The fact that building with a system consumes less material than conventional construction is apparent at first glance: The prefabricated concrete elements are significantly more filigree compared to conventional solid construction - with identical functionality. But we wanted to know more precisely.
Who performs better in terms of its CO₂ balance: an MSCP built using conventional construction or construction using system elements? And what is the CO₂ balance over different life cycle phases? We have investigated this on the basis of a typical MSCP.
How much CO₂ does a multi-storey car park from Goldbeck save compared to conventional steel skeleton construction with in-situ concrete ceilings and rolled section beams, taking into account production, deconstruction and recycling potential?
A project already realized by Goldbeck is closely examined and our construction method is compared by calculation with the conventional construction method. The differences to the conventional construction are presumably mainly in the shell construction. The focus is therefore on the Goldbeck precast concrete MSCP slabs (ramp and ceiling slabs) and the MSCP system beams (steel beams), which make up a significant part of the MSCP. The raw material extraction, the supply transport to the production plant, manufacturing, waste treatment and disposal as well as the reuse, recovery and recycling potential are analyzed.
The Goldbeck P2 employee multi-storey car park at the Bielefeld headquarters is used for consideration. The key data:
In order to minimize traffic searching for parking spaces and the resulting CO₂ emissions, as well as to make optimum use of the available parking capacities, our parking guidance system with individual space detection including LED displays is used. The MSCP also provides storage for around 30 bicycles. A photovoltaic system is installed on the roof of the building to generate electricity. These and other measures can contribute to the sustainability of the building over and above the CO₂ savings from the construction system. A typical Goldbeck multi-storey car park.
The comparison building in conventional construction was fictitiously modeled by Goldbeck. Benchmarks from the ÖKOBAUDAT platform - a platform of the German Federal Ministry of Housing, Urban Development and Building (BMWSB) - were used as a basis. This provides a standardized database for the life cycle assessment of buildings. The respective CO₂ balance was then calculated using GaBi - the standard software for such tasks - and in accordance with the life cycle assessment regulations of the German Sustainable Building Council (DGNB).
The differences are serious. The MSCP realized in the Goldbeck building system emits over 20 percent less CO₂ than the comparative object across manufacturing, deconstruction and recycling. This corresponds to a total of around 223 metric tons of CO₂ - almost 328 round-trip flights from Düsseldorf to Mallorca. Per square meter, this means a saving of around 20.6 kilograms of CO₂.
Considering only the manufacture of the components, the reduction in material consumption is as much as 32 percent* or 462 metric tons of CO₂ - almost 680 round-trip flights from Düsseldorf to Mallorca. Calculated downwards, the Goldbeck MSCP is therefore around 43 kilograms of CO₂ per square meter.
* In the first consideration over manufacture, deconstruction and recycling, the recycling potential is assessed and credited during disposal. Due to the lower use of steel and sheet metal compared to conventional construction, the advantage over the three phases is relativized to 20 percent.
Our decades of experience in construction, the protected and at the same time modern production environment as well as series effects ensure continuous optimization of our components: We only produce what is actually statically necessary.
For example, our in-house produced welded cross-sections optimized for our use can save a considerable amount of material compared to rolled sections used in conventional construction. The 11-meter welded cross-section is around 15 percent lighter than the corresponding rolled section. For the 16-meter welded cross-section, the weight saving is around 40 percent. The GOLDBECK MSCP ceiling slabs, with a thickness of around 10 centimeters, are also on average more than 28 percent slimmer than those produced with in-situ concret ...
... This is also due - in addition to the continuous optimization of our construction performance - to the fact that with a special concrete formulation and in a protected industrial production environment, significantly less concrete is required to achieve the necessary load-bearing capacity. This also has an effect on the impermeability and corrosion protection of the slabs: the Goldbeck Multi-storey car park ceiling slabs do not require any additional coating. An anti-slip effect is achieved by the structured surface. Further savings result from the resulting lower total weight in the load-bearing components and the foundation. However, they were neglected in the present comparison of construction methods. Another advantage: Due to serial prefabrication in the factory, formwork required for casting reinforced concrete components can be reused instead of remaining in the building as "lost formwork" after the end of the conventional construction phase.