Design Awards: 2009

No 2 Spinningfields Square Manchester

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Architect

SHEPPARD ROBSON

Structural Engineer

CAPITA SYMONDS STRUCTURES

Steelwork Contractor

WILLIAM HARE LTD

Main Contractor

BOVIS LEND LEASE

Client

ALLIED LONDON PROPERTIES

The building provides 2,400m2 of high quality grade A office accommodation and 1,380m2 of restaurant and retail space over six floors within a new landmark structure at the entrance to the Spinningfields business and retail development in Manchester city centre.

The building takes the form of two parallelograms on plan, oppositely handed and positioned one above the other, creating at level 2 a roof terrace to the West elevation and a 23m long cantilever to the East. The external cladding and façade diagonal form reflect and complement the structural geometry of the building, drawing attention away from the horizontal plane of the floors.

The design of the building achieved an excellent BREEAM (2005) rating by taking a holistic approach considering all environmental factors. The high proportion of solid insulated panels within the façade benefited the energy demand of the building through a consequent reduction in solar gain.

The office floors have been designed so that they can be fitted out on either an open plan or cellular basis, and the servicing has been provided so that each floor can be sub-divided into two separate tenancies. The floors also have built-in loading allowances for future storage capability and soft spots for tenant plant requirements.

Materials for the building components were selected for their durability and maintenance requirements. In particular the structure was specified for 60 years design life and major components of the envelope 25 years.

The use of steel was the only way such a demanding structure could be delivered economically. The integrated services solution meant that floor zones were minimised, the reduced self weight of the structure meant that the loads to be resolved by the cantilever and the foundations were kept as small as possible, and the high load capacity of steel meant that the cantilever elements could be kept as compact as possible.

The floor construction comprises a 150mm thick concrete slab on composite metal decking on a grid of secondary and primary Fabsec beams.

400mm diameter openings in the 550mm deep beams allowed for integration of the services within the structure zone. The cells were distributed in a regular grid through the irregular beam layout to aid coordination of the service provision. The Fabsec beams were also fire engineered to provide a least cost design considering both the beam weight and intumescent paint thickness.

The 23m cantilever was resolved by making the perimeter steelwork into a 3-storey deep truss, achieving the most economical frame solution possible. The truss philosophy was applied to all four elevations to provide both vertical support to the edge of the floor plate and lateral stability to the upper block. As a result it was possible to omit the concrete cores above second floor level saving money and time.

The structure was engineered to suit the cladding deflection requirements. The linearelastic properties of steel allowed for accurate 3D modeling and prediction of the behavior of the structure, which was then replicated in the on-site deflection measurements achieved by the frame.

The accuracy of construction which was achieved on site is a testament to the high level of skill and workmanship employed by the steelwork contractor in designing and fabricating the complex connections of the structure.

Judges’ Comment

s:

The building plan of two overlaying parallelograms produces a huge cantilever at the front, which provides a clear view of a notable historic building. The diagonal bracings of the 3-storey frame are cleverly aligned with the herring-bone pattern of the curtain walling, concealing the heavy cantilever trusses from the exterior.

A building of obvious quality in many respects.

A2/A282 Dartford Improvement Scheme

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Architect

JACOBS

Steelwork Contractor

FAIRFIELD-MABEY LTD

Main Contractor

COSTAIN

Client

HIGHWAYS AGENCY

The Highways Agency identified the need for a major road improvement programme at the A2/A282 intersection in north Kent. The aim of the project was to divert traffic away from the roundabout sitting below the M25 and above the A2. This was achieved by constructing a link to carry traffic from the A2 westbound onto the A282 northbound, and another from the A282 southbound to the A2 eastbound. A third dedicated lane on the A2 westbound funnels traffic to the southbound M25. These link roads required four new bridges to carry traffic over the existing highways.

More than 4,000t of weather resistant steel was used for the construction of the four new structures. One of the main considerations was that the bridges would need as little maintenance as possible due to access constraints. With weather resistant steel the rust ‘patina’ develops under conditions of alternate wetting and drying to produce a protective barrier, which impedes further access of oxygen and moisture and eliminates the need for it to be painted with safety, environmental and cost benefits.

The four structures consist of the main east to north link flyover, which is a 420m long nine span viaduct with more than 1,800t of steel. Two parallel five span bridges of 1,000t of steel each are both 250m long and run on either side of the existing A2. The fourth and final structure that was erected required 230t of steel and carries southbound A282 traffic over a small slip road before linking up with the A2.

Work on site for the east to north link flyover began in January 2007, with erection in February. Some sections were assembled on site with the majority of steelwork being lifted using a 1,000t telescopic crane. In May, a critical milestone was reached with the final section of the structure lifted in overnight to link the A2/A282 east-north viaduct. The middle section of the bridge was erected first, followed by the remaining spans toward the south abutment, completing six of the nine spans in one sequence. The remaining spans toward the north abutment were erected thereafter. The nine bridge spans carry the structure over eight piers. Five of the concrete formed piers have four columns while the three middle piers only have two columns. The middle three spans traverse open ground so there was enough room for temporary trestles to support the steelwork during erection.

All nine spans of the east to north link flyover vary in length from the longest at 59m to the shortest at 38m. The structure is curved in both plan and elevation. Steelwork for the bridge deck consists of two braced pairs of girders for each span which were paired on site and lifted into position using the AK680 crane. Cross members are situated at 8m intervals. Each pair of girders consists of four steel sections which were bolted together on site and prepared for erection.

At the design stage it was decided to fit the GRP permanent formwork onto the preassembled steelwork at ground level, which reduced the amount of working at height and meant fewer road closures. Seven optimum positions for one crane to lift all of the bridge decks into place during the steel erection process were worked out. The concrete deck was then poured following on three spans behind the steelwork.

The A2/A282 scheme was completed in December 2007, five months earlier than expected.

Judges’ Comment

s:

A large, busy interchange with one large bridge and three smaller ones. The composition of the bridges, with consistent architectural language, works well in the gently rolling landscape. The plate girder spans were pre-assembled with the decks, and exceptionally heavy lifts minimised traffic disruption.

The innovative use of weathering steel on this scale is practical and appropriate.

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

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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.

The Tank Museum Bovington

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Architect

KENNEDY O’CALLAGHAN

Structural Engineer

AKS WARD

Steelwork Contractor

BOURNE SPECIAL PROJECTS LTD

Main Contractor

NORWEST HOLST LTD

Client

THE TANK MUSEUM

The Bridge Academy Hackney

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Architect

BDP

Structural Engineer

BDP

Steelwork Contractor

WATSON STEEL STRUCTURES LTD

Main Contractor

MACE PLUS

Client

DEPARTMENT FOR CHILDREN, SCHOOLS & FAMILIES UBS AG

30 Crown Place London EC2

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Architect

RHWL ARCHITECTS

Structural Engineer

RAMBOLL

Steelwork Contractor

ROWEN STRUCTURES LTD

Main Contractor

SKANSKA

Cost Consultant

DAVIS LANGDON LLP

Development Manager

CITY OFFICES REAL ESTATE

Client

GREYCOAT CROWN PLACE LIMITED PARTNERSHIP

5 Aldermanbury Square London

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Architect

ERIC PARRY ARCHITECTS

Structural Engineer

RAMBOLL

Steelwork Contractor

SEVERFIELD-REEVE STRUCTURES LTD

Main Contractor

BOVIS LEND LEASE

Development Manager

HANOVER CUBE

Client

SCOTTISH WIDOWS