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Hengrove Park Leisure Centre, Bristol | 3 Pedestrian and cycle bridge in Czech Republic | 5 Rocksalt Seafood Restaurant, Folkestone | 8 Stockholm Exhibition Centre | 10

International Magazine

ISSN 1363-0148

www.hdgmagazine.co.uk

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Regeneration is a prominent

theme reflected through some

of the projects featured in this

issue. A spectacular leisure

facility has been built on a

former airport site in Bristol.

on a smaller scale but just as

important for the regeneration

of Folkestone is the addition

of a seafood restaurant on the

seafront.

Linking old with new, a

cycle and pedestrian bridge in Czech Republic provides a simple

design solution that blends easily with its surroundings. on a

slightly different vein is the weaving of a galvanized facade into a

prominent structure in Stockholm.

We also feature an important article from European General

Galvanizers Association (EGGA) and Swera KiMAB, a leading

institute within corrosion and materials research based in

Stockholm. the article highlights the incorrect modern-day use

of salt spray testing. originally used for quality control of specific

coatings or materials, the test has morphed into one that is used

to generate misleading information on performance comparisons

between different coatings.

Swera and EGGA do a commendable job in clarifying the reasons

behind the misuse of this testing method.

iqbal Johal, Editor

Hot Dip Galvanizing – An international journal published jointly

by the galvanizing associations of Germany, Great Britain and Spain.

Edited by: i. Johal, G. Deimel, H. Glinde (Editor in Chief), . Published by: Galvanizers Association, Wren‘s Court, 56 Victoria Road,

Sutton Coldfield, West Midlands B72 1SY, UK;

tel: +44 (0) 121 355 8838, Fax: +44 (0) 121 355 8727,

E-Mail: ga@hdg.org.uk, internet: www.galvanizing.org.uk

Distributed in Australia by: Galvanizers Association of Australia,

124 Exhibition Street, Melbourne, Victoria 3000, Australia, tel: 039 6541266,

Fax: 039 6541136, E-mail: gaa@gaa.com.au

this magazine may not be copied without the written permisson of the editor

© 2013

Photo front cover | Kier Construction 3

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The opening of Hengrove Park leisure Centre was a date to celebrate for thousands

of local people in Bristol. The state-of-the-art pool and leisure centre opened its doors,

ready to showcase the region’s newest and most spectacular, multi-million pound

leisure facility.

the £35m Hengrove Park Leisure Centre has been built on the site of a former airport. its facilities

include a 10-lane, 50m international-standard swimming pool, a 20m teaching pool with a moveable

floor, sports hall, a dedicated spin studio, climbing wall, a 150-station fitness gym, a healthy living

centre, and café and crèche. Bristol City Council along with contractors, Kier Construction, leisure

provider, Parkwood Leisure, LA Architects and Ramboll formed the team that have brought the

project to fruition. the architectural design features large areas of curtain walling that are almost

transparent, giving a feeling of space and provide unobstructed views from the interior out on to the

landscaped central plaza. the glazed facades also provide high levels of natural light and give the

building a calm reflective feel at night.

DiaphanousFrameHengrove Park Leisure Centre, Bristol

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1 | Hengrove Park at night

2 | Eliptical opening helps to flood the pool with natural light

3 | Landscaping integrates the leisure centre to its surroundings

4 | Cafe kitchen within a gold facade

5 | Facade bracing detail

by Iqbal Johal

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the pool has a structural steel frame with the roof supported on a

network of cellular beams spanning 37.5metres. in order to enhance light

levels and create an interesting feature for swimmers, an elevated

‘bubble effect’ has been created over the central portion of the pool roof.

the steelwork in this area is partially hidden by a suspended ceiling

formed from a series of acoustic baffles that filter light and sound.

the Local Authority requirements called for the main structure to have a

guaranteed life of 60 years with minimal maintenance. traditional

painting methods, utilising Chlorinated Rubber, were quickly discounted

and the benefits of a factory applied, robust, homogenous finish led to

hot dip galvanizing being selected. in addition to the main frame,

galvanized components were used extensively throughout the project

including structural steel frames around plant equipment and galvanized

angle framework that supported the extensive suspended ceilings

throughout the facility.

Structural Engineer for the project, Ramboll, researched the benefits of

using galvanizing on a wider front. the sustainability benefits gained by

using galvanizing over other methods of protection were quickly realised,

in fact Hengrove is the first centre in the UK with a 50m swimming pool

to achieve a BREEAM ‘excellent’ rating.

Architect | LA ArchitectsConstructor | Kier ConstructionEngineer | RambollPhotos | Kier Construction

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Engineered to lastPedestrian and cycle bridge in Czech Republic

The Bohemian city of Hradec Králové, which lies between the Elbe and adler rivers, provides a

collage-like mixture of historical buildings from various periods of history. Medieval houses and

counter-reformation Baroque styles can be found, together with Postmodernist and contemporary

structures.

Erecting a new structure against this background calls for a high degree of sensitivity, respect and discipline.

these were some of the issues that architectural firm baum & baroš were faced with when they were

commissioned to design a pedestrian and cycle bridge to link the historic town centre and its university

campus. the bridge would fall within the protected environmental zone of Jirásek Park so all aspects of the

design had to be carefully considered. 1 | Simple, modular steel design

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by Holger Glinde

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production, installation, economics, maintenance, aesthetics

and long-term acceptance by the public also played a role in the

multi-disciplinary planning for the bridge. this led to very close

collaboration between the structural design team from Kosch –

Führer – Jürges and the architects from baum & baroš . After

careful consideration, it was decided to create a simple, modular

steel structure fulfilling the following criteria:

minimise cost through the selection of a simple, statically

defined system

reduce on-site operations to a minimum

pre-fabrication of all constructional elements and selection

of their dimensions with consideration being given to hot dip

galvanizing of the steel

minimise maintenance costs

minimise repair costs by using bolted connections

rapid installation with limited use of expensive lifting gear and

ancillary structures

sustainability to be a guiding principal throughout the project

Design

the designers rejected an asymmetrical suspension type

solution, which would be the usual choice in such cases, due

to the size of the load-bearing mast that would be required

and the visual impact caused within the Park.

the final design solution incorporates a truss with an under-

stressed structure, derived from a Polonceau girder, with

the upper beam forming the deck which is divided into two

articulated sections. A tensioned cable in the form of a five-sided

polygon creates the bottom chord of the truss. the transfer

of loads is aided by the incorporation of three compressively

stressed elements between the deck structure and the tensioned

chord.

Rigidity was guaranteed in the horizontal plane by spacer bars

and diagonal bracing. to enhance the lightweight construction

and to reduce maintenance costs, a transparent and permeable

structure made from 2.25 x 0.75m close-meshed galvanized

grid plates was chosen for the surface of the deck. No vibration

damping was required due to the inbuilt dynamic of the design.

When the project was completed, a simple, transparent and

comprehensible structure was revealed. it has succeeded in not

only creating a new link from the town centre to the university

campus but also successfully integrating with its surroundings.

the silver grey sheen of galvanizing will over time turn to a

mottled grey that will naturally fade into the landscape of Jirásek

Park.

2 | Careful consideration was given to the existing woodland setting

3 | Detail of the underside of the bridge

4 | Imaginative lighting has been designed for the structure

Architect | baum & baroš ArchitektenPhotos | baum & baroš Architekten

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Architekt | Héctor Fernández ElorzaFotos | Héctor Fernández Elorza

+ Bilder

Mehr Infos im Online- und iPad-Magazin:www.feuerverzinken.com/zeitschrift

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Rocksalt Restaurant and Bar is a newly built destination restaurant in Folkestone

Harbour and is the first restaurant venture for executive chef Mark Sargeant. The

restaurant and bar forms a crucial milestone in the regeneration of Folkestone’s

‘Old Town’ and harbour, serving to reconnect visitors and the population of the

coastal town with the working harbour and seafront. The restaurant is located on

Folkestone’s harbour edge, adjacent to its working slipway where local fishermen

unload their catch, delivering fresh fish to the restaurant daily.

Perched in the corner of the tidal harbour between a listed brick viaduct and cobbled street, the

restaurant faces the former fish market. Folkestone boasts a small fishing fleet who off-load catches

on to the slipway directly adjacent to the restaurant. the building sits on a new curved sea wall and

borrows back land to form a wine cellar, and timber dolphin piles protect the building from stray

boats. the building’s close proximity to the harbour waters meant that it was essential that the

chosen materials were robust in order to withstand the marine environment.

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Waterside DiningRocksalt Seafood Restaurant, Folkestone

1 | Sliding doors extend the dining area out onto the cantilevered balcony

2 | The slate steps leading to the entrance merge into public bench seating at the top of the jetty facing out to sea

3 | Dolphin piles protect the building from stray boats

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by Iqbal Johal

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under a brick arch and then peels away from

the cobbled street to reveal the harbour.

three curved walls, decreasing in height, are

clad in shot-blasted black larch to echo the

surrounding context. A slate plinth raises the

building from the flood risk zone and elevates

the views. Angled reveals on picture windows

allow views into the kitchen, reflecting the

working nature of the fish market, and offer

views back to the street. the slate steps

leading to the entrance merge into public

bench seating at the top of the jetty facing out

to sea.

At ground floor level, large glass sliding doors

allow uninterrupted panoramic views of fishing

boats at high tide and sandy shingle flats at

low tide. three large sliding doors expand

the dining area to a cantilevered balcony

with a glass balustrade and curved zinc

soffit, ideal for alfresco dining. the interior of

the restaurant takes strong influences from

the immediate context. the interior colours

emulate colours of the sea and sky – rising

from dark, aquatic greens and dark tones

of timber at ground floor; rising to a lighter

palette of blues, greys and whites, contrasting

with warmer shades of iroko on the first floor

bar and terrace.

A steel frame construction was ideal for the

architectural ambition of the building and

allowed a tight programme to be achieved.

Galvanized elements were a fundamental

part of the steel frame in areas open and

semi-exposed to the elements. on the ground

floor balcony, iroko decking slats sit on large

galvanized steel balcony support brackets

bolted to the concrete slab, allowing the

elegant structure to cantilever over the sea.

Galvanized steel was also specified for semi-

exposed areas of the external canopies on

the ground and first floor terraces, helping to

achieve slender cantilevered roof spans.

the completed building sees its concept

realised by re-engaging visitors and local

residents alike with Folkestone’s rich coastal

heritage, serving as a catalyst to revitalise the

local area.

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Architect | Guy Hollaway ArchitectsPhotos | Ashley Gendek

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When it is dark for more than half the year, a bit of indoor greenery can help brighten

up the day. at least that was the idea behind the long ‘green’ walls inside Stockholm

international Fairs which has recently been expanded and upgraded. Reflective

surfaces and living walls help make the building feel larger, while specialized energy-

efficient lighting brightens up the space. Designed by Stockholm-based Rosenbergs

architects, the large exhibition centre stands behind a rigorous sustainability policy

aimed at reducing its impact.

the Stockholmsmässan international Fairs in Älvsjö is one of the world’s leading organisers of

trade events, attracting 10,000 exhibitors and 1.5 million visitors annually. Rosenbergs architects

has carried out a number of projects at the site since 1998. their latest addition to the premises

is a new multifunctional space intended for conferences and large exhibitions, the AE-Hall, which

has now become one of the main venues of many fairs, such as the recent Stockholm Furniture

Fair. the hall is connected to the existing complex by a gallery which has also been completely

renovated, with new mirror-like ceilings and ‘green’ walls.

the new building makes innovative use of steel throughout the main structure and cladding system,

which are closely integrated. Externally the AE-Hall is wrapped in a galvanized steel facade; a giant

metallic shell which creates an embossing effect that is enhanced by the lighting fixtures integrated

within the galvanized structure. the screen is made from 1,500 partly perforated galvanized steel

panels.

Woven FacadeStockholm Exhibition Centre

1 | Entrance to the Exhibition Centre

2 | The facade consists of 1,500 partly perforated galvanized steel sheet panels

3 | Woven pattern of the facade

4 | Galvanized facade creates a metallic shimmer

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From inside the AE-gallery, a pond with fountains is visible along most

of its 100m length. the walls of the pool structure are clad in expanded

metal screens with integrated sliding gates, revealing entrances to the

subterranean car park below.

All of the visible roofs are covered in sedum plants and the centre

features an energy-saving system with movement detectors that

regulate lighting and temperature depending on how many people are

in each venue. the exhibition centre also buys recycled office materials,

uses eco-friendly cleaning agents, sources 60% of power from renewable

energy sources and recycles 60% of its waste.

the large exhibition space is very versatile as it can be divided into

smaller units, down to the size of a conference room if required. A more

intimate ceiling height is achieved by height-adjustable lighting trusses,

which are LED-illuminated. the sliding partitions are clad with aluminum

panels, creating an intricate, lace-like pattern. the walls can be stacked

in storage rooms along the hall, which helps to create a sound barrier to

the train tracks to the north of the site.

the design for the facade screens was developed in close collaboration

with Carl Hans Järnarbeten in Eskilstuna who built full-scale mock-ups

where several crucial factors, such as light fixtures and the assembly

system, were evaluated and tested. this resulted in a structure that

could be optimized to serve multiple purposes in order to cut costs and

avoid redundant structural systems. the perforated facade panels not

only act as a cladding system, but also provide shade and support the

lighting fixtures.

the versatility of galvanized steel allowed the designers to use one single

material for the whole facade, only varying the methods of processing:

expanded, perforated or flat.

the concept behind the project is described by Alessandro Ripellino:

“We designed the facade of the building to be almost a woven fabric. it

comprises of a network of galvanized steel sheets in varying forms. the

idea was to create a very modern facade. this modernity is important

for us in Northern Europe - where it is dark for six months of the year

and the influence of light on the facade was a very important aspect of

our design. We started this project ten years ago and galvanizing has

been part of the process since the very beginning. With our latest phase

however, we wanted to use it to create something that was a bit out of

the ordinary and quite unique. the facade concept was inspired by the

pattern within a wicker-type basket weave.”

Galvanized steel has enabled the designers to achieve the fascinating

aesthetic that they wanted - a shimmering, reflective surface that offers

light during the dark days of winter but also a variation when wet or dry

and a totally different shimmer in the summer.

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Architect | Rosenbergs ArkitekterPhotos |Rosenbergs Arkitekter

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Undulating Rythmic FormBus Station in Calpe, Spain

a new bus station on the outskirts of the small town of Calpe,

Eastern Spain, has added a much needed local facility. Built

alongside the intersection of two main throughfares into the

town centre, the new station brings order and punctuality to

the local public transport network.

A bird’s eye view of the site before development revealed a rectangular

plot 73m x 68m with the complicating factor of having a natural slope,

in elevation, of six metres. the planning brief required the design of a

small-scale transport hub that would predominately be used for buses

but would also allow parking space for taxis and drop-off zones. the hub

needed to handle the influx of passengers from a minimum of 10 buses

at any given time and cater for the transfer of passengers. Although

the requirements of the brief were not overly onerous, an important

stipulation was that of creating a solution that fitted into the local context.

Architect Alberto Mengual spent some time in considering the site,

particularly the integration of the six metre slope. A series of tall

undulating pergolas made from galvanized steel frames and iroko

timber form the main structural components of the final design. they

help to create a very open, light, yet understated series of platforms

that passengers can use as waiting areas or transfer to connecting

buses. the gentle rhythmic shape of the iroko timber slats form dreamy

shadows across the spaces between the platforms, echoing warmth and

openness. Painted in the traditional white of its surroundings, the only

fully enclosed structure is a small concrete block that forms the ticket

office. A gently sloping ramp and two staircases connect the station

to the upper end of the site. this very simple project incorporates the

harmonious use of galvanized steel and timber to give this project a

light and delicate feel that sits comfortably within its local context.

Architect| Alberto MengualPhotos | Alberto Mengual

1 | Harmonic balance between galvanized steel and timber

2 | Undulating pergolas provide shade for waiting passengers

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if you are a user of protective coatings in the construction, manufacturing

or engineering industry, there is one aspect of corrosion science that

requires your careful understanding – that is the role and limitations of

accelerated corrosion testing. For decades, the so-called ‘salt spray test’

has generated misleading information about coating performance and its

results still feature prominently in the marketing materials of products

that, artificially, yield more favourable outcomes than in the real world.

So what is wrong with the ‘salt spray test’?

Firstly, the test does have some value for quality control of a specific material or

coating. this is what the test was originally designed for and it is used successfully

by some industries for this purpose. Although, it is now

largely abandoned even by the automotive industry.

the serious misuse of the ‘salt spray test’ is its use to

compare, or rank, different materials or coatings that

have differing characteristics. it is especially misleading

to use the test to compare paints with metallic coatings.

it is equally misleading to compare different metallic

coatings. For example, comparisons between zinc and

zinc alloy coatings (such as those containing small

additions of magnesium and aluminium) can produce

comparative results that are vastly different to real in-field

performance.

1 | Typical salt spray chamber

2 | More reliable predictions are available from long-term exposure tests for galvanized coatings

Beware – Salt Spray Testing!Misleading accelerated corrosion tests

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Unfortunately, material comparisons are still made using the test despite

the international standard for the test (iSo 9227) clearly stating that

‘there is seldom a direct relation between resistance to the action of

salt spray and resistance to corrosion in other media, because several

factors influencing the progress of corrosion, such as the formation of

protective films, vary greatly with the conditions encountered. therefore,

the test results should not be regarded as a direct guide to the corrosion

resistance of the tested metallic materials in all environments where

these materials might be used. Also, the performance of different

materials during the test should not be taken as a direct guide to the

corrosion resistance of these materials in service.’ [1]

instead, iSo 9227 recommends that salt spray tests are suitable only

as quality control tests. A large number of peer-reviewed papers have

also given clear warnings about the use of the salt spray test. Here are

some extracts from just a few:

‘in fact, it has been recognised for many years that when ranking

the performance levels of organic coating systems, there is little, if

any, correlation between results from standard salt spray tests and

practical experience’. [2]

‘Salt spray is the most widely used accelerated test. it was developed

more than 50 years ago for testing metallic coatings in marine

environments. Although it has been demonstrated that this test does

not provide a good indication of outdoor service performance of

coatings (even in a salt atmosphere), its use has become entrenched in

the coatings industry’. [3]

‘the well-known AStM B-117 salt spray test provides a comparison

of cold-rolled and galvanized steel within several hundred hours.

Unfortunately, the salt spray test is unable to predict the well-known

superior corrosion resistance of galvanized relative to uncoated rolled

steel sheet.’ [4]

‘Salt spray provides rapid degradation but has shown poor correlation

with outdoor exposures; it often produces degradation by mechanisms

different from those seen outdoors and has relatively poor precision’. [3]

Unfortunately, despite these warnings, salt spray testing is still used

in communications to introduce new coatings and materials to the

market.

Why does salt spray testing give misleadingresults?

to understand why the ‘salt spray test’ fails to reliably predict real

corrosion performance, it is important to look at the test procedure.

Samples under test are inserted into a temperature-controlled chamber

where a salt-containing solution is sprayed, at 35°C, as a very fine

fog mist over the samples. As the spray is continuous, the samples

are constantly wet, and therefore, constantly subject to corrosion.

Performance is rated by recording the number hours to reach defined

levels of surface rusting. test duration ranges from 24 hours to 1000

hours or more.

there are some obvious reasons why the salt spray test does not

correlate with real world exposure conditions, in particular:

the surface of the test coupons is constantly wet, with no cyclic

drying, which does not happen in reality. this prevents metals, such

as zinc, from forming a passive film as it would in the field.

3 | St Antony ironworks in Ruhr, Germany3

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the chloride content is very high (normally 5% NaCl) resulting in highly accelerated conditions

with different acceleration factors for different metals and metal constituents.

these are unusual and severe conditions that probably never occur during normal outdoor

exposure.

Salt spray testing cannot successfully comparecorrosion resistance of materials

it is well accepted that the good performance of metallic zinc coatings in real outdoor conditions

relies on drying between periods of wetness. the development of a passive and relatively stable

oxide and/or carbonate film during the drying cycle contributes to the excellent performance of

galvanized coatings. the continual wetness during the salt spray test does not allow this passive

oxide/carbonate layer to develop. the test therefore artificially reduces the performance of zinc

coatings.

When painted material is evaluated using the salt spray test, there is no exposure to ultraviolet

light, a common cause of breakdown of paints. this is a serious omission, since the main failure

mechanism that causes painted steel to deteriorate is not included as a condition in the salt spray

test.

the salt spray test can give similarly misleading results when comparing different variants of zinc

coatings. For example, small additions of magnesium or aluminium to a zinc coating will produce

salt spray test results that differ significantly from real exposure conditions.

Magnesium ions, whether from the environment (sea salt) or in a zinc alloy, promote the

formation of protective corrosion products in the presence of sodium chloride, thus reducing

corrosion rates. this explains why zinc-magnesium-aluminium coatings show artificially better

performance, as compared to zinc, in accelerated tests involving high time of wetness and high

chloride load. this effect also occurs in field exposure tests in some, e.g. marine atmospheres but

with a substantially lower level of improvement than is indicated by salt spray test results.

Summary The use of salt spray test results to guide selection of protective coatings for steel remains a serious problem in the engineering community. Despite the well understood limitations of the test in the ‘corrosion world’, it is still used to promote the use of coatings whose properties happen to produce apparently favourable results. It is hoped that this article has given some insight into the scientific background to the limitations of this type of accelerated testing. Regardless of the attractiveness of quick and short-term information, there is no substitute for corrosion data generated from long-term exposure testing and case history information from real structures or components in service.

References [1] iSo 9227 ‘Corrosion tests in artificial

atmospheres – salt spray tests’.

[2] Skerry, J S, Alavi, A and Lindgren, K i.

‘Environmental and Electrochemical test

Methods for the Evaluation of Protective

organic Coatings’, J of Coatings techno-

logy, vol 60, No 765, p97.1988.

[3] Appleman, B. ‘Cyclic Accelerated testing:

the Prospects for improved Coating Per-

formance Evaluation’, J Protective Coa-

tings & Linings, p71-79. Nov 1989.

[4] townsend, H E. ‘Development of an

improved Laboratory Corrosion test by

the Automotive and Steel industries’,

Proceedings of the 4th Annual ESD

Advanced Coating Conference, Dearborn,

USA, 1994.4

Swerea KIMAB

Swerea KiMAB is a leading institute

within corrosion and materials

research, based in Stockholm,

specialising in surface technology,

corrosion and corrosion protection

of metals, corrosion testing and field

exposures, corrosion of polymers and

material analysis and metallography.

Authors | Lena Sjögren, Coordinator – Consulting Services and Corrosion Swerea KIMAB and Murray Cook, Managing Director of European General Galvanizers Association

Photos | Swerea KIMAP (1), IKS Dresden GmbH (2), ARGE Ahlbrecht Scheidt-Kasprusch (3), Institut Feuerverzinken (4)

Aggressive Xpansion

Galvanizing Delight

“Aggressive Xpansion” is the third piece of work

by Spanish neo-futurist artist Viktor Ferrando,

within a series of related works called “Planet

Ferrovia”. Railway scrap materials have been

used to build up each of the individual sculptures

and in the case of “Aggressive Xpansion” all the

steel has been galvanized. this has enabled the

sculpture to be exhibited at coastal locations

throughout Spain and several major cities across

Europe.

Photo | Angel Rosique