Quarco unveils a major innovation for mixed construction: the Wood Concrete Connector

The Wood Concrete Connector (CBB) is a fundamental assembly element for the development of mixed wood-concrete construction systems. It is the only technical solution allowing the combination of concrete floors and vertical wooden frames (MOB, CLT or glued laminated wood structure in posts/beams) imagined by INNOVONS, the QUARCO solutions incubator.

The CBB, a patented “made in France” system, shows the commitment of the Nantes collective to sustainable and responsible construction.

The CBB, the key to efficiency for all types of construction (new or renovation)

The Wood Concrete Connector is the best construction device capable of responding to the problems and constraints of mixed wood-concrete constructions, without requiring specific technical training. A piece of steel measuring 10 cm x 5 cm high x 3 mm thick at the base, the CBB makes it possible to combine concrete floors (such as a reinforced concrete pre-slab or slab joists) with structures. wooden verticals in a pragmatic and rational manner, while preserving the economic balance of real estate operations.

This solution makes it possible to construct mixed buildings (concrete base and wooden frame facades) with up to 3 superimposed levels for wooden frame walls (MOB) and up to 5 levels for post/beam glued laminated walls or CLT structure. (cross laminated timber). The CBB therefore opens up the field of possibilities for all types of mixed constructions, individual housing, collective housing, public facilities, tertiary buildings and rehabilitation.

Applicable to all seismic zones, the CBB is installed in the workshop during the manufacture of wooden frame walls. Once transported to the site, the assembly is integrated into the structural work cycle, without changing the habits of the workers on site. The construction time is optimized, the technical solution achieved and guaranteed (stability, resistance, durability).

The CBB, a low-tech, low-carbon solution

The Environmental Regulation 2020 (RE 2020) encourages the construction of buildings with low environmental impact, so that construction tends towards carbon neutrality in 2050. In a sector which represents 43%* of annual energy consumption and generates 23%** of emissions greenhouse gas (GHG) emissions in France, developing construction processes is therefore a requirement.

The objective is to draw the attention of developers and construction stakeholders to the thermal, acoustic and economic advantages of the Wood Concrete Connector and to make them aware of the benefits to be derived from these qualities to “connect” the world of construction with environmental issues. The CBB is in fact a decisive link in going even further in the wood-concrete mix and in making constructions ever more efficient thanks also to workshop prefabrication which allows the advantages of off-site.

The athletes' village for 2024, an emblematic project for QUARCO and the CBB

In the heart of the eco river district of Ile-Saint-Denis, a batch of 6 buildings with a floor area of approximately 5000 m2, intended to accommodate athletes next July, has emerged from the ground:

5 concrete ground floor buildings and 3 wooden frame levels
1 concrete ground floor building and 2 wooden frame levels

The Roux company (Gipen group), winner of the call for tenders, had very early on requested QUARCO to present a file that was innovative in every way. Together, the two entities developed and finalized the CBB to integrate it into site management. The specifications, which were validated by the project owner, opened the way to an efficient intervention, in terms of product and use benefits, in compliance with RE 2020:

lifting and installation of MOB walls integrated into the production cycle,
implementation of concrete floors connected to the MOB wooden frame uprights allowing the incorporation of slab networks,
removal of the post-beam structure at the edge of the floor, installation of the CBB in the workshop.
500 hours were necessary for the employees of Abak Ingénierie Nantes and GRIF Paris, which are the two agencies of the group to have carried out the concrete and wood execution studies, QUARCO having ensured the production of the execution plans and the positioning of the connectors on wooden frame walls, then installed in the workshop.

For the floor team leader of the Athletes' Village, the choice of the CBB on this site was relevant in several respects: "The implementation of the CBB is much simpler on a mixed construction site than on an all-concrete site where it There is a wait between levels. The CBB solution is a huge time saver for the team in terms of floor reinforcement. Usually, with load-bearing concrete sails on the facade there can be a loss of time when connecting the chaining steels with the expectations at the top of the sails. With the Wood Concrete Connector solution, I no longer have this problem when arranging the steel on supports and the horizontal chains in connection with the connectors.”

The CBB, chronology of an already acclaimed innovation:

2018: QUARCO, launch of CBB development
2020: patent for the CBB invention
2021: laboratory tests
2022: request for ETN (New Technique Survey) with support from SOCOTEC
2023: 3 sites under construction or delivered, i.e. more than 1500 CBBs installed
2023: QUARCO is winner of the Eco Innovation Factory by Atlanpole*** program

The QUARCO collective

4 associate directors: François-Xavier Guillard President – Angélique Lyon Technical Director -Julien Boudvillain, Managing Director and Northern Sector Manager – Christophe Deserce, Southern Sector Manager
110 employees
15 agencies in mainland France
8 M € turnover in 2022
5 professions: engineering of multi-material structures, design and rehabilitation of individual houses, project management (construction economics and operations management), diagnosis, advice and assistance to project management (AMO).

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