Testimonio II, a model for the Group’s environmental ambition

22 January 2021 - Projects update and handover - France

Since 2017, teams from VINCI Construction* have been working with Caroli BAT and Caroli TP on the Testimonio II project in Monaco for Groupe Marzocco and VINCI Immobilier. The project’s immense scale comes not only from the complexity of the work involved, but also the extensive range of environmental measures applied.

The complex will comprise almost 340 housing units in two residential towers, as well as around 50 luxury apartments, in addition to villas, parking spaces, a crèche and Monaco’s International School.
Located on the last large building plot in Monaco, situated between Boulevard d’Italie and Avenue Princesse-Grace, the site presents a number of challenges due to its narrow and sloping form and complex groundwater hydrology and underground geotechnical considerations, as well as other issues.

But the project’s immense scale comes not only from the complexity of the work involved, but also the extensive range of environmental measures applied – particularly in relation to reducing greenhouse gas emissions, protecting natural habitats and preserving resources, the three main focuses of the VINCI Group’s environmental ambition.

Innovations to reduce the project’s carbon footprint

Examples from the range of low carbon, very low carbon and ultra low carbon concretes developed by VINCI Construction that launched in 2020, Exegy®, have also been implemented in the project.
Although traditional concrete contains just 12% cement, that small proportion accounts for 85% of the material’s greenhouse gas emissions.
A joint operation carried out by materials laboratories for Soletanche Bachy, VINCI Construction and concrete provider (EMT) identified a formula with less clinker, the material responsible for concrete’s significant carbon footprint, replacing it with industrial by products: fly ash from Gardanne and furnace slag from Fos-sur-Mer.
Moreover, a very low carbon concrete has been developed. It will reduce C0₂ emissions by over 6,000 tonnes in the foundations for the moulded walls and barrette piles alone, which account for just a quarter of the concrete used in the project.

Another standout innovation on this project is the HC05GE, a compact Hydrofraise with electric grippers^® used to excavate deep foundations. This tool will not only save almost 5,000 litres of fuel per week of work but also reduce noise pollution for local residents as well as the vibration produced by the excavations.

The HC05GE, a compact Hydrofraise with electric grippers^®
Photo credit: Cédric Helsly.

Protecting freshwater springs and the sea

The Testimonio freshwater spring runs through the site, while another, Marie, runs alongside it.
Water from both is collected, either providing a significant share of Monaco’s freshwater supply or being discharged into the sea.
It was therefore crucial that the project protect these natural resources without discharging any mud or grout into the sea.
The teams have built a drainage gallery to collect water from the Testimonio spring, and installed pumps and turbidimeters in the valley where both springs flow before reaching the sea. These instruments can, if necessary, recover and treat any water that may mix with drilling mud.

Aerial view of the project

Preserving resources as part of a circular economy approach

The people and technical resources monitoring the different phases of the project have made it possible to optimise and even eliminate certain structures. For example, Soletanche Bachy’s Starsol® method produced piles, reducing concrete and rubble by 30%.

As part of a circular economy approach, teams have also used water available on site (from the springs or pumps) where possible for drilling and washing, as well as recycled drilling water as part of a closed circuit.
They have also mostly used crushed concrete from recycled materials for some work platforms.

By the time the project is completed in 2024, other initiatives to reduce its impact on the environment and local residents will be carried out.

The Starsol^® F2800 drilling machine
Photo credit: Cédric Helsly.

For further information

^* Soletanche SAM, local subsidiary of Soletanche Bachy, VINCI Construction Monaco and GTM Sud (VINCI Construction France)