Galvanized Steel - Keeping Decarbonisation on Track by Galvanizers Association

Galvanized Steel

Keeping Decarbonisation On Track

Galvanized Steel - Keeping Decarbonisation On Track

Foreword From Director William J. Smith

Sustainability and durability have long been a central concern to the galvanizing industry. Before environmental responsibility became the leading priority it is today, Galvanizers Association were focused on the need to extend the design life of public buildings and infrastructure. We also voiced concerns over developments and projects, which despite considerable operational carbon savings, were still hindered by carbon costly maintenance burdens. Given the demand for growth to be sustainable and clean, UK construction can no longer rely on single life components and disposable materials, and GA welcomes the idea that the principles of circular economics will underpin all future construction, including transport and infrastructure. The planned investment in UK rail is vital to the development of an efficient and effective national transport infrastructure. HS2 and the further modernisation of existing rail infrastructure, aligned with UK Rail’s ambitious decarbonisation plan, have the potential to be real agents for change, reaching an extensive supply chain, and impacting diverse communities across the UK. The electrification of UK Rail, additional green

traction projects and a low carbon delivery of HS2 are central to the UK’s transition to a sustainable, healthier future. We are hopeful they will offer up a model of regenerative development that can withstand scrutiny from across the globe. Our industry developed an Environment Product Declaration (EPD) in 2008 and Galvanizers Association has since invested in research that examines the environmental benefits of galvanized steel. We offer reliable data that predicts the durability and performance of galvanized steel for a range of atmospheric conditions across the UK. Clearly, only materials that offer durable solutions and which are aligned with the circular economy will meet the demands of a climate resilient infrastructure network. This guide outlines how galvanized steel aligns with circular principles and the role it can play in decarbonised public transport design. Our industry has a relationship with UK rail spanning centuries. We look forward to many more years of positive collaboration.

Galvanized Steel - Keeping Decarbonisation On Track

Contents 4

Introduction Case study - Vienna Central Station

Galvanized Steel And The Circular Economy

Durability Supports Decarbonisation

2.1

Predictable And Measurable

2.2

Lydlinch Bridge - 80 Years On

2.3

The Eiffel Tower - A Maintenance Legacy

- Vienna Central Railway Station 4.

Local Supply Chains

Case study - Haymarket Station, Edinburgh

- Euston Station Walkway, London

- Leeds Station Southern Entrance (LSSE)

Galvanized steel - A Complementary Material

Case study - Crossrail Place Foster + Partners

Case study - Rail Freight Terminal, Northamptonshire

Summary

A Circular Material

Image Credits

3.1

Reuse of Steel Structures

3.2

Design For Reuse of Galvanized Steel

3.3

Grandstand at Gramsbergen

3.4

Reuse Of Steel Staircase

3.5

Biopartner 5 Laboratory

3.6

Carbon savings with Regalvanizing

Case study - Crossrail West Gantries - Global Rail

Throughout this document the term ‘galvanized steel’ refers to steel articles that have been immersed in molten zinc after the articles have been fabricated or manufactured. This is the process of batch (or ‘general’) galvanizing that is usually carried out according to EN ISO 1461.

Galvanized Steel - Keeping Decarbonisation On Track

Introduction

Steel is already one of the most commonly used materials in the railway sector. It is strong, versatile and cost-efficient, plus it offers sustainable solutions for the UK and Ireland as they transition to a more decarbonised, circular economy.

Making the right decisions first Corrosion and maintenance could cost the rail industry many millions of pounds and manhours annually, not to mention unacceptable disruption to services. This is why the valuable steel that is used in railway construction must be protected. The corrosion protection that is chosen for railways today will impact greatly the amount of time and money that must be

spent tomorrow. Choosing galvanized steel is a cost-effective, efficient way to protect important infrastructure over the long term.

further routine and costly maintenance. At Haymarket in Edinburgh, galvanized steelwork has helped to create a larger passenger friendly station.

No limitations on scale

Galvanized steel helps ensure that our railway is set for the long term. Modernisation should lead to well-designed rail networks and stations, built to last, sensitive to the environment and which harness the benefits of galvanized steel.

Galvanized steel and railway infrastructure go hand in hand. From historic stations in London like Paddington, to the modern iconic design of international hubs such as Vienna Hauptbahnhof, galvanized steel has been, and remains, a reliable choice, suitable for many building applications. If projects are designed with galvanizing in mind, there are no limitations to the scale of ambition. Stations like the Hauptbahnhof in Vienna prove that innovative, super-scaled roof structures can be made using galvanized steel and require no

Galvanized Steel - Keeping Decarbonisation On Track

Galvanized Steel Solutions for HS2 Introduction

Vienna Central Station The lozenge roof of the new Vienna Central railway station was the worthy winner of the Austrian Steel Construction Prize. The roof structure is six times the size of a football pitch and is one of the most complicated and beautiful galvanized steel construction projects in Austria. It incorporates approximately 7,000 tonnes of steel and can be seen from miles around.

“

It’s a turntable in a Vienna which is open to Europe. The lozenge roof makes an important contribution to this as, with its dynamic design, its rhythm and the way it seems to float in the air, it acts as a structural synonym for Vienna, the world-renowned city of music

”

Galvanized Steel - Keeping Decarbonisation On Track

1. Galvanized Steel And The Circular Economy

Galvanized steel aligns well with the requirements of the new circular economy and is considered a sustainable material, that can deliver multiple life cycles. It is ideally suited to infrastructure projects and can help decarbonise public transport.

The galvanizing industry in the UK and Ireland welcomes the increasing focus on the creation of a circular economy and embraces flexible design for durability, deconstruction, and disassembly. Galvanized steel readily facilitates the reuse, remanufacturing or recovery of materials and galvanized steel structures and components are ideal circular materials. If a material system was specially designed for the circular economy,

hot dip galvanizing would be a perfect example because: 1. Hot dip galvanizing of steel products after fabrication delivers the highest levels of corrosion protection – the steel structure will often achieve its design life with no maintenance. 2. The galvanized coating can follow the steel structure through multiple cycles of reuse. 3. Galvanized coatings are metallurgically bonded to the steel – allowing the steel product to be reused along with the original coating without need for recoating. 4. Galvanized steel components that have reached the end of their design life, or are uninstalled for any other reason, can be regalvanized and returned to the

original use. 5. If the re-use cycles come to an end, both steel and zinc are recycled together in the well-established steel recycling processes. The zinc being returned, without loss of properties, to zinc production plants and eventually back into the galvanizing process.

Galvanized Steel - Keeping Decarbonisation On Track

Make Galvanizing of steel products is an efficient dip process - giving the highest level of protection. It maximises their durability, reuse and recycling

Recycle Steel and zinc are recycled together - without loss of properties - if the long life of galvanized steel eventually ends

Remake Galvanized steel products can be re-galvanized and put back into service - avoiding production of new steel. Repurposing of galvanized steel products possible without regalvanizing

Use Galvanized steel is completely covered with a durable coating that can last the lifetime of the component - avoiding resource use for replacement or maintenance

Reuse Galvanized steel is robust and easily dismantled for reuse in multiple life cycles. The coating stays with the steel component in its next life cycle Fig. 1 Circularity of galvanized steel

Galvanized Steel - Keeping Decarbonisation On Track

2. Durability Supports Decarbonisation

In accordance with the hierarchy of approaches in meeting the circular economy, building for net zero should mean building to last. Using products that are reliable and durable can significantly reduce carbon footprint over the lifetime of the construction.

Galvanizing’s ability to optimise the durability of steel structures and components has important environmental, economic and social advantages making it a valuable option when looking to decarbonise a project. In addition, the long-term durability provided by galvanizing is achieved at a relatively low environmental burden in terms of energy and other globally relevant impacts, especially when

compared to the energy value of the steel it is protecting. Whether it is by reducing maintenance operations or avoiding the premature replacement of steel products, galvanizing will reduce the embodied carbon of construction.

Hot Dip Galvanizing offers many advantages including: •

Protection of steel for up to 170 years

•

Predictability

•

Ease of inspection

•

Makes steel more reusable

Galvanized Steel - Keeping Decarbonisation On Track

2.1 Predictable And Measurable

A galvanized coating offers predictable corrosion protection that weathers in a linear fashion. Coating thicknesses are measurable and offer lifespans that can be easily forecast and relied upon.

The longevity of galvanized steel offers zero maintenance solutions and avoids costly, carbon intensive repairs, which makes it an ideal solution for today’s infrastructure needs. Galvanizers Association can provide up to date information on the performance of galvanizing. A key reference source is the Atmospheric Corrosion Map that provides

atmospheric performance data for a hot dip galvanized coating across the UK and Ireland.

Atmospheric Corrosion Rate of Hot Dip Galvanizing

Fig. 2 Atmospheric Corrosion Map

Galvanized Steel - Keeping Decarbonisation On Track

2.2 Lydlinch Twofords Bridge - 80 Years On

In 1942 the Ministry of Defence ordered the hasty and covert erection of a Callender Hamilton Bridge on the road to Poole Harbour, in order to facilitate the speedy movement of troops for the D-Day landings.

At the time Ted Taylor, Dorset’s chief bridge engineer said “We have had no real trouble ensuring that this ‘temporary bridge’ is brought up to the new standard and the bridge was in remarkably good shape.

The resulting structure may have begun life as a temporary solution but it is still in use nearly 80 years after it was completed.

The strengthening consisted of bolting ‘T’ sections to the existing transverse deck beams and the addition of some longitudinal beams. The two main trusses were left as they were in 1942. Engineering forethought meant that on a few sections where a lot of cutting and readjustment of design had taken place, the sections were re-galvanized”.

The bridge has seen only minor changes to its original design since it was erected. Timber deck repairs were carried out in 1985 and 2009. The only work of any structural note was some strengthening works carried out in 1996, to enable it to conform to new standards for carrying 40t lorries.

‘Temporary’ bridge, Lydlinch, Dorset constructed in 1942

Galvanized Steel - Keeping Decarbonisation On Track

Inspection of the bridge After an initial inspection in 1999, the bridge was re-inspected on 14 October 2014 by GA staff with assistance from Dorset County Engineers. “Despite all that‘s thrown at it, flood water, mud and grit salt, the galvanized exposed members are still in very good condition.” Les Lock, Project Engineer.

random from both sides of the bridge. Average coating thicknesses on the diagonal trusses ranged from 126μm to 167μm. On the plate sections the average thicknesses were 131μm to 136μm. The galvanized coating has stood the test of time exceptionally well and is expected to provide a life well in excess of 120 years, a tribute to the designers and the men who built it.

Coating thickness measurements were taken on steel members chosen at

“

Despite all that’s thrown at it, floodwater, mud and grit salt, the galvanized exposed members are still in very good condition

”

Hot dip galvanizing estimated to provide over a 120 years of protection

Galvanized Steel - Keeping Decarbonisation On Track

2.3 The Eiffel Tower - A Maintenance Legacy

When Gustave Eiffel constructed his famous tower in 1889 for the International Exposition and centennial celebrations of the French Revolution, it was envisaged to be a temporary structure. Little did he know that it would still stand as the much-loved landmark of Paris over 130 years later.

This burden increases when taking in to account the carbon cost of resources used, the risk to worker safety, not to mention the structural risks associated with this kind of repeated repainting, all of which remain unseen by the millions of tourists that visit the iconic structure.

However, this longevity has come at a price. The Eiffel Tower’s ironwork has been repainted an incredible nineteen times with a single maintenance painting cycle taking 18 months, at a cost of €4 million. Repainting costs are estimated to be ~14% of the equivalent current construction costs of the tower today.

Galvanized Steel - Keeping Decarbonisation On Track

Fig. 3 Schematic showing maintenance legacy.

Galvanized Steel - Keeping Decarbonisation On Track

Rail Freight Terminal, Northamptonshire A rail freight terminal in Northamptonshire has become the first in the UK to demonstrate an innovative overhead electrification system, which could spell the end for diesel on electrified rail routes and boost the industry’s net zero ambitions. The Decarbonisation & Electrification of Freight Terminals (DEFT) project, funded by the Department for Transport and Innovate UK, has seen project partners demonstrate a new way of decarbonising rail and lessen freight’s impact on passenger journeys by using galvanized steelwork. The system is based on one developed for passenger train depots, used by Eurostar and LNER, and has been installed by SPL Powerlines. The DEFT project is one of 30 ground-breaking initiatives that have won a share of £9 million from the Department for Transport, in partnership with Innovate UK. The competition is focused on developing pioneering technology and exceptional ideas that can improve journeys for travellers, encourage passengers back onto the network and reduce the environmental impacts of rail.

Galvanized Steel - Keeping Decarbonisation On Track

3. A Circular Material

Galvanized steel is the perfect circular material to ensure that buildings and structures can be designed with maximum flexibility and to enable construction products to be used across multiple life cycles.

Future designs of steel structures will become more modular and utilise bolted connections to ease deconstruction and make components more widely suitable for reuse. Galvanizing creates more value to these reused components, as they do not require further protective treatment and the components themselves will be in good condition at the point of reuse. Galvanized steel will not suffer from demounting and remounting activities,

as opposed to painted steel which will need to be repainted or at least repaired. Moreover, galvanizing offers longer lifetime expectations to steel than other coating systems, which allows frequent reuse of the material. Current end-of-life scenarios for two of the most common construction materials, steel and concrete, show that 93% of steel is recycled and 6% is reused – a growing natural resource as opposed to concrete which is 20% recycled and 75% down cycled.

Durability, Robustness and Adaptability of Galvanized Steel

Avoid Maintenance

Avoid Replacement

Facilitate Reuse

Save Carbon

Galvanized Steel - Keeping Decarbonisation On Track

Carbon Efficiencies on Site The unique nature of the galvanizing process provides a tough and abrasion resistant coating which means less site damage and speedy erection of structures. Cohesion Unlike most protective coatings, which rely solely on the preparation of the steel to obtain adequate adhesion, hot dip galvanizing produces a coating which is bonded metallurgically to the steel. In other words, the iron and the zinc react together to form a series of alloys which make the coating an integral part of the steel component or article with excellent cohesion.

shock of an initial impact during handling. The alloy layers beneath are generally harder than the base steel itself. This combination provides a robust and abrasion resistant coating. Barrier protection Galvanizing provides a barrier between all internal and external steel surfaces and their environment. Hot dip galvanizing provides fabricated iron or steel products with maximum protection through a continuous, tough, metallurgically bonded coating.

Toughness Resistance to mechanical damage of protective coatings during handling, storage, transport, erection and reuse is very important. It can save cost and carbon. The outer layer of pure zinc is relatively soft and absorbs much of the

Fig. 4 Micro-section of hot dip galvanized coating showing variations in hardness through the coating. The zinc-iron alloys are harder than the base steel.

Galvanized Steel - Keeping Decarbonisation On Track

3.1 Reuse Of Steel Structures

PROGRESS (PROvisions for GREater reuse of Steel Structures) was an EU RFCS-funded project focused on the reuse of singlestorey buildings. The study and its recommendations provide additional impetus to the future use of galvanized steel to maximise reuse opportunities.

steel construction. For example, the use of bolted connections has the dual benefit of enhancing prospects of reuse whilst also increasing the size of structures that can be hot dip galvanized.

Provisions for Greater reuse of Steel Structures. For further information: www.steelconstruct.com/eu-projects/progress

The project has delivered recommendations and practical information on the fabrication and detailing of single storey buildings made from reclaimed steel, and on the design of buildings for future demounting and reuse. Future optimization of connections and other design details will further reinforce the partnership between galvanizing and

“Galvanized steel solutions are preferable for structures with possible multiple assembling and dismantling cycles”

Fig. 5 Steel reuse flowchart

Galvanized Steel - Keeping Decarbonisation On Track

3.2 Design For Reuse Of Galvanized Steel

Galvanized steel buildings and structures can be designed with maximum flexibility and to ensure their construction materials can enjoy multiple life cycles. Future designs of steel structures will become more modular, utilize bolted connections to ease deconstruction and make components more widely suitable for reuse. Galvanizing creates more value to these reused components as they do not require further protective treatment and the components themselves will be in good condition at the point of reuse. The ability of galvanized steel to withstand multiple life cycles of a reused structure is illustrated by the growing use of temporary parking systems that provide flexible solutions that are rapid

to construct when and where additional parking capacity is needed. Temporary parking systems can be dismantled and reused, either immediately or stored for future use. The same approach can also be applied to other steel structures if they are also designed for reuse and have the benefit of a tough, abrasion resistant and highly durable galvanized coating that will accompany the steel components through their multiple life cycles.

Galvanized Steel - Keeping Decarbonisation On Track

3.3 Grandstand At Gramsbergen

An existing Elascon stand was saved from demolition thanks to the enthusiasm and decisiveness of one man. In summer 2011, Harry Haverkotte, former board member of SV Gramsbergen, heard that their neighbours from Hoogeveen would move to a new sports park. The good condition of the main grandstand caught his eye so he bought it for €7,000 including the cost of disassembly. The stand was originally built in 1976. Back then, the board of Hoogeveen awarded the construction for 139,200 Dutch florins. If you convert this to today’s value, that is ~€163,000. Within two years, a wonderful 32 metre long stand arose from the ground. Eventually, the stand only cost €35,000 while a new building would have cost

€200,000. Everything was reused, apart from the bolts, nuts and the old wooden boards.

•

Cost saving €165,000

•

Over 100 year predicted performance

•

Carbon savings through steel reuse

Galvanized Steel - Keeping Decarbonisation On Track

3.4 Reuse Of Steel Staircase

An existing factory building has been extended by the addition of three floors, providing studio and workshop space. The design concept for the extension was based on material reuse. The K118 project in Zurich has a large and varied range of reused components including windows, natural stone slabs, wooden roof and steel. A steel frame that once supported a distribution centre in Basel forms the supporting structure to the three-storey extension. A 28-year-old galvanized steel escape staircase has been demounted and reused within the project. The 22 m high structure was originally built in 1990 for the Zurich Orion office building. It now provides access to the new extension.

No maintenance was needed for the galvanized steelwork, only minor modifications were necessary in order for it to fit the new dimensions for its new use.

•

28 year old galvanized steel staircase reused

•

Reused steel saved 80t CO2

•

Total material reuse saved 494t CO2

Galvanized Steel - Keeping Decarbonisation On Track

3.5 Biopartner 5 Laboratory

Over 165 tons of hot dip galvanized steel have found a second home in the new Biopartner 5 Laboratory in Leiden, the Netherlands. For 50 years, the galvanized steel components were used as the supporting structure of a nearby university high-rise building. Architects, Popma ter Steege, set a clear goal for the project - to keep the ecological footprint of the building as low as possible. The objectives for the project were achieved by the reuse of materials mostly from a neighbouring building that had been in use for 50 years. A key material that forms the main building block for the new laboratory is the inviting steel frame structure that forms the entrance to the new building.

The result is a building that meets the highest sustainability requirements. It considered not only the in-use energy consumption, but also the carbon data for the materials used. The reuse of the hot dip galvanized steel components have made a significant contribution.

The first laboratory building in the Netherlands to receive the “Paris Proof” environmental certificate from the Dutch Green Building Council © Rene de Wit Biopartner 5 Laboratory, Leiden

Galvanized Steel - Keeping Decarbonisation On Track

3.6 Carbon Savings With Regalvanizing

CE Delft first examined the opportunities for regalvanizing motorway guard rails in the Netherlands in 2017. They reported that every year 350 kilometres of highway guard rails were replaced, many of which were reusable.

is a saving that can be seen immediately through implementation of the repair and reuse principles of the circular economy.

Their study showed that, on average, 67% of these valuable components were suitable for reuse – which is entirely feasible by cleaning, stripping and regalvanizing. CE Delft calculated that this simple procedure could save 26,000 tonnes of CO2. This equates to more than 8.3 million car kilometres. This is because for each one metre of installed guard rail, there is a saving of 112kg CO2 when utilizing re-galvanized guard rails. That

Fig. 6 Reductions in Global Warming Potential by regalvanizing of used highway guard rails

Crossrail West Gantries – Global Rail Global Rail Construction Limited completed a package of work for Network Rail that included the design, supply and installation of several large galvanized steel signal structures. It includes a 5-track gantry signal structure, a large 2-track cantilever structure and several smaller galvanized steel lightweight gantry and cantilever structures. Global Rail Construction used the project to demonstrate significant cost and programme efficiencies with the inclusion of new strategies for end of life scenarios.

An important aspect of the new strategy centred around the use of galvanized helical steel foundations, as they delivered many advantages over traditional steel and concrete piled foundations. One of the many advantages of galvanized helical piles and their associated galvanized steel support grillages were that at the end of the installation’s life, the system could be easily removed, reused or recycled.

Galvanized Steel - Keeping Decarbonisation On Track

Vienna Central Railway Station Vienna Hauptbahnhof is a recent, landmark project which harnesses the zero maintenance benefits of galvanized steel. It has one of the most ambitious roof structures in contemporary station design in answer to a design specification stipulating a 120 year lifespan with essentially a zero maintenance burden. The station is a central hub in the transEurope rail network, which aims to be used by more than 1,000 trains and by 145,000 people every day. The station’s steel and glass lozenge roof, 200 metres long and 120 metres wide, has become a symbol of modern mobility and functionality, and distinguishes the building from everything around it.

The roof structure, which is made up of 14 individual diamond shapes, arches over five platforms and varies in height between six and fifteen metres. The entire roof (including the forecourt canopy) is made up of more than 57,000 sections, 286,000 sheets of metal, and almost 340,000 screw fittings which are concealed beneath the cladding. The creation of the gigantic structure was a demanding challenge for the contractors and the steel construction company Unger Steel, not only from the technological point of view, but also with regard to the logistics of the project. As the complexity of the roof structure meant that it would be virtually impossible to maintain, the design allowed for individual members to be galvanized and bolted together to form the complex rhombus for

each subsection of the roof. The result is a towering example of zero maintenance brilliance. Each of the 14 diamond trusses in the station canopy measure 76 metres and are all supported by solid twin supports every 38 metres. In the centre of the lozenge, the structure opens up to provide a skylight in the form of a crystal shaped opening measuring 6 x 30 metres which alongside the integrated glass elements make it translucent. The building’s interior is flooded with daylight and at night, special lighting gives the roof a remarkable 3D effect.

Galvanized Steel - Keeping Decarbonisation On Track

4. Local Supply Chain

As we decarbonise our transport system, the entire supply chain will need to withstand scrutiny through the lens of the circular economy.

If your galvanizing is prioritised in the same way that other parts of a project are, hot dip galvanizing will be a seamless, time-efficient process.

There is a wide spread of galvanizing plants across the UK and Ireland that offer an integrated service with local fabricators and manufacturers. With the right communication, you can get steel galvanized within 24 hours.

Galvanizing can take place locally and has a fast turnaround

Galvanizing is not a time-consuming process and in reality, it can take just a few minutes to dip prepared steelwork into molten zinc to form a durable, reliable coating.

The Galvanizing Process

Galvanized Steel - Keeping Decarbonisation On Track

Turnaround time can be minimized if you follow a few simple steps: •

It pays to communicate with your galvanizer and a quick phone call a few days ahead is all it requires to plan work into a busy galvanizing schedule.

•

Sending in ‘clean’ steelwork will save preparation time. Work that is contaminated with material which will not be removed by the normal galvanizing pre-treatment, will need special steps to remove it.

•

The same applies for venting and drainage. As a dip process, galvanizing will protect the inside of steel sections as well as the outside. Ensuring that there are correct vent and drain holes in hollow steelwork and that these holes are in the right places, saves the galvanizer valuable time, as they would have to complete that work for you.

•

Finally, it pays to liaise on transport. If the galvanizer is providing transport, liaise about the regular runs and plan around them. Galvanized steelwork may even be able to go directly to site.

Map of galvanizing plants across the UK and Ireland

Galvanizing plants across the UK and Ireland

Galvanized Steel - Keeping Decarbonisation On Track

Haymarket Station, Edinburgh Haymarket, Scotland’s fourth busiest train station, received a major refurbishment and extension. The new transport hub in Edinburgh’s West End has been created to accommodate a predicted 6 million increase in passenger numbers. The project included the refurbishment of an existing Grade A listed station building dating back to 1842. The new concourse building was constructed in a former car park adjacent to the station. This allowed for the project to be run while the station was fully operational. The vision for Haymarket station was to provide a modern station facility to

celebrate the experience of modern rail travel. The new additions to the station will enable it to become a transport interchange hub providing enhanced connections with the bus and tram network. The prominent galvanized sections along the platforms will be able to withstand the daily commuter traffic that will spill onto the platforms. The extra station capacity and facilities will address increasing passenger numbers travelling to and from Haymarket. The new concourse building which bridges the platforms and rail lines, were constructed in a former car park adjacent to the station and resulted in two 110 tonne modules being lifted into place overnight. This allowed for the project to be run while the

station was fully operational with minimal disruption to train services. The £25 million revamp has added a state of the art facility that has tripled the concourse floor space to 8,700 m2, having been designed to cater for a predicted 125% increase in passenger numbers over the next 15 years.

Galvanized Steel - Keeping Decarbonisation On Track

Euston Station Walkway, London As part of the major regeneration of Euston Station under the HS2 project, a series of canopied structures provide passengers with cover at the temporary Taxi Rank associated with Euston Station. While the structure at Euston Station was always meant to be part of a temporary taxi rank solution, with the correct engineering the bespoke canopy can be moved to a new location. This was taken into consideration from the outset of this project and, the client indicated this would be an option that would be considered in the future. This temporary Taxi Rank will provide weather protection to passengers until the next phase will accommodate a redesign for this area of the station. © Broxap

Leeds Station Southern Entrance (LSSE) Leeds Station is the second busiest railway station outside London and sits at the heart of the region’s economy. More than 100,000 passengers use it each day. Increasing passenger demand, congestion to the existing northern entrance and an aspiration to reduce journey times to the expanding south of the city resulted in the need for the new Leeds Station Southern Entrance (LSSE). The new entrance is expected to serve up to 20,000 passengers daily.

Innovative thinking

Technical excellence

The southern entrance is located over the River Aire, where residential towers, an electrified railway and a pedestrian bridge all constrained the site. It was, however, the ideal location to meet the project objectives of accessibility from the south and to create a landmark building. An innovative approach was adopted to deliver the required solutions, this included:

Many of the innovative solutions for the project lie unseen below the new building. The foundations comprise two concrete piers supported on 24.9 m diametre piles socketed into bedrock below the river bed.

• • • • •

use of prefabrication and barged delivery to site strengthening of the existing Victorian masonry viaduct and station roof use of overwater ground investigation to inform the pier design tailored working methods in and around the three operational railway lines FE analysis of the soil structure interaction for the pile design use of bespoke lifting equipment.

Over water ground investigation proved essential to confirm the depth to rock; its highly fractured nature led to a change in piling methodology prior to construction. Advanced soil structure interaction, verified by finite element analysis, was undertaken together with consideration of flexural rigidity of the composite pile sections. The piers support a concourse deck formed from a grillage of 600 mm deep galvanized steel beams, which support the superstructure, transferring column loads to the new piers. Fifty percent of the concourse is constructed below the existing viaduct and above the river. Galvanized up-stand trusses supporting the new floor and escalator pit span through one of the barrel vaults, transferring load to new foundations outboard.

Galvanized Steel - Keeping Decarbonisation On Track

5. Galvanized Steel - A Complementary Material

There are many benefits for using galvanizing to protect steel; its durability, toughness, the metallurgical bond that develops between the steel and zinc, but maybe one of the most endearing is the alchemy of its aesthetics. The natural reaction that occurs between clean iron and zinc is reflected within the finish achieved on the surface of the coating. This will change depending on the thickness of steel presented to the molten zinc, its chemistry, and variations within its surface. This is why galvanizing can sometimes be compared to developing a camera film; the natural surface chemistry of which will influence what develops above.

described as an “industrial” finish, true in that it was the sector that first used the process. Today it has many diverse uses. Its aesthetics can vary from shimmering silver, a crystalline patination through to dark blue-grey, and reflect the natural unfinished character of the coating. These characteristics make for an ideal combination with timber. Many projects have shown how the two materials can complement each other. At times, timber can be the major load carrier and galvanized steel the connector, transferring loads between timber members. On other occasions, this relationship is reversed.

In the past, galvanizing has been

Flimwell Park, Steven Johnson, Architecture Ensemble

Galvanized Steel - Keeping Decarbonisation On Track

Crossrail Place Foster + Partners In 2008, Foster + Partners were commissioned to design a mixed-use scheme encompassing the over-ground elements of a new station for the Crossrail project at Canary Wharf. Central to the scheme, was a new enclosure unifying the station and other elements including new retail units and a park, as well as furthering the main aim of the Crossrail project – to open up London from east to west. The building is enclosed by a distinctive roof, which wraps around it like a protective shell. This 300 metre long timber lattice structure opens in the centre to draw in light and rain for natural irrigation. Timber has a great nautical and architectural history on the Wharf and this building is uniquely situated within the waters of West India Dock. The design of the roof lattice is a fusion of architecture and engineering. Despite the smooth curve of the enclosure, there are only four curved timber beams in the whole structure. To seamlessly connect the straight beams, which rotate successively along the diagonals, the design team developed an innovative system of steel nodes, which resolve the twist.

The visual simplicity of the arching timber lattice belies the geometric complexity of the structure, which is made up of 1,418 beams and 564 nodes, 364 of which are unique. The nodes and beams support large triangular ethylene tetrafluoroethylene (ETFE) cushions. Geometrically, the nodes are the most complex component of the roof. This made protecting them using hot dip galvanizing particularly appropriate, as it could be carried out as a batch process off site, rather than painting, which would have made the process extremely labour intensive. The axis of each successive diagonal beam twists as it coils around the roof, and this twist is taken up at the nodes. In addition, as the geometry of the building

accelerates out over the cantilever, the incoming angles get successively more acute and asymmetric. The nodes vary in size to accommodate this. In the central section of the roof the configuration of diamond shaped openings in the roof means that nodes with two, three, four, or five connecting beams stand alongside the typical nodes with six connections. To manage the complexity, the nodes were modelled parametrically and generated from the same geometric logic. Each node connects to a beam plate fixed to the end of each glulam beam via timber screws. One of the advantages of using hot dip galvanized steel was the uniformity of the protective coating, which could be applied in a much shorter time.

The node design was developed by Foster + Partners in collaboration with Wiehag, who fed back data on structural analysis and fabrication constraints. To achieve the high level of accuracy demanded by the ETFE structure, the geometry of the nodes had to be very precise and a special jig was developed for construction. One of the key advantages of galvanizing the nodes was that it offered the most versatile and cost-effective way of protecting the steel in the long-term and allowed for ease of inspection during maintenance reviews. The galvanized nodes were delivered ready for use, without compromising the programme. © Nigel Young / Foster + Partners

Galvanized Steel - Keeping Decarbonisation On Track

6. Summary No other coating currently on the market will achieve the same design life as galvanizing and ensure such visible, reliable and proven corrosion protection. Galvanizing can help extend the life of steel by over 100 years and is the most robust coating system available today. For a number of years, Galvanizers Association has worked to highlight the sustainable benefits of hot dip galvanizing steel and have a range of information and publications available to help professionals through the specification, design and fabrication of galvanized steel components and structures. Recent projects in both rail, and more widely within sustainable construction, indicate that galvanized steel is a valuable and adaptable material that is increasingly used within circular design. Not only is the coating robust, it also offers zero maintenance solutions that allow for architectural and engineering ambition within a sustainable model of construction. Over the past few years numerous projects have combined the strength and longevity benefits of galvanized steel along-

Galvanized Steel - Keeping Decarbonisation On Track

side other organic materials. The result has been to produce sensitive public spaces that can improve wellbeing and community interaction alongside meeting harder business concerns such as cost effectiveness and carbon footprint reduction. Going forward, there will be a demand for ambitious, decarbonised railway infrastructure which aligns with the needs of the planet, people, and business; a rail network fit for the 21st century and

beyond. The galvanizing industry knows it can meet those demands and is ready to make its contribution. Further information is available at galvanizing.org.uk.

Galvanized Steel - Keeping Decarbonisation On Track

7. Image credits Project Section

Page Number

Photographer

Cover Photo Introduction Vienna Central Railway Station Lydlinch Twofords Bridge - 80 years on The Eiffel Tower - A Maintenance Legacy Rail Freight Terminal, Northamptonshire Structural Steelwork Grandstand at Gramsbergen – Rebirth after 40 years K118 Project Biopartner 5 Laboratory, Leiden Crossrail West Gantries – Global Rail Haymarket Station, Edinburgh Euston Station Walkway Leeds Station Southern Entrance (LSSE) Rising Path Flimwell Park Crossrail Place Foster + Partners Summary

1 5 6, 7, 28, 29 12, 13 14 16, 17 21 22 23 24 26, 27 32 33 34 36 36 37, 38, 39 40, 41

iStock.com/CHUNYIP WONG iStock.com/Den-belitsky Renee Del Missier Galvanizers Association Stephane Compoint Furrer+Frey GB iStock.com/Difydave Maité Thijssen/Zink Info Benelux Martin Zeller Rene de Wit Global Rail Construction David Cadzow Broxap David Hopkinson, AHR, Mott MacDonald CDC Studio Shootlab Nigel Young / Foster + Partners Galvanizers Association

Galvanized Steel - Keeping Decarbonisation On Track

GALVANIZERS ASSOCIATION Wren’s Court, 56 Victoria Rd Sutton Coldfield B72 1SY +44 (0) 121 355 8838 ga@hdg.org.uk www.galvanizing.org.uk