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Bernard Weatherill House, Croydon | 3 Sport Facility, Spain | 6 Lydlinch Bridge, Dorset | 12 Bradfield College Greek Theatre | 14

International Magazine

ISSN 1363-0148

www.hdgmagazine.co.uk

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1 | Old meets new: the civic hub sits alongside its Victorian neighbour

EditorialGovernment continues to

emphasise the importance

of infrastructure on our road

to recovery. Two featured

projects illustrate the best

way to invest our finite

resource.

The Stoneham Bridge is an

innovative design solution that

optimises use of materials to

obtain a 75 year life for the

structure. On an entirely different note, road users travelling along

the A357 over the river Lydden cross what looks like any ordinary

steel bridge on their way south. If they had the opportunity to take

a closer look they would be confronted by a story that spans over

70 years.

The Lydlinch bridge started its life as a temporary structure during

World War Two so that tanks could use the road south to Poole

Harbour and Weymouth during the build-up of forces for the

invasion of Europe.

On a recent site visit, I was struck by the elegant efficiency of the

Callender-Hamilton design concept, the longevity of the galvanized

coating and on a more poignant note the skill of the Canadian

Engineer Corps that built it.

The bridge has become an important symbol locally and remains

a fitting tribute to the men that erected it.

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

© 2014

Photo front cover | Stephane Groleau

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Tonalityand subtle variation Bernard Weatherill House, Croydon

The newly completed Bernard Weatherill House is located adjacent to the Grade II listed Victorian

Town Hall and forms a revitalised civic hub in the centre of Croydon. The brief, for EPR Architects

Ltd, was to design an administrative headquarters for up to 2,700 staff that was public facing and that

also reflects Croydon Council’s aspiration to be a forward thinking, transparent authority. The building

should be highly sustainable and offer flexible accommodation to support the council’s current and

future methods of working.

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by Iqbal Johal and Julian Barrett

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EPR took the brief on board and based its

design solution on a life cycle cost approach

using high quality materials and ensuring

minimum ongoing maintenance costs.

Climate Wall

The completed building is wrapped within a

shimmering climate wall which provides a

protective veil to maximise natural daylight

while minimising solar penetration. The

shading solution utilises a ceramic fritted

pattern applied to the outer layer of glass,

rather than relying on shading devices in the

cavity between the inner and outer glazed

skins. The combination of a second skin of

glazing with a frit applied in thin bands across

it, adds depth and richness to the facade

whilst maintaining the desired transparency.

Exposed galvanized steel has been utilized

across the entire scheme, forming a large

part of the climate wall structure. It has also

been used at street level to form gates and

barriers, to tie in with the facade materials.

The decision to use galvanized steel rather

than painted sections was driven by its

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2014negligible maintenance costs and desired

aesthetics. During early detailed development

of the climate wall with Italian cladding

contractor Focchi, calculations indicated

that the mullions and transoms supporting

the climate wall glazing would need to be

steel, to deal with the structural loads. EPR

were keen to explore the use of an exposed

galvanized finish, as the inherent tonality and

subtle variation was attractive to the design

team and worked well against the crisp

white spandrel panels, fritted glass and dark

internal aluminum mullions. Coupled with

this, maintenance walkway grilles between

the two glazed skins were to be formed from

galvanized grating for cost and durability

reasons, and that the overall external climate

wall structure read as one material.

Sustainability

Integration of a multistorey double skin

facade providing good daylight into the

internal space whilst creating an envelope

efficient at reducing solar gain in summer

and improving thermal insulation in the

winter was quite an achievement. An atrium

in the middle of the building provides daylight

to the internal office areas reducing the

lighting demand. An exposed concrete soffit

provides thermal mass to the building to aid

in the cooling and heating. Limiting U and G

values was achieved by optimisation of high

performance glazing. The equivalent G value

for the climate wall was 0.19 with a U value

of 1.20 W/m2k while still able to provide

good light transmittance. This far exceeded

the requirements of the regulations at time

of design. The efficient design and material

selection of the facade allows the building

to use chilled beams to supply heating

and cooling to the office areas. Central air

handling units with heat recovery supplying

straight runs of ductwork have allowed

specific fan powers to be very low at 1.80

w/l/s.

Finished Article

The quality of the curtain walling is of a very

high standard combining optimal design

that is well conceived and skilfully executed.

Combined with clean, unfussy detailing, it

has allowed the fritted glass planes to read

strongly when viewed from far and forms

an attractive palette in detail. It has resulted

in well-mannered facades, with tonality and

subtly provided by the galvanized coating

that counterpoint elegantly with the Grade II

listed Town Hall adjacent.

2 & 3 | The building is wrapped within a shimmering climate wall to provide a protective veil and maximise natural daylight while minimising solar penetration

Architect | EPR ArchitectsPhotos | Charlotte Wood (1);

Jim Stephenson (2-5)

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4 | Frit applied in thin bands across the glazing skin add depth and richness

5 | The galvanized supports frame magnificent views over the town

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Modulating solar gainSport facility in Mendizorrotza, Spain

The new sports facility for Mendizorrotza is located in Vitoria-Gasteiz, the capital city of the

Spanish Basque country and was designed to be both energy-efficient and climate-friendly thanks

to its architectural coherency and the use of semi-transparent solar modules.

Constructed from a framework of 1,000 tonnes of galvanized steel which supports the glass shell, the building

appears to float on top of its concrete base. Nevertheless, architectural weightlessness is not the only unique

characteristic of this striking building: the municipal building owner also wanted to send a clear message on

sustainability. Vitoria-Gasteiz ranks as one of Spain’s pioneers and won the European Green Capital Award 2012.

“Our goal was to integrate all of the solutions into one rational design that would significantly lower the power

consumption of the sports complex,” explains Fernando Bajo Martínez de Murguía, the Spanish architect, planner

and site manager from Vitoria.

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With a total of 9,702 m² of floor space, the

indoor swimming area houses a children’s

swimming pool along with an Olympic

pool which contains a submerged pontoon

providing movable partitioning. In addition,

several other facilities for competitive and

recreational sports are spread across various

floors.

The design also includes a double glazed

climate control system that serves as a

thermal air cushion to modulate solar gain.

To utilize the concentrated solar energy that is

generated from the long south-facing facade,

56 semi-transparent photovoltaic modules

have been integrated into the facade. The

modules generate an estimated annual power

output of 6,450 kilowatt hours (kWh). In terms

of the Spanish energy mix, this means a

reduction in emissions of roughly three tonnes

of carbon dioxide. In addition, the semi-

transparent modules also offer shading from

the sun and thus help prevent the halls from

overheating, in addition to conserving the

energy needed for cooling and lighting.

1 | With a total of 9,702m² of floor space, the indoor pool houses an olympic, as well as a children’s swimming pool

2 | A gem-like lustre is created from light reflected off the pool’s surface and the internal steel frame

3 | The incorporation of galvanized steel and an innovative south-facing facade contribute to a rational design that significantly lowers power consumption

Architect | Fernando Bajo Martínez de MurguíaPhotos | Fernando Bajo Martínez de Murguía

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Metallicpermeable skinTechnopolis Science Park, Delft

Standard grating panels are essentially conceived of as being

load-bearing surfaces used for walkways. The Dutch architects

Cepezed, however, have used the grids vertically as facade

elements for a data centre.

The Technopolis Science Park in Delft contains a high-tech data centre

belonging to the Datacenter group, with 2,500 m² of server space. It is

reputed to be the most modern data processing and storage facility in

the Netherlands. In particular, extensive precautions have been taken

in connection with fire prevention and power supply. This also applies

to the building’s shell. The three-storey, windowless concrete structure

is enclosed by a facade made from vertically mounted grating panels.

Both the panels and the facade sub-structure have been constructed

from hot dip galvanized steel. The galvanized surfaces are impressive,

not only because of their outstanding corrosion prevention properties,

but also because of their metallic appearance. “The attractive thing

about galvanizing is the colour which the material acquires with time”

says Michiel Cohen, who was one of the founders of Cepezed a decade

ago, in an interview with Hot Dip Galvanizing Magazine. A total of

1,514 hot dip galvanized panels with lengths of between 6 and 2.1m

and widths of between 0.4 and 0.2m envelop this cube-shaped part of

the structure. The facades also protect the building services equipment

installed externally. Thanks to a high degree of air permeability of up

to 80%, a very high proportion of the installation’s heat is extracted.

Simultaneously, the comparatively light facade panels reduce the wind

loading and offer effective protection against vandalism, sabotage and

graffiti.

1 | From afar the galvanized facade creates a highly permeable skin

2 | A total of 1,514 galvanized panels were used ranging from 2.1 to 6m in length and 0.2 to 0.4m in width

3 | A substantial galvanized frame supports the network of panels to create the facade

by Holger Glinde

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Seen from a distance, the data centre looks like a tightly closed

metal box. As you get nearer to the building, the facade reveals

the technological equipment which lies behind it. This effect is

predominantly caused by the serrated webs which are almost vertical

in the grid, and thus cause the facade to appear flat or transparent,

depending on the angle of observation.

Architect | cepezedPhotos | cepezed (thumbnail,1,3), Graepel Seehausen (2)

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The Stoneham Bridge, erected in 2011, is distinguished not

only by its outstanding architectural and structural quality, but

also by its innovative use of hot dip galvanized steel. Both the

steel structure of the bridge and the reinforcing steel of the

concrete arches and the road surface were hot dip galvanized.

At the early design stage for the bridge, a structural solution using a

central pier was excluded on grounds of safety. The bridge had to cross

the new Highway 73 in Quebec, Canada, at an unusual angle of 49

degrees. A central pier would also have called for additional measures

from a safety point of view such as, for example, the construction of

an extra 600 metres of guard rails. The engineers CIMA+ opted for

a bridge made of two parallel arches rising up to 20 metres above

Highway 73. The concrete arches are 1.5m wide at the base and 2.4m

high, and each tapers down to half this width as it rises upwards. The

bridge’s clear span is 68.5 metres, and the total width, including arches

and overhangs, is 18.5 metres. 34 steel cables, with a diameter of 48

mm, are linked to the road surface steel structure through integrated

anchor plates in the concrete arches. Here, the cross girders of the steel

structure form the bridge’s spine rather than the longitudinal girders

which normally serve this function.

Elegant use ofgalvanized steelStoneham Bridge, Quebec 1

by Holger Glinde

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The Stoneham Bridge has been designed for a 75 year life, with

maintenance work being limited to replacing elements subject to wear,

such as the carriageway surfacing. Since the climate of Quebec is

characterised by long, snowy winters, with temperatures below freezing

for periods of up to five months, the strongest corrosive elements to

which the bridge is exposed comes from de-icing salt. For this reason,

corrosion prevention through hot dip galvanizing was used for both the

steelwork of the bridge and the reinforcing steel of the concrete arches

and the road surface.

1 & 4 | The sites topographical constraints led the engineers to design an innovative through-arch bridge with a span of 72m and a 13.4m width

2 & 3| All the reinforcement for the bridge deck and concrete arch structures has been galvanized to maximise corrosion protection

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Architect | Lemay & AssociésPhotos | American Galvanizers (1,2,3), Stephane Groleau (4)

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Seventy Twoyears youngLydlinch Bridge, Dorset

The old adage of size is not everything comes to mind when considering the history and

performance of the Callender-Hamilton bridge at Two Fords, Lydlinch in Dorset.

As early as 1942 the Ministry of Defence was considering outline plans for the D-Day invasion. Where and

when the landings would take place were top secret, but the speedy movement of the invasion force to the

south coast ports was a common factor to all alternatives. One such route, the A357 through Dorset to

Poole Harbour, needed to be improved. At Lydlinch, the picturesque, narrow stone bridge over the River

Lydden would not withstand the weight of heavy tanks. In 1942 Canadian army engineers erected a tempor-

ary galvanized steel Callender-Hamilton bridge alongside the older structure. The tanks and heavy equipment

were diverted over the galvanized bridge on their way to Europe.

by Iqbal Johal

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2014Temporary Structure

The bridge was not intended to be a permanent structure,

but has stayed in service having been passed into Dorset

County Council’s control after the war. It has carried the

road’s eastbound traffic ever since. 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 that of

strengthening the bridge in 1996 to enable it to conform

to new standards in order to carry 40t lorries. 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”. In actual fact, 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.

Inspection

As a follow-up to an inspection carried out by Galvanizers

Association in conjunction with Dorset County Engineers

in 1999, the bridge was re-inspected on 14 October

2014 by GA staff with assistance from Dorset County

Engineers. The bridge still looks in very good condition

and on first sight the areas that look to have a slightly

weary appearance are mostly due to dirt deposits and

growth of moss on the steel surfaces. Coating thickness

measurements were taken on steel members chosen at

random from both sides of the bridge after wire brushing

so as to remove any surface contaminants or build-up of

corrosion products. The members inspected included the

main truss diagonals, joining plates and some bolt heads.

Average coating thicknesses on the diagonal trusses

ranged from 126µm to 167µm. On the plate sections

the average thicknesses were 131µm to 136µm. On bolt

heads average coating thicknesses ranged from 55µm to

91µm. Les Lock, Project Engineer said “Despite all that‘s

thrown at it, floodwater, mud and grit salt, after 72 years

the galvanized exposed members are still in very good

condition.”

Seventy Two years young

Having started life as a temporary structure, the

Callender-Hamiliton bridge at Two Fords, Lydlinch, is

still in fine fettle 72 years after it was first erected. The

bridge has now become part of Dorset folklore and it

surely can‘t be far off becoming a listed structure. The

galvanized coating has stood the test of time exceptionally

well and taking the remaining coating thicknesses into

account along-side zinc corrosion data, the coating can be

expected to provide a life well in excess of 100 years, a

tribute to the designers and the men who built it.

1 | The once temporary bridge at Lydlinch, Dorset that has withstood the test of time for 72 years

2 | Cleaned areas for coating thickness measurements show the coating to be in very good condition

3 | The bottom chords of the bridge are submerged by river water at times of high rainfall

Photos | Iqbal Johal

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The bridge inspection was carried out with the kind permission and assistance of Dorset County Council with particular thanks to Les Lock, Project Engineer, Bridge Inspections.

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Platform fora star performanceBradfield College Greek Theatre

Bradfield College is an independent school situated in the Berkshire

countryside. At the heart of the school is a 1,000 seat amphitheatre formed

from a disused chalk quarry. Headmaster Dr Herbert Branston Gray started

the Greek plays to save the school from bankruptcy. Since Antigone in 1890,

the school has been staging a world-renowned Greek play every third year.

The students who act in the Greek tragedies receive no formal training in speaking

ancient Greek, and have only nine months to learn the lines and direction, while

keeping up with their other studies. The Greek Theatre closed in 2009 for restoration

and, following a £1.3 million appeal, reopened with a performance of Antigone

on 20th June 2014. In 2012 Studio Octopi were appointed to undertake the

modernisation of the theatre with the intention to reopen in time for a performance

in June 2014. The original ‘temple’ theatre building was condemned in 2009, so

the College needed a new theatre building or Skene that would enable increased

versatility of the theatre. From Studio Octopi’s first visit they were intent on

preserving the wild and picturesque setting. Forming a new entrance to the theatre

was key and this naturally informed the journey thereon in. Set out over the ruins of

the previous entrance stair, the new Agora commands spectacular views over the

auditorium. Leading off the granite terrace with the donors’ names engraved into it,

a galvanized steel deck cantilevers out over the terraces below.

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2014Punctuating the deck is one of the most elegant

trees on the site. Tall and graceful, its presence

signals the determination to keep nature at the

forefront of the architectural proposals. Descending

into the theatre the Grand Staircase effortlessly

glides over the chalk cutting below. Each step is

lit from a linear LED mounted to the underside

of the tread above. At dusk the LEDs provide a

spectacular floating stair suspended over the chalk

and undergrowth below. The walkway is 85m

long and spans almost the full 270 degrees of the

theatre terraces. Off the Walkway there are five

staircases to distribute the audience down onto

the existing concrete aisle steps to their seats. As

well as circulation, the Walkway offers a peripatetic

vantage point during performances. The galvanized

mesh balustrade panels bolted to the edge of the

Walkway concrete each have a leaning plate on

top, a place to contemplate the performance from.

Halfway along the Walkway, centred to the Skene,

is the Control Hut. From here the permanent house

lighting and temporary performance lighting is

controlled. The Hut is constructed entirely from

galvanized louvered panels and cantilevered from

the Walkway. To the front, a 4.3m wide hinged

panel rises on gas struts to provide uninterrupted

views of the stage. The 10mm thick galvanized steel

plate roof has one of five performance lighting rigs

mounted on top. The Skene function and siting is

based on the traditional Greek theatre layout and

has been designed to provide support for temporary

scenery on the stage. The building is clad in cedar

shingles and to the sliding doors at the front,

cedar batons. Internally the structure is entirely

standardised and exposed, providing opportunity for

a cost-effective but honest and striking workspace.

The front elevation is designed to be fully openable

at ground floor (with a series of sliding doors) and

partially at first floor (with a series of hinged double

doors). The cantilever structure at first floor level

enables the loggia to be fully opened-up (12m clear

span) with no structural elements to constrain the

theatrical use of the space.

The Bradfield Greek Theatre continues to feel part

of a larger English garden, wild and intoxicating.

At the height of summer, the theatre takes on a

truly unique appearance, as the light drops the

theatre lights take over, and the magic of outdoor

performance comes alive.

Architect | Studio OctopiPhotos | Philip Vile

1 | The magic of outdoor performance comes alive with an evening showing of Antigone

2 & 3 | Keeping nature at the forefront of the architectural proposals, a tree punctuates the galvanized steel deck which leads off from the granite terrace

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Galvanizing Delight

The Pyramidenkogel (Pyramid Cake) Tower near the

Austrian town of Keutschach am See is 100 metres

high. The hybrid structure is constructed from hot dip

galvanized steel and timber. Ten elliptical galvanized

steel rings rotate at 6.4 metre intervals around the

structure and 80 hot dip galvanized diagonal braces

provide rigidity for the 16 larchwood supports of the

tower. The various levels and viewing platforms are

connected by a series of galvanized stairs. The high

tower attracts not only tourists, but also base jumpers,

who have already started jumping off the viewing plat-

form, which is 70 metres high.

Architects | Klaura, Kaden und Partner, Klagenfurt Structural Design | Lackner und Raml, Villach Photos | John Jaritz