C2 residential tower
The C2 residential tower at Salford Central forms one of the last phases of the £1bn Salford Central regeneration. Comprising 23 stories and 198 apartments, the Muse-developed tower will be a welcome addition to Salford Central, adding much-needed living space to the 50-acre masterplan.
Featuring a mixture of beautifully modern one, two and three-bedroom apartments, the residences are perfect for anyone looking for a home in the heart of Salford’s business district and only a stone’s throw away from Manchester city centre.
The engineering challenge
As structural and civil engineers for the project, we’ve been tasked with delivering an efficient structural design that’s both financially viable and hits carbon targets.
Here at renaissance, we’re experienced in delivering extremely efficient designs, especially for towers and high-rise buildings. For the C2 residential tower at Salford Central, there was plenty of opportunity for us to rationalise the structure.
Delivering an efficient grid and a rationalised slab
The floor plates of a tower are one of the most carbon-intensive elements of the building. If you’re able to reduce their thickness, you can remove considerable amounts of concrete and carbon from the structure.
The need to optimise the number of apartments was key to unlocking the design. The issue was that the variety of different apartment sizes made integrating an optimal column grid with the spatial arrangement challenging.
Working closely with the team we developed an efficient structural grid that delivered a consistent regular floor span, therefore enabling us to reduce the thickness of the floor plate from our previously standard 225mm down to 215mm.
Delivering an efficient core with better integration of services
Not only were we able to thin down the core walls, but we also delivered a design that integrated the installation of services more seamlessly than on traditional structures.
We worked closely with the architect and the services engineer to refine the core walls. We delivered an optimised corridor linkage arrangement, enabling us to safely remove concrete from the structure while simplifying the coordination of services in the core.
We did this by creating a 450mm structural zone without penetrations, generating a stiff link across the corridor that maximises the efficiency of the core walls. By creating this stiff outer box that utilises the depth of the whole core, we were able to optimise the stability system in other areas. We reduced the thickness of the internal walls within the core to 225mm, removing concrete and carbon from the structure.
Additionally, we eliminated several of the internal walls over the height of the core at the service risers. This gave the MEP contractors unobstructed access to the corridors in which to distribute services left and right. In essence, this has allowed us to future-proof the project, making the installation of services much more simplified and less disruptive.
This important work allowed us to remove more embodied carbon from the tower.
Rationalising the concrete mix
Across the whole development, the specified concrete mixes will adopt cement replacement, make use of Ground Granulated Blast Furnace Slag (GGBS). This waste product from the steel smelting process is effectively a zero-carbon material, bringing with it the added benefit of improved structural stiffness, less shrinkage during the curing process and as a result less cracking.
By factoring GBBS into the concrete mix, we’re able to reduce the embodied carbon of the structure before we’ve even removed any concrete.
The results of our carbon studies
In the RIBA Stage 2, the building had a SCORS rating of “D”, equivalent to 273kg of CO2e per m2. After the rationalisation and refinement of the structure, we were able to dramatically reduce this rating.
The C2 scheme is now SCORS rated at RIBA Stage 4 as “B”, equivalent to 192kg of CO2 per m2. This puts it in close to the LETI 2030 target values.