Design Awards: 2017: Merit

A400M MRO Facility, RAF Brize Norton

© Balfour Beatty

Architect
AWW Architects

Structural Engineer
Arup

Steelwork Contractor
Billington Structures Ltd

Main Contractor
Balfour Beatty

Client
Defence Infrastructure Organisation

The 22,000m2 three-bay maintenance hangar based at RAF Brize Norton in Oxfordshire was built to service A400M and C17 military transport aircraft. In addition to housing three aircraft in bays equipped with overhead cranes, the building contains specialist workshops together with parts stores, offices, welfare and mission planning functions. The design and build was heavily constrained by the demands of the airbase, in particular the need to avoid interference with radar and aircraft guidance systems.

A metallic blue colour was chosen for the building to reflect the colour of the sky and complement the natural surroundings. A large rounded cladding profile was chosen to soften the building’s form to help break down the hard edges of the building. The building has an A rated EPC, BREEAM ‘Excellent’ rating, and achieved an air pressure test rating on first pass of 1.98m3/h/m2, which is all the more remarkable bearing in mind the size of the hangar doors which are up to 64m wide and 20m high.

The impact of the building on the operational environment of the airbase was carefully considered. A radar impact assessment indicated the need for radar diffusing cladding at high level on the sides of the building facing the runway. Modelling was necessary to prove that PV panels on the roof would not cause glare to pilots from reflected sunlight.

The main building’s structure is a steel-framed construction with the roof consisting of primary girders spanning up to 67m supporting secondary trusses. This allows the hangars, stores and workshops to remain column-free spaces. The roof supports the rails of a number of travelling cranes. Supporting the cranes directly from the roof structure avoided the need to provide additional steel columns for crane runway beam support, thus increasing the usable ground floor area. The design of the roof was carefully developed to ensure that the deflection of the primary roof structure would be compatible with the deflection limitations of the cranes.

The use of a 3D BIM model was especially beneficial in the complex 3,000 tonne frame as it allowed the structural engineering team to rapidly assess coordination areas, such as secondary cladding support and crane runway beam setting out. The 3D structural model was issued to the steelwork contractor, where it was invaluable in early tonnage take-offs and construction programming and phasing.

This functional building at RAF Brize Norton is also aesthetically pleasing and sympathetic to its surroundings.

Judges’ Comment

This 22,000m2 three-bay maintenance hangar was built to service specific military transport aircraft, with the roof having main girders spanning 67m. The design and construction were heavily constrained by the operational demands of the airbase, particularly avoiding interference to radar and aircraft guidance systems.

Satisfying the constraints and the client was a noteworthy success for large steelwork.

Wellcome Collection Dynamic Stair, London

© Wellcome Trust

Architect
WilkinsonEyre

Structural Engineer
AKT II

Architectural Metalworker
Clifford Chapman Staircases Ltd

Main Contractor
Overbury

Client
Wellcome Trust

The Dynamic Stair is a key feature of the Wellcome Collection’s development project and the concept was to create a free- flowing form, travelling from floor to floor without any visually intrusive supports.

Building the stair within the confines of an existing building presented a series of constraints in terms of capacity and accessibility.

To install the stair the team was required to make significant alterations to the first and second floors, firstly introducing an opening to facilitate the stair’s insertion and then to provide the supporting steelwork to carry the stair loading back to the historic primary structure. Access below ground floor was not possible and so the strengthening of this floor, or the vertical structure, would be impossible. Hence, it became clear that steel was the only realistic option for the stair, exploiting the strength and stiffness of this material and its readiness to be worked into complex forms.

For the stair itself, the chosen solution uses the inner balustrade and floor components as a structural monocoque that exploits every part of the stair as part of the structural system. This provides the vertical and torsional stiffness necessary to deliver the desired vibrational characteristics and architectural aesthetic in an efficient and lightweight manner.

Each of the 18 sections was made up of 8mm thick steel plates which were formed by a mixture of pressing or cold rolling and then welded together. The heaviest of the sections weighed 3.5 tonnes and was lifted in to position via a bespoke temporary structure and lifting strategy.

The aspiration for the finish of the stair was to exploit the natural steelwork as much as possible. The final solution was for the outside face to be shot blasted and sealed with clear lacquer. The inside faces were sprayed with a cold zinc and hot stainless steel solution. The inside surfaces were then hand polished.

The Dynamic Stair now provides the renovated Wellcome Collection with a strong central visual statement. The simplicity and tactile nature of the polished whirling form allows the crafted steel of the stair to be displayed and celebrated. The outer balustrade glass accentuates the movement of visitors around the staircase and up through the building, allowing visibility throughout the floors. Generous breakout spaces surrounding the stair give it room to breathe as a sculptural object in its own right.

Judges’ Comment

This finely crafted staircase winds its way through two floors, with a changing geometry to fit the tight constraints of the existing floor structures. The combination of galvanizing and hot-applied stainless steel spray, which was hand-buffed, creates a most attractive finish.

The merits of this finely crafted project have helped to enable visitor numbers to double.

Market Place Shopping Centre Redevelopment, Bolton


Architect
Wren Architecture and Design

Structural Engineer
Ramboll

Steelwork Contractor
Shipley Structures Ltd

Main Contractor
McLaren Construction Ltd

Client
Moorgarth Properties Ltd

The historic ‘Market Place Shopping Centre’ was originally constructed in 1851, utilising a cast iron framework with feature fretwork panels and dowel pinned lattice roof trusses. The redevelopment adds a nine-screen cinema complex extension on the roof of the existing building, and restructures the central feature atrium to provide further restaurants, bars and cafés in the underground ‘Victorian’ arched vaults.

A steel-framed solution was selected to maintain the slimline effect of the existing structure and minimise the weight of the cinema extension. Steel also suited the restrictive nature of the site, where the shopping centre had to remain fully operational throughout, in terms of the speed of erection and omission of temporary works.

The 250 tonne 30,000ft2 steel-framed cinema extension adopted a beam and column arrangement with long-span rafters, internal clear heights of 10m and structurally independent internal seating support frames and maintenance walkways. S355 grade steel sections were used throughout and the new frame was spliced onto the existing building columns and floor structures.

Internal strengthening and remodelling of the existing four-storey steel framework was needed to carry the additional loading from the cinema extension and amended escalator runs. This included the installation of underslung stiffening beams to the existing floor members, and the incorporation of two new 16m long 762 x 267 UB battening beams to the underside of the existing floor at level 2, to facilitate the removal of the central section of a primary existing steel column in order to provide clear unrestricted access to Cinema Screens 1 to 4.

The restructuring of the central Atrium area included the provision of a fully welded 21m high exposed ‘feature’ steel lift shaft, infill link bridges and the creation of a new 14m x 10m opening in the ground floor slab.

A feature ‘space-frame’ roof structure at the head of the remodelled central Atrium, incorporating ‘T’ section top chords and a suspended circular tie rod bracing system, replicates the original roof detail on the adjacent cast iron framework.

Whilst a tower crane was available for approximately 60% of the upper roof extension with a working radius of 78m, the balance of the cinema above level 2 had to be installed using a series of spider cranes and Roust-A-Bout lifting frames.

All of the internal steel members for the strengthening and remodelling works between basement and second floor level had to be hoisted through service holes in the existing concrete slabs and ‘hand- balled’ into position.

Judges’ Comment

The new steelwork provides for the addition of a nine-screen cinema over a Grade II listed shopping centre. Construction was particularly demanding because the Centre was required to function throughout the contract period. The tower crane reached only 60% of the works, so many components had to be manhandled into position.

The tough logistical challenge was met in a meritorious way.

Waterford Fire Station


Architect
McCullough Mulvin Architects

Structural Engineer
O’Connor Sutton Cronin

Steelwork Contractor
Steel & Roofing Systems

Main Contractor
Duggan Brothers Contractors Ltd

Client
Waterford City & County Council

Shaped around active service where function is paramount, the building form derives from tracking the movements of fire tenders leaving the appliance bays at speed and returning after firefighting. A strong form wrapped in zinc is folded – origami- like – to enclose a drill yard with different training zones.

Organised in a spiral, rising from single storey vehicle parking, workshops and dormitories to first floor offices, canteen, leisure and study facilities and terminating at a second floor lecture theatre, the zinc roof is angled and cut away to provide sheltered inside-outside spaces overlooking the yard, where the drill tower acts as urban beacon in a new public space.

The steel structure is supported on strip foundations and supports precast concrete planks which form the floor slab. The building is formed from inclined planes and folded volumes and the flexibility in design of the steelwork facilitated the complex geometries of the structure, while expediting following trades such as zinc, drywall, blockwork, mechanical and electrical services. This allowed a shorter and simpler build programme. Steel trusses are utilised to give long spans in the appliance bay to facilitate the appliances driving to and from the drill yard to outside active duty.

The building brings together many differing uses, requiring a variety of structural solutions to achieve the desired functionality for the client.

The large open-plan appliance bay, with sufficient space for 10 appliances, is achieved using long span steel trusses. Above this open space, a mixture of blockwork and steel provides the structure to the office area. A second wing, consisting of load bearing blockwork and precast hollowcore slabs, provides training facilities and living quarters over two storeys.

Both wings of the building, together with a covered car parking area to the rear, serve to enclose the large central training yard. The roof to all covered areas consists of a steel frame sloped to suit the profile of the roof. This steel frame supports a timber build-up underlying the finished sheeting.

Judges’ Comment

The scheme is characterised by the architectural concept of a ribbon of accommodation wrapping around a courtyard in which emergency vehicles circulate and drills are carried out. The distinctive ‘origami-folded’ roof, formed from cranked steel beams, twists and rises over the different levels of accommodation.

A most interesting addition to the town.

Layered Gallery, London

© Gianni Botsford Architects

Architect
Gianni Botsford Architects

Structural Engineer
Entuitive

Steelwork Contractor
Trescher Fabrications Ltd

Main Contractor
Verona Construction

The Layered Gallery is an extension to a private residence, housing the owner’s collection of photographs, prints, pastels and lithographs.

The design concept was based on a series of superimposed screens, creating a layered effect against a blank brick wall. The outermost ‘layer’ is a structural gridded screen made of weathering steel. The second is a weathering steel-framed glazed façade of museum quality UV-treated glass, which opens to allow natural ventilation. Inside the extension, two additional layers hang from each storey’s ceiling: red blinds, which protect the collection of artworks, and the weathering steel display screens that showcase the collection.

The dendritic façade of the gallery is supported by the visible structural weathering steel frame on the building’s exterior. Made from flat stiffened plates branching out over the three-storey structure, the entire frame is supported off just two 120mm x 12mm steel posts with a stiffening rib on the rear face, creating a T-shaped section. In a reversal of the usual structural hierarchy, this façade is also the main structural frame of the gallery, supporting all the floors and roof as well as providing lateral stability. Around 25 steel members make up the façade, each falling into a family of just three sizes: 120mm, 100mm and 70mm wide T-sections – all fabricated from flat weathering steel plate. At the upper storey, the steel members also wrap over the top of the extension and support the glazed ceiling, ensuring a coherent structural system and aesthetic for the entire extension.

Cranage at the site was impossible due to the constricted space and protected surroundings, so all structural components were sized to be carried into the courtyard through the house. The components that comprise the structural frame were precision fabricated offsite and erected within the courtyard as a kit-of-parts using only scaffolding.

Thoughtful connection design and careful detailing were key to the building’s success. As the façade is the structural frame and, therefore, outside the building envelope, the floor beams, which connect to the façade, are detailed with a thermal break at the glazing line. Further, the numerous connections (45+) were each carefully coordinated to ensure ease of assembly between the members, and were detailed to conceal many of the bolts which are countersunk into the plate.

The Layered Gallery exploits the aesthetic and structural possibilities of weathering steel in nearly every detail, providing a space that blends the interior and exterior through its lightness of construction and its innovative structural solution.

Judges’ Comment

This delightful filigree extension has completely transformed this historic house for its art-collector owner. Forming the backdrop to a new oasis of calm in a frenetic area of London, the building draws inspiration from organic forms of courtyard planting. Exposed weathering steel and external glazing systems are cleverly integrated.

This is a thoroughly contemporary take on a historic gallery and courtyard.

Maxwell Centre, Cambridge


Architect
BDP

Structural Engineer
Ramboll

Steelwork Contractor
The Wall Engineering Co Ltd

Main Contractor
SDC

Client
University of Cambridge Estate Management

The BREEAM ‘Excellent’ rated Maxwell Centre forms the latest development for The University of Cambridge. The new four-storey building contains research laboratories and offices complemented by seminar rooms, interactive spaces and dedicated hubs.

During the early stages of the project the design team investigated a number of different structural schemes. However, as the design developed, it became clear that a steel frame with precast planks was the only solution that could deliver the architectural aspirations within typical structural zones of just 350mm on 13m spans.

Steelwork was also the obvious choice to realise the architectural intent which features a doubly curved roof.

The 1200m2 laboratories’ area at lower ground level has no movement joints in the floor slab and just seven internal columns, allowing the laboratories to be easily changed in the future to cater for different configurations. The heavily serviced laboratory area benefits from a large bulkhead at the external perimeter allowing future flexibility for service installations. In addition, a generous allowance was included to suspend services from the precast plank soffit above.

The complex and challenging doubly curved roof was designed to reflect the curved roof of the adjacent Physics of Medicine Building. The roof was created using a series of curved steel beams, each with a slightly different radius.

The different uses of space between lower ground and the upper floors meant that there were many constraints on the structural layout. For example, to avoid columns disrupting the seminar room, the business lounge above is partly hung from the main roof beams. An 18m truss made up of open sections was used, suspended from three points in the roof. A truss concealed in a wall was utilised as the increased stiffness mobilised more mass and improved the vibration performance within the business lounge.

The centre of the building also boasts a three-storey central courtyard covered with an ETFE roof. Within this courtyard two meeting pods cantilever out within the space, as well as an open balcony suspended from the frame.

The exposed precast plank soffits are an important visual element and are also utilised for thermal mass in the naturally ventilated upper levels. The coordination of the steelwork support details was therefore of great importance, particularly at the column to soffit junction which included support plates for the planks, substantial torsional connections for the beams, and a connection for an inverted tee beam which acts as a frame tie.

Judges’ Comment

Flexibility and efficient distribution of services were critical to this project. The solution was to use long-span floors supported on steel slimfloor beams, which also enabled natural ventilation. Four storeys are arranged under a doubly curved roof, reflecting the adjacent building to which it neatly links.

The result is an efficient and elegant building.