OA18497A - Construction type prefabricated posts and beams. - Google Patents

Abstract

A construction system which carries out an advanced prefabrication of the structure of buildings of the column and beam type, prefabrication which allows an industrialization of this type of construction. The main arrangement which makes it possible to achieve this objective under the same technical conditions, or even better than in the conventional system, is the massive use of bracing both vertically and horizontally. Such a construction system is of special interest for regions with a high seismic risk, since the building is very light, consisting of a set of structurally self-supporting units, strongly triangulated and therefore very little deformable, all this at a relatively cost. reduced.

Description

The present invention relates to the construction of buildings type prefabricated posts and beams, whether they are made of wood, reinforced concrete or any other material.

Prior art

Reinforced concrete buildings of the post-beam type are rather rare, because it is more advantageous to carry out horizontal and vertical chains, in one piece for each floor, as far as possible: reinforcement and pouring concrete. In the context of timber construction, on the other hand, posts and beams are widely used. They are always prefabricated and brought to construction sites to be assembled using various spikes and / or fittings.

Disclosure of the invention

The present invention relates to a construction technique in wood, reinforced concrete or any other material, which consists in using posts and beams prefabricated in the factory, and in carrying out their connection on the construction site, on the one hand by a system of vertical and horizontal bracing, and on the other hand by a reinforced concrete junction at their intersection.

A central role is played by the bracings which securely hold the columns and beams in their final position as soon as their installation is complete. They make a connection that we qualify here as a peripheral, as opposed to the central connection made at the intersection of said columns and beams.

Threaded rods are the most suitable means of joining bracing to columns and beams.

The central junction can itself be cast on site; we are talking about partial prefabrication, or prefabricated, and we are talking about total pre-fabrication.

The contact surface between a bracing and a column or beam can be simple, without any special provision. In this case, if there is a force which tends to open or close the angle formed by the column and the beam, the bracing will play its role in opposing it. But so that the bracing does not slide along the column or the beam, the connecting rod will be stressed in shear and must therefore be of large section. To remedy this problem, roughness is provided on said surfaces, a notch in the post or beam, a notch into which fits a wedge provided at the end of the bracing, etc. Such a system prevents any risk of the bracing slipping against the column or against the beam in the event of a force tending to modify the angle formed by the column and the beam. The outer notch prevents the said corner from closing, and the inner notch prevents it from opening. For more efficiency, the inner notch is longer than the outer notch, and can even form an acute angle with the centerline of the post or beam.

To prevent, reduce or eliminate possible fires between the prefabricated elements, namely columns, beams, bracings and junction blocks, but also to achieve a certain junction between said elements, a joint is applied at their intersection under form of cement mortar for example.

We are not limited in the number or inclination of the bracing pieces, nor in the number or type of their attachment to posts or beams: bolts, dowels, rivets, nails, etc. The same applies to the connection between the terminal blocks and the ends of the columns and beams described below.

Case of partial prefabrication casting of the function on site

The beams are prefabricated in the factory, with bars or holding bars that will enter the junctions.

For the posts, a zone of around 20 cm is provided at the base, which will be concreted on site when they are installed, with holding bars. At the top of the posts, idlers of sufficient length are provided to form part of the junction, and to serve as idlers for the subsequent assembly of the upper story post.

The columns and beams are securely held in their final position by bracing in the horizontal and vertical direction. The ends of said columns and beams form a formwork lost when the concrete is poured into the junction.

When installing the beams in view of their fixing on the bracing, it is useful to first fix removable intermediate supports on the side and at the top of the posts, on which the beams will rest, which facilitates the adjustment. and fixing the bracing.

Insofar as the junction from which the concrete is poured on site occupies a small area, one can afford to use a very high dosage of the concrete, to use the welding of the reinforcement in the connection instead of the usual overlapping by juxtaposition holding irons, etc.

In a node of the construction intersect the many wait bars of the column and adjacent beams. Their positioning can be a problem during construction due to their great rigidity and the smallness of the space they occupy. To remedy this, the reinforcement of the junction is prefabricated, either entirely or partially. It can take the form of a metal frame, preferably welded.

Columns and beams with prefabricated reinforcement entering the junction are provided with small pieces of holding iron to which the prefabricated junction reinforcement will be welded.

Case of total prefabrication: prefabricated terminal blocks

Here we manufacture in the factory, for each node, a complete junction block with as many branches as there are columns and beams in this node. The branches of said junction block will be connected to the ends of the posts and beams which enter the node. The assembly area of a branch of the block with a post or a beam can be cut along an oblique line, i.e. bevelled, along a straight line, along a broken line, i.e. in a staircase, etc. .

The junction blocks, as well as the ends of the columns and beams that form the junction are manufactured in such a way as to ensure their high mechanical resistance: dense reinforcement and the maximum dosage of concrete.

The contact surfaces have deep grooves or other forms of roughness, intended to prevent the relative movement of the elements to be joined. Threaded rods are the most suitable means of joining posts and beams to terminal blocks

The connection between these elements can also be improved by increasing their contact surface, on the one hand in the longitudinal direction to the columns and beams by increasing the length of the branches of the prefabricated junction block, and on the other hand in the orthogonal direction to the posts and beams by increasing the width of said branches. In the latter case, it is as if the prefabricated terminal block has been cut out of a building, severing not only the posts and beams, but also the corners of adjacent walls and floors.

The ends of the columns and beams which enter this node then take the shape of a T to correspond to the dimensions of the junction block thus formed. The thickness of the different parts of the junction block must take into account the thickness of the ends of the columns and beams to which it will be linked, so that the total thickness does not differ too much from the thickness of the columns and beams, for example example 20 cm.

Thus, the central part of the junction block, which is not contiguous to any end of the column or beam, keeps the thickness of the columns and beams, 20 cm in our example.

The areas of the junction block to which a single end of post 5 or beam is attached have a thickness of the order of 10 cm in our example, half the thickness of the structure of the construction. The same is true, mutatis mutandis, of the areas of the terminal block which are crossed by two ends.

It goes without saying that the thickness of one end of a post or beam must in turn take into account the thickness of the other ends and of the branch of the terminal block 10 with which they will be in contact. in the knot, to make a total thickness of 20 cm in our example.

Case of construction in bowls

Usually, the assembly of columns and beams is usually done using various fittings. But in the context of the present invention, the junction is made of reinforced concrete. It is then a question of securely fixing steel bars at the ends of the posts and beams, so that they present holding bars which will participate in the realization of said junction.

The present invention also takes advantage of the cross nailing for a good fixing of the wooden bracings, on the posts and the beams also in wood. The 20 areas that are at risk of cracking or bursting following intensive nailing are surrounded by restraining brackets, which at the same time increases the pressure exerted on the nails used and consequently improves the bond achieved.

Brief description of the drawings

Figure 1/20 shows the sectional view of the foundation and the lower linkage (2) of the building under construction.

We distinguish the foundation of the building (1), the lower chaining (2), as well as the holding bars for the installation of a post of the first level or ground floor (3).

Figure 2/20 shows a sectional view of the installation of a post in the event of partial prefabrication.

We can distinguish the prefabricated area of the post to be installed (4), the holding bars in the area of the post to be concreted on site (5).

Figure 3/20 represents the post at the time of its installation on the lower chaining. A distinction is made between the holding bars of the foundation or the lower storey and of the post (5), the braces (6), as well as the assembly rods for the connection of the braces with the posts and beams (7) .

Figure 4/20 shows a column whose junction with the lower linkage is already concreted: the link is finished.

Figure 5/20 represents the installation of the beams which will form the upper chain of the floor.

We distinguish a beam (8), as well as the reinforcement of the junction (9) consisting of the 10 holding bars of the left beam, those of the right beam and those of the upper end of the column.

Figure 6/20 shows the same elements as the previous figure, but after the concreting of the junction: the realization of the junction is therefore finished.

Figure 7/20 shows a sectional view of all the connections in a node 15 of the construction, highlighting the parts concreted on site.

Figure 8/20 shows a prefabricated junction block for the connection of the various columns and beams which enter the node, in the case of total prefabrication.

There are two branches for the connection of two posts, and two branches for the connection of two beams, as well as holes (10) waiting for the passage of the assembly rods 20.

Figure 9/20 shows a terminal block that is already attached to the post. There is an assembly rod (11), and two beams (12) awaiting attachment to the block.

Figure 10/20 shows an enlarged terminal block. The areas of the enlarged terminal block can be distinguished at the corners of adjacent walls and floors (13).

Figure 11/20 shows an enlarged terminal block which is already attached to the post. There are three assembly rods (11), and two beams (12) awaiting attachment to the block.

Figure 12/20 shows the diagram of an assembly of a beam with a bracing. No special provision has been made for the contact area.

In the event of a force tending to open or close the angle formed by the post and the beam, the bracing will oppose it. The assembly rod will be subjected to shear and must be highly dimensioned.

Figure 13/20 shows the diagram of the same beam - bracing assembly in which there is provided in the beam, a notch in which fits a wedge 5 provided on the bracing, to prevent the sliding of the bracing against the beam, and the forces of shear that would result to the assembly rod.

Figure 14/20 shows the schematic of the same beam-bracing assembly in which the inner bracing locking notch is deeper than the outer notch.

Figure 15/20 shows the diagram of the same beam - bracing connection in which the notch provided in the column or beam is Less than 90 ^e .

Figure 16/20 shows a sectional view of a typical construction junction.

We distinguish the post (4), a beam (8), a bracing (6), and the reinforcement of the junction (9).

Figure 17/20 shows a sectional view of a prefabricated junction reinforcement. We can distinguish the reinforcement of the prefabricated junction (14).

Figure 18/20 shows a sectional view of a typical construction node, before the installation of the prefabricated reinforcement.

We distinguish the post (4), a beam (8), and the removable intermediate support (15).

Figure 19/20 shows the end of a beam in detail when using prefabricated reinforcement.

We can distinguish the beam (8), as well as the ends of the holding bars on which the prefabricated reinforcement will be welded (16).

Figure 20/20 shows the assembly of the prefabricated reinforcement on the beams.

There is a beam (8), and the prefabricated reinforcement (14).

Best way to make the invention

The best way to carry out the invention is described below:

^1st Manufacturing Factory of all columns, beams and bracing.

On the beams, the ends of waiting bars of about 4 cm in length are provided, on which the reinforcement of the junctions, also prefabricated, will be welded (Fig. 19/20). On the other hand, the posts will be provided with holding bars about 20 cm long at the base, and holding bars about 40 cm at the top (Fig. 2/20).

2 * Construction of a conventional foundation for reinforced concrete construction.

Waiting bars are planned for the future posts (Rg. 1/20).

^3rd Exposure poles of the first level construction.

The waiting bars of their base intersect with the waiting bars provided in the foundation. The posts are retained in a vertical position by the braces connecting the said posts to the lower chaining (Fig. 3/20). The horizontal bracing connecting the beams constituting the lower chaining, adjacent to each column, is fixed. After checking the verticality of the columns, we proceed to formwork and concreting of this part of the columns. As long as the posts are securely held in their final positions by the bracing system, construction work can continue shortly after the concrete is poured into the joints, or even before said pouring.

4 ° Laying of the beams that will form the upper chaining of the floor.

To do this, removable supports are fixed laterally on the upper part of the posts, then the beams, then the bracing (Fig. 18/20). After fixing the vertical and horizontal braces, the removable brackets are removed and construction work can continue.

5 ° Fixing of reinforcements of prefabricated junctions.

The prefabricated reinforcement is welded to the holding bars of the columns and beams (Fig. 20/20). The formwork is then carried out where it is necessary, that is to say in the nodes which include two or three beams, keeping in mind that the ends of the columns and beams constitute a lost formwork, then the concrete is poured. in the junction.

6 ° We make the slab, then we repeat step 3 ’to continue the construction of the next floor. '

It should be noted that it is possible to pour concrete into the joints once and for all, at the end of the construction work of the whole structure.

Possibilities of industrial application

The primary goal of the invention is the most advanced possible prefabrication of the structure of buildings of the post and beam type, prefabrication which allows industrialization of this type of construction. The main development qqi makes it possible to achieve this objective under the same technical conditions, or even better than in the conventional system, is the massive use of bracing both vertically and horizontally. They form a solid, peripheral junction that connects columns and beams on the one hand and beams to each other on the other.

The central junction, which takes place at the intersection of columns and beams, can be made on site or prefabricated, and therefore industrialized, or at least highly standardized.

Whether it is in the case of making the junctions on site or in the case of the use of prefabricated terminal blocks, everything is practically done in the factory, with the resulting advantages: standardization of manufacture, quality and speed of execution, reduction construction costs and times.

In addition, the weight of the building will also be reduced, because for the same resistance to vertical and horizontal loads, this modular truss structure is lighter than a conventional structure. The main constraint of the system is that the braces occupy the axis of the walls for more efficiency, which prevents or reduces the use of usual materials in the construction of walls such as bricks and blocks of all kinds. But this will push builders to adopt more often the walls and walls adapted to this type of structure, for example the panels currently used in the construction in bowls.

Finally, this constraint will be largely offset by the many additional advantages that will result from the use of lightweight walls and walls, to such an extent that one could even bet on a multiplier effect in terms of weight reduction, cost and construction completion times.

Such a construction system is of special interest for regions with high seismic risk, because the building is light, made up of a set of structurally self-supporting units, strongly triangulated and therefore very little deformable, all at a relatively modest cost. .

Claims (8)

1. A construction technique of the prefabricated posts and beams type, whether in bowls, reinforced concrete or any other material, characterized by a systematic and modular prefabrication of the posts and beams, their connection taking place on the construction site of '' on the one hand by a system of vertical and horizontal bracing, and on the other hand by a reinforced concrete junction at their intersection, the lower end of the posts being however concreted on site to ensure their connection with the nodes on which they are support because these were made when the foundation or lower storey was being built. 2. A construction technique according to the preceding claim, where the junction is not carried out on site, but prefabricated in the factory in the form of a junction block to which the ends of columns and beams will be connected. 3. A building system according to the preceding claim, wherein the prefabricated terminal block is widened at the corners of adjacent walls and floors, the ends of posts and attached beams being widened accordingly. 4. A building system according to the first claim, wherein the reinforcement of a junction is prefabricated separately from the columns and beams and takes the form of a welded metal frame, which prefabricated reinforcement will be welded to the ends of the reinforcement of the columns and /. or back beams on construction site. 5. A building system according to the first or the fourth claim, wherein removable intermediate supports are placed laterally on the upper part of the posts, and on which the beams will rest before or during the fixing of the braces. 6. A building system according to any one of the preceding claims, characterized by the use of joints, for example in the form of cement mortar, to prevent, reduce or eliminate possible clearances between the various prefabricated building elements, and also for make a certain connection between said elements. I 7. A building system according to any one of the preceding claims, characterized in that the posts, beams and contrcvcntcments are provided with anti-slip devices, such as notches, wedges and lugs. 8. A technique according to any one of the preceding claims in the context of timber construction, characterized by the installation of restraining brackets in areas where an element is at risk of cracking or bursting as a result of intensive nailing.