Design Awards: 2009: Certificate of Merit

Hafod Eryri Snowdonia National Park

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Architect

RAY HOLE ARCHITECTS

Structural Engineer

ARUP

Steelwork Contractor

EVADX LTD

Main Contractor

CARILLION

Client

SNOWDONIA NATIONAL PARK AUTHORITY

Hafod Eryri is a single storey braced steel frame located on the summit of Snowdon which replaces the original building constructed in the 1930s. The adoption of a steel frame enabled the client to change the design radically from the original concept, allowing the building to be opened up so that the view from the summit could be fully appreciated.

A major benefit of using steel for this project was the fact that it is lighter to transport than precast concrete, as all materials had to taken up to the summit by train. Transporting over 100 tonnes of steel and more than 2,500 bolts up the mountainside was never going to be an easy feat – everything had to fit on a 11m long x 2.5m wide bespoke flat bed truck. All the parts of the steel frame had to be precisely numbered, distributed in numerical order and each phase was colour coded, so that they would reach the summit in the correct order ready for unloading and construction.

Design was undertaken to withstand the onerous applied loads and constraints such as:

  • 150mph winds
  • 5m high snowdrifts
  • freezing temperatures (in winter temperatures can reach -40°C – galvanized steel is durable even at these temperatures)
  • heavy roof cladding (there is approximately 90 tonnes of granite slabs on the roof)
  • deep roof build-up reduced the maximum depth of the 13m long beams

The main café area does not have a vertical column, most are raked in both planes to create the complicated shape. Roof beams over the main café also had to be tapered at the ends to suit the ceiling. Services zones were provided to avoid passing services through the beams which were already working hard.

The visual aspect of the exposed steelwork determined the choice of material – stainless steel CHS columns were used in the glazed areas. The isolation of the stainless and mild steels was essential even at complicated junctions where large forces had to be transferred from one member to another.

Fabrication, erection and on-site checking was made easier due to the trial assembly which also assisted the design of the other items, such as cladding, windows and the roofing system etc. A trial construction of the frame was carried out offsite before being galvanized to ensure that the plant and machinery were suitable, and that the phasing would work due to the unusual shape of the building. Everything was also checked for fit before going to site.

In terms of its environmental impact, the building is clad with granite and the whole roof is covered in granite slabs. This helps the building blend in with its environment, plus its weight also keeps the building from blowing away. The outer cloaking is designed to be all self-finished where possible. The majority of the steelwork is galvanized to ensure the durability of the steel frame. Where the steelwork is exposed, it is stainless and has been given the ceramic ball blast treatment to give it a high quality finish.

Hafod Eryri has been designed to be inherently a non-combustible building as evacuating the building would be more dangerous, due its location, than staying inside.

Judges’ Comment

s:

Rarely can a site and logistics be more challenging than this. The largely granite cladding and roof required a heavy steel frame, carefully modularised for tightly planned transport to the summit on the narrow-gauge railway.

It all worked well in very tough conditions – a meritorious effort by all the team.

Lakeside Energy From Waste Plant Colnbrook

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Architect

ROYAL HASKONING

Steelwork Contractor

WATSON STEEL STRUCTURES LTD

Main Contractor

BAM NUTTALL LTD

Client

LAKESIDE ENERGY FROM WASTE LTD
Lakeside Energy from Waste plant is a state-of-the-art facility to convert household waste into electrical energy. The new plant consists of three processes:-

  • A clinical waste incinerator which provides a safe means of disposing of waste from the healthcare centre
  • A material recycling facility to separate out any materials from commercial and household waste which can be re-used – up to 40,000 tonnes per year of waste is planned to be re-cycled
  • The remaining waste (approx 400,000 tonnes per year) is incinerated, and the energy released is converted into electricity – the facility will produce 32 mega-watts of power

Adopting a steel solution enabled a building of over 40m high to be constructed whilst maximising the internal space. This was achieved by using a series of long span beams and trusses for roof construction and unrestrained central columns up to 42m in length. The overall delivery programme required many sections of the plant process equipment to be installed prior to the roof structure installation. The frame was required to be erected in four main stages within the overall programme, thus each part frame needed to be independently framed for overall stability under temporary loading conditions.

The weight and component size of the process plant contained within the building dictated that the shell had to be constructed from the inside out – hence the main components of the generating process and all the associated pipe works and support steel had to be installed first while crane access was available from above. The shell had then to be erected over the top of this, which meant that all crane and man access had to be from outside of the building shell. The steel was designed in long span sections to minimise the number and weight of connections that needed to be accessed. The bracing was concentrated around the perimeter where access by MEWP was possible and columns were spliced to minimise length when being lifted over existing structures.

The sides of the building are curved on plan, translating an ovoid shape on the ground, and the roof is a curve which changes in pitch, steepening towards the chimney. The combination of these factors resulted in eaves that transcribe a spiral along the building, which made accuracy of fabrication and erection paramount. The geometry of the Y shaped columns is different at each location and these were required to be welded in-situ due to transportation limitations, requiring a high degree of accuracy of fabrication and considerable skill by the welders and engineering staff on site.

The building contains several free standing columns of up to 42m in height. These are formed from two UB sections welded into both symmetric and asymmetric cruciform sections – the straightness of these sections was vital.

In order to minimise the visual impact of the external plant on the roof, two large downstand recesses (18m by 10m by 2m deep) were framed into the overall roof profile. The chimney flues extend vertically by 75 metres and therefore are the most visual part of the building. The architect cleverly extended the roof structure around the chimney by incorporating a dipped curved edge, which represents the tip of the ‘aeroplane wing’.

This striking building combines the functional requirements of an industrial process with excellent architecture and demonstrates that industrial buildings can be both attractive and efficient.

Judges’ Comment

s:

A large multi facetted waste plant and offices have been accommodated in a dramatic, racy envelope. The heavy long-span steel roof structure is practical and economic, and erection so close to the Heathrow flight paths was a major challenge.

An important project demonstrating how unpopular, but increasingly common, waste incineration/energy plants can be handled prominently and effectively.

The Weather Room Monken Handley

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Architect

LIDDICOAT & GOLDHILL

Structural Engineer

LYONS O’NEILL

Steelwork Contractor

GOODALL SERVICES

Main Contractor

STEPHENS & JAMES

Client

DR & MRS D R GOLDHILL

White Lodge is a Grade II-listed house in Monken Hadley, North London. The oldest parts date to the 17th Century, and inchoate additions and alterations have taken place periodically ever since. The Weather Room is the latest layer added to this historic building. The brief was to reunite disconnected wings of the house and open the building to its extensive gardens.

The form of the new space was dictated by the strictures of working on a listed building in a very tightly controlled Conservation Area. The detail of the construction became the focus, and a close working relationship developed between the architect, the contractor, the engineer and the steelwork contractor. Much time was spent at the steelwork contractor’s workshop, where each component and connection was drawn, prototyped and refined.

The structure of the room is simple; powdercoated steel glazing bars form a portal frame which supports the structural double-glazing over. Steel was chosen to allow very fine (45mm) sight lines through to the garden, while still being capable of bearing people and scaffolding on the roof to allow maintenance of the windows and roofs above.

The glazing bars were hand-made by welding a ‘sandwich’ of bright steel flats together. A narrow rebate was created to the inside of the bars, allowing installation of an adhesive LED light tape. This highly-efficient, lowenergy lighting system solved the conundrum of providing even, atmospheric light in a space with a glazed ceiling without obtrusive luminaries. The resultant effect is of warm ribbons of light glowing from the sharp edge of the steel.

The interior is tempered by the external condition; the structure plays a crucial role in this relationship. By day, it animates the space through the play of light and shadow from the glass and steel flats. As night falls, concealed blades of light within the steel succeed the sun and the space develops an entirely different character.

Judges’ Comment

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An elegant gem used for connecting parts of a listed building, and for dining purposes. The light, plated steel frames each carry glazing and LED lighting along the beams and columns in a fully integrated way.

An excellent small example of a sensitive modern addition to an historic setting.

Unilever House Leatherhead

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Architect

DN-A

Structural Engineer (Main Frame)

MOTT MACDONALD

Structural Engineer (Feature Steelwork)

WEBB YATES ENGINEERS LTD

Steelwork Contractor (Main Frame)

CAUNTON ENGINEERING LTD

Steelwork Contractor (Feature Steelwork)

ALLOYFABWELD LTD

Main Contractor

BOWMER & KIRKLAND LTD

Client

LANDID AND RREEF

Leatherhead proved to be the ideal location for Unilever to bring together its separate UK business units into a single headquarters building.

The design process resulted in a three storey office building springing from a podium deck. Taking advantage of the natural fall across the site provided the opportunity for undercroft parking. Both the podium deck and the building are steel framed structures.

The office accommodation is arranged in a number of linear wings wrapped around a central full height entrance atrium and an external courtyard. A series of secondary atria spaces on either side of the courtyard ensures clear circulation patterns and houses lift cores and feature stairs.

The central atrium, the heart of the building, acts not only as a first impression on visitors, but also as a space to showcase and launch new products. The three storey space is top-lit by a striking northlight roof comprising a series of steel stressed-skin prismatic arch trusses which span across the 18m width and support glass infill panels in between. To create the trusses, standard D100 profiled steel decking sheets were used. They fall into the three-dimensional hypar form with ease and form a shear diaphragm, unifying steel corner angle sections to create a stiff ‘Toblerone’ box-like truss. The trusses were pre-fabricated offsite and lifted into place in one piece. The use of standard materials and lack of any applied internal finishes made this a cost-effective solution, with spectacular visual results. For consistency, the exposed structural steel deck ceiling has been carried through to the secondary atria, where it was installed flat.

The fully glazed south-west facing façade to the entrance atrium received an elegant external louvred brise soleil screen. Besides protecting the atrium from the sun’s heat and glare, this screen serves two further functions: The hangers support maintenance walkways at each storey level, suspended between the louvre screen and the glazing. Fabricated from slim steel box sections and perforated sheet, they act as a truss and double up as lateral support to the curtain walling. Therefore mullion back boxes are kept small and unobtrusive and the need for further internal columns and intermediate supports was eliminated.

Each atrium is fitted with a helical feature stair. The steel stairs were fabricated with an internal stringer extended in height to double up as the balustrade. This piece of steel needed to be relatively thick (at 24mm) and shaped into a tight radius helix which would be extremely difficult to roll. A novel alternative solution was found when the subcontractor proposed to cut the stringer from a large diameter tubular section. The stair was constructed around this and the stringer/balustrade profile cut afterwards.

Vertical support to the frame was primarily provided by CHS columns. This meant the columns within the large expanse of open plan office space could be fire protected with intumescent paint and remain exposed. The perimeter column line is located inboard, clear from the external wall to allow for maximum freedom in façade glazing configuration and for glass to glass corners, exploiting the views of the countryside.

Cellform beams allow for service runs within the depth of the steelwork which ensured generous ceiling heights could be maintained whilst keeping the overall storey height and, therefore, cost low. This relatively light solution also proved effective with regard to keeping the foundations minimal.

The adaptability of the steel frame means a potential second phase could be implemented for future expansion.

Judges’ Comment

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Three speculative office buildings have been integrated by atria providing generous circulation, under a design/build contract. Large steel-framed floors are on three levels, but the highlights are the atria. The reception atrium is dominated by northlights of stressed-skin prismatic trussed decking and glazing. Helical plated stairs land on wish-bone brackets at floor levels, and full-height glazed walling, brise-soleil and maintenance walkways are all combined with economy and elegance.

This shows that design & build can produce dramatic results.