FR2548718A1 - Devices eliminating the damage caused by shoring to the underfaces of the insulating floors ribbed with reinforced concrete - Google Patents

Abstract

The invention relates to two devices with which it is possible to transmit the shoring reaction 2 to the concreted rib 3 without excessive deformation likely to damage the protective panels 1 situated on the underface. The first of these devices consists of a continuous insulating sheet 4 which is preferably made of cellular plastic material and whose mechanical strength is sufficient to transmit the forces in question. The second device consists of metal brackets 5 which are preferably spaced uniformly and are likewise capable of transmitting the same forces. These two devices can be used together or separately.

Description

 The present invention relates to two devices improving the behavior, on temporary props, of ribbed concrete floors with integrated thermal insulation.

 The technology of this type of floor, which has appeared over the past twenty years, is known. They consist of rigid insulating materials used as formwork lost to a ribbing, most often in reinforced concrete, locally reducing the thickness of these insulators; because of this structural characteristic, there is a heat loss zone at each rib, designated by the pictorial term of thermal "bridge".

 To correct these losses localized to the rib, we first placed in this area insulating materials such as wood, or various lignocellulosic agglomerates. Then, we improved this thermal break by making it in cellular plastic, insulators even more effective, but requiring protection on the underside because of their low mechanical resistance, and the particular risk that some of them present to the regard to the fire.

 This protection on the underside is carried out by glued panels, made of rigid and incombustible materials of known type: Fibragglos, concrete, various agglomerates, plasters or mortars armed with lignocellulosic fibers etc ...

 The minimum thickness of these protective panels is fixed by safety rules, depending on the duration of the firebreak to be obtained, and it is therefore advantageous to limit their thickness to what is strictly necessary, but this way of seeing has drawbacks, because these floors are, in the majority of the cases, implemented on a temporary shoring, which exerts important localized efforts, known as "forestay reaction" efforts which apply to their underside.

 If the insulation placed between the concrete rib and the forestay does not have sufficient mechanical strength, and the protective panel, which is too thin, cannot provide sufficient force distribution, the forestay reaction causes the crushing of the insulation, and sinking of the protective panel.

 This results in significant aesthetic damage beneath the floors and sometimes even deterioration of the panels, reducing their effectiveness from the point of view of fire safety.

 The object of the present invention consists of two devices making it possible to eliminate the drawbacks exposed, without reducing the efficiency of the thermal rib break, and by making it possible to limit the thickness of the protective panel to the minimum required by the rules of security.

 The first of the devices proposed according to the invention consists in interposing between the protective panel and the concrete rib, an insulating plate of cellular plastic material, preferably, whose mechanical resistance allows, without excessive deformation, the transmission of the reaction of was with a concrete rib.

 The thermal conductivity of this insulating plate is identical to or very close to that of the insulation forming the ribbing.

 Its thickness is never less than 1 cm, but its width may be less, equal or greater than that of the ribbing.

 The second of the devices proposed according to the invention consists of trestles of an appropriate shape, preferably made of metal, whose own rigidity also makes it possible to transmit to the concrete rib, the reaction due to the presence of the forestay.

 These easels are arranged at regular intervals, at the junction between the protective panels. Due to their very small relative surface, these cnevalets do not cause any significant heat loss.

 This second device offers the additional advantage of allowing, by its appropriate shape, exact positioning of the reinforcements in the concrete rib, at the stage of its manufacture; advantageously, it replaces the compulsory metal connections between the concrete rib and the protective panel, if we want to comply with fire safety rules.

Each of the two devices described makes it possible to obtain the result sought mainly, which is to improve the behavior on forestay of ribbed insulating concrete floors, they can be used together, or separately, knowing that in the case of the first device proposed according to the invention, the accessory advantages of positioning the armatures and mechanical connection of the protection to the structure can be obtained - less advantageously - by known means (plastic spacers placed manually on the armatures, and metallic wires arranged in standby.)
FIG. 1 shows, seen from the side, the disadvantage that the devices proposed according to the invention have the object of eliminating.

 FIG. 2 represents, in section, the first of the two devices proposed according to the invention.

 FIG. 3 represents, in section, the second of the two devices proposed according to the invention.

Figure 4 shows, in section; the combination of the two devices
FIG. 5 represents, in perspective, one of the embodiments of the easel (5) showing its horizontal (6) and vertical (7) positioning means, of fixing (8) in the protective panels (1) and the housings ( 9) reinforcements (10) of the concrete rib (3).

 Figure 6 shows, in section, an easel (5) arranged at the junction between two protective panels (1) contiguous, and placed vertically on a forestay (2).

 The first of the devices proposed according to the invention allows iui alone to obtain the desired result, which is to avoid deterioration of a protective panel of thickness corresponding to the minimum required by fire safety rules.

 The second of the devices proposed according to the invention, while making it possible to obtain an identical result, allows the use of an insulating plate (4) of mechanical strength and of lower cost.

 Incidentally, this device performs the function of armature positioner (10) and of safety fixing (8) of the protection panel (1).

Claims (5)

 1) Device for preventing deterioration on forestay of the undersides of ribbed insulating concrete floors, characterized in that it comprises between the concrete rib (3) and the forestay (2) an insulating plate (4) made of plastic material al véolar, preferably, whose mechanical strength is sufficient to transmit, without excessive deformation, the forestay reaction (2) to the concrete rib (3).  2) Device according to claim 1 characterized because it comprises, at regular intervals, metal trestles (5), preferably also capable of transmitting, without excessive deformation, the forestay reaction (2) to the concrete rib (3).  3) Device according to claim 1 characterized in that the insulating plate (4) in cellular plastic material, preferably, may know a width less, prop or the greater than that of the concrete rib (3).  4) Device according to claim 2 characterized in that the easels (5) have means or horizontal positioning means (6) vertical (7) and fixing (8) and also comprising housings (9) which can incidentally receiving the steels (10) from the born concrete rib (3).  5) Device according to claims 2 and 3 characterized in that the insulating plate (4) may, in application of claim 2, have a lower mechanical strength, it may also, in application of claim 3, have a width equal or different from that of the concrete rib (3).