Mixed slab systems
With over 30 years of experience, the ARVAL mixed slab systems are now rated among the most efficient on the French and European markets. They are compatible with various types of building architecture and they can be used both for new constructions and for renovations.
ARVAL is often cited as a prime example in all spheres of construction in France and abroad, thus confirming their rating as leader. Full technical assistance, advice on technical reports, design notes, as well as the Cofra 4 software sent on request, reinforce this position.
Today, we can see there are three types of slabs that use steel floor profiles : composite floors, formwork floors and prefabricated composite floors.
COMPOSITE FLOORS
For composite floors, the ribbed steel profile contributes to the intrinsic and composite strength of the slab. It fulfills the role of formwork and also assists the concrete. ARVAL has three types of composite steel floor profiles : Cofrastra 40, Cofraplus 60 and Cofrastra 70.
Floors with formwork
For floors with formwork, the ribbed steel profile does not contribute to the composite strength of the slab. Its only role is to serve as shuttering for the concrete slab. Once cover plates have been positioned, it permits trafficking while the worksite is in progress and remains there after the props have been removed. Hacierco decking is used for this type of flooring.
Prefabricated composite floor
The Cofradal 200 is a factory manufactured floor system combining steel and concrete. The absence of propping or any added concrete, as well as the speed with which it can be installed, make this an economical solution. It is two to three times as light as traditional slabs and provides the ability to cover wide spans, thereby reducing the cost of the load bearing structure of the building.
There are diverse fields of application for these floors : offices, industrial buildings, storage buildings, public facilities, housing, school buildings, car parks… The good performance characteristics of the composite slabs make them designed for use in buildings that have quite high live loads. They also allow for normal usage spans without propping.
Composite floors are now justified by the principles of the CSTB Technical Report and will, in the near future, be in accordance with Eurocode 4.
There are numerous advantages to using mixed slab systems.
The ribbed steel profile fixed onto the framework of the building serves as a horizontal wind brace, a work platform, shuttering and flexural reinforcement of the bottom of the slab. It can, therefore, immediately contribute to wind bracing and the stability of the building due to a diaphragm effect (Eurocode 3.1.3)..
The steel profiles are fixed onto the supports and serve as a work platform, thereby allowing trafficking in good working and safety conditions before the concrete is laid
Once the profiles have been installed, the underside of the floor is watertight, efficient and clean with a finished appearance. Pre-painting is possible with the exception of Cofrastra 40.
The shape of the ribs sets the steel profile securely in the concrete. The reinforcement of the Cofrastra or Cofraplus section often makes it unnecessary to have span reinforcements. All you need to do is finish off the slab with a welded mesh and possibly top bars. Without adding any extra reinforcement at the bottom, the composite floors have a half an hour firewall.
The use of mixed slab systems enables you to save in many ways :
in the time spent on the worksite and on the use of lifting appliances
in the weight of the concrete due to the shape of the ribbed profile, about 100 daN/m².
Reducing the weight of the slab effects the dimensioning of the rest of the structure, beams and posts that are thereby lighter and lessen the load on the foundations. The steel profiles can be manually carried and once they have been placed on the floor girders, they can be rapidly moved, which is a great asset in renovating work. There are other advantages in the use of a mixed slab system compared to the prefabricated concrete slab, such as the possibility to achieve irregular shapes, curves or special floor openings.
For the requirements of mixed material buildings, ARVAL has developed factory drilled profiles that link to the beam connectors and join up both elements. This technique allows a considerable saving in steel and concrete, up to 30 % of the weight of the girder. The factory drilled profile means quick on-site installation. It also makes the factory fixing of connectors onto the girders easier. The ARVAL pre-drilled floor profiles are approved in the technical Reports.
