A PILLAR FOR THE REALISATION OF A STRUCTURAL ANTI-SEISMIC NODE AND SUCH A STRUCTURAL ANTI-SEISMIC NODE

Technical field

The present invention refers to the technical field relative to the structures for the realization of fabricated and prefabricated buildings of conglomerated reinforced concrete.

In particular, the invention refers to an innovative type of combination of beams and pillars in order to realize a final prefabricated structure with anti-seismic node and whose structural components are realizable in plant and compoundable directly in the construction site.

Background art

Technologies that allow the realization of linear prefabricated structures composed of vertical elements (pillars) have long been known, which combine with horizontal components (beams) in order to realize a final bearing structure. The connection point between the pillars and the beams is called node. Nodes can be realized dry, generally with structures and hooks of steel, or at humid realized by means of the integration of castings.

An example of structure and of node with humid connections can be deduced from Italian patent n. 1066568 in the name of Borghi Sergio, wherein a system suitable for the realization of the structural elemaafcs (pillars and beams) is mainly described, these elements being afterwards used for the formation of the prefabricated structure in question and therefore of the node.

Just as a way of example figure 1 and figure 2 of the present patent application accurately repeat figures from 8 to 10 relative to the Italian patent mentioned above.

In figure 1 the pillars (PI, P2) are therefore highlighted in transversal section, overlapped one to the other and to which the beams (Tl, T2) are connected transversally in order to realize the structural prefabricated node. Always figure 1 shows a top view to highlight the two beams that are connected by head and the pockets 30' belonging to the pillar PI and whose function will be described right below.

The pillars PI and P2 are identical between them and structurally formed by a reinforcement that is positioned in a mould or caisson in which the concrete is poured for the formation of the pillar. The inferior base of the pillar forms a receiving channel 34 (see transversal section of figure 1) , while the superior base foresees a pipe 29 fixed to the pillar itself in a permanent manner and exiting from its superior base. In particular, the pipe is arranged in the cast of the pillar. In correspondence of the superior base, in the area around the permanent fixing point of the pipe, receiving pockets 30' are then obtained suitable for holding the exiting iron sections and belonging to the internal reinforcement of an overlapped superior pillar (see always transversal section in figure 1) .

That being said, the pillar P2 is overlapped to the pillar PI in such a way that the receiving channel 34 holds the pipe 29 exiting from the superior base of the underlying pillar PI. In this position the iron sections exiting from the pillar P2 and belonging to its reinforcement are inserted in the pockets 30' . The distance between the two pillars, guaranteed by the pipe, corresponds to the floor height foreseen and permits the coupling with the horizontal beams in such a way as to be able to make the cast and consolidate the whole as per figure 2. The consolidation cast is made by casting concrete precisely in the space of node realized.

This type of structure has, however, the technical disadvantage of not answering to the always more rigid anti-seismic norms and, therefore, it is not a functional solution in high anti-seismic risk areas. This type of structure functions very well in case of ordinary stresses but, in case of a seism in which the flexional component prevails, the shape of the pockets 30' results not idoneous to respond to the different stresses since it does not permit the introduction of reinforcements on all the four sides of the base section of the pillar. Another technical disadvantage of such a structure is that the pipe 29 is integral to the pillar. The pipe renders the manoeuvre of the pillar and the subsequent plumbing phase difficult .

Disclosure of invention

It is therefore the aim of the present invention to provide a type of structure or structural node that solves said technical inconveniences.

In particular, the need for a structure that answers well to the always more rigid anti-seismic norms is felt (for example the NTC 2008 D.M. 14.01.2008 in Italy) in such a way as to obtain high levels of ductility of the structure as a whole and render at the same time the vertical support elements (the pillars) over-resistant with respect to the horizontal beams so as to safeguard as much as possible the integrity of the building that the structure forms.

It is at the same time the aim of the present invention to provide a structure, and therefore a structural node, of easy realization, not being prefabricated in plant for a good quantity of the reinforcements and completed in the construction site just for the integral ones and for the node stirrups.

These and other aims are therefore obtained with the present pillar (A, B) for the realization of a structural anti-seismic node (A, B, 100, 200, 300, 400) in accordance with claim 1.

The pillar (A, B) comprises an internal reinforcement (50) comprising a plurality of long-shaped elements (51) that extend along its length. In addition, the pillar (A, B) further forms a superior base (3) and an inferior base (6) .

In accordance with the invention, in correspondence of the superior base (3), a cavity (4) is obtained that from the superior base (3) penetrates inside the pillar (A, B) towards the inferior base (6), the cavity being positioned in a centered or substantially centered way with respect to the longitudinal axis (a-a) of the pillar, the cavity terminating with a further receiving seat (4') suitable for holding in a removable manner a pipe (C) emerging from the cavity, said long-shaped elements (51) exiting from the pillar in part of their length from the opposite part to that in which the cavity (4) is obtained, preferably from the inferior base (6).

Said type of pillar easily solves said technical inconveniences.

In particular, the centered cavity allows to hold the long-shaped elements exiting from a further overlapped pillar (preferably but not necessarily identical to the underlying one) . In this way, following the concrete casting, the system that solidifies results more compact and resistant to flexional loads. In addition, the cavity is configured to receive the pipe C in a removable way through the receiving seat 4' . In such a manner the pipe, which serves as spacer for the overlying pipe, can be arranged after the fixing of the pillar, the whole simplifying the operations of manoeuvre of the pillar itself and its positioning at plumb. Obviously, the iron sections exiting from the base opposed to that of the cavity render such a pillar suitable for overlapping other ones or to be fixed solidly to the foundations.

Advantageously, it is further obtained a receiving seat (6') in correspondence of the base (3, 6) opposed to that in which the cavity (4) is obtained.

In such a manner, in use, it is possible to insert in said receiving seat (6') the end of a pipe (C) applied to a further underlying pillar (A, B) when the two pillars are overlapped.

The centering of the two overlapped posts is therefore quick and precise.

Advantageously, said receiving seat (6') is centered or substantially centered with respect to the longitudinal axis (a-a) of the pillar.

In this way, the two overlapped pillars are in axis between them.

Advantageously, the internal walls delimiting the cavity (4) foresee a plurality of tracks (10) .

In this way, following the consolidation casting, the cast cement or concrete has a better seal.

Advantageously, said tracks (10) are in truncated- pyramid shape.

Advantageously, said cavity has a depth comprised within a range between 60cm and 80 cm and, advantageously, the walls delimiting said cavity can have a thickness comprised within a range between 3cm and 5cm.

Such sizes guarantee the realization of a structure resistant to inflexions.

Advantageously, the long-shaped elements (51) are arranged in the pillar in such a way that the parts exiting from the inferior base (6) of the pillar can be inserted in the cavity (4) of a further identical pillar (A, B) when said two pillars (A, B) are overlapped.

Advantageously, said pillar is of concrete.

It is also here described a structural anti-seismic node (A, B, 100, 200, 300, 400) comprising a first pillar (A) , for example emerging vertically with respect to the ground, which foresees an internal reinforcement (50) formed by a plurality of long-shaped elements (51) that extend along its length. Said first pillar (A) further forms a superior base (3) and an inferior base (6) .

In accordance with the invention, in correspondence of said superior base (3) of the first pillar (A), a cavity (4) is obtained that from the superior base (3) penetrates inside the pillar (A) towards the inferior base. The cavity is positioned in a centered or substantially centered way with respect to the longitudinal axis (a-a) of the first pillar (A) and terminates with a further receiving seat (4') in which a pipe (C) emerging from the cavity results arranged in a removable manner. The long-shaped elements (51) exit in part of their length from the inferior base (6). A second pillar (B) is overlapped to said first pillar (A) , the second pillar (B) having a plurality of exiting long- shaped elements (51) in such a way as to be inserted in the cavity (4) of the underlying first pillar, the overlapped second pillar (B) foreseeing in correspondence of its inferior base (6) a receiving seat (6') in which the end of the pipe (C) is inserted emerging from the cavity (4) of the underlying first pillar.

Such a structural node, for the reasons indicated above, results to be particularly resistant to the inflexions due to seisms.

Advantageously, one or more beams (100, 200, 300) are further foreseen, which are connected transversally between the first (A) and the second pillar (B) .

~ _* Advantageously, said first and second pillar are identical between them.

Advantageously, the long-shaped elements (51) exiting from the inferior base (6) of the first pillar (A) are inserted in the foundations casting or in the cavity of a further underlying pillar.

Advantageously, three beams (100, 200, 300) are foreseen, and of which two beams (100, 200) of the angled type and arranged by head and a further third flat beam (300) arranged orthogonally with respect to said two angle beams .

Advantageously, a consolidation casting is foreseen. Brief description of drawings

Further features and advantages of the present anti- seismic structures, according to the invention, will result clearer with the description that follows of one of its embodiments, made to illustrate but not to limit, with reference to the annexed drawings, wherein:

- Figures 1 and 2 represent a structural system that realizes a node in accordance with the background art;

- Figure 3 represents a structure in axonometric view in accordance with the invention;

- Figure 4 shows the same structure of figure 3 when consolidated;

- Figure 5 shows a section of the pillar necessary for the realization of such a type of structural node;

- Figure 6 and figure 7 are further sections of the structural node;

- Figure 8 is a detail relative to the pillar from the part in which the pipe exits and highlights the truncated- pyramid tracks 10;

- Figure 9 is still an axonometric view of the components in the mounting phase for realizing the structure that is the object of the invention;

- Figure 10 is an exploded view just of the reinforcement irons or bars for stabilizing the structure in the mounting phase;

- Figure 11 is an axonometric detail of the node;

- Figure 12 is always a further axonometric view of the structure .

- Figure 13 is a further axonometric view of a node in accordance with the invention for the realization of a level of building;

- Figure 14 further shows a section relative to the node once the cast has occurred;

- Figure 15 shows in section the arrangement of the foundations;

- Figure 16 shows a front view of the central beam.

Description of some preferred embodiments

With reference to figure 3 an anti-seismic structure is described in accordance with the invention.

It is substantially formed by at least two overlapped pillars (A, B) and to which one or more (three in the example) horizontal beams are connected by head, in particular a central beam 300 e edge beams (100, 200). Figure 3 shows the two pillars spaced between them, while figure 4 shows an axonometric view of the whole with the two pillars in final position.

The pillar A and the pillar B can be not identical but anyway each pillar is such as to be able to be overlapped to a further pillar, realizing in the overlapping area a connection point for the horizontal beams and therefore the node.

Obviously, the embodiment in which the pillar A and B are identical between them is preferred since it allows the quick repeatability of the structure during the realization of a construction.

As shown in the section of figure 5, the pillar (A, B) foresees on one of its parts 3 (from now on called superior base) a single receiving seat 4 which, unlike the background art, is now coaxial with the longitudinal axis A-A of the pillar.

The receiving seat 4 leaves an external shell 5 whose size can go (in terms of thickness) from the 3cm to the 5cm and has a depth that varies from 60 to 80 cm.

In this way, as clarified right below, the connection between the parts results much more adequate to answer to flexional loads due to seismic events.

As always shown in the section of figure 5, the base of the receiving seat 4 further presents a cylindrical cavity 4' in which it is inserted, in a removable manner, the pipe C shown in figure 3 which, in the background art, was fixed permanently in the pillar casting.

Always the section of figure 5 shows, on the opposite part to the superior base 3, the inferior base 6 which has in turn a receiving seat 6' suitable for holding the end of a pipe exiting from the superior base of an underlying pillar when these are overlapped one to the other .

Always the section of figure 5 shows the cage 50 constituting the reinforcement of the pillar which is inserted in the concrete used for the realization of the pillar. Figure 5 shows the reinforcement 50 which is formed by longitudinal long iron sections 51 (that is that run along all the longitudinal length of the pillar) and that in part exit from the inferior base 6 and by transversal stirrups (see transversal lines 52), preferably placed with variable pitch along the length of the pillar, in such a way as to realize a cage. The cage can be formed by four, six, eight or more iron sections of reinforcement, which in part exit from the inferior base 6; in figure 3 six are indicated, for example.

The iron sections forming the reinforcement of the cage are indicated with the letter D in figure 3.

In the present description the term long iron sections 51 is not limited to the use of just the iron metal but it is a more general term for indicating the long-shaped internal reinforcement elements which can have any section (square or round, for example) and be of any material (for example metal such as iron, or alloys such as steel or aluminum) .

In the mounting phase, unlike the background art, six or more iron sections 51 can be inserted in the receiving seat 4 (see figure 3) which, as said, is now coaxial to the pillar where it is obtained. In this way, following the cement casting, a single central body is created that fills the cavity 4 that contains the iron sections immersed in it, creating a structure that is significantly resistant to flexions.

The pipe C, as said, is not fixed anymore but rather removable and this solves a further series of technical problems linked to the movement of the pillar itself in the storage and mounting phase. A less rigid pipe further facilitates the positioning at plumb of the pillar before the casting.

As always shown in the section of figure 5 and in the view of figure 8, in the cavity 4 are present, in correspondence of its four internal walls that delimit it, a plurality of tracks 10 (hollows of truncated-pyramid shape) whose function is that of increasing the adhesion between the concrete of the pillar and the integrative concrete cast and render mainly a single body the elements of the node connected between them. In this way, the behavior to the stresses of the integral node castings is further improved.

Going on with the structural description of the invention, the section of figure 6 and the section of figure 7 show the connection occurred between two overlapped pillars (A, B) and the horizontal beams through the concrete casting. Both figures highlight well the pipe C inserted in the receiving seat 6' obtained in the inferior base 6 of the pillar B that overlaps the pillar A. In this case, therefore, the pipe is installed in the cavity 4 through the receiving seat 4' as described above and in a removable manner.

Figure 7 clearly shows the iron sections 51 of the reinforcement exiting from the inferior base 6 of the overlying pillar B and that are inserted in the cavity 4 of the underlying pillar A.

The reinforcements, even if realizable in any metallic material, are preferably in the form of steel bars with improved adherence.

Going back to figure 4, the three beams (100, 200, 300) that couple head-first are described.

The beam 300, as also shown in figure 9 and in figure 16, is the so-called central beam and is structurally formed by a cage 302 of stirrups and reinforcements forming a base framework inserted in a sole of concrete having a flat surface 301 (therefore with rectangular transversal section) . In particular, the central beam is a concrete bottom plate in which the cage 302 is half-drowned.

The edge beams 100 and 200 are instead in shape in a triangle-like transversal section in such a way as to contain the casting on the edge of the platform and are always represented in figure 9. At the ends of them pockets for the insertion of the continuity reinforcements are foreseen in the concrete. Also these beams, like the central beams 300, are composed by cages semi-drowned in the concrete.

The semi-cast beams in plant will be completed with the integral castings in the construction site.

Figure 10 extrapolates in a separate manner the integral reinforcement 400 which is inserted during the installation, as clarified in the subsequent mounting description, to guarantee the continuity of the reinforcements in the node.

It comprises reinforcement bars (i) of inferior node, reinforcement bars of superior node (j) and the node stirrups (k) .

In particular, as it is clear from figure 11, the bars (i, j) are inserted in the cage of the beams (100, 200, 300) in such a way as to realize the necessary continuity of reinforcement subsequently consolidated following the cast.

In particular, in the example of figure 10 two types of integral reinforcements are indicated: those nodes passing between the beams 100 and 200 and those node terminals of the beam 300. All the types of reinforcement have conformations derived from the technique of the constructions and from the technical norms. In the mounting phase the structural system is therefore mounted in the following mode.

The procedure is repeated on the basis of the number of levels to obtain.

With reference, for example, to the realization of a single piano, the arrangement of the pillar A occurs by fixing it on the reinforcements of foundations before the cast (see for example figures 14 and 15) . This takes place through the irons 51 and a pipe of adequate length that are cast directly with the foundations, guaranteeing the structural monolithic feature. The positioning of the beams (100,200,300) takes place then leaned to the edge of the cavity 4. At this point the positioning of the pipe C inside the receiving seat 4' occurs in such a way that the pipe is emerging from the cavity 4. The pipe serves as centering for the superior pillar B.

At this point the overlapping of the superior pillar B (see for example figure 6 or figure 14) occurs in such a way that the exiting iron sections 51 are inserted in the cavity 4, being careful of having inserted previously the node stirrups k in the same. The arrangement of the irons (i, j) occurs as well in such a way that the irons (i, j) enter in the cages of the beams in the foreseen positions. At this point the level is completed, as per the background art, arranging floors and all that is required. The cast of concrete occurs then, so as to obtain a final monolithic structure as that of figure 6.

The advantages of such a structure are evident and multiple .

The node results particularly flexible and resistant to flexional loads, since the centered cavity and the entering irons render the monolithic structure a single conglomerate, also thanks to the tracks 10.

Obviously, the present invention is destined to the construction of trestled multi-layer structures, for example for private and public buildings with different intended uses: residential, commercial, artisan, directive, educational, hospital uses, etc.