SSDA 2026: Merit projects and finalists

With limited visibility beneath the surface, construction required carefully coordinated marine operations and a detailed sequence for divers, lifting equipment and the installation team.

The underwater foundations were formed using precast manhole rings as cofferdams. Steel plunge columns had to be positioned accurately within them before concrete was
poured underwater. 

The 4t supporting frame was fabricated almost entirely from reclaimed steel sections, recovered from decommissioned pipelines, cancelled projects, surplus stock and demolished buildings. 

The PUMA Flagship Store is the company’s largest-ever European shop and demonstrates how careful analysis and onsite steelwork alterations can transform an existing building.

Occupying the basement, ground and first floors of a commercial building, the new PUMA store has been inserted into a structure that has four storeys of occupied offices above. 

The transformative refurbishment programme included the upgrading of the store’s retail frontage with a new 10m-high glazed façade. 

The principal structural challenge was replacing the entrance’s heavy, fragmented appearance with a slender exposed steel frame, while continuing to support the occupied building. Rather than removing the existing three-storey columns, the design retained, reshaped and strengthened them, reducing waste, temporary works and disruption.

Internally, a large exposed steel staircase and cantilevered mezzanine extension contribute to the flagship store’s architectural identity. Steel provided the slender sections, precise finishes and installation flexibility required within the constrained programme and occupied building. 

A redundant 1970s office building at a prominent gateway into Newcastle city centre has been converted into a residential development with a distinctive steel-framed identity.

The Sandyford House project has extended a retained structure both vertically and in plan, with a new braced steel frame that accommodates a 14-storey residential block with more than 90 apartments.

Changing the design from office to residential loading required a detailed feasibility study, which assessed the capacity of the existing reinforced concrete frame after removal of its heavy cladding. 

Surveys and structural analysis also established whether the cores could resist the additional lateral forces created by the proposed extensions.

These investigations defined the parameters for a new braced steel frame. The material’s relatively low weight allowed additional floors and a plan extension to be introduced without significantly overloading the retained structure. 

Retaining and repurposing the existing structure saved more than 1,375tCO₂e compared with a new-build alternative.

Stonecutter is a London 13-storey steel-framed commercial development that has delivered substantial embodied carbon reductions via careful material specification and procurement.

Work on the Stonecutter project began with the demolition of the site’s previous eight-storey concrete-framed office block. 

Having removed what was above ground, much of the substructure was retained in order to drive the sustainability credentials of the scheme.

“We reused most of the existing piled foundations to support a new steel-framed structure,” explains Thornton Tomasetti director Eddie Jump.“

Steelwork also allowed the design to minimise the number of internal columns, with only three in this building, compared to seven in the previous scheme.”

Enhancing the sustainability of the project, much of the steelwork was sourced from Electric Arc Furnace (EAF) production facilities.

Repurposed steelwork has helped create the distinctive architectural form of a 53m-long, triple-span railway bridge in Wokingham.

Completed in November 2024, the Tan House Footbridge replaces two obsolete pedestrian bridges and connects parkland with a new residential development in Wokingham, Berkshire. The structure comprises a stiffened U-frame deck suspended from fan-shaped columns, with 14m-long stair structures at each end. The arrangement creates a slender and visually porous crossing, allowing users to see the trains below, while maintaining a strong sense of enclosure and safety.

The design uses a high proportion of recovered steel that might otherwise have been treated as waste, reducing demand for newly manufactured material while demonstrating how reclaimed sections can be incorporated into permanent railway infrastructure.

“By using and adapting to available stock of repurposed steel tubes, the scheme significantly reduced upfront embodied carbon,” says Format Engineers associate Camille Chevrier.

Produced by BCSA and Steel for Life in association with Construction Management.