Design Awards: 2015

Retail Development Plateau, Bargoed

Retail Development Pleateau 1

Architect
Holder Mathias Architects

Structural Engineer
Capita Symonds Ltd

Steelwork Contractor
Caunton Engineering Ltd

Main Contractor
Simons Construction

Client
Caerphilly Borough Council

The former South Wales mining town of Bargoed is in the midst of a £30m regeneration scheme, a programme that aims to revitalise the community.

Central to the overall plan is the rejuvenation of commerce and this will be achieved with a large scale retail development, based around a 5,200m2 Morrisons supermarket constructed in the town centre. Known as the Retail Development Plateau, the 2.2 hectare site is situated on a 300m long by 20m high reinforced embankment.

Sitting on top of the plateau and abutting the retaining wall, the steel-framed retail development consists of a lower level undercroft car park for 400 vehicles, with the main Morrisons retail floor positioned above, along with second car park level. Above the main supermarket floor is a series of further decks, set back from the valley elevation, accommodating independent retail outlets and rooftop plant areas.

Judges’ comment

This development successfully regenerates a site created by the use of old mining spoil, and links the town and the valley.

The steelwork is a conventional frame on a rectangular grid, including a horizontal truss spanning 80m to restrain a high retaining wall. The integration of geometrically complex heavily- loaded nodes into the other elements involved the whole team comprehensively adopting a Building Information Model approach.

A successful use of BIM in a steel project.

St James’s Gateway, London

St Jamess Gateway 1

Architect
Eric Parry Architects

Structural Engineer
Waterman Group

Steelwork Contractor
William Hare Ltd

Main Contractor
Lend Lease

Client
The Crown Estate

The St James’s Gateway redevelopment includes 57,000ft2 office space, 28,000ft2 retail space and 18,000ft2 residential space.

The existing structure was replaced generally with a composite steel frame with normal weight concrete floor construction utilising composite metal decking. The grid varies with a maximum of 15m spans. This challenging, bespoke and innovative scheme involved digging out a two storey basement, installing 2,500m of closed-loop geothermal pipework, constructing a 1.2m-thick waterproof concrete raft foundation and erecting a braced steel core at the heart of the steel frame.

The Piccadilly façade embraced a steel Vierendeel frame construction to accommodate the large window frontage. As part of the development, the existing building at 27 Regent Street was refurbished; this included an architectural steelwork stair that was installed within the existing fire escape.

Judges’ comment

Several diverse properties owned by the Crown Estate on a prominent site in Piccadilly, central London, have been given a new life as upmarket retail, office and residential accommodation. A pragmatic steel structure throughout has effectively enabled a sensitive restructuring, and combination of façade retention and invention.

The steelwork was key to meeting the complex programme.

Tottenham Hale Bus Station Canopies

Tottenham Hale Bus Station 1

Architect
Landolt + Brown Architects

Structural Engineer
Mott MacDonald

Steelwork Contractor
S H Structures Ltd

Main Contractor
Balfour Beatty

Client
Transport for London

The canopy design is based on a series of six steel ‘trees’, each comprising a central tapering trunk supporting six cantilevered branches. At canopy level, a triangulated perimeter beam runs between the tips of each branch to form the outer connection point for a series of tensile cables which radiate from the centre of each canopy to support a single foil ETFE roof. The use of these central columns and cantilevered beams minimises the number of ground level supports, freeing-up the ground plane beneath for the most efficient movement of pedestrians and buses.

The creative collaboration between the design team was key to the successful resolution of every detail, resulting in a design which is easy and inexpensive to maintain, is suitably robust with a steelwork design life of 60+ years, as well as being aesthetically sophisticated.

Judges’ comment

Emerging from Tottenham Hale tube station, there is little doubt where the bus station is located as this imposing steel structure provides a beacon, as well as shelter for bus travellers. The structure is superbly fabricated and finished.

This steelwork is almost crafted to be a sculpture.

Weathering Steel House, Putney

Weathering Steel House Putney 1

Architect
Eldridge London

Structural Engineer
Elliott Wood

Steelwork Contractor
Suffolk Welding

Main Contractor
Famella

This project involved redevelopment of a garage building in south west London into a high-spec private house set out over four floors including a single basement. The rust- like appearance of the weathering steel cladding is a striking feature of the cutting- edge design of this private dwelling.

The house is in two distinct parts. At the front is the main four storey building, clad in weathering steel sheets interspersed with large glazed areas. At the rear is a separate single storey living space complete with glazed elevations and a green roof. The two areas are joined at ground floor level by a transparent corridor complete with a glazed roof, walls and floor sections; below ground the areas are also linked by a concrete basement which runs to the edge of the single storey living space.

The concept for the superstructure of the house was for it to be a monocoque, whereby the façade system also acted as the primary structure to the building. The finished material therefore needed to be sufficiently stiff to act structurally, as well as provide a weathertight enclosure and architectural interest. In addition to the architectural requirements, the constructional issues were significant. The footprint of the proposed house stretches between the boundary lines, leaving little working space for the contractor when onsite and required careful planning to construct a significantly challenging structure.

Steelwork was adopted as the primary structural material, with weathering steel as the external finish. This met the architectural requirements set out, as well as allowing the use of cladding as a stressed skin in combination with ribs, minimising requirements for additional primary structure to the perimeter. The use of a monocoque type structure was developed towards a series of prefabricated pods that could be erected onsite quickly and accurately. Connections were achieved by simply bolting the pods together onsite and then welding the weathering steel at its ‘seams’ to form a weatherproof envelope. To minimise heat loss, the connections between the panel and the internal floor structures were carefully detailed to prevent the junction creating a thermal bridge.

The prefabricated boxes were initially trial erected in the steelwork contractor’s workshop, which gave the opportunity to begin structural glass procurement far earlier in the programme than would usually be possible. This greatly improved speed of construction of the structural elements.

Judges’ comment

A house for a private client with individual demands, this elevates the use of structural weathering steel in domestic architecture to the level of bespoke tailoring. It illustrates what can be achieved by the closest attention to detail, and unified teamwork by architect, engineer and steelwork contractor/erector, as all details have been considered, coordinated and beautifully made.

Congratulations to the team for a meritorious labour of love.