Design Awards: 2012

Deptford Lounge, London

deptford_lounge

Architect

Pollard Thomas Edwards architects

Structural Engineer

Atkins

Steelwork Contractor

Conder Allslade Ltd

Main Contractor

Galliford Try

Client

London Borough of Lewisham

 

The brief was for the Giffin Street Redevelopment to form a focal point for the local community. The Deptford Lounge, serving the community, will hold something for everyone, regardless of age, income, cultural and ethnic background.

The visionary concept combines a replacement primary school, Tidemill School, with the Lounge – a new state-of- the-art district library offering community facilities, and Resolution Studios – providing new homes, studios and exhibition space for local artists. The upper floors of the Lounge are designed for shared school and community use thus maximising the resources available to both the school and the wider community.

The Lounge is a three-storey steel framed building with reinforced concrete stair and lift cores providing the stability to the primary frame. The key structural challenges have been the buildability issues associated with the busy city centre site and the location of the four main buildings to maximise all available space, including the positioning of the ball court on the roof of the Lounge Building and the external play area on the roof of the South school building.

The requirement for flexible open spaces resulted in large structural spans over the ground floor library with 15.5m clear spans. The twin 2.1m diameter Victorian masonry sewers running beneath the Lounge building needed to be protected and the loads imposed onto them limited to below 60kPa. As a result it was essential for the superstructure above to be a lightweight construction.

Structurally the provision for services required careful co-ordination to position openings through the webs of the deep long span beams. Sustainability considerations included natural ventilation to the classrooms and offices and the integration of the bio mass boiler within the basement and duct routes for pellet deliveries.

The external cladding to the Lounge building comprises a twin layered system. The internal layer is a rendered external wall insulation system on blockwork with the external layer consisting of tensioned cables supporting perforated copper sheets. The perforated cladding system is a bespoke system designed to provide a striking appearance, whilst controlling light and shading. The degree of perforation varies across the facade to create interest in the aesthetics and to control the degree of light perforation for the classrooms, sustaining a high quality of natural light without the need for additional shading.

To the south facade the external perforated cladding system is offset from the primary steelwork frame by up to 2.5m. A series of secondary steelwork trusses span between compression struts which are braced back to the primary steel columns at the top and base of the cladding system.

There were a number of technical complexities in the structural design of the ball court which was designed to be structurally isolated from the adjacent offices. This was achieved through the use of double beams on the edges of the ball court, a structurally separated floor slab from the adjacent office spaces and high-load rotational pot bearings. A detailed analysis on the ball court floor structure was undertaken to ascertain the natural frequency and prevent excessive vibrations due to synchronised activity.

Careful consideration was made of the required one-hour fire protection (typical between floors). This was achieved primarily through the use of fire-boarding to the main frame. An intumescent coating was applied to exposed steelwork with a cosmetic top coat to fit in with aesthetic requirements.

Judges’ Comment

The requirement for 15m clear span at ground level against a fast programme and tight budget meant that steelwork was the material of choice.

Careful design and attention to detail, with acoustic and thermal isolations between many different space uses, have led to a genuinely flexible, vibrant and striking hub for Deptford.

Steelwork is key to this remarkably successful building.

 

Garsington Opera Pavilion, Wormsley

garsington_opera

Architect

Snell Associates

Structural Engineer

Momentum

Steelwork Contractor

Sheetfabs (NOTTM) Ltd

Main Contractor

Unusual Rigging Ltd

Client

Garsington Opera

 

The new auditorium, which provides 600 seats and six wheelchair positions, occupies a commanding yet intimate and sheltered position within the Park at Wormsley. It is conceived as an elegant lightweight pavilion set within its parkland setting, elevated above the ground giving the appearance of ‘floating’ above the landscape.

The auditorium design takes its cue from a traditional Japanese pavilion in its relationship to its landscape setting and its use of sliding screens and verandas to link it to the landscape, both visually and physically.

The site allows the division of areas between front of house gardens and back of house technical spaces, which remain screened from view. The ha-ha follows the contours of the land and naturally creates the orchestra pit and under-stage trap room.

The layout of the new structure is planned to allow the auditorium, verandas and terraces to face towards the landscape views. The stage, side stages and backstage store rooms are discretely located to the rear of the theatre next to the surrounding woodland, screening the areas from public view and allowing easy access for sets and performers.

The auditorium is made from timber, fabric and steel. Hardwood timber features for the decked areas of the verandas, terraces and stage walls. The enclosing walls of the auditorium use stressed fabric sails shaped to enhance the room acoustic and a double layer fabric roof absorbs rain noise like the flysheet of a tent. The sides of the auditorium are enclosed with transparent PVC fabric sails to minimise draughts within the auditorium whilst retaining views out over the adjacent gardens. The feeling of space has been retained and the auditorium ceiling and walls have been specially designed to improve the room acoustics.

The new opera pavilion was constructed using pre-fabricated techniques which minimised material waste, reduced the construction time spent on site and allow the building to be assembled/disassembled as quickly and economically as possible.

The requirement for the structure to be demountable led to an entirely bespoke structure being preferred to allow the roof and column trusses to be divisible into the minimum number of modular pre-fabricated elements that can be lifted by crane, minimising construction time and cost.

The whole steel structure was pre-fabricated in the factory and galvanized, providing a maintenance-free, durable and corrosion resistant protective finish.

As the building is modular and entirely demountable, it is an extremely flexible structure which can be adjusted as required to suit the changing opera performances. The sliding screens’ track allows the outer line of the building envelope to be adjusted

in a matter of minutes to reflect climatic conditions, and the design of the tracks allows for additional screens to be installed as required.

The integration of services requirements was carefully considered at the design stage to coordinate both the theatrical and house lighting positions and integrate them into the structure. Radiant heating panels are also used to heat the audience on cold evenings and these are suspended from purlins running between the roof trusses.

The whole structure is conceived as a ‘Rig for Opera’.

Judges’ Comment

The brief was for a theatre with full facilities, yet to be demountable annually. Techniques used in ‘instant’ open-air concert staging have been used and developed, with lightweight superstructure and heavier floor and terraces, all with ingenious membrane cladding.

The result is a delightful and cost-effective pavilion which sits lightly on the wooded hillside so successfully that it has now been agreed that it may remain in place.

 

Energy from Waste Facility, La Collette, Jersey

energy_from_waste

Concept Architect

Hopkins Architects

Executive Architect

EPR Architects

Structural Engineer

Campbell Reith Hill LLP

Steelwork Contractor

Bourne Steel Ltd

Main Contractor

CSBC

Client

States of Jersey Transport and Technical Services Department

 

The Jersey Government’s new Energy from Waste (EfW) facility at La Collette replaces the ageing Bellozanne incinerator on the island. Two new buildings were to be constructed:

 

  • EfW Building – containing waste bunker, incinerators, boiler hall, electricity turbines and gas treatment area.
  • Bulky Waste Facility (BWF) Building – a single storey portal frame structure adjacent to the main EfW building.

 

The site is located adjacent to the existing Jersey power station enabling the EfW plant to share the chimney, cooling water and other auxiliary services, minimising the environmental impact of the development.

To achieve a high architectural building, the structure was expressed externally beyond the building envelope and set to a 16m grid allowing the rhythm of the internal process to be reflected in the external structural arrangement, and also for the scale of the building in height and span to be represented in the column and truss engineering.

With regard to the geometry of the building, steel was the obvious solution due to the long span opportunities provided with steel. The exposed steel frame comprises six 36m long roof trusses together with four lines of 16m long secondary trusses, all supported on 37m high large diameter CHS columns at 16m intervals.

The roof steelwork supports a flat standing seam composite steel panel roof which in turn hangs from the external trusses. The end walls are glazed to reveal the structure’s bracing and the clarity of the single clear span over the process within. The profiled metal cladding to the long elevations is supported by seven lines of bespoke cladding/wind rails over the height of the building. These rails have feature openings and remain exposed beyond the line of the cladding to create patterns in light and shadow. Two vertical Macalloy bars restrain the rails at mid-span and connect back to the main roof structure.

To make the steelwork as light and efficient as possible adopting 864mm x 12mm CHS sections worked both structurally and aesthetically. The CHS tubes forming the trusses were varied in thickness to suit loadings, ensuring the structures are as light and efficient as possible.

A 3m deep, 40m long sunken plant roofwell containing M&E equipment was required. Suspending the plant area from the roof structure ensured the equipment did not foul the appearance of the feature roof trusses.

The 1,000 tonnes of fabricated trusses and columns were ferried to the island in two and three sections respectively, then welded together prior to erection in a site workshop allowing for rapid construction of the frame and cladding. The size and complexity of the process engineering equipment resulted in the majority of it being assembled in advance of the steel frame. This added challenges in erecting the envelope steel frame above and around the equipment already installed.

The steelwork was protected against the hostile marine environment by applying a C5 high build epoxy protective paint coating to all members providing a cost- effective method of minimising future maintenance expenditure. A sprinkler system within the building also removed the need for any additional fire protection to the steelwork or cladding.

Full operation commenced in May 2011, with the new facility providing up to 7% of the island’s electricity.

Judges’ Comment

Prominently sited on a coastal headland, this required a clever solution to assimilate the disparate shapes and volumes of an EfW plant into a large cubical pavilion. The columns and roof trusses boldly articulate the building, as part of a cost-effective steel structure.

Visually reducing the impact of this plant has been an important structural success.

 

Borough High Street Bridge, London

borough_high_street_bridge

Architect

Jestico + Whiles

Structural Engineer

Atkins

Steelwork Contractor

Watson Steel Structures Ltd (Severfield-Rowen Plc)

Main Contractor

Skanska Civil Engineering Ltd

Client

Network Rail

 

The bridge is located within a conservation area and the busy Borough Market. The steelwork contract consists of 128m of approach viaduct to the west, the main 70m span Borough High Street Bridge and a further 50m of viaduct to the east.

The approach viaducts are a standard through-deck plate girder design with deck beams spanning 7.6m between the 2.0m deep edge girders, which in turn are supported on concrete piers at approximately 25m centres. The permanent formwork soffit is formed with precast concrete panels incorporating white cement and a coffered profile.

The iconic feature bridge is 70m long, 9m high in the centre and incorporates 850 tonnes of steel with a further 400 tonnes of concrete in the deck.

The main span has a unique trapezoidal girder constructed from large diameter tubes with tapering ends. The north elevation of the bridge is close to an existing railway bridge and is not visible and therefore the girder along this elevation is a simple and economic plate girder.

The main tubes are up to 1200mm diameter with 50mm wall thick thickness and, due to the overall size and the design requirements, many of the major joints had to be butt welded on site. The bottom chords have significant torsional stiffness ensuring continuity between the cross girders and the internal tubular steel members of the truss. Fine grained steels Grade S355 NL were required to provide the required notch ductility.

The entire girder was first assembled in the fabrication workshop to ensure fit up before being dismantled and sent to site in large sections of up to 65 tonnes each.

The major challenge was how to construct the bridge within the extremely confined site. It was just possible to construct the approach viaducts conventionally using a crane operating within the footprint of the site to place the girders and deck beams.

The main span over Borough High Street however had to be installed during a weekend road closure which, because of the requirement to site weld the major tubular connections, meant that the bridge would need to be assembled off site and somehow moved into position.

An innovative installation solution was developed which was to first build the western approach viaduct, install the precast deck units and provide temporary bracing to the top flanges. Then using this deck as a working platform and the edge plate girders as supports, the main span was assembled at an elevated position on top. Extensive temporary supports were required to make this feasible because the main span was up to 3m wider than the viaduct on which it was assembled.

When the bridge steelwork was complete and the concrete deck units installed the bridge was prepared for installation. The rear end of the bridge was supported on a slide track with Teflon pads. The front end of the bridge was supported on hydraulic towers which in turn rested on multi-axle vehicles.

On the designated weekend, the bridge was rolled across Borough High Street at the rate of a few centimetres per minute and was then lowered down onto the bearings on the new concrete supports. Great care was required during this operation as the launch path of the bridge passed within a few centimetres of existing buildings.

This iconic structure, located in what must be one of the most congested locations in London, required the highest calibre of engineering and innovation in order to achieve the successful installation which was completed within the designated time period.

Judges’ Comment

Substantial additional rail capacity is threaded through the busy historic Borough Market area by means of this new viaduct and bridge. To achieve this on a key commuter route tested the ingenuity of the team.

The technique of launching the main span from the viaduct itself was inspired. The bridge is both attractive and practical – another railway success by steelwork.

 

Rise, Belfast

rise

Architect

Wolfgang Buttress

Structural Engineer

Price & Myers

Steelwork Contractor

M Hasson & Sons Ltd

Main Contractor

Wolfgang Buttress

Client

Belfast City Council

 

RISE is a large scale piece of public art, visible to thousands of pedestrians, motorists and air passengers travelling via George Best Belfast City Airport.

The structural design of RISE itself was carried out by structural engineers specialising in the design of geometrically challenging structures. RISE is a unique manifestation of the form, with its pair of concentric spheres supported on tangential and normal columns. However, through efficiency of design and selection of a favourable geodesic scheme, the structural fabric of the sculpture was optimised to consist of a relatively small number of fundamental components. Over 4,000 components, connected with c10,000 bolts, were distilled down to less than 60 individual types. This standardisation allowed the steelwork contractor to focus on delivering the level of accuracy required to ensure that every member would adopt its correct position on the surface of each ‘sphere’.

To ensure continuity from the sculptor’s design models right through to the finished structure, StruCad’s import features were used to take in centreline geometry from the structural engineer’s master model. This geometry formed the basis of numerous subsequent models used to fabricate the structural fabric of RISE itself, as well as a complex array of temporary works, lifting frames and installation aids deployed on site to enable safe and accurate erection of the work.

A number of prototype assemblies, up to and including one complete geodesic panel, were prepared which allowed the erection team to start planning for a most complex steelwork erection task. From an engineering standpoint, the trial assemblies provided invaluable insight into the actual, often non- linear, behaviour of the geodesic frameworks during lifting and up-ending operations.

As detailing of the structure progressed, 3D geometric modelling techniques were brought to bear on some particularly challenging aspects, such as the optimal degree of dishing to be applied to the circular node plates which hold the spheres together. The interaction of the two spheres, the supporting columns and surrounding bed of steel ‘reeds’, all coated in brilliant white, has created varied and dramatic views.

From the outset it was recognised that the erection of RISE would be extremely challenging due to the nature of the site centred on a major roundabout, which compounded the challenges associated with complex and sometimes prolonged lifting operations. Whilst the geodesic form of each sphere is highly stiff and stable once complete, great care was required to ensure stability during erection before final strength was achieved. A series of bespoke temporary works, lifting appliances and associated accessories to minimise erection risks were designed to ensure intermediate and final stability and accuracy of the sculpture.

Maximising the number of connections made at or near ground level, catering for the highly non-linear nature of the partly completed structure, and ensuring safety during removal of temporary steel were essential aspects of the design and execution of the temporary works. The final operation of transferring the weight of the inner sphere off the temporary stability mast through the 72 steel suspension cables and onto the outer sphere brought a welcome conclusion to a series of increasingly complex lifting operations.

The creation of RISE owes a great deal to the quality, versatility and efficiency of structural steel.

Judges’ Comment

Inspired by a summer sunrise seen through rushes, this large sculpture is impressive for its geometric form and precision. Intelligent analysis, precision fabrication and safe assembly on a road-locked site have produced steelwork of fine quality.

Linking two distinct Belfast communities, this is a stunning and popular landmark.

 

NEO Bankside, London

neo_bankside

Architect

Rogers Stirk Harbour + Partners

Structural Engineer

Waterman Structures Ltd

Steelwork Contractor

Watson Steel Structures Ltd (Severfield-Rowen Plc)

Main Contractor

Carillion

Client

GC Bankside LLP

 

Following NEO Bankside’s successful planning application, investigations began into the possibility of relocating the bracing outside of the cladding plane allowing it to be expressed as the distinct and legible system.

Although the primary structure of the four residential pavilions comprises traditional in-situ reinforced concrete frames, the perimeter bracing serves three key purposes: provides lateral stability under wind load contributing up to 75% of the overall stability; reduces the requirement for shear walls allowing greater flexibility of internal planning and servicing arrangements; and provides support for the winter-garden elements at the prows of the building.

Building stability forces are transferred into the external perimeter bracing system via nodes arranged on a six-storey interval vertically and three-storey interval horizontally, and connected back to the primary concrete columns and slabs by steel ‘spindles’ that project through the cladding. The nodes transfer the lateral stability forces that act on the structural frame into the bracing system, and allow for the transfer of bracing forces between OHS members in the plane of the framework. Lateral loads from the intermediate floors are transferred to the nodal floors by reinforced concrete walls arranged around the core which act as vertical beams.

The spindles and node fin-plate assemblies were delivered to site prefabricated onto 4.5m long steel stanchions that were embedded within the primary concrete columns and locked into the floor-plates by high-strength large-diameter anchor bars. This meant that both fabrication and site erection tolerances had to be very tightly controlled to ensure that the bracings would fit between the node fin-plates. The bracings taper at their ends and attach to the node fin-plates via cast fork-ends, with close-tolerance pins of up to 100mm in diameter. This pin tolerance is an essential factor in controlling overall building sway by limiting the free movement within the pin-holes under load-reversal conditions.

The colour of the external perimeter bracing was an important factor affecting the structural design, with implications to the range of thermal stresses and movements to which the system would be subjected.

The external diagrid bracing system provides gravity load support to the promontory winter-gardens at each end of the pavilions by utilising a system of external hangers or struts at their apexes.

The offset of the bracing from the facade means that a fire inside the apartment never reaches sufficient temperatures at the bracing members to require intumescent treatment; also the system has been designed to remain stable even if, due to a catastrophic fire in one apartment, up to three nodes failed. At ground level the OHS elements are concrete filled to protect against impact.

Glazed lift towers are expressed separately to the pavilions on each of their east elevations. The lift enclosures are supported by elegant gallows frames arranged on a three-storey interval to bring all of the gravity loads back to just four columns that sit in pairs to either side of each of the lift doors. Lateral stability is provided by cantilevering the lobby slabs and steel-edge beams horizontally from the primary concrete frames.

The exposed tubular braces and exposed stair and lift structures required a highly architectural finish.

Site installation of the nodes was particularly challenging because of the extremely tight tolerances that were required. The accurate positioning was achieved by adapting a two-stage concrete pour strategy which allowed the nodes to be fixed and held back securely to the partially complete concrete structure with temporary supports while the second pour was carried out which then locked them finally in position.

The dramatic appearance of the nodes has become a selling point, with buyers requesting nodal apartments.

Judges’ Comment

This project is outstanding in its rigour and attention to detail.

Intelligently conceived, designed and beautifully built, it is clear that the whole team was immersed in every aspect. The prominent elliptical external structural bracing has a refined architectural quality. The elegant stair/lift cores are a delight.

Impressive quality achieved on a design- and-build project.

 

West Burton Power Station

west_burton_power_station

Architect

EDF Energy

Structural Engineer

EDF Energy

Steelwork Contractor

Fisher Engineering Ltd (Severfield-Rowen Plc)

Main Contractor

Kier Construction Ltd

Client

EDF Energy

 

The new EDF Energy Power Station is a 1300 MW Combined Cycle Gas Turbine (CCGT) unit which supplies enough energy for 1.5 million homes. The three turbine halls dominate the new CCGT facility. They are identical steel portal frames with 32m eaves height and an 82m x 35m footprint and are founded on CFA piles.

Typically the steel portal frames are at 12.5m centres and consist of 35m span roof trusses supported off stepped plate girder columns to the elevations. The turbine halls also contain a number of access platform levels, together with a 100 tonne overhead travelling crane located at 23.5m above finished floor level.

The columns are substantial fabricated plate girder sections with fully fixed moment bases. At their base, the fabricated I sections are 1800mm deep by 600mm wide with 60mm flanges and a 15mm web. At a height of 15.75m the flange width of the 1800 deep section is reduced to 450mm to save on column weight and there is also a step in the column at the crane beam level (23.5m). The top 8m of the column shaft is formed from a 900mm deep by 450mm wide plate girder section fabricated from 30mm flanges and a 12mm web. The changes in column section required fully welded splices which were formed using full penetration butt welds and tapered flange sections to reduce local stresses.

To limit the overall section weights for transport a bolted splice was also provided within the lower shaft.

The roof trusses have a maximum depth of 4.5m with 280mm deep top and bottom booms. The internal truss members vary in section type with a combination of I sections, channels and angles adopted according to load requirements.

The crane beams are also fabricated plate girder sections with a maximum span of 15m and an overall depth of 1500mm. They are designed as single spanning off rocker bearings and are formed from 40mm flanges and a 15mm web.

Full moment connections are provided for the main portal columns. These are substantial fabrications requiring 1.5m long M64 holding down bolts, together with 50mm thick base plates with stiffeners and heavy washer plates to locate the bolts.

As the columns were too large to transport they were delivered to site as 24 tonne and 9 tonne pieces. The full column was then assembled on the ground before being erected as a single piece. Similarly, the roof trusses were delivered as three equal sections, with two parts bolted together on site before being joined with the third section in the air as part of a tandem lift involving two mobile cranes.

The three turbine halls were erected sequentially from one end of the site. Initially, three mobile cranes were required to allow the erection of two portal frames and associated bracing to ensure a stable core for subsequent erection.

Careful sequencing of the various site activities was required. Each turbine hall has two internal floors which could only be installed following installation of the concrete slabs, plinths and pedestals required for the generating equipment. These internal floors in turn contribute to the overall frame stability and, as a consequence, the 40,000m2 of external cladding to the buildings could not be fitted until these floors were erected.

Judges’ Comment

Three large identical portal frames provide the turbine halls for this new 1300 MW facility. Designed, fabricated and erected very fast, this is one of the first major projects to conform to the Eurocodes.

A good example of practical and economical use of heavy steelwork.

 

Jarrold Bridge, Norwich

jarrold_bridge

Architect

Ramboll

Structural Engineer

Ramboll

Steelwork Contractor

S H Structures Ltd

Main Contractor

R G Carter Ltd

Client

Jarrold (St. James) Ltd

 

Jarrold Bridge, at just over 80m in length, is a dynamic and unique bridge form that appears to float over the site with little visible means of support.

The two landing points – the boulevard to the north and a raised platform protected by the river wall to the south – were determined at an early stage. The curvilinear 3D geometry follows the most efficient path between these two points that simultaneously accommodates clearances for both river traffic and the riverside’s cycleway without ever being steeper than 1 in 20, thus allowing access for all over the bridge.

Fixed by concrete abutments at each end and propped by two slender pin-jointed stainless steel columns, the bridge acts as two mutually stabilising propped cantilevers.

The main structure is fabricated from weathering steel chosen for its aesthetic and long term maintenance benefits. It also develops a deep-brown oxidized coating over time, sealing the structure and protecting it against further corrosion.

The deck surface is untreated renewable hardwood selected for its density, strength and durability. A unique hidden clamp system fixes the strips to bearers which are then bolted invisibly to the steel structure. Inset fibreglass strips ensure slip-resistance in all weathers. Stainless steel top rails accentuate the curved form and a lightweight stainless steel mesh encloses the deck, allowing full visibility along the river. There are no applied finishes anywhere on the bridge reducing maintenance requirements, and lifetime costs, to a minimum.

At each abutment there are two bearings: one fixed uplift bearing below the box girder and one sliding guided bearing under the balustrade end of each bearing beam which provide a vertical, lateral and torsional restraint at the abutments.

A closed steel box beam represents the optimum form to resist the bending and torsion experienced by the deck, and allows manipulation of the cross-sectional shape to achieve the optimum aesthetic and structural form.

This trapezoidal beam is the spine of the bridge; all load from the deck and balustrade is transferred to the cross-beams which cantilever from the box girder. This applies torsion and bending to the girders, the torsion in one arm of the bridge being resisted by the bending capacity of the other.

Thermal expansion is realised as bending in the corresponding perpendicular ‘arm’. Thermal stresses are thereby locked-in and the structure is designed to accommodate this. The pin-jointed columns provide vertical support but allow rotation and lateral movement as the beam flexes.

The bridge resists horizontal loading by acting as an arch supported by the bracing which ties the box girder, the edge beam and the cross beams together.

A tuned mass damper located inside the spine box girder at mid-span dampens vertical accelerations induced by resonant pedestrian loading.

The primary beam incorporates a detail where adjacent weathering steel plates oversail each other. Off-site manufacture delivered significant benefits such as:

 

  • Site welds were minimised to control welding and dimensional requirements in workshop conditions
  • Bridge component size and weight were controlled to minimise transport and lifting operations
  • A bolted splice connection was developed at mid-span to remove any need for temporary works within the river during installation
  • Perfect fit of complex interface details was ensured by matching elements in the Works

 

Successful installation of the whole bridge was completed in a matter of hours over two days in November 2011.

Judges’ Comment

An elegant architectural solution, the bridge is sensitive to its setting and the topography.

Curving vertically and on plan, the simple palette of self-finished materials, particularly the weathering steel and hardwood, enables the bridge to integrate with its mature surroundings and should minimise maintenance.

This beautifully crafted structure gives an impression of already being well established in its setting.

 

McLaren Production Centre, Woking

mclaren

Architect

Foster + Partners

Structural Engineer

Buro Happold

Steelwork Contractor

Atlas Ward Structures Ltd (Severfield-Rowen Plc)

Main Contractor

Sir Robert McAlpine

Client

McLaren

 

McLaren’s new Production Centre in Woking is the manufacturing facility for the McLaren MP4-12C super sports car, providing 34,500m2 of internal area.

As the site was located in greenbelt, the design had to comply with very tight planning restrictions on building height that was set by the small grassy knoll located in the centre of the site. This necessitated sinking the building within the landscape that involved the excavation of 180,000m3 of soil that was retained and used to re-landscape the site.

The resulting building is two-storey, with the buried portion being concrete and the above ground elements being steel. Steelwork was the obvious choice for the Production Centre as:

 

  • Steelwork was a cost-effective solution
  • Pre-fabrication and rapid site erection worked within the compressed programme
  • Steelwork allowed for the large spans the brief demanded
  • The majority of steelwork required no fire protection and the steel was left exposed
  • The high level of finish obtainable with steel eliminated the need for architectural cladding

 

The super-structure is designed using double primary beams and columns such that all the servicing is concealed within the structural steel frame. The air is supplied at low level within the double columns to provide ventilation via displacement providing improved environmental conditions for less energy. Beneath the air supply is a slot for panels installed during the fit-out to provide data, single and three phase power and compressed air required for the assembly process.

Key aspects to the design are its simplicity and the high level of repetition. A cross grid 18m, 21m, 21m, 21m and 18m was selected to optimise the working aisle widths beneath. These were then repeated on an 18m grid for 12 bays along the length of the building. Primary, secondary and tertiary beams were then optimised for these spans and repeated throughout the building. The detailing of the key interfaces was carefully considered and a prototype of a typical bay was fabricated and installed. On approval of the prototype, fabrication commenced and the steel was erected on site as the concrete box progressed.

Although the bulk of the internal steel elements are standardised, the perimeter of the building and the entrance drums are expressed to match the visual appearance of the Technology Centre. Elegantly detailed spiral stairs and viewing galleries were added to enhance the visitor’s experience when entering from the Technology Centre.

In the majority of locations the steelwork is left exposed. These areas received a high quality painted finish that matched the paint quality of any architectural finishes to give a very clean and consistent aesthetic to the space. Ceilings are used to conceal the services along the main distribution spines that run the length of the building that incorporated acoustic absorbency to control the reverberation of the space. Detailing avoids ledges and recesses to help maintain a pristine environment.

The building was designed in parallel with the development of the process equipment and recesses and voids were left for these items, including double height paint booths, testing and washing booths. The inherent flexibility of steel allowed for minor modifications to be made on site to account for the final detailed interface, which gave confidence to proceed with the production of the steel frame before the detailed fit-out requirements were known.

Judges’ Comment

An automotive production building which is almost surreal in its clinical precision. Following the ethos of previous development on the site, the steel framed structure is closely coordinated with the integrated building services within double beams and columns. The clarity of purpose, careful repetition and tight tolerances are exceptional.

This shows what can be achieved if sufficient care is taken over all aspects of a project.

 

The Walbrook Building, London

walbrook_building

Architect

Foster + Partners

Structural Engineer

ARUP

Steelwork Contractor

William Hare Ltd

Main Contractor

Skanska UK Plc

Client

Minerva Ltd

 

The Walbrook Building, developed on the previous Walbrook House, St Swithin’s House and Granite House site, directly opposite Cannon Street Station, is a 10- storey steel-framed structure comprising 6,313 tonnes of structural steelwork.

The building falls within the height limitation band imposed by St Paul’s Cathedral, close to the remains of where the Roman Temple of Mithras was discovered in the 1950s. Its L-shaped floor plate is based on a 9m grid with only 10 internal columns on a typical floor plate, providing around 3,693 sq m of retail space, plus 35,283 sq m of high quality office space, as well as two basement areas.

The superstructure generally consists of structural steel columns and beams with composite floor slabs cast in-situ on metal decking with cellular beams used extensively to facilitate services distribution. Two atria from third to ninth floor allow increased daylight penetration into the office space.

The frame is designed for a target maximum vibration Response Factor of six, while still maximising the areas of column free space and minimising construction depth.

The extensive use of Fibre-Reinforced Polymer (FRP) solar shading is the first time that FRP has been used so extensively for a building, and will keep the building cool in summer.

The floor plate design and long open spans create space suitable for the broadest possible range of occupiers and were designed to suit a financial sector tenant with provision for trading floors made on both the first and second floors.

The most complex aspect of the job was the raking columns, which rake in mansard style up the height of the building. The columns change in inclination resulted in high axial forces in the beams which had to be considered as part of the connection design.

Below the sixth floor the frame is based on a relatively simple beam and column layout, above floor six the members crank in multiple locations resulting in some complex nodes with members clustered at awkward angles. Where floor beams intersect the underside of the mansard cranks, the ends of the beams had to be double cut so as to match the different skews of the columns. Therefore, fabrication accuracy was key to ensuring a good fit up on site.

The unconventional framing pattern meant that careful consideration was required to temporary stability above the sixth floor.

The roof level design was further complicated by the provision of a Building Maintenance Unit track (BMU), which had to cantilever over the curved face of the building resulting in large uplift forces and complex connections.

The environmental impact of the building was a key consideration from initial design stage, with many features that allowed it to achieve a BREEAM ‘Excellent’ rating, with 38% less CO2 emissions than Building Regulations and a 4% improvement over the GLA target on CO2 reductions from renewable energy.

This impressive building is a first-class example of steel providing the creation of a dramatic, yet functional, commercial building.

Judges’ Comment

With large open trading floors and clear spans of 21m, this marks the latest in the design development of office buildings for the City of London. Progress has been evolutionary rather than revolutionary, but with ingenious construction methodology and refinements in fire engineering, this structure is impressively light, economical and efficient for the users.

Further developing steelwork’s capabilities for offices.