, and lacers, which are straight rods of steel. They carve into the female piles with their greater strength (how very sexist!), interlocking the structure.

What happens when you have finished interlocking the piles?

Once complete we will excavate out inside the basement and install temporary props to support the walls during construction. Upon completion of the excavation we will cover the bottom of the excavation with a layer of blinding concrete before fixing the 170 tonnes of steel reinforcement required for the main tower foundation.

Who is in charge of the piling?

Gary is our chief piler!

The CFA rig belongs to Simplex Westpile, a leading specialist in the piling industry. They seemed pretty happy to be on such a sunny site yesterday. Let’s hope the impending rain does not dampen their spirits!!

Welcome to the i360 site folks!

Let it flow – a major milestone reached as the sewer diversion is signed off!

Tags

engineering, sewer, Thorne

It is the end of a chapter on the i360 site. For months we have been working on the sewer diversion – planning how we would break into the Victorian sewer, how we would divert the flow during the works and how we manage the impact on the public, all documented in a previous blog. Yesterday Southern Water signed off the final two manholes – the sewer diversion is finished! A major milestone ticked off the list.

The end of the sewer also means the end of our time with CJ Thorne, sub-contracted by our principal contractor, Mackley, to do the diversion work. Our previous blog covered the innovative process they used to divert the sewer, so we thought this would be a good time to talk to the man behind the method – Thorne’s Site Manager, Cerwin Meijer. We wanted to find out where the idea came from, how the process went and what has been happening since the bungs were inflated and we all became obsessed with sewage flows!

What have you been doing since the original break in?

Once we broke into the sewer we were able to get inside and inflate the bungs. This meant we could divert the flow. Only one man got his feet wet in that whole process!

Lucky man!

He was fully kitted up in protective clothing. He didn’t look too closely at what was flowing past him – the treatment works are at Black Rock and so the sewage had not been filtered or treated at this point! Stuart (Slark, from Southern Water) told us that he once found a 19th century gold ring at the bottom of the sewage pipe before it hit the filters. He still wears it. 

Why was the diversion so innovative?

Pumping was not really an acceptable solution. It would have involved digging up the area around the new arches and running 24 hour diesel pumps. There would also have been pipelines all over the site. It was looking like a very costly and problematic project. I proposed using Lampe bypass stoppers (the bungs), a brand new way of diverting pipes. Until now, this kind of job would have used Trelleborg stoppers, which are much heavier and not as versatile. The Lampe ones inflate and deflate a lot quicker and they seal to the sewer wall, staying in position even when deflated.

Why are Lampe bypass stoppers not standard?

The innovative doughnut!

They will be now! I had to prove it would work as it was an untried method. It is also  a very high profile site so we had to be sure it would work. My method statement was agreed – that was a fantastic feeling.

It must have been even better when it worked!

Yes. We had to be very careful to lift the brickwork out in sections to make sure that it did not cave in. I cheered when the first piece came away cleanly! And when the bungs were in place and we were sure there was no leakage – amazing feeling!

So once the bungs were in place?

We had to build up around the diversion to create the proper pipe connectors.

Once those were in place, we were able to deflate the bungs and let the good stuff flow!

So what about the old sewer?

We had to remove the central part of the sewer that was in the way of the foundations. Southern Water are going to keep some of this for their tours. The rest we filled with concrete and sealed off.

Are you happy with how it all went?

Yes! There is still a bit of filling in to do, but the temporary bungs were deflated over the last week and the flows are all looking good (if sewage flows are your thing!).  Southern Water are taking on this method going forward for other diversions.

What’s coming up next for Thornes?

The i360 Thorne’s team finish this week to start on another exciting project. You will still see our trucks though – we are working for the Council to finish the arches, so we shall remain your neighbours!

Have you enjoyed working on the i360?

Yes I have. Working next to the beach is fantastic and this is totally different to the usual civils work or reinforced concrete (rc) frames that I do. I’ll miss working down here. Knowing that Brighton will have the tallest tower is exciting and it will be great to say I was a part of it!

More than just a view

Tags

Accelormittal Orbit, Blackpool Tower, Brighton i360, Spinnaker Tower, The Shard

Last week we looked at why observation towers have become so popular around the world; an exhilarating and fascinating change in perspective now being one of the ‘must-do’ activities for any visitor to a town hosting one of these lofty platforms. We also looked at how towers have a second level of importance; standing head and shoulders above the city means they can easily become a symbol or icon, particularly if they have a pioneering design.

This week we are looking at experience. Skyscrapers are getting higher and higher, and though height is important for an observation deck, it is not the only thing that compels people to travel to the viewing deck at the top of a building. It is the experience offered by the observation towers that make them so fascinating and exciting, and this week we are looking at how 4 other towers in the UK have ‘enhanced the view’ by making more of the experience.

Spinnaker Tower, Portsmouth

https://www.flickr.com/photos/miketendler/14349034596/in/photolist-aEkwd6-oSmaqz-fgZYZ2-nRYy5d-9joWDz-5HPipc-6N6gxp-4yi3J-fZAHpB-9AtEhi-cQbFQS-6HnnK1-9joXnH-6ruWA-gebyz4-oGCxJb-5UGeb-4VAamB-cMT2gU-nSGuE5-mXGGgq-bA1jb5-bwF3P7-ay4LTj-kg4gBM-p4V3J1-ojG8Fm-a2scnJ-qmVmJs-5LCps6-cXMjoS-ii5T9-fh6wuv-6E7aDN-8SFxYU-a2pidv-5AvuoK-oeAti7-bdSdfT-79TWNe-8XopVX-6gQia7-6tA1eU-6tzZsE-2FvBj6-bKzLGn-oUXc6q-mVB2Qk-bwF3Ws-kg4ifr

The Spinnaker Tower, at a height of 170 m above sea level, is one of the tallest accessible structures in the United Kingdom outside London and is a member of Great Towers. The unique structure is designed to look like sails billowing in the wind – a key link to the maritime history of Portsmouth – and it is owned by the city. It has been hugely successful and has become an icon for the South Coast.

Viewing towers in London have a plethora of easily-identifiable buildings, but if you move outside of the capital city, it is important to help people understand what they are looking at. Visitors to the Spinnaker can enjoy three different viewing decks and their experience is enhanced through audio guides and interactive touch-screens that that draw focus to the maritime aspect of Portsmouth. There is even a gadget that helps you see which ships are coming and going!

As we progress the i360, we are already looking at how we can make the view interactive. Whether it is a link with the UNESCO biosphere to help visitors understand how the downs, city and sea link together, or through partnerships within the city, encouraging people to visit areas or buildings that they spotted and learnt about whilst in the tower. We will even have a host on board who can provide a commentary tailored to the group, so you can learn more about the architecture or history or engineering… whatever your preference!

Blackpool Tower

The Blackpool Tower is based in the North West of England and is a Grade I listed building, based on the Eiffel Tower. It opened in 1894 and has seen several updates, the most recent one in 2011 when the whole complex was renovated. It is iconic to the city and the North West of the UK and brings in an enormous amount of revenue for Blackpool Council.

The Blackpool Tower Eye has a viewing platform at 122m and a five centimetre thick glass viewing platform at 116m that runs along one wall. On a clear day you can see as far as the Lake District, Wales and Liverpool. What makes Blackpool such a great destination though, is more than just this spectacular view. Their USP is the history of the site. Although observation platforms were popular in 1894, so was dancing. The Blackpool Tower Ballroom sits at the base of the tower – an architectural feat in its own right – a stunning setting of Victorian splendour. Dancers have whirled around the room for over a century and it has long attracted the world’s best movers, particularly with Strictly Come Dancing staging one of their broadcasts from the room.

Linking the viewing experience with the history of the location is close to our hearts. The i360 is based on the site of the West Pier and we are going to be using lots of salvaged parts within our base building. The old ticket booths will be resurrected in their original spots on the Kings Road (one is being repaired and one is being faithfully copied) and there will be some of the old columns in our base building. Like Blackpool, we plan to embrace the heritage of our site and make sure visitors can enjoy both the modern and historical aspects.

And though we may not have a Victorian ballroom at the bottom of our tower, our event space has been designed to take advantage of what we do have downstairs… the beach. We will have event rooms with private decks as well as a brasserie restaurant – all perfect for parties, dining out and people watching! We will also have a kids soft play area and exhibition space.

ArcelorMittal Orbit

We have looked at how towers embrace the history of a site and a city, but what about a new site and a new tower? The ArcelorMittal Orbit is a 114.5 metre (376 feet) tall sculpture and observation tower designed by Sir Anish Kapoor. It was built as part of the Queen Elizabeth Olympic Park in Stratford, London and was intended to be a lasting legacy of our Olympic and Paralympic Games.

There are two observation platforms from which visitors can look over the Olympic site. You can take a lift up to the highest, at 80m, but it is recommended that you descend via the stairs so that you can see how the view changes and hear the ‘sounds of London’. There are interactive viewing opportunities to help you understand the view and the chance to try the distinctive Kapoor-designed concave mirrors that will flip your perspective and turn the horizon on its head.

The idea of challenging people with a complex design is exciting to us too. The ArcelorMittal Orbit is the UK’s largest piece of public art and the whole experience encourages you to explore what you are looking at – whether it is London from a new angle, the sculpture itself from the various heights or the topsy-turvy mirrors – it gets you talking! The i360 will do the same – we are using complicated and innovative engineering techniques to create a tower that will seem to defy gravity. It is so slender, yet it can carry a huge glass pod full of 200 freestanding individuals. How?!

The Shard

What tower discussion could be complete without reference to the View from the Shard?! This is the UK’s tallest tower and viewing platform, part of the Shard skyscraper – described as a vertical city where people could live, work and relax. It comprises world-class offices, award-wining restaurants, the 5-star Shangri-La Hotel, exclusive residences as well the viewing tower.

There are three different viewing platforms with stunning 360° views, multimedia displays and digital telescopes to help you understand what you can see. Stairs lead up to Level 72, where you can get out in the elements and stare up at the sharp pinnacles of glass – the reason the building is called the Shard.

We began this blog by saying that height is not the only important thing, and that people don’t just want to look out at the view, but we didn’t touch on the important accolade of being the tallest, and how this USP can become the main part of a bigger experience. The Shard has interactive commentaries and ways to focus in on the city below, but for them, it is all about height.

We too are the biggest – we are the world’s highest moving observation tower! When Marks Barfield designed the tower, they made sure we went just that little bit higher than the tallest moving platform to date… their very own London Eye. Quite simply, people love to get to the top and the i360 not only takes them there, it provides a space in which they can do more than just look at the view: an evening Sky Bar for you to enjoy a drink; a private space for up to 200 so that you can get married or host a special party; a unique event space for theatre or music… all at the top of the highest moving tower. That is a pretty unique USP!

Moving onwards and upwards!

Tags

Observation towers; tall buildings; icons

2014 was all about moving from concept to reality for the i360 as we reached financial close and began digging down. 2015, in contrast, is about moving up – our tower build begins this year and we can’t wait to finally see the i360 emerge on the Brighton and Hove seafront.

Our tower emerging from the seafront

With all this talk of tall buildings, we felt it was time to look at observation towers in a bit more detail. Why do they remain some of the most popular attractions in the world? What is it about them that appeals to visitors? Why are we building one in Brighton and how will we stack up against other tall towers? Like skyscrapers, they continue to challenge the boundaries of engineering, seeming to defy gravity, so is it more than just height that is important? So many questions! Too many, in fact, to answer in one blog; this week we will narrow it down, focusing on the universal fascination with the ‘view from the top’ and why tall towers need to be more than just tall!

Head and shoulders above the rest – why we love tall towers

David Marks put this simply, “there is a universal desire for people to get up high to enjoy a great view”. 

Controversial design for a historic city

A fascination with climbing to the top of something to see the view goes back to the beginning of time. It gives you a sense of place, spreading the immediate world below you and giving you a drastically different perspective.

Of course views could only be found at the top of mountains before man-made structures came along. Centuries ago, German aristocrats constructed them as a symbol of their wealth; TV and radio companies had to build them to transmit; lookouts were crucial for everything from war to forest-fire watches and so forth. Tall buildings became more commonplace. It wasn’t until 1889 though, when the Eiffel Tower was unveiled, that tall buildings became more than just a great view or a way to transmit.

The Eiffel Tower was created as the entrance arch to the World Fair and it had a bold and highly controversial design that Parisians hated but the rest of the world were entranced by. Visitors flocked to visit the tower and it became something of a symbol of the city. Nowadays it is still one of the most-visited attractions in Paris and receives almost 7 million people a year, making it the most visited paid-for monument in the world. The unhappy Parisians were soon won round and now it is a much-loved icon of the whole country, going to show that even the most controversial designs can become part of the city they inhabit.

Iconic status

The London Eye now dominates the city skyline

The Eiffel Tower did not turn into a global icon just because it was tall. It had visual presence and people recognised it – even it’s silhouette shape. The race was on to do the same in other cities; new, architecturally-challenging, observation towers popped up all over the world. In fact they continue to do so – as we build higher, the view gets better and more people visit!

Of course it is not just about visitors. Growing cities need a way to identify and separate themselves. For a long time Brighton has traded on imagery of the Royal Pavilion and the two piers, particularly the West Pier – so what will we do when it finally crumbles away?  As our city rapidly grows and becomes a bigger industry player, we need something to represent our regeneration and forward-thinking attitude. We are not just a seaside town that’s nice for tourists to wander around, we are on the cusp of becoming an international destination that can attract a much wider market. We would love the futuristic i360 to become an icon for Brighton as we really believe it is at the forefront of all the exciting regeneration plans based around the seafront.

Becoming an icon

You can’t just build a tall tower and become an icon. People need to learn about you and understand where you fit on the landscape. Many of the most iconic tall buildings have achieved their status through film and television – popping up to denote a location or to provide a huge panoramic backdrop.

King Kong holds on to the Empire State Building

Sleepless in Seattle had a pivotal scene on the Empire State Building when Meg Ryan and Tom Hank’s characters finally meet; Wimbledon stars Lizzie (Kirsten Dunst) and Peter (Paul Bettany) go on a ‘flight’ on the London Eye (presumably on a different night to the one in which Harry Potter (Daniel Radcliffe) flew past in on a broomstick!); Austin Powers (Mike Myers) used the Seattle Space Needle as his base of operations, making the most of Seattle’s coffee history to tie in with the film’s plot line; Bond (Roger Moore) jumped from the Eiffel Tower in A View to a Kill…and the list goes on.

So how will we stack up against the world’s tallest towers?

The Burj Khalifa dominates the skyline

We will be the tallest… well, the tallest moving observation tower anyway! There is a massive difference between the lift up to an observation deck in a very tall building and a tower built solely to be an observation experience. We weren’t trying to compete in height with the likes of the Burj Khalifa in Dubai, which at 829.8 m high is 5 times the size of the i360, instead Marks Barfield wanted to provide an observation tower that used innovative engineering to offer visitors the chance to experience a changing view, something they felt was the key factor in the London Eye’s success. As you glide up to the top of the i360 the view will unfold before your eyes. It is also something of an engineering marvel – how can we travel to such heights on such a slender tower? You can read more about this on a previous blog: The Science Behind the Tower. 

Seeing the landscape from a ‘new perspective’ is close to the heart of Brighton; Fred Gray’s book about the West Pier, ‘Walking on Water’, talks about how the West Pier provided visitors with a whole new way of viewing the city. Now that the pier is slowly falling into the sea, it seems fitting that a ‘vertical pier’ is being built that offers a new take on the observational experience.

So height doesn’t really matter then?

An artist’s impression of the i360 pod looking out at the landscape

Height matters with any observation tower – the higher you are, the further you can see! Of course this must be balanced out against the weather patterns of the destination – you don’t want to end up in the clouds with zero visibility! In Brighton, the curvature of the earth means that from the i360 you will be able to see just over 26 miles… the distance of a marathon. This is the perfect height to experience the beautiful Sussex Coastline – a UNESCO heritage Biosphere.

So where do we sit in relation to the other viewing towers in the UK? Watch this space – that’s a topic for another week!

Delivering Dampers!

Tags

dampers, vortex shedding, wind

While work continues welding the flanges to the tower cans in Holland, we are busy preparing for the next stages of the tower construction process: the secondary steel work. This includes things like the internal platforms and ladders, but also some clever little gadgets called dampers.

Preparing the dampers

What is a damper?

A damper is a device used to offset any vibration of the tower caused by the wind – in particular the movements caused by vortex shedding.

What is vortex shedding?

Our tower is very tall and because of its circular nature, when the wind hits it, it is forced to flow around the structure. This creates a series of vortices – mini whirlwinds – that detach periodically from the tower on alternate sides. This phenomenon is called “vortex shedding”. If the frequency of vortex shedding matches the resonant natural frequency of the i360, the tower can start to vibrate. We talked a bit about vortex shedding in a recent blog about the science behind the i360 building.

What is resonant frequency?

The i360 tower is very tall and slender

The natural frequencies of vibration of a structure depend on its mass and stiffness (or how flexible it is). Tall structures tend to have more flexibility and so have lower natural frequencies. The i360 tower is particularly sensitive to vibration because it is very tall and very slender.

What frequency affects the i360?

It is not as simple as one frequency. There are several different natural frequencies that can affect the tower and make it vibrate. We have calculated the three lowest natural frequencies that could occur, which we call Mode1, Mode 2 and Mode 3.

How do you prevent it vibrating?

The tower has perforated aluminium cladding

The first and most important step is to reduce the likelihood of vortex shedding, and to assist in this we are installing aluminium cladding around the tower. The cladding has a rough surface and is perforated to allow the wind to flow through it, disrupting the regular formation of vortices and so reducing the likelihood of an occurrence of vortex shedding.

The second step is to put in place measures to help offset the vibrations, should they still occur. We have a series of measures in place and one of the most important of these is the dampers.

What do the dampers do?

Filling the dampers

We use what are called “liquid sloshing dampers” that are fitted inside the tower. When the wind hits the tower and it begins to move, the liquid inside the dampers sloshes to one side. The uneven height of the water produces a force acting on the tower in the opposite direction to the force of the wind, stopping, or at least limiting, the vibrations. There are Mode 1, 2 and 3 dampers in the tower, and each type is specifically designed to operate at the frequency of the different Modes.

What do the dampers look like?

They effectively small sealed boxes – about twice the size of a tin of biscuits. They are made out of stainless steel and half-filled with liquid. The liquid has anti-freeze added to it to ensure that the dampers can still work on freezing cold days. Each of the different dampers looks similar, but the exact geometry is slightly different depending on the mode type.

The dampers are stacked on top of each other with shallower height dampers at the bottom and larger height at the top.

That small? How many do you need?

One quadrant of stacked dampers

We have approximately 50 in the tower placed at three different levels, and a further 8 located in the pod. The majority are at the top of the tower where they are most effective in damping Modes 1 and 2. Further Mode 2 dampers and the Mode 3 dampers are located at precisely calculated lower levels. During the build we will have an extra, temporary set at the top too. These are designed specifically to operate during the construction of the tower, when it can vibrate at different frequencies as the height is gradually increased.

Why are you building in Australia?

We did not choose Australia particularly; we chose specialist engineer Professor Max Irvine who is based in Sydney. He has designed the dampers and has commissioned them to be made in a small workshop in NSW, Australia so that he can closely oversee the process.

What next?

In January 2015 the tower dampers will be sent to Rotterdam to meet the tower cans. They will be fitted to the tower ready for the journey to Brighton.

A focus on flanges

Tags

flanges, holland, hollandia, i360 tower, tower cans, welding

The flanges have now arrived at the factory in Southern Holland, where our tower cans were originally manufactured. This is really exciting news for all those following the progress of our build as the flanges are crucial to the design – without them there would be no way of building the i360 tower.

For the next 6 weeks we will be welding the flanges to the tower cans and so we decided to investigate the process further. They may look like simple rings of steel but, as with all the elements of the i360 project that we have focussed on to date, the engineering behind them is fascinating and complex.

What is a flange?

A flange is an external or internal ridge / rim that is welded onto an object so that it can attach more effectively to another. Imagine two gas pipes – you need to keep them firmly together to stop gas escaping, so you would either weld the pipes to create a seal, or weld flanges to the pipes so that they could be moved into and out of position easily, forming a pressure seal once bolted together.

Why do we use flanges?

We have 17 cans for our tower and we need to keep them firmly together! The problem we have is that each one is a perfectly smooth tube with walls that are, in ratio, the thickness of a bean can. We are building from the top down, so as we lift each can we need to attach it to the one below. High strength bolts “clamp” them tightly together so that they are firmly fixed.

If they don’t need to be moved, why don’t we weld?

The best way to attach each can would be to weld them together, but for a tower of this scale we face a welder’s biggest problem: moisture. Although the South East may get less rain than the rest of the country, it does get rainfall all year. It also gets some incredible winds – great news for the Rampion Wind Farm, not so great for the welders! We also have the sea air to cope with – anyone who lives close to the coast will tell you, once the salt gets in to your metalwork, it doesn’t come out easily. The only way to build the i360 safely would be to do it indoors, which is why we are welding our flanges in a factory.

What do our flanges look like?

The image above shows a pile of flanges ready to be welded to the cans in the background. There are 33 of them in total – 16 of the cans need one at each end but the top can only needs a flange at one end.

How are they made?

Each of the 33 flanges is being made by forging a red hot single ingot of steel into a ring shape of the correct diameter. The material used in the ingot is exactly the same strength as the steel used to make the cans.

When the forging is the right shape, the steel is allowed to cool in a very controlled manner. This improves the strength and fatigue resistance of the flange.

Won’t the flanges detract from the smooth look of the tower?

No. As you can see in the image above, the flanges will be hidden within the cans.

Why did we use a factory in Spain?

Because of the very precise nature of our cans, we couldn’t just forge them anywhere. The factory we used in Spain is believed to be the only factory in Europe where this operation can be carried out.

How do you ensure they are the right size if they are made in a different location?

The forged flange is only approximately the correct size at the first stage in the manufacturing process, and has to be machined to the exact size required.  Now the flanges have arrived in Holland, we join them to the cans and then machine them in another large lathe. This gives them an extremely flat surface that is at exactly 90 degrees to the can. If we did not do this, the i360 could become the Leaning Tower of Brighton! We then measure the cans with a laser to make sure they are exactly the right size.

Once they have been welded on, are they finished?

The integrity of the weld must be checked by Quality Control. Our QA officer from Hollandia joins the team from SIF to inspect each of the welds. The inside of the can is quite dark, so they use flashlights to make sure each weld is good.

Let’s talk bolts…

Up to 72 bolts are used at each joint, spaced out evenly around the circumference, and the bolts are up to 75mm (about 3 inches) diameter. A single bolt of this size can carry a load of as much as 440 tonnes. If you want an indication of what this means, a single 75mm bolt could lift 30 double decker buses!

How many bolts do you need?

In total more than 1,500 flange bolts are needed at the flanges – the total weight of these bolts is about 100 tonnes. A blue whale weighs a similar amount!

What happens if a bolt malfunctions?

Each bolt is galvanised (the steel bolt is submerged into a bath of molten zinc) and then wrapped in a special impregnated tape to give long term protection against corrosion. Even so, the bolts form such an important part of the tower structure that randomly selected bolts will be inspected each year. The bolts can be safely removed and replaced (one at a time, of course) if necessary during the lifetime of the tower.

What happens if the bolt holes don’t match up during the build?

We’ve all drilled holes in the walls, only to find we are out by a few mm (or several cm in some cases!). It would be far too late to find a mismatch while the tower is under construction, so we make sure they fit beforehand.  The holes through the flanges are drilled in pairs to ensure the bolts will all fit, then each pair of cans is “trial assembled” in the factory. This is done in sequence – can 1 is fitted to can 2, then these two are taken apart and can 2 is fitted to can 3, and so on.

What’s next?

Once we have welded all the flanges, we will move the cans to Hollandia’s factory where they will have all the interior steelwork added (e.g. platforms, towers, bull wheels for the cable car etc.).