FR3118081A1 - Construction method comprising the production of at least one non-prestressed concrete and wooden slab, and concrete and wooden slab - Google Patents

Abstract

The present invention relates to a construction method, comprising the production of at least one slab (1) according to the following steps: - laying of metal stiffeners (2); - casting of a concrete slab (3), by causing the stiffeners (2) above the concrete; - preparation of blocks of wood (p1-p3); - laying of blocks of wood between the stiffeners (2) emerging from the concrete slab (3), leaving a space between the adjacent blocks of wood (p1-p3); - casting ribs (n1, n2) of concrete between the blocks of wood (p1-p3), by embedding the stiffeners (2) at least in part; and- drying the non-prestressed slab (1) consisting of the concrete slab (3), the stiffeners (2), the wooden blocks (p1-p3) and the ribs (n1, n2) made of concrete. Figure for abstract: Fig. 1

Description

Construction method comprising the production of at least one non-prestressed concrete and wooden slab, and concrete and wooden slab

The present invention relates to the technical field of building construction, and more particularly reinforced concrete construction.

PRIOR ART

It is known from the state of the art several ways of treating a concrete floor. The two most common solutions are:
- casting in place, i.e. on a construction site, using formwork,
- the use of pre-slabs generally manufactured in the factory, outside the site.

Cast-in-place has the disadvantage of the time and labor required for its implementation. In particular, a significant time is essential for the drying of the concrete before the construction of an upper floor can be started.

Existing hollow core slabs have an unattractive appearance. In addition, these hollow core slabs do not allow easy integration of reservations for water pipes, ventilation pipes, electrical cables, etc. As a result, the use of hollow core slabs is generally limited to industrial buildings or car parks. Thus, there is a need to adapt floor slabs for use in housing and offices.

Ecological requirements are becoming increasingly important in construction. Thus, CO2 emissions during construction must be limited. However, the cement needed to make concrete remains a major source of CO2 emissions. It is therefore conceivable that the reduction in the use of cement is desired. In addition, the introduction of bio-sourced insulating panels between the concrete ribs allows an additional reduction in the CO2 footprint of the finished floor.

DE102004059590 describes a process for constructing a ceiling, comprising hollow bodies aimed at lightening the construction. The hollow bodies are an inverted U shape or a wavy shape. Hollow bodies can be made of metal, plastic, wood, chipboard or corrugated cardboard. The hollow bodies leave voids in the slab, which is not entirely satisfactory in terms of mechanical strength, and acoustic and thermal performance. When workers walk on the site, they risk deforming the hollow bodies before they are covered by a compression slab.

GB1401439 describes a method for constructing a slab, comprising light blocks aimed at lightening the construction. The blocks located at the ends of the slab are provided with a lower height than the blocks located between the ends. Blocks can be polystyrene, wood wool, metal or cardboard. Polystyrene is not entirely satisfactory in terms of mechanical resistance and ecological footprint. Metal is not entirely satisfactory in terms of cost, ecological footprint, and acoustic and thermal performance. Wood wool and cardboard are not entirely satisfactory in terms of mechanical resistance, and acoustic and thermal performance.

WO2019/086791 describes a process for constructing a slab, with the casting of a concrete slab, then the installation of metal stiffeners in the still fresh concrete slab. However, significant effort is required to penetrate the stiffeners into the fresh concrete. In addition, the positioning of the stiffeners in the fresh concrete slab makes it necessary to respect a tight timing, before drying and hardening of the slab, to prevent the ribs from being cast on a slab whose drying is too advanced. In addition, the “blind” positioning of the stiffeners in the fresh concrete slab may lack precision.

One of the aims of the invention is therefore to propose an improved construction method, the method comprising the production of at least one concrete and wooden slab. The slab resulting from the process must be aesthetic, resistant, easy to install, ecological to produce, and have good acoustic and thermal performance.

Another objective of the invention is to facilitate the integration of reservations for conduits and cables, and thus allow the method according to the invention to be used in the construction of buildings, in particular housing.

To this end, the subject of the invention is a construction method, comprising the production of at least one slab according to the following steps:

- installation of metal stiffeners;
- pouring a concrete slab, by making the stiffeners emerge above the concrete;
- preparation of wooden loaves;
- laying blocks of wood between the stiffeners emerging from the concrete slab, leaving a space between the adjacent blocks of wood;
- pouring concrete ribs between the wooden slabs, by embedding the stiffeners at least in part; And
- drying of the non-prestressed slab consisting of the concrete slab, the stiffeners, the blocks of wood and the concrete ribs.

In practice, the process comprising the laying of stiffeners then the casting of a concrete slab is simpler to carry out and makes it possible to position the stiffeners with greater precision, in comparison with a process comprising the casting of the slab then the incorporation of stiffeners in the thickness of the still fresh concrete slab.

In the latter case, the installation of the stiffeners requires significant effort, tight timing, and may lack precision.

The process comprising the installation of stiffeners then the casting of a concrete slab is particularly well suited to construction on a carousel.

Wood blocks are denser, more insulating and more resistant (to mechanical stress, fire and humidity), compared to wood wool, polystyrene or cardboard.

According to other advantageous characteristics of the invention, taken individually or in combination:

- The laying of stiffeners, the casting of the concrete slab, the laying of the wooden blocks, and the casting of the ribs are carried out on the same prefabrication table, mobile between different stations of a carousel.
- The laying of the wooden slabs is carried out on the still fresh concrete slab. This reinforces the adhesion between the wooden slabs and the slab.
- The pouring of the concrete ribs between the blocks of wood, by drowning the stiffeners at least in part, is carried out on the still fresh concrete slab. This ensures cohesion between the ribs and the slab.
- The preparation of the wooden blocks includes a cutting operation. In particular, this cutting aims for the blocks of wood to have dimensions adapted to the predefined spacing between stiffeners and to the predefined width of the ribs.
- The wood block cutting operation is carried out by water jet. Alternatively, the cutting operation can be carried out by other techniques.
- The preparation of the wooden slabs includes a milling operation to form housings for receiving sheaths, in particular electrical sheaths. The blocks of wood can be provided with housings having different paths and different depths depending on the number of ducts to be integrated. The same housing can have variable depths to accommodate three ducts, then two, then only one, depending on the routing plan of the ducts.
- The preparation of the blocks of wood includes an operation for marking the housings for receiving the sheaths, to identify each of the sheaths. This facilitates the positioning of the ducts in the factory or on the construction site.
- The preparation of the wooden slabs includes an operation of marking information representative of their position within the slab, and sheaths intended to be integrated into the wooden slabs. This facilitates the laying of the wooden blocks in the correct position on the slab, and the subsequent installation of the ducts.
- Marking operations can be carried out by painting, engraving, labeling, or any other technique.
- The preparation of the wooden blocks is carried out on a single machine designed to carry out cutting, milling and marking operations.
- The stiffeners are placed on wedges, which are then embedded in the concrete slab.
- Additional elements are positioned on, in or between the stiffeners before casting the slab, for example spacer vents, reservation tubes, electric pots, or lifting devices.
- The spacer vents have a dual function of positioning the adjacent blocks of wood and circulating air through the slab.
- The blocks of wood have a density of between 80 and 200 kg/m3.
- Wood slabs have a thermal conductivity between 0.038 and 0.044 W/(mK).
- The wood blocks are made of wood fibres.
- The wood is natural, for example fir and/or spruce, from responsible and local forestry operations.
- The wood slabs are cut from single-layer wood fiber insulation panels.
- The slab is dried in an oven.
- The drying of the slab is carried out on a heating table. The heating table can be the manufacturing table, or another table.
- The drying of the slab is carried out by exposure to the ambient temperature, without means of heating requiring an energy supply, and therefore in a natural way.
- The method comprises, prior to the laying of the stiffeners, a step of identifying areas of interference between, on the one hand, the ribs, and on the other hand, reservations provided in the slab. The metal stiffeners associated with the ribs outside the interference zones are placed with a reference gap between them. The metal stiffeners associated with the ribs in the interference zones are laid offset with the reference gap, to avoid said interference.
- The reference gap between the metal stiffeners is of the order of 60 cm, while the offset is of the order of 10 cm on one side or the other.
- The method includes additional steps: laying the slab consisting of the stiffeners, the concrete slab, the blocks of wood and the ribs which incorporate the stiffeners and are secured to the slab; installation of a metal frame on the slab; then casting a compression slab above the reinforcement and the slab, covering the wooden blocks and the ribs.
- The metal frame is a welded mesh.
- During the step of casting the concrete ribs between the wooden blocks, the stiffeners are only partially embedded in the concrete and emerge at the top of the ribs.
- The concrete slab is between 4 and 8 cm thick.
- The concrete slab has an average thickness of 6 cm.
- The slab has a width of up to 3.80 m.

Thanks to the invention, the slab can support the weight of the concrete poured on site (compression slab), give the floor complex (concrete of the slab, blocks of wood, concrete of the compression slab (cast on site)) good acoustic and thermal performance, and have a very favorable balance in terms of CO2 emissions.

Workers can walk on the slab on site, without the risk of deforming it, before casting the compression slab. Blocks of wood can support the weight of workers without deforming, which would not be the case with hollow elements or light materials. This facilitates the installation of networks (electrical, fluids, etc.).

DESCRIPTION OF FIGURES

Other characteristics and advantages of the invention will emerge clearly from the description which is made of it below, by way of indication and in no way limiting, with reference to the appended figures, in which:

there is a sectional view of the slab obtained by the process according to the invention;

there is a schematic representation in perspective of the slab with the stiffeners, before the laying of the wooden slabs;

there is a layout plan comprising zones of interference between ribs and reservations, said interference being able to be avoided by the use of the slab according to the invention;

there is a plane similar to the , but with the ribs displaced to avoid interference;

there is a layout drawing representing an area in which a slab with the reference gap between ribs can be used;

there is a layout plan showing an area in which the offset of the ribs does not make it possible to avoid reservations

there is a cut analogous to , for another slab obtained by the process according to the invention;

there is a schematic representation in perspective analogous to the , for the slab of the ;

there is a representation in perspective of another slab obtained by the process according to the invention, surmounted by a trellis and a compression slab;

there is a top view of the slab of the , without the trellis and the compression slab; And

there is a partial cross-section of the slab of the .

For the purpose of simplification, the same elements bear the same reference numerals in the different figures.

DETAILED DESCRIPTION OF THE INVENTION

The invention relates to a construction method, comprising the production of at least one slab 1 of reinforced concrete and wood, called BB slab.

As shown in Figures 1 and 2, the slab 1 is composed of metal stiffeners 2, a concrete slab 3, ribs n1 and n2 projecting from the slab 3, and wooden blocks p1 to p3 arranged between and next to ribs n1 and n2. The stiffeners 2 are embedded in the concrete of the slab 3 and the ribs n1 and n2.

Once the slab 1 is in place on its supports, a metal reinforcement 20 of the "welded mesh" type is placed on the slab 1, and an upper layer of concrete, called the compression slab 30, is poured on the slab 1 and the armature 20, as shown in the .

P1-p3 wood slabs have a density between 80 and 200 kg/m3. The p1-p3 wood slabs have a thermal conductivity preferably between 0.036 and 0.046 W/(mK), preferably between 0.038 and 0.044 W/(mK).

The p1-p3 wood slabs are preferably made of wood fibers. Again preferably, the p1-p3 wood blocks are obtained from single-layer, rigid or semi-rigid, wood fiber insulating panels. The panels can have a thickness of between 3 and 22 cm, preferably equal to 9 or 12 cm. The panels have a fire behavior corresponding to class E, according to standard EN 13501-1.

A significant problem with existing hollow core slabs is their lack of adaptability. Indeed, they are difficult to use for building housing or offices whose plans are very diversified, and require accepting a large number of reservations for water pipes, gas, ventilation, as well as for electrical cables. , telecommunications, etc.

According to the invention, the offset of the ribs makes it possible to adapt the slab 1 to the specific needs of each construction project.

To implement the method according to the invention, a preliminary step consists in identifying on the layout plan areas where a (virtual) "collision" occurs between the ribs and the recesses.

Thus, three different types of zones can be identified.
- In the first type of zone, there are no collisions (cf. ) between ribs n8 to n11 and reservations r4 to r7. Thus, a slab 1 with the reference gap of 60 cm between ribs n8 to n11 can be used.
- The second type of zone, called interference zone ZI, presents collisions (cf. ). A first interference zone ZI is identified between the rib n1 and the reservation r1, and a second interference zone ZI between the rib n5 and the reservation r3. The movement of the ribs by a maximum of 10 cm in relation to the reference deviation allows the reservations to be avoided (cf. ). Thus, a slab 1 with ribs n1 and n5 offset with respect to the reference deviation can be implemented.
- The third type of zone (cf. ) designates ZC conflict zones, where the displacement of ribs by a maximum of 10 cm does not make it possible to avoid collisions. This is the case of the collision between the rib n12 and the reservation r8, the displacement of which would cause a collision with the reservation r9. Thus, in this zone ZC, a floor must be cast in place, or be formed from conventional pre-slabs, without ribs or integrated insulation.

The process for manufacturing the slab 1 according to the invention, described in detail below, comprises the following steps:

1] Installation of metal stiffeners 2 on a prefabrication table, at positions which depend on the reservations and the interference zones ZI, as described above. The stiffeners include vertical elements 2a and horizontal elements 2b. The elements 2a and 2b can be manufactured separately, with steels of different sections, and preassembled before installation, in particular by welding. The stiffeners 2 are preferably placed on wedges placed on the table. The vertical elements 2a are positioned either with the reference gap between them (preferably 60 cm), or with a gap greater or less than the reference gap, to avoid interference zones ZI. The stiffeners 2 can receive additional elements before casting of the slab 3, for example spacer vents (having a dual function of positioning the wooden slabs and circulating air), reservation tubes and/or lifting devices .

2] Casting of a concrete slab 3 on the prefabrication table, causing the stiffeners 2 to emerge from the slab 3. The vertical elements 2a protrude from the slab 3, while the horizontal elements 2b are fully integrated into the slab 3. Preferably, the slab 3 has a thickness of between 4 and 8 cm. Again preferably, the slab 3 has an average thickness of 6 cm. Thanks to the invention, its width can reach 3.8 m.

3] Preparation of the wooden slabs p1 to p3 before they are laid on the slab 3. Different preparation operations can be carried out on the wooden slabs, in particular cutting, milling and marking operations. Advantageously, these preparation operations can be carried out in a single machine designed for this purpose. The wooden blocks p1-p3 are cut to the correct dimensions, preferably by water jet, or by other techniques. Preferably, the wood blocks are cut from single-layer wood fiber insulating panels, having a density of between 80 and 200 kg/m3, and a thermal conductivity of between 0.038 and 0.044 W/(mK). The wood fibers can come from sawing offcuts, or other sources. The wood fibers can be bonded by additives to form the panels. Preferably, the cut wooden slabs p1 to p3 can have a width of 48 cm, and a height of 9 or 12 cm. The length of the blocks of wood p1 to p3 cut out depends in particular on the length of the slab 1 to be produced. Through-openings can be formed in the blocks of wood p1 to p3 to serve, for example, as cable passages. Of course, other conduits and pipes can be passed through these openings.

4] Laying of the wooden slabs p1 to p3 between the vertical elements 2a of the stiffeners 2 emerging from the concrete slab 3. Preferably, the blocks of wood p1 to p3 are laid when the concrete of the slab 3 is still fresh. Thus, the blocks of wood p1 to p3 are secured to the slab 3 by adhesion between the wood and the fresh concrete, then during the drying of the concrete.

5] Casting of the ribs n1 and n2 between the wooden blocks p1 to p3, by embedding the vertical elements 2a of the stiffeners 2 in whole or in part. Preferably, the ribs are cast when the concrete of the slab 3 is still fresh. Thus, cohesion is ensured between the ribs and the slab 3.

6] Laying on site of each slab 1 consisting of stiffeners 2, slab 3, blocks of wood p1 to p3 and ribs n1 and n2, which incorporate the vertical elements 2a of stiffeners 2 and are secured to slab 3.

7] Places a metal reinforcement 20 of the "welded mesh" type on the slab 1.

8] Casting of a compression slab 30, preferably 5 cm thick, above each slab 1 and reinforcement 20.

Of course, a floor can be composed of a plurality of adjacent slabs 1. Thus, the laying of the reinforcement 20 can be carried out simultaneously on several slabs 1. Also, the casting of the compression slab 30 can be carried out simultaneously for several slabs 1.

Steps 1) to 5) are preferably carried out off-site, for example at the factory, while steps 6), 7) and 8) are carried out on site.

The number of operations carried out on site is minimized.

Alternatively, it may be envisaged to carry out steps 1) and 2) in the factory, while steps 3) to 8) are carried out on site.

The invention makes it possible to improve the CO2 balance of slab 1. This improvement is made possible thanks to the lightening of slab 1, which is no longer a solid slab. The p1-p3 wooden slabs reduce the use of primary materials by more than 35%, while maintaining the original lift, according to the experiments that led to the invention. Also to reduce the CO2 balance, one possibility is to replace traditional concrete with low-carbon concrete, certified by an FDES sheet. In addition, the metals integrated into the slab 1 can be recycled metals.

By lightening the floors, it is also possible to reduce the size of the concrete structure made up of posts, beams, foundations, etc.

The blocks of wood p1-p3, storing CO2 throughout their lifetime, make it possible to further improve the CO2 balance of slab 1. The use of wood in construction makes it possible to preserve the CO2 stored by the trees during their growth . Indeed, if they were not cut so that we can use their wood, these trees would decompose in nature, releasing CO2 into the atmosphere.

The p1-p3 blocks of wood also improve the thermal and acoustic insulation of slab 1. In practice, wood provides thermal insulation fifteen times more effective than that of concrete.

P1-p3 wood slabs made from wood fibers have good fire resistance properties, compared to polystyrene, wood wool or cardboard. P1-p3 wood slabs also have good moisture resistance properties, compared to wood wool or cardboard.

The use of slag, or any solution that reduces the carbon impact, is advantageously possible.

Advantageously, the length of the slab 1 can be less than, greater than or equal to 7.50 m. The length of the slab 1 is only limited by its mechanical strength.

The slabs 1 according to the invention have a width of 0.70 m to 3.80 m. Slabs between 0.70 m and 2.50 m will be transported by tray. The 2.51 m to 3.80 m slabs will be transported "on edge" with specific trailers, then rotated on site. The choice of a width of 3.80 m makes it possible to reduce the number of joints to be treated. Thus, the laying of the slabs 1, obtained by the process according to the invention, is simpler and faster than with the existing pre-slabs.

When laying slab 1, it is possible, in some cases, not to position stabilization props on the underside, saving time, material and difficulty.

Preferably, additional elements can be positioned on the stiffeners 2, in the stiffeners 2, or between the stiffeners 2, before casting the slab 3. These elements can be spacer vents, reservation tubes, electrical pots, or lifting devices.

Because these elements, reservations and passages are already integrated into the slab 1, the construction method according to the invention is particularly quick and simple to implement, minimizing the operations necessary on the site.

Other embodiments of a slab 1 in accordance with the invention are shown in FIGS. 7 to 11. Certain constituent elements of the slab 1 are comparable to those of the first embodiment described above and, for the purpose of simplification , bear the same reference numerals.

In Figures 7 and 8 is shown a slab 1 comprising metal stiffeners 2, a slab 3 of concrete, ribs n1 to n3 projecting from the slab 3, and wooden blocks p1 to p4 arranged between and beside ribs n1 to n3.

The slab 1 comprises spacer vents 4, designed in the form of tubes arranged in horizontal housings 5 provided for this purpose through the ribs n1 to n3. Alternatively, the spacer vents 4 can have other configurations. The first function of the spacer vents 4 is to ensure the spacing between the wooden slabs p1 to p4, before the casting of the ribs n1 to n3 between the wooden slabs p1 to p4. The second function of the spacer vents 4 is useful in the event of a fire and a strong rise in temperature. The hollow vents will allow the free circulation of steam through the slab 1, and its escape through an outlet.

The stiffeners 2 are placed on wedges 6, which are then embedded in the concrete slab 3. The wedges 6 can be made of plastic material, concrete, wood or any material capable of ensuring the distance of the stiffeners 2 from the surface bottom of the slab 3.

In Figures 9 to 11 is shown a slab 1 comprising metal stiffeners 2, a concrete slab 3, ribs n1 to n6 projecting from the slab 3, and rows of wooden blocks p1 to p7 arranged between and next to ribs n1 to n6.

Once the slab 1 is in place on its supports, a metal reinforcement 20 of the "welded mesh" type is placed on the slab 1, and an upper layer of concrete, called the compression slab 30, is poured on the slab 1 and the frame 20.

Ribs n5 and n6 are closer together than the others, because they are positioned at the edge of an expansion joint.

The slab 1 comprises electric pots 7 and sheaths 8. The pots 7 are positioned in reservations provided for this purpose in the wooden slabs. Similarly, the sheaths 8 are positioned in housings provided for this purpose in the wooden blocks and through the ribs.

The blocks of wood p1 to p7 can be fitted with housings having different paths and different depths depending on the number of sheaths 8 to be integrated.

As shown on the , the same housing can have variable depths to accommodate three ducts 8, then two, then only one, depending on the routing plan of the ducts 8.

The preparation of the blocks of wood may include an operation for marking the housings for receiving the sheaths 8, to identify each of them. This facilitates the positioning of the sheaths 8 in the factory or on the site.

In addition, the preparation of the blocks of wood may include an operation of marking information representative of their position within the slab 1, and the sheaths 8 intended to be integrated into the blocks of wood. This facilitates the laying of the blocks of wood in the correct position on the slab 2, and the subsequent installation of the sheaths 8.

As also shown on the , the blocks of wood p1 to p7 can have suitable profiles, so as to fit into each other on each row between two ribs.

Furthermore, the slabs 1 and the construction can be shaped differently from Figures 1 to 11 without departing from the scope of the invention. In addition, the technical characteristics of the various embodiments and variants mentioned above can be, in whole or for some of them, combined with each other. Thus, the slab 1 can be adapted in terms of cost, functionalities and performance.

Claims (1)

Construction method, comprising the production of at least one slab (1) according to the following steps:
- installation of metal stiffeners (2);
- Casting of a slab (3) of concrete, by making the stiffeners (2) emerge above the concrete;
- preparation of wood loaves (p1-p3);
- laying of wooden blocks (p1-p3) between the stiffeners (2) emerging from the concrete slab (3), leaving a space between the adjacent wooden blocks (p1-p3);
- casting ribs (n1-n6) of concrete between the wooden slabs (p1-p3), by embedding the stiffeners (2) at least in part; And
- drying of the non-prestressed slab (1) consisting of the concrete slab (3), the stiffeners (2), the wooden slabs (p1-p3) and the ribs (n1-n6) in concrete.
2. Construction method according to claim 1, characterized in that the laying of stiffeners (2), the casting of the concrete slab (3), the laying of the wooden blocks (p1-p3) and the casting of the ribs ( n1-n6) are made on the same prefabrication table, mobile between different stations of a carousel.
3. Construction method according to any one of the preceding claims, characterized in that the laying of the wooden blocks (p1-p3) is carried out on the slab (3) of still fresh concrete.
4. Construction method according to any one of the preceding claims, characterized in that the casting of ribs (n1-n6) of concrete between the wooden blocks (p1-p3), by embedding the stiffeners (2) at least in part, is carried out on the slab (3) of still fresh concrete.
5. Construction method according to any one of the preceding claims, characterized in that the preparation of the wooden slabs (p1-p3) comprises a cutting operation.
6. Construction method according to any one of the preceding claims, characterized in that the preparation of the wooden blocks (p1-p3) comprises a milling operation to form housings for receiving ducts.
7. Construction method according to any one of the preceding claims, characterized in that the preparation of the blocks of wood (p1-p3) comprises an operation for marking the housings for receiving ducts, to identify each of the ducts.
8. Construction method according to any one of the preceding claims, characterized in that the preparation of the blocks of wood (p1-p3) comprises an operation of marking information representative of their position within the slab (1).
9. Construction method according to any one of the preceding claims, characterized in that the preparation of the wooden blocks (p1-p3) is carried out on a single machine designed to carry out cutting, milling and marking operations.
10. Construction method according to any one of the preceding claims, characterized in that the stiffeners (2) are placed on wedges (6), which are then embedded in the concrete slab (3).
11. Construction method according to any one of the preceding claims, characterized in that additional elements are positioned on, in or between the stiffeners (2) before casting the slab (3), for example spacer vents (4) , reservation tubes, electric pots, or lifting devices.
12. Construction method according to any one of the preceding claims, characterized in that it comprises prior to the laying of the stiffeners (2):
- a step of identifying interference zones (ZI) between, on the one hand, the ribs (n1-n16) and, on the other hand, reservations (r1-r11) provided in the slab (1);
and in that :
- the metal stiffeners (2) associated with the ribs (n2-n4, n8-n11) outside interference zones (ZI) are placed with a reference gap between them; And
- the metal stiffeners (2) associated with the ribs (n1, n5) in the interference zones (ZI) are placed offset with the reference gap to avoid said interference.
13. Construction method according to claim 12, characterized in that the reference gap between the metal stiffeners (2) is 60 cm, while the offset is 10 cm on one side or the other.
14. Construction method according to any one of the preceding claims, characterized in that it comprises the following additional steps:
- laying of the slab (1) made up of the stiffeners (2), the concrete slab (3), the wooden blocks (p1-p3) and the ribs (n1, n2) which integrate the stiffeners (2) and are secured to the slab (3);
- Laying a metal frame (20) on the slab (1); Then
- Casting of a compression slab (30) above the reinforcement and the slab (1), covering the wooden slabs (p1-p3) and the ribs (n1, n2).
15. Construction method according to claim 14, characterized in that the metal reinforcement (30) is a welded mesh.